From 3f0c4b573eb69e3dc743b7a1a8ba0f1390c5204d Mon Sep 17 00:00:00 2001
From: Valery Piashchynski <piashchynski_valery@hotmail.com>
Date: Fri, 2 Oct 2020 14:04:01 +0300
Subject: [PATCH 01/29] Create codeql-analysis.yml

---
 .github/workflows/codeql-analysis.yml | 71 +++++++++++++++++++++++++++
 1 file changed, 71 insertions(+)
 create mode 100644 .github/workflows/codeql-analysis.yml

diff --git a/.github/workflows/codeql-analysis.yml b/.github/workflows/codeql-analysis.yml
new file mode 100644
index 0000000..7e8ead3
--- /dev/null
+++ b/.github/workflows/codeql-analysis.yml
@@ -0,0 +1,71 @@
+# For most projects, this workflow file will not need changing; you simply need
+# to commit it to your repository.
+#
+# You may wish to alter this file to override the set of languages analyzed,
+# or to provide custom queries or build logic.
+name: "CodeQL"
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+    # The branches below must be a subset of the branches above
+    branches: [master]
+  schedule:
+    - cron: '0 12 * * 6'
+
+jobs:
+  analyze:
+    name: Analyze
+    runs-on: ubuntu-latest
+
+    strategy:
+      fail-fast: false
+      matrix:
+        # Override automatic language detection by changing the below list
+        # Supported options are ['csharp', 'cpp', 'go', 'java', 'javascript', 'python']
+        language: ['go']
+        # Learn more...
+        # https://docs.github.com/en/github/finding-security-vulnerabilities-and-errors-in-your-code/configuring-code-scanning#overriding-automatic-language-detection
+
+    steps:
+    - name: Checkout repository
+      uses: actions/checkout@v2
+      with:
+        # We must fetch at least the immediate parents so that if this is
+        # a pull request then we can checkout the head.
+        fetch-depth: 2
+
+    # If this run was triggered by a pull request event, then checkout
+    # the head of the pull request instead of the merge commit.
+    - run: git checkout HEAD^2
+      if: ${{ github.event_name == 'pull_request' }}
+
+    # Initializes the CodeQL tools for scanning.
+    - name: Initialize CodeQL
+      uses: github/codeql-action/init@v1
+      with:
+        languages: ${{ matrix.language }}
+        # If you wish to specify custom queries, you can do so here or in a config file.
+        # By default, queries listed here will override any specified in a config file. 
+        # Prefix the list here with "+" to use these queries and those in the config file.
+        # queries: ./path/to/local/query, your-org/your-repo/queries@main
+
+    # Autobuild attempts to build any compiled languages  (C/C++, C#, or Java).
+    # If this step fails, then you should remove it and run the build manually (see below)
+    - name: Autobuild
+      uses: github/codeql-action/autobuild@v1
+
+    # ℹ️ Command-line programs to run using the OS shell.
+    # 📚 https://git.io/JvXDl
+
+    # ✏️ If the Autobuild fails above, remove it and uncomment the following three lines
+    #    and modify them (or add more) to build your code if your project
+    #    uses a compiled language
+
+    #- run: |
+    #   make bootstrap
+    #   make release
+
+    - name: Perform CodeQL Analysis
+      uses: github/codeql-action/analyze@v1

From 7a3d77d132db20f1e432c429d86a9b5e1b9504b1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=D0=90=D0=BB=D0=B5=D1=81=D1=8C=20=D0=95=D1=80=D0=B5=D0=BC?=
 =?UTF-8?q?=D0=B5=D0=B5=D0=B2?= <ales.a@nakukop.com>
Date: Tue, 13 Oct 2020 13:07:26 +0200
Subject: [PATCH 02/29] Server error details #50 [server configuration options,
 only 'debug' for now]

---
 example/server/worker.php |  1 +
 src/Server.php            | 33 +++++++++++++++++++++++++++++++--
 2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/example/server/worker.php b/example/server/worker.php
index 9a13fcd..b089ed5 100644
--- a/example/server/worker.php
+++ b/example/server/worker.php
@@ -9,6 +9,7 @@
 ini_set('display_errors', 'stderr');
 require "vendor/autoload.php";
 
+//To run server in debug mode - new \Spiral\GRPC\Server(null, ['debug' => true]);
 $server = new \Spiral\GRPC\Server();
 $server->registerService(\Service\EchoInterface::class, new EchoService());
 
diff --git a/src/Server.php b/src/Server.php
index d56ba50..2f9fe7b 100644
--- a/src/Server.php
+++ b/src/Server.php
@@ -29,12 +29,19 @@ final class Server
     /** @var ServiceWrapper[] */
     private $services = [];
 
+    /**
+     * @var array
+     */
+    private $options;
+
     /**
      * @param InvokerInterface|null $invoker
+     * @param array $options
      */
-    public function __construct(InvokerInterface $invoker = null)
+    public function __construct(InvokerInterface $invoker = null, array $options = [])
     {
         $this->invoker = $invoker ?? new Invoker();
+        $this->options = $options;
     }
 
     /**
@@ -86,7 +93,13 @@ public function serve(Worker $worker, callable $finalize = null): void
             } catch (GRPCException $e) {
                 $worker->error($this->packError($e));
             } catch (\Throwable $e) {
-                $worker->error((string)$e);
+                if ($this->isDebugMode()) {
+                    $errorText = $e->__toString();
+                } else {
+                    $errorText = $e->getMessage();
+                }
+
+                $worker->error($errorText);
             } finally {
                 if ($finalize !== null) {
                     call_user_func($finalize, $e ?? null);
@@ -148,4 +161,20 @@ private function packError(GRPCException $e): string
 
         return implode('|:|', $data);
     }
+
+    /**
+     * If server runs in debug mode
+     *
+     * @return bool
+     */
+    private function isDebugMode(): bool
+    {
+        $debug = false;
+
+        if (isset($this->options['debug'])) {
+            $debug = filter_var($this->options['debug'], FILTER_VALIDATE_BOOLEAN);
+        }
+
+        return $debug;
+    }
 }

From 49c351c3e1e108dd6b940cbaf9d285dc4be4c579 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=D0=90=D0=BB=D0=B5=D1=81=D1=8C=20=D0=95=D1=80=D0=B5=D0=BC?=
 =?UTF-8?q?=D0=B5=D0=B5=D0=B2?= <ales.a@nakukop.com>
Date: Tue, 13 Oct 2020 13:38:11 +0200
Subject: [PATCH 03/29] Server error details #50 [add test]

---
 tests/GRPC/ServerTest.php      | 22 ++++++++++++++++++++++
 tests/src/Test/TestService.php |  3 +++
 2 files changed, 25 insertions(+)

diff --git a/tests/GRPC/ServerTest.php b/tests/GRPC/ServerTest.php
index 8409269..205399e 100644
--- a/tests/GRPC/ServerTest.php
+++ b/tests/GRPC/ServerTest.php
@@ -85,6 +85,28 @@ public function testNotFound2(): void
         $this->assertTrue($w->done());
     }
 
+    public function testServerDebugModeNotEnabled(): void
+    {
+        $s = new Server();
+        $s->registerService(TestInterface::class, new TestService());
+
+        $w = new TestWorker($this, [
+            [
+                'ctx'   => [
+                    'service' => 'service.Test',
+                    'method'  => 'Throw',
+                    'context' => [],
+                ],
+                'send'  => $this->packMessage('regularException'),
+                'error' => 'Just another exception'
+            ]
+        ]);
+
+        $s->serve($w);
+
+        $this->assertTrue($w->done());
+    }
+
     private function packMessage(string $message): string
     {
         $m = new Message();
diff --git a/tests/src/Test/TestService.php b/tests/src/Test/TestService.php
index 6d4a385..12b9479 100644
--- a/tests/src/Test/TestService.php
+++ b/tests/src/Test/TestService.php
@@ -33,6 +33,9 @@ public function Throw(ContextInterface $ctx, Message $in): Message
                 $grpcException = new GRPCException("main exception message", 3, [$detailsMessage]);
 
                 throw $grpcException;
+            case "regularException": {
+                throw new \Exception("Just another exception");
+            }
         }
 
         return $out;

From eaf06f911528a3626da589bf05bdfd50f284ac72 Mon Sep 17 00:00:00 2001
From: Valery Piashchynski <piashchynski_valery@hotmail.com>
Date: Tue, 13 Oct 2020 15:40:42 +0300
Subject: [PATCH 04/29] release 1.4.1

---
 CHANGELOG.md | 6 ++++++
 build.sh     | 2 +-
 go.mod       | 4 ++--
 3 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 87f720f..0a3e96e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,12 @@
 CHANGELOG
 =========
 
+v1.4.1 (13.10.2020)
+-------------------
+- RoadRunner version update to 1.8.3
+- Golang version in go.mod bump to 1.15
+- Add server configuration options (debug) (@aldump)
+
 v1.4.0 (1.08.2020)
 -------------------
 - Add all major gRPC configuration options. [Docs](https://github.com/spiral/docs/blob/master/grpc/configuration.md#application-server)
diff --git a/build.sh b/build.sh
index fa12e35..f7bed77 100755
--- a/build.sh
+++ b/build.sh
@@ -2,7 +2,7 @@
 cd $(dirname "${BASH_SOURCE[0]}")
 OD="$(pwd)"
 # Pushes application version into the build information.
-RR_VERSION=1.4.0
+RR_VERSION=1.4.1
 
 # Hardcode some values to the core package
 LDFLAGS="$LDFLAGS -X github.com/spiral/roadrunner/cmd/rr/cmd.Version=${RR_VERSION}"
diff --git a/go.mod b/go.mod
index 657ba32..55cd06a 100644
--- a/go.mod
+++ b/go.mod
@@ -1,6 +1,6 @@
 module github.com/spiral/php-grpc
 
-go 1.13
+go 1.15
 
 require (
 	github.com/buger/goterm v0.0.0-20200322175922-2f3e71b85129
@@ -10,7 +10,7 @@ require (
 	github.com/prometheus/client_golang v1.6.0
 	github.com/sirupsen/logrus v1.6.0
 	github.com/spf13/cobra v1.0.0
-	github.com/spiral/roadrunner v1.8.2
+	github.com/spiral/roadrunner v1.8.3
 	github.com/stretchr/testify v1.5.1
 	golang.org/x/net v0.0.0-20200520182314-0ba52f642ac2
 	google.golang.org/grpc v1.29.1

From 3918e66902eca87d7a419b6377d832ea0f3f5531 Mon Sep 17 00:00:00 2001
From: Kirill Nesmeyanov <nesk@xakep.ru>
Date: Mon, 21 Dec 2020 14:34:41 +0300
Subject: [PATCH 05/29] Update composer.json

---
 composer.json | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/composer.json b/composer.json
index 0da593d..8963b2e 100644
--- a/composer.json
+++ b/composer.json
@@ -10,7 +10,7 @@
     }
   ],
   "require": {
-    "php": "^7.2",
+    "php": ">=7.2",
     "ext-json": "*",
     "google/protobuf": "^3.7",
     "spiral/roadrunner": "^1.8"

From d6c0f997aa9296316f810797f0a463094bce474b Mon Sep 17 00:00:00 2001
From: lampatrampa <30873408+lampatrampa@users.noreply.github.com>
Date: Tue, 9 Feb 2021 16:40:57 +0300
Subject: [PATCH 06/29] fix reflection deprecated php 8.0 methods

---
 src/Method.php | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/Method.php b/src/Method.php
index a5f9a4b..3696e91 100644
--- a/src/Method.php
+++ b/src/Method.php
@@ -64,9 +64,12 @@ public static function match(\ReflectionMethod $method): bool
         if ($method->getNumberOfParameters() != 2) {
             return false;
         }
+        
+        $ctxType = $method->getParameters()[0]->getType();
+        $inType = $method->getParameters()[1]->getType();
 
-        $ctx = $method->getParameters()[0]->getClass();
-        $in = $method->getParameters()[1]->getClass();
+        $ctx = $ctxType && ! $ctxType->isBuiltin() ? new \ReflectionClass($ctxType->getName()) : null;
+        $in = $inType && ! $inType->isBuiltin() ? new \ReflectionClass($inType->getName()) : null;
 
         if (empty($ctx) || !$ctx->implementsInterface(ContextInterface::class)) {
             return false;
@@ -110,7 +113,7 @@ public static function parse(\ReflectionMethod $method): Method
 
         $m = new self();
         $m->name = $method->getName();
-        $m->input = $method->getParameters()[1]->getClass()->getName();
+        $m->input = $method->getParameters()[1]->getType()->getName();
         $m->output = $method->getReturnType()->getName();
 
         return $m;

From fe8bf7fa08ac1c2498c43746a0bd31a41dabab65 Mon Sep 17 00:00:00 2001
From: lampatrampa <30873408+lampatrampa@users.noreply.github.com>
Date: Wed, 10 Feb 2021 09:25:48 +0300
Subject: [PATCH 07/29] remove whitespace

---
 src/Method.php | 2 --
 1 file changed, 2 deletions(-)

diff --git a/src/Method.php b/src/Method.php
index 3696e91..9546a7b 100644
--- a/src/Method.php
+++ b/src/Method.php
@@ -64,10 +64,8 @@ public static function match(\ReflectionMethod $method): bool
         if ($method->getNumberOfParameters() != 2) {
             return false;
         }
-        
         $ctxType = $method->getParameters()[0]->getType();
         $inType = $method->getParameters()[1]->getType();
-
         $ctx = $ctxType && ! $ctxType->isBuiltin() ? new \ReflectionClass($ctxType->getName()) : null;
         $in = $inType && ! $inType->isBuiltin() ? new \ReflectionClass($inType->getName()) : null;
 

From db2c50360018327dc0b39809ee30f1c8a070d331 Mon Sep 17 00:00:00 2001
From: lampatrampa <30873408+lampatrampa@users.noreply.github.com>
Date: Wed, 10 Mar 2021 15:52:55 +0300
Subject: [PATCH 08/29] Checking types are instance of ReflectionNamedType

---
 src/Method.php | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Method.php b/src/Method.php
index 9546a7b..df22f24 100644
--- a/src/Method.php
+++ b/src/Method.php
@@ -66,8 +66,8 @@ public static function match(\ReflectionMethod $method): bool
         }
         $ctxType = $method->getParameters()[0]->getType();
         $inType = $method->getParameters()[1]->getType();
-        $ctx = $ctxType && ! $ctxType->isBuiltin() ? new \ReflectionClass($ctxType->getName()) : null;
-        $in = $inType && ! $inType->isBuiltin() ? new \ReflectionClass($inType->getName()) : null;
+        $ctx = $ctxType && $ctxType instanceof \ReflectionNamedType && !$ctxType->isBuiltin() ? new \ReflectionClass($ctxType->getName()) : null;
+        $in = $inType && $inType instanceof \ReflectionNamedType && ! $inType->isBuiltin() ? new \ReflectionClass($inType->getName()) : null;
 
         if (empty($ctx) || !$ctx->implementsInterface(ContextInterface::class)) {
             return false;

From 7ce5f931256a49eeb465132576f0689479b492b1 Mon Sep 17 00:00:00 2001
From: SerafimArts <nesk@xakep.ru>
Date: Thu, 25 Mar 2021 21:33:10 +0300
Subject: [PATCH 09/29] Code improvements

---
 .phpunit.result.cache                         |   1 +
 composer.json                                 |  84 +++--
 example/server/composer.json                  |  16 +-
 phpunit.xml                                   |  16 +-
 psalm.xml                                     |  26 ++
 src/Context.php                               |  92 +++++-
 src/ContextInterface.php                      |  14 +-
 src/Exception/GRPCException.php               |  88 ++++--
 src/Exception/GRPCExceptionInterface.php      |  36 +++
 src/Exception/InvokeException.php             |   9 +-
 .../MutableGRPCExceptionInterface.php         |  31 ++
 src/Exception/NotFoundException.php           |   9 +-
 src/Exception/ServiceException.php            |   9 +-
 src/Exception/UnauthenticatedException.php    |   9 +-
 src/Exception/UnimplementedException.php      |   9 +-
 src/Invoker.php                               | 101 ++++--
 src/InvokerInterface.php                      |  20 +-
 src/Method.php                                | 287 +++++++++++++++---
 src/ResponseHeaders.php                       |  70 ++++-
 src/Server.php                                |  10 +-
 src/ServiceInterface.php                      |   6 +-
 src/ServiceWrapper.php                        |  41 ++-
 src/StatusCode.php                            | 253 +++++++++------
 tests/GRPC/InvokerTest.php                    |  19 +-
 tests/GRPC/MethodTest.php                     |   5 +-
 tests/GRPC/ServiceWrapperTest.php             |  20 +-
 26 files changed, 945 insertions(+), 336 deletions(-)
 create mode 100644 .phpunit.result.cache
 create mode 100644 psalm.xml
 create mode 100644 src/Exception/GRPCExceptionInterface.php
 create mode 100644 src/Exception/MutableGRPCExceptionInterface.php

diff --git a/.phpunit.result.cache b/.phpunit.result.cache
new file mode 100644
index 0000000..c23c558
--- /dev/null
+++ b/.phpunit.result.cache
@@ -0,0 +1 @@
+C:37:"PHPUnit\Runner\DefaultTestResultCache":2131:{a:2:{s:7:"defects";a:0:{}s:5:"times";a:35:{s:43:"Spiral\GRPC\Tests\ContextTest::testGetValue";d:0.004;s:47:"Spiral\GRPC\Tests\ContextTest::testGetNullValue";d:0;s:44:"Spiral\GRPC\Tests\ContextTest::testGetValues";d:0;s:44:"Spiral\GRPC\Tests\ContextTest::testWithValue";d:0;s:52:"Spiral\GRPC\Tests\ContextTest::testGetOutgoingHeader";d:0;s:53:"Spiral\GRPC\Tests\ContextTest::testGetOutgoingHeaders";d:0;s:44:"Spiral\GRPC\Tests\ExceptionTest::testDefault";d:0.001;s:45:"Spiral\GRPC\Tests\ExceptionTest::testNotFound";d:0;s:43:"Spiral\GRPC\Tests\ExceptionTest::testInvoke";d:0;s:52:"Spiral\GRPC\Tests\ExceptionTest::testUnauthenticated";d:0;s:50:"Spiral\GRPC\Tests\ExceptionTest::testUnimplemented";d:0;s:41:"Spiral\GRPC\Tests\InvokerTest::testInvoke";d:0.014;s:46:"Spiral\GRPC\Tests\InvokerTest::testInvokeError";d:0.001;s:46:"Spiral\GRPC\Tests\MethodTest::testInvalidParse";d:0;s:39:"Spiral\GRPC\Tests\MethodTest::testMatch";d:0;s:41:"Spiral\GRPC\Tests\MethodTest::testNoMatch";d:0;s:42:"Spiral\GRPC\Tests\MethodTest::testNoMatch2";d:0;s:42:"Spiral\GRPC\Tests\MethodTest::testNoMatch3";d:0;s:42:"Spiral\GRPC\Tests\MethodTest::testNoMatch4";d:0;s:42:"Spiral\GRPC\Tests\MethodTest::testNoMatch5";d:0;s:44:"Spiral\GRPC\Tests\MethodTest::testMethodName";d:0;s:49:"Spiral\GRPC\Tests\MethodTest::testMethodInputType";d:0;s:50:"Spiral\GRPC\Tests\MethodTest::testMethodOutputType";d:0;s:40:"Spiral\GRPC\Tests\ServerTest::testInvoke";d:0.003;s:42:"Spiral\GRPC\Tests\ServerTest::testNotFound";d:0;s:43:"Spiral\GRPC\Tests\ServerTest::testNotFound2";d:0;s:59:"Spiral\GRPC\Tests\ServerTest::testServerDebugModeNotEnabled";d:0;s:46:"Spiral\GRPC\Tests\ServiceWrapperTest::testName";d:0;s:49:"Spiral\GRPC\Tests\ServiceWrapperTest::testService";d:0;s:49:"Spiral\GRPC\Tests\ServiceWrapperTest::testMethods";d:0;s:56:"Spiral\GRPC\Tests\ServiceWrapperTest::testInvokeNotFound";d:0;s:48:"Spiral\GRPC\Tests\ServiceWrapperTest::testInvoke";d:0;s:56:"Spiral\GRPC\Tests\ServiceWrapperTest::testNotImplemented";d:0;s:58:"Spiral\GRPC\Tests\ServiceWrapperTest::testInvalidInterface";d:0;s:59:"Spiral\GRPC\Tests\ServiceWrapperTest::testInvalidInterface2";d:0;}}}
\ No newline at end of file
diff --git a/composer.json b/composer.json
index 8963b2e..cb350cd 100644
--- a/composer.json
+++ b/composer.json
@@ -1,33 +1,55 @@
 {
-  "name": "spiral/php-grpc",
-  "type": "server",
-  "description": "High-Performance GRPC server for PHP applications",
-  "license": "MIT",
-  "authors": [
-    {
-      "name": "Anton Titov / Wolfy-J",
-      "email": "wolfy.jd@gmail.com"
-    }
-  ],
-  "require": {
-    "php": ">=7.2",
-    "ext-json": "*",
-    "google/protobuf": "^3.7",
-    "spiral/roadrunner": "^1.8"
-  },
-  "require-dev": {
-    "phpunit/phpunit": "~7.0",
-    "spiral/code-style": "^1.0"
-  },
-  "autoload": {
-    "psr-4": {
-      "Spiral\\GRPC\\": "src/"
-    }
-  },
-  "autoload-dev": {
-    "psr-4": {
-      "": "tests/src/",
-      "Spiral\\GRPC\\Tests\\": "tests/GRPC/"
-    }
-  }
+    "name": "spiral/php-grpc",
+    "type": "library",
+    "description": "High-Performance GRPC server for PHP applications",
+    "license": "MIT",
+    "authors": [
+        {
+            "name": "Anton Titov / Wolfy-J",
+            "email": "wolfy.jd@gmail.com"
+        }
+    ],
+    "require": {
+        "php": ">=7.2",
+        "ext-json": "*",
+        "symfony/polyfill-php80": "^1.22",
+        "symfony/polyfill-php73": "^1.22",
+        "google/protobuf": "^3.7",
+        "spiral/roadrunner": "^1.8"
+    },
+    "require-dev": {
+        "phpunit/phpunit": "^8.5|^9.0",
+        "spiral/code-style": "^1.0",
+        "jetbrains/phpstorm-attributes": "^1.0",
+        "symfony/var-dumper": ">=4.4",
+        "vimeo/psalm": "^4.6"
+    },
+    "autoload": {
+        "psr-4": {
+            "Spiral\\GRPC\\": "src"
+        }
+    },
+    "autoload-dev": {
+        "psr-4": {
+            "": "tests/src",
+            "Spiral\\GRPC\\Tests\\": "tests/GRPC"
+        }
+    },
+    "scripts": {
+        "test": [
+            "spiral-cs check src tests/GRPC",
+            "psalm --no-cache",
+            "phpunit"
+        ]
+    },
+    "extra": {
+        "branch-alias": {
+            "dev-master": "2.0.x-dev"
+        }
+    },
+    "config": {
+        "sort-packages": true
+    },
+    "minimum-stability": "dev",
+    "prefer-stable": true
 }
diff --git a/example/server/composer.json b/example/server/composer.json
index 71825a7..bdcd633 100644
--- a/example/server/composer.json
+++ b/example/server/composer.json
@@ -1,10 +1,12 @@
 {
-  "require": {
-    "spiral/php-grpc": "^1.0"
-  },
-  "autoload": {
-    "psr-4": {
-      "": "src/"
+    "name": "app/example-grpc-server",
+    "description": "Example GRPC Server",
+    "require": {
+        "spiral/php-grpc": "^1.0"
+    },
+    "autoload": {
+        "psr-4": {
+            "": "src"
+        }
     }
-  }
 }
diff --git a/phpunit.xml b/phpunit.xml
index 563ac8f..fbd70dd 100644
--- a/phpunit.xml
+++ b/phpunit.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<phpunit bootstrap="tests/bootstrap.php"
+<phpunit bootstrap="vendor/autoload.php"
          backupGlobals="false"
          backupStaticAttributes="false"
          colors="true"
@@ -10,17 +10,19 @@
          processIsolation="false"
          stopOnFailure="false"
          stopOnError="false"
->
-
+         stderr="true">
     <testsuites>
-        <testsuite name="High-Performance GRPC server for PHP applications">
-            <directory>./tests/</directory>
+        <testsuite name="Test Suite">
+            <directory>tests</directory>
         </testsuite>
     </testsuites>
-
     <filter>
         <whitelist>
             <directory>src</directory>
         </whitelist>
     </filter>
-</phpunit>
\ No newline at end of file
+    <php>
+        <ini name="error_reporting" value="-1"/>
+        <ini name="memory_limit" value="-1"/>
+    </php>
+</phpunit>
diff --git a/psalm.xml b/psalm.xml
new file mode 100644
index 0000000..0218777
--- /dev/null
+++ b/psalm.xml
@@ -0,0 +1,26 @@
+<?xml version="1.0"?>
+<psalm
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xmlns="https://getpsalm.org/schema/config"
+    xsi:schemaLocation="https://getpsalm.org/schema/config vendor/vimeo/psalm/config.xsd"
+
+    errorLevel="1"
+    hoistConstants="true"
+    resolveFromConfigFile="true"
+    allowPhpStormGenerics="true"
+    findUnusedPsalmSuppress="true"
+    findUnusedVariablesAndParams="true"
+    ensureArrayStringOffsetsExist="true"
+    addParamDefaultToDocblockType="true"
+>
+    <issueHandlers>
+        <RedundantConditionGivenDocblockType errorLevel="suppress" />
+        <MixedReturnStatement errorLevel="suppress" />
+    </issueHandlers>
+    <projectFiles>
+        <directory name="src" />
+        <ignoreFiles>
+            <directory name="vendor" />
+        </ignoreFiles>
+    </projectFiles>
+</psalm>
diff --git a/src/Context.php b/src/Context.php
index ec224bf..07d876f 100644
--- a/src/Context.php
+++ b/src/Context.php
@@ -1,23 +1,29 @@
 <?php
 
 /**
- * Spiral Framework.
+ * This file is part of RoadRunner GRPC package.
  *
- * @license   MIT
- * @author    Anton Titov (Wolfy-J)
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
  */
 
 declare(strict_types=1);
 
 namespace Spiral\GRPC;
 
-final class Context implements ContextInterface
+/**
+ * @template-implements \IteratorAggregate<string, mixed>
+ * @template-implements \ArrayAccess<string, mixed>
+ */
+final class Context implements ContextInterface, \IteratorAggregate, \Countable, \ArrayAccess
 {
-    /** @var array */
+    /**
+     * @var array<string, mixed>
+     */
     private $values;
 
     /**
-     * @param array $values
+     * @param array<string, mixed> $values
      */
     public function __construct(array $values)
     {
@@ -25,7 +31,7 @@ public function __construct(array $values)
     }
 
     /**
-     * @inheritdoc
+     * {@inheritDoc}
      */
     public function withValue(string $key, $value): ContextInterface
     {
@@ -36,18 +42,82 @@ public function withValue(string $key, $value): ContextInterface
     }
 
     /**
-     * @inheritdoc
+     * {@inheritDoc}
+     * @param mixed|null $default
      */
-    public function getValue(string $key)
+    public function getValue(string $key, $default = null)
     {
-        return $this->values[$key] ?? null;
+        return $this->values[$key] ?? $default;
     }
 
     /**
-     * @inheritdoc
+     * {@inheritDoc}
      */
     public function getValues(): array
     {
         return $this->values;
     }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function offsetExists($offset): bool
+    {
+        assert(\is_string($offset), 'Offset argument must be a type of string');
+
+        /**
+         * Note: PHP Opcode optimisation
+         * @see https://www.php.net/manual/pt_BR/internals2.opcodes.isset-isempty-var.php
+         *
+         * Priority use `ZEND_ISSET_ISEMPTY_VAR !0` opcode instead of `DO_FCALL 'array_key_exists'`.
+         */
+        return isset($this->values[$offset]) || \array_key_exists($offset, $this->values);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function offsetGet($offset)
+    {
+        assert(\is_string($offset), 'Offset argument must be a type of string');
+
+        return $this->values[$offset] ?? null;
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function offsetSet($offset, $value): void
+    {
+        assert(\is_string($offset), 'Offset argument must be a type of string');
+
+        throw new \LogicException(__METHOD__ . ' not implemented yet');
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function offsetUnset($offset): void
+    {
+        assert(\is_string($offset), 'Offset argument must be a type of string');
+
+        unset($this->values[$offset]);
+    }
+
+
+    /**
+     * {@inheritDoc}
+     */
+    public function getIterator(): \Traversable
+    {
+        return new \ArrayIterator($this->values);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function count(): int
+    {
+        return \count($this->values);
+    }
 }
diff --git a/src/ContextInterface.php b/src/ContextInterface.php
index 9fa7558..2d53297 100644
--- a/src/ContextInterface.php
+++ b/src/ContextInterface.php
@@ -1,10 +1,10 @@
 <?php
 
 /**
- * Spiral Framework.
+ * This file is part of RoadRunner GRPC package.
  *
- * @license   MIT
- * @author    Anton Titov (Wolfy-J)
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
  */
 
 declare(strict_types=1);
@@ -20,10 +20,10 @@ interface ContextInterface
      * Create context with new value.
      *
      * @param string $key
-     * @param mixed  $value
-     * @return ContextInterface
+     * @param mixed $value
+     * @return $this
      */
-    public function withValue(string $key, $value): ContextInterface;
+    public function withValue(string $key, $value): self;
 
     /**
      * Get context value or return null.
@@ -36,7 +36,7 @@ public function getValue(string $key);
     /**
      * Return all context values.
      *
-     * @return array
+     * @return array<string, mixed>
      */
     public function getValues(): array;
 }
diff --git a/src/Exception/GRPCException.php b/src/Exception/GRPCException.php
index 23ef36e..b146129 100644
--- a/src/Exception/GRPCException.php
+++ b/src/Exception/GRPCException.php
@@ -1,10 +1,10 @@
 <?php
 
 /**
- * Spiral Framework.
+ * This file is part of RoadRunner GRPC package.
  *
- * @license   MIT
- * @author    Anton Titov (Wolfy-J)
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
  */
 
 declare(strict_types=1);
@@ -12,42 +12,70 @@
 namespace Spiral\GRPC\Exception;
 
 use Google\Protobuf\Internal\Message;
+use JetBrains\PhpStorm\Deprecated;
+use JetBrains\PhpStorm\ExpectedValues;
 use Spiral\GRPC\StatusCode;
-use Throwable;
 
-class GRPCException extends \RuntimeException
+/**
+ * @psalm-import-type StatusCodeType from StatusCode
+ */
+class GRPCException extends \RuntimeException implements MutableGRPCExceptionInterface
 {
+    /**
+     * Can be overridden by child classes.
+     *
+     * @psalm-var StatusCodeType
+     * @var int
+     */
     protected const CODE = StatusCode::UNKNOWN;
 
     /**
-     * Collection of protobuf messages for describing error which will be converted to google.protobuf.Any during
-     * sending as response.
+     * Collection of protobuf messages for describing error which will be
+     * converted to google.protobuf. Any during sending as response.
      *
      * @see https://cloud.google.com/apis/design/errors
      *
-     * @var array|Message[]
+     * @var array<Message>
      */
     private $details;
 
     /**
-     * @param string         $message
-     * @param int            $code
-     * @param array          $details
-     * @param Throwable|null $previous
+     * @param string $message
+     * @param StatusCodeType|null $code
+     * @param array<Message> $details
+     * @param \Throwable|null $previous
      */
-    public function __construct(string $message = '', int $code = 0, $details = [], Throwable $previous = null)
-    {
-        if ($code == 0) {
-            $code = static::CODE;
-        }
-
-        parent::__construct($message, $code, $previous);
+    final public function __construct(
+        string $message = '',
+        #[ExpectedValues(valuesFromClass: StatusCode::class)]
+        int $code = null,
+        array $details = [],
+        \Throwable $previous = null
+    ) {
+        parent::__construct($message, (int)($code ?? static::CODE), $previous);
 
         $this->details = $details;
     }
 
     /**
-     * @return array
+     * @param string $message
+     * @param StatusCodeType|null $code
+     * @param array<Message> $details
+     * @param \Throwable|null $previous
+     * @return static
+     */
+    public static function create(
+        string $message,
+        #[ExpectedValues(valuesFromClass: StatusCode::class)]
+        int $code = null,
+        \Throwable $previous = null,
+        array $details = []
+    ): self {
+        return new static($message, $code, $details, $previous);
+    }
+
+    /**
+     * {@inheritDoc}
      */
     public function getDetails(): array
     {
@@ -55,22 +83,32 @@ public function getDetails(): array
     }
 
     /**
-     * @param array $details
+     * {@inheritDoc}
      */
     public function setDetails(array $details): void
     {
         $this->details = $details;
     }
 
+    /**
+     * {@inheritDoc}
+     */
+    public function addDetails(Message $message): void
+    {
+        $this->details[] = $message;
+    }
+
     /**
      * Push details message to the exception.
      *
-     * @param $details
-     *
+     * @param Message $details
      * @return $this
+     * @deprecated Please use {@see GRPCException::addDetails()} method instead.
      */
-    public function withDetails($details)
-    {
+    #[Deprecated('Please use GRPCException::addDetails() instead', '%class%::addDetails(%parameter0%)')]
+    public function withDetails(
+        $details
+    ): self {
         $this->details[] = $details;
 
         return $this;
diff --git a/src/Exception/GRPCExceptionInterface.php b/src/Exception/GRPCExceptionInterface.php
new file mode 100644
index 0000000..df9cba8
--- /dev/null
+++ b/src/Exception/GRPCExceptionInterface.php
@@ -0,0 +1,36 @@
+<?php
+
+/**
+ * This file is part of RoadRunner GRPC package.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace Spiral\GRPC\Exception;
+
+use Google\Protobuf\Internal\Message;
+use JetBrains\PhpStorm\ExpectedValues;
+use Spiral\GRPC\StatusCode;
+
+/**
+ * @psalm-import-type StatusCodeType from StatusCode
+ */
+interface GRPCExceptionInterface extends \Throwable
+{
+    /**
+     * Returns GRPC exception status code.
+     *
+     * @psalm-return StatusCodeType
+     * @return int
+     */
+    #[ExpectedValues(valuesFromClass: StatusCode::class)]
+    public function getCode();
+
+    /**
+     * @return array<Message>
+     */
+    public function getDetails(): array;
+}
diff --git a/src/Exception/InvokeException.php b/src/Exception/InvokeException.php
index a19ba72..ee18751 100644
--- a/src/Exception/InvokeException.php
+++ b/src/Exception/InvokeException.php
@@ -1,10 +1,10 @@
 <?php
 
 /**
- * Spiral Framework.
+ * This file is part of RoadRunner GRPC package.
  *
- * @license   MIT
- * @author    Anton Titov (Wolfy-J)
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
  */
 
 declare(strict_types=1);
@@ -15,5 +15,8 @@
 
 class InvokeException extends GRPCException
 {
+    /**
+     * {@inheritDoc}
+     */
     protected const CODE = StatusCode::UNAVAILABLE;
 }
diff --git a/src/Exception/MutableGRPCExceptionInterface.php b/src/Exception/MutableGRPCExceptionInterface.php
new file mode 100644
index 0000000..994c72f
--- /dev/null
+++ b/src/Exception/MutableGRPCExceptionInterface.php
@@ -0,0 +1,31 @@
+<?php
+
+/**
+ * This file is part of RoadRunner GRPC package.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace Spiral\GRPC\Exception;
+
+use Google\Protobuf\Internal\Message;
+
+interface MutableGRPCExceptionInterface extends GRPCExceptionInterface
+{
+    /**
+     * Rewrites details message in the GRPC Exception.
+     *
+     * @param array<Message> $details
+     */
+    public function setDetails(array $details): void;
+
+    /**
+     * Appends details message to the GRPC Exception.
+     *
+     * @param Message $message
+     */
+    public function addDetails(Message $message): void;
+}
diff --git a/src/Exception/NotFoundException.php b/src/Exception/NotFoundException.php
index 384704a..8ce0a7c 100644
--- a/src/Exception/NotFoundException.php
+++ b/src/Exception/NotFoundException.php
@@ -1,10 +1,10 @@
 <?php
 
 /**
- * Spiral Framework.
+ * This file is part of RoadRunner GRPC package.
  *
- * @license   MIT
- * @author    Anton Titov (Wolfy-J)
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
  */
 
 declare(strict_types=1);
@@ -15,5 +15,8 @@
 
 class NotFoundException extends InvokeException
 {
+    /**
+     * {@inheritDoc}
+     */
     protected const CODE = StatusCode::NOT_FOUND;
 }
diff --git a/src/Exception/ServiceException.php b/src/Exception/ServiceException.php
index bcdd55c..32a99da 100644
--- a/src/Exception/ServiceException.php
+++ b/src/Exception/ServiceException.php
@@ -1,10 +1,10 @@
 <?php
 
 /**
- * Spiral Framework.
+ * This file is part of RoadRunner GRPC package.
  *
- * @license   MIT
- * @author    Anton Titov (Wolfy-J)
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
  */
 
 declare(strict_types=1);
@@ -15,5 +15,8 @@
 
 class ServiceException extends GRPCException
 {
+    /**
+     * {@inheritDoc}
+     */
     protected const CODE = StatusCode::INTERNAL;
 }
diff --git a/src/Exception/UnauthenticatedException.php b/src/Exception/UnauthenticatedException.php
index 1c88806..00b43b8 100644
--- a/src/Exception/UnauthenticatedException.php
+++ b/src/Exception/UnauthenticatedException.php
@@ -1,10 +1,10 @@
 <?php
 
 /**
- * Spiral Framework.
+ * This file is part of RoadRunner GRPC package.
  *
- * @license   MIT
- * @author    Anton Titov (Wolfy-J)
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
  */
 
 declare(strict_types=1);
@@ -15,5 +15,8 @@
 
 class UnauthenticatedException extends InvokeException
 {
+    /**
+     * {@inheritDoc}
+     */
     protected const CODE = StatusCode::UNAUTHENTICATED;
 }
diff --git a/src/Exception/UnimplementedException.php b/src/Exception/UnimplementedException.php
index 23f6c55..ed0b2eb 100644
--- a/src/Exception/UnimplementedException.php
+++ b/src/Exception/UnimplementedException.php
@@ -1,10 +1,10 @@
 <?php
 
 /**
- * Spiral Framework.
+ * This file is part of RoadRunner GRPC package.
  *
- * @license   MIT
- * @author    Anton Titov (Wolfy-J)
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
  */
 
 declare(strict_types=1);
@@ -15,5 +15,8 @@
 
 class UnimplementedException extends GRPCException
 {
+    /**
+     * {@inheritDoc}
+     */
     protected const CODE = StatusCode::UNIMPLEMENTED;
 }
diff --git a/src/Invoker.php b/src/Invoker.php
index e5bef54..2a80423 100644
--- a/src/Invoker.php
+++ b/src/Invoker.php
@@ -1,10 +1,10 @@
 <?php
 
 /**
- * Spiral Framework.
+ * This file is part of RoadRunner GRPC package.
  *
- * @license   MIT
- * @author    Anton Titov (Wolfy-J)
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
  */
 
 declare(strict_types=1);
@@ -17,47 +17,110 @@
 final class Invoker implements InvokerInterface
 {
     /**
-     * @inheritdoc
+     * @var string
      */
-    public function invoke(
-        ServiceInterface $service,
-        Method $method,
-        ContextInterface $context,
-        ?string $input
-    ): string {
-        $out = call_user_func_array(
-            [$service, $method->getName()],
-            [&$context,$this->makeInput($method, $input)]
-        );
+    private const ERROR_METHOD_RETURN =
+        'Method %s must return an object that instance of %s, ' .
+        'but the result provides type of %s';
+
+    /**
+     * @var string
+     */
+    private const ERROR_METHOD_IN_TYPE =
+        'Method %s input type must be an instance of %s, ' .
+        'but the input is type of %s'
+    ;
+
+    /**
+     * {@inheritDoc}
+     */
+    public function invoke(ServiceInterface $service, Method $method, ContextInterface $ctx, ?string $input): string
+    {
+        /** @var callable $callable */
+        $callable = [$service, $method->getName()];
 
         try {
-            return $out->serializeToString();
+            /** @var Message $message */
+            $message = $callable($ctx, $this->makeInput($method, $input));
+
+            // Note: This validation will only work if the
+            // assertions option ("zend.assertions") is enabled.
+            assert($this->assertResultType($method, $message));
+
+            return $message->serializeToString();
         } catch (\Throwable $e) {
-            throw new InvokeException($e->getMessage(), StatusCode::INTERNAL, [], $e);
+            throw InvokeException::create($e->getMessage(), StatusCode::INTERNAL, $e);
         }
     }
 
     /**
+     * Checks that the result from the GRPC service method returns the
+     * Message object.
+     *
      * @param Method $method
-     * @param string $body
+     * @param mixed $result
+     * @return bool
+     * @throws \BadFunctionCallException
+     */
+    private function assertResultType(Method $method, $result): bool
+    {
+        if (! $result instanceof Message) {
+            $type = \is_object($result) ? \get_class($result) : \get_debug_type($result);
+
+            throw new \BadFunctionCallException(
+                \sprintf(self::ERROR_METHOD_RETURN, $method->getName(), Message::class, $type)
+            );
+        }
+
+        return true;
+    }
+
+    /**
+     * @param Method $method
+     * @param string|null $body
      * @return Message
-     *
      * @throws InvokeException
+     * @psalm-suppress InvalidStringClass
      */
     private function makeInput(Method $method, ?string $body): Message
     {
         try {
             $class = $method->getInputType();
 
+            // Note: This validation will only work if the
+            // assertions option ("zend.assertions") is enabled.
+            assert($this->assertInputType($method, $class));
+
             /** @var Message $in */
             $in = new $class();
+
             if ($body !== null) {
                 $in->mergeFromString($body);
             }
 
             return $in;
         } catch (\Throwable $e) {
-            throw new InvokeException($e->getMessage(), StatusCode::INTERNAL, [], $e);
+            throw InvokeException::create($e->getMessage(), StatusCode::INTERNAL, $e);
         }
     }
+
+    /**
+     * Checks that the input of the GRPC service method contains the
+     * Message object.
+     *
+     * @param Method $method
+     * @param string $class
+     * @return bool
+     * @throws \InvalidArgumentException
+     */
+    private function assertInputType(Method $method, string $class): bool
+    {
+        if (! \is_subclass_of($class, Message::class)) {
+            throw new \InvalidArgumentException(
+                \sprintf(self::ERROR_METHOD_IN_TYPE, $method->getName(), Message::class, $class)
+            );
+        }
+
+        return true;
+    }
 }
diff --git a/src/InvokerInterface.php b/src/InvokerInterface.php
index 8b10f97..80e2afe 100644
--- a/src/InvokerInterface.php
+++ b/src/InvokerInterface.php
@@ -1,10 +1,10 @@
 <?php
 
 /**
- * Spiral Framework.
+ * This file is part of RoadRunner GRPC package.
  *
- * @license   MIT
- * @author    Anton Titov (Wolfy-J)
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
  */
 
 declare(strict_types=1);
@@ -20,17 +20,11 @@ interface InvokerInterface
 {
     /**
      * @param ServiceInterface $service
-     * @param Method           $method
-     * @param ContextInterface $context
-     * @param string           $input
+     * @param Method $method
+     * @param ContextInterface $ctx
+     * @param string|null $input
      * @return string
-     *
      * @throws InvokeException
      */
-    public function invoke(
-        ServiceInterface $service,
-        Method $method,
-        ContextInterface $context,
-        string $input
-    ): string;
+    public function invoke(ServiceInterface $service, Method $method, ContextInterface $ctx, ?string $input): string;
 }
diff --git a/src/Method.php b/src/Method.php
index df22f24..9406647 100644
--- a/src/Method.php
+++ b/src/Method.php
@@ -1,10 +1,10 @@
 <?php
 
 /**
- * Spiral Framework.
+ * This file is part of RoadRunner GRPC package.
  *
- * @license   MIT
- * @author    Anton Titov (Wolfy-J)
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
  */
 
 declare(strict_types=1);
@@ -15,20 +15,83 @@
 use Spiral\GRPC\Exception\GRPCException;
 
 /**
- * Method carry information about one specific RPC method, it's input and return types. Provides
- * ability to detect GRPC methods based on given class declaration.
+ * Method carry information about one specific RPC method, it's input and
+ * return types. Provides ability to detect GRPC methods based on given
+ * class declaration.
  */
 final class Method
 {
-    /** @var string */
+    /**
+     * @var string
+     */
+    private const ERROR_PARAMS_COUNT =
+        'The GRPC method %s can only contain 2 parameters (input and output), but ' .
+        'signature contains an %d parameters';
+
+    /**
+     * @var string
+     */
+    private const ERROR_PARAM_UNION_TYPE =
+        'Parameter $%s of the GRPC method %s cannot be declared using union type';
+
+    /**
+     * @var string
+     */
+    private const ERROR_PARAM_CONTEXT_TYPE =
+        'The first parameter $%s of the GRPC method %s can only take an instance of %s';
+
+    /**
+     * @var string
+     */
+    private const ERROR_PARAM_INPUT_TYPE =
+        'The second (input) parameter $%s of the GRPC method %s can only take ' .
+        'an instance of %s, but type %s is indicated';
+
+    /**
+     * @var string
+     */
+    private const ERROR_RETURN_UNION_TYPE =
+        'Return type of the GRPC method %s cannot be declared using union type';
+
+    /**
+     * @var string
+     */
+    private const ERROR_RETURN_TYPE =
+        'Return type of the GRPC method %s must return ' .
+        'an instance of %s, but type %s is indicated';
+
+    /**
+     * @var string
+     */
+    private const ERROR_INVALID_GRPC_METHOD = 'Method %s is not valid GRPC method.';
+
+    /**
+     * @var string
+     */
     private $name;
 
-    /** @var string */
+    /**
+     * @var class-string<Message>
+     */
     private $input;
 
-    /** @var string */
+    /**
+     * @var class-string<Message>
+     */
     private $output;
 
+    /**
+     * @param string $name
+     * @param class-string<Message> $input
+     * @param class-string<Message> $output
+     */
+    private function __construct(string $name, string $input, string $output)
+    {
+        $this->name = $name;
+        $this->input = $input;
+        $this->output = $output;
+    }
+
     /**
      * @return string
      */
@@ -38,7 +101,7 @@ public function getName(): string
     }
 
     /**
-     * @return string
+     * @return class-string<Message>
      */
     public function getInputType(): string
     {
@@ -46,13 +109,27 @@ public function getInputType(): string
     }
 
     /**
-     * @return string
+     * @return class-string<Message>
      */
     public function getOutputType(): string
     {
         return $this->output;
     }
 
+    /**
+     * @param \ReflectionType|null $type
+     * @return \ReflectionClass|null
+     * @throws \ReflectionException
+     */
+    private static function getReflectionClassByType(?\ReflectionType $type): ?\ReflectionClass
+    {
+        if ($type instanceof \ReflectionNamedType && ! $type->isBuiltin()) {
+            return new \ReflectionClass($type->getName());
+        }
+
+        return null;
+    }
+
     /**
      * Returns true if method signature matches.
      *
@@ -61,59 +138,187 @@ public function getOutputType(): string
      */
     public static function match(\ReflectionMethod $method): bool
     {
-        if ($method->getNumberOfParameters() != 2) {
+        try {
+            self::assertMethodSignature($method);
+        } catch (\Throwable $e) {
             return false;
         }
-        $ctxType = $method->getParameters()[0]->getType();
-        $inType = $method->getParameters()[1]->getType();
-        $ctx = $ctxType && $ctxType instanceof \ReflectionNamedType && !$ctxType->isBuiltin() ? new \ReflectionClass($ctxType->getName()) : null;
-        $in = $inType && $inType instanceof \ReflectionNamedType && ! $inType->isBuiltin() ? new \ReflectionClass($inType->getName()) : null;
 
-        if (empty($ctx) || !$ctx->implementsInterface(ContextInterface::class)) {
-            return false;
+        return true;
+    }
+
+    /**
+     * @param \ReflectionMethod $method
+     * @param \ReflectionParameter $context
+     * @throws \ReflectionException
+     */
+    private static function assertContextParameter(\ReflectionMethod $method, \ReflectionParameter $context): void
+    {
+        $type = $context->getType();
+
+        // When the type is not specified, it means that it is declared as
+        // a "mixed" type, which is a valid case
+        if ($type !== null) {
+            if (! $type instanceof \ReflectionNamedType) {
+                $message = \sprintf(self::ERROR_PARAM_UNION_TYPE, $context->getName(), $method->getName());
+                throw new \DomainException($message, 0x02);
+            }
+
+            // If the type is not declared as a generic "mixed" or "object",
+            // then it can only be a type that implements ContextInterface.
+            if (! \in_array($type->getName(), ['mixed', 'object'], true)) {
+                /** @psalm-suppress ArgumentTypeCoercion */
+                $isContextImplementedType = ! $type->isBuiltin()
+                    && (new \ReflectionClass($type->getName()))
+                        ->implementsInterface(ContextInterface::class)
+                ;
+
+                // Checking that the signature can accept the context.
+                //
+                // TODO If the type is any other implementation of the Spiral\GRPC\ContextInterface other than
+                //      class Spiral\GRPC\Context, it may cause an error.
+                //      It might make sense to check for such cases?
+                if (! $isContextImplementedType) {
+                    $message = \vsprintf(self::ERROR_PARAM_CONTEXT_TYPE, [
+                        $context->getName(),
+                        $method->getName(),
+                        ContextInterface::class
+                    ]);
+
+                    throw new \DomainException($message, 0x03);
+                }
+            }
         }
+    }
 
-        if (empty($in) || !$in->isSubclassOf(Message::class)) {
-            return false;
+    /**
+     * @param \ReflectionMethod $method
+     * @param \ReflectionParameter $input
+     * @throws \ReflectionException
+     */
+    private static function assertInputParameter(\ReflectionMethod $method, \ReflectionParameter $input): void
+    {
+        $type = $input->getType();
+
+        // Parameter type cannot be omitted ("mixed")
+        if ($type === null) {
+            $message = \vsprintf(self::ERROR_PARAM_INPUT_TYPE, [
+                $input->getName(),
+                $method->getName(),
+                Message::class,
+                'mixed'
+            ]);
+
+            throw new \DomainException($message, 0x04);
         }
 
-        if (empty($method->getReturnType())) {
-            return false;
+        // Parameter type cannot be declared as singular non-named type
+        if (! $type instanceof \ReflectionNamedType) {
+            $message = \sprintf(self::ERROR_PARAM_UNION_TYPE, $input->getName(), $method->getName());
+            throw new \DomainException($message, 0x05);
         }
 
-        try {
-            $return = $method->getReturnType()->getName();
-            if (!class_exists($return)) {
-                return false;
-            }
-            $return = new \ReflectionClass($return);
-        } catch (\ReflectionException $e) {
-            return false;
+        /** @psalm-suppress ArgumentTypeCoercion */
+        $isProtobufMessageType = ! $type->isBuiltin()
+            && (new \ReflectionClass($type->getName()))
+                ->isSubclassOf(Message::class)
+        ;
+
+        if (! $isProtobufMessageType) {
+            $message = \vsprintf(self::ERROR_PARAM_INPUT_TYPE, [
+                $input->getName(),
+                $method->getName(),
+                Message::class,
+                $type->getName(),
+            ]);
+            throw new \DomainException($message, 0x06);
         }
+    }
 
-        return $return->isSubclassOf(Message::class);
+    /**
+     * @param \ReflectionMethod $method
+     * @throws \ReflectionException
+     */
+    private static function assertOutputReturnType(\ReflectionMethod $method): void
+    {
+        $type = $method->getReturnType();
+
+        // Return type cannot be omitted ("mixed")
+        if ($type === null) {
+            $message = \sprintf(self::ERROR_RETURN_TYPE, $method->getName(), Message::class, 'mixed');
+            throw new \DomainException($message, 0x07);
+        }
+
+        // Return type cannot be declared as singular non-named type
+        if (! $type instanceof \ReflectionNamedType) {
+            $message = \sprintf(self::ERROR_RETURN_UNION_TYPE, $method->getName());
+            throw new \DomainException($message, 0x08);
+        }
+
+        /** @psalm-suppress ArgumentTypeCoercion */
+        $isProtobufMessageType = ! $type->isBuiltin()
+            && (new \ReflectionClass($type->getName()))
+                ->isSubclassOf(Message::class)
+        ;
+
+        if (! $isProtobufMessageType) {
+            $message = \sprintf(self::ERROR_RETURN_TYPE, $method->getName(), Message::class, $type->getName());
+            throw new \DomainException($message, 0x09);
+        }
     }
 
     /**
-     * Returns true if method signature matches.
+     * @param \ReflectionMethod $method
+     * @throws \ReflectionException
+     * @throws \DomainException
+     */
+    private static function assertMethodSignature(\ReflectionMethod $method): void
+    {
+        // Check that there are only two parameters
+        if ($method->getNumberOfParameters() !== 2) {
+            $message = \sprintf(self::ERROR_PARAMS_COUNT, $method->getName(), $method->getNumberOfParameters());
+            throw new \DomainException($message, 0x01);
+        }
+
+        /**
+         * @var \ReflectionParameter $context
+         * @var \ReflectionParameter $input
+         */
+        [$context, $input] = $method->getParameters();
+
+        // The first parameter can only take a context object
+        self::assertContextParameter($method, $context);
+
+        // The second argument can only be a subtype of the Google\Protobuf\Internal\Message class
+        self::assertInputParameter($method, $input);
+
+        // The return type must be declared as a Google\Protobuf\Internal\Message class
+        self::assertOutputReturnType($method);
+    }
+
+    /**
+     * Creates a new {@see Method} object from a {@see \ReflectionMethod} object.
      *
      * @param \ReflectionMethod $method
      * @return Method
      */
     public static function parse(\ReflectionMethod $method): Method
     {
-        if (!self::match($method)) {
-            throw new GRPCException(
-                "Method `{$method->getName()}` is not valid GRPC method.",
-                StatusCode::INTERNAL
-            );
+        try {
+            self::assertMethodSignature($method);
+        } catch (\Throwable $e) {
+            $message = \sprintf(self::ERROR_INVALID_GRPC_METHOD, $method->getName());
+            throw GRPCException::create($message, StatusCode::INTERNAL, $e);
         }
 
-        $m = new self();
-        $m->name = $method->getName();
-        $m->input = $method->getParameters()[1]->getType()->getName();
-        $m->output = $method->getReturnType()->getName();
+        [,$input] = $method->getParameters();
+
+        /** @var \ReflectionNamedType $inputType */
+        $inputType = $input->getType();
+
+        /** @var \ReflectionNamedType $returnType */
+        $returnType = $method->getReturnType();
 
-        return $m;
+        return new self($method->getName(), $inputType->getName(), $returnType->getName());
     }
 }
diff --git a/src/ResponseHeaders.php b/src/ResponseHeaders.php
index 71d6455..a15cb94 100644
--- a/src/ResponseHeaders.php
+++ b/src/ResponseHeaders.php
@@ -1,27 +1,34 @@
 <?php
 
 /**
- * Spiral Framework.
+ * This file is part of RoadRunner GRPC package.
  *
- * @license   MIT
- * @author    Anton Titov (Wolfy-J)
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
  */
 
 declare(strict_types=1);
 
 namespace Spiral\GRPC;
 
-final class ResponseHeaders implements \IteratorAggregate
+/**
+ * @template-implements \IteratorAggregate<string, string>
+ */
+final class ResponseHeaders implements \IteratorAggregate, \Countable
 {
-    /** @var array */
-    private $headers;
+    /**
+     * @var array<string, string>
+     */
+    private $headers = [];
 
     /**
-     * @param array $headers
+     * @param iterable<string, string> $headers
      */
-    public function __construct(array $headers = [])
+    public function __construct(iterable $headers = [])
     {
-        $this->headers = $headers;
+        foreach ($headers as $key => $value) {
+            $this->set($key, $value);
+        }
     }
 
     /**
@@ -35,8 +42,8 @@ public function set(string $key, string $value): void
 
     /**
      * @param string $key
-     * @param string $default $default
-     * @return string $default|null
+     * @param string|null $default
+     * @return string|null
      */
     public function get(string $key, string $default = null): ?string
     {
@@ -44,22 +51,55 @@ public function get(string $key, string $default = null): ?string
     }
 
     /**
-     * @return array
+     * {@inheritDoc}
+     */
+    public function getIterator(): \Traversable
+    {
+        return new \ArrayIterator($this->headers);
+    }
+
+    /**
+     * @return int
      */
-    public function getIterator(): array
+    public function count(): int
     {
-        return $this->headers;
+        return \count($this->headers);
     }
 
     /**
      * @return string
+     * @throws \JsonException
      */
     public function packHeaders(): string
     {
+        // If an empty array is serialized, it is cast to the string "[]"
+        // instead of object string "{}"
         if ($this->headers === []) {
             return '{}';
         }
 
-        return json_encode($this->headers);
+        $flags = \defined('\\JSON_THROW_ON_ERROR')
+            // Avoid PHP DCE constant inlining
+            ? \constant('\\JSON_THROW_ON_ERROR')
+            : 0;
+
+        return $this->toJsonString($this->headers, $flags);
+    }
+
+    /**
+     * @param array $payload
+     * @param int $flags
+     * @return string
+     * @throws \JsonException
+     */
+    private function toJsonString(array $payload, int $flags = 0): string
+    {
+        $result = @\json_encode($payload, $flags);
+
+        if (($code = \json_last_error()) !== \JSON_ERROR_NONE) {
+            throw new \JsonException(\json_last_error_msg(), $code);
+        }
+
+        return $result;
     }
 }
diff --git a/src/Server.php b/src/Server.php
index 2f9fe7b..f2265e8 100644
--- a/src/Server.php
+++ b/src/Server.php
@@ -1,10 +1,10 @@
 <?php
 
 /**
- * Spiral Framework.
+ * This file is part of RoadRunner GRPC package.
  *
- * @license   MIT
- * @author    Anton Titov (Wolfy-J)
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
  */
 
 declare(strict_types=1);
@@ -114,7 +114,7 @@ public function serve(Worker $worker, callable $finalize = null): void
      * @param string  $service
      * @param string  $method
      * @param Context $context
-     * @param string  $body
+     * @param string|null  $body
      * @return string
      *
      * @throws GRPCException
@@ -127,7 +127,7 @@ protected function invoke(
         ?string $body
     ): string {
         if (!isset($this->services[$service])) {
-            throw new NotFoundException("Service `{$service}` not found.", StatusCode::NOT_FOUND);
+            throw NotFoundException::create("Service `{$service}` not found.", StatusCode::NOT_FOUND);
         }
 
         return $this->services[$service]->invoke($method, $context, $body);
diff --git a/src/ServiceInterface.php b/src/ServiceInterface.php
index 074aefe..991ae1f 100644
--- a/src/ServiceInterface.php
+++ b/src/ServiceInterface.php
@@ -1,10 +1,10 @@
 <?php
 
 /**
- * Spiral Framework.
+ * This file is part of RoadRunner GRPC package.
  *
- * @license   MIT
- * @author    Anton Titov (Wolfy-J)
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
  */
 
 declare(strict_types=1);
diff --git a/src/ServiceWrapper.php b/src/ServiceWrapper.php
index 4ea806b..23b1ba1 100644
--- a/src/ServiceWrapper.php
+++ b/src/ServiceWrapper.php
@@ -1,10 +1,10 @@
 <?php
 
 /**
- * Spiral Framework.
+ * This file is part of RoadRunner GRPC package.
  *
- * @license   MIT
- * @author    Anton Titov (Wolfy-J)
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
  */
 
 declare(strict_types=1);
@@ -34,7 +34,7 @@ final class ServiceWrapper
 
     /**
      * @param InvokerInterface $invoker
-     * @param string           $interface Service interface name.
+     * @param string $interface Service interface name.
      * @param ServiceInterface $service
      *
      * @throws ServiceException
@@ -73,10 +73,10 @@ public function getMethods(): array
     }
 
     /**
-     * @param string           $method
+     * @param string $method
      * @param ContextInterface $context
-     * @param string           $input
-     * @param array            $metadata
+     * @param string|null $input
+     * @param array $metadata
      * @return string
      *
      * @throws NotFoundException
@@ -84,8 +84,8 @@ public function getMethods(): array
      */
     public function invoke(string $method, ContextInterface $context, ?string $input, array &$metadata = []): string
     {
-        if (!isset($this->methods[$method])) {
-            throw new NotFoundException("Method `{$method}` not found in service `{$this->name}`.");
+        if (! isset($this->methods[$method])) {
+            throw NotFoundException::create("Method `{$method}` not found in service `{$this->name}`.");
         }
 
         return $this->invoker->invoke($this->service, $this->methods[$method], $context, $input, $metadata);
@@ -94,7 +94,7 @@ public function invoke(string $method, ContextInterface $context, ?string $input
     /**
      * Configure service name and methods.
      *
-     * @param string           $interface
+     * @param string $interface
      * @param ServiceInterface $service
      *
      * @throws ServiceException
@@ -103,23 +103,20 @@ protected function configure(string $interface, ServiceInterface $service): void
     {
         try {
             $r = new \ReflectionClass($interface);
-            if (!$r->hasConstant('NAME')) {
-                throw new ServiceException(
-                    "Invalid service interface `{$interface}`, constant `NAME` not found."
-                );
+
+            if (! $r->hasConstant('NAME')) {
+                $message = "Invalid service interface `{$interface}`, constant `NAME` not found.";
+                throw ServiceException::create($message);
             }
+
             $this->name = $r->getConstant('NAME');
         } catch (\ReflectionException $e) {
-            throw new ServiceException(
-                "Invalid service interface `{$interface}`.",
-                StatusCode::INTERNAL,
-                [],
-                $e
-            );
+            $message = "Invalid service interface `{$interface}`.";
+            throw ServiceException::create($message, StatusCode::INTERNAL, $e);
         }
 
-        if (!$service instanceof $interface) {
-            throw new ServiceException("Service handler does not implement `{$interface}`.");
+        if (! $service instanceof $interface) {
+            throw ServiceException::create("Service handler does not implement `{$interface}`.");
         }
 
         $this->service = $service;
diff --git a/src/StatusCode.php b/src/StatusCode.php
index 7c0f7fd..5ff9c30 100644
--- a/src/StatusCode.php
+++ b/src/StatusCode.php
@@ -1,10 +1,10 @@
 <?php
 
 /**
- * Spiral Framework.
+ * This file is part of RoadRunner GRPC package.
  *
- * @license   MIT
- * @author    Anton Titov (Wolfy-J)
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
  */
 
 declare(strict_types=1);
@@ -13,122 +13,205 @@
 
 /**
  * GRPC specific status codes. Sources from Go/GRPC implementation.
+ *
+ * @see https://github.com/grpc/grpc-go/blob/v1.35.1/codes/codes.go#L31
+ *
+ * @psalm-type StatusCodeType = StatusCode::*
  */
 final class StatusCode
 {
-    // OK is returned on success.
+    /**
+     * OK is returned on success.
+     *
+     * @see https://github.com/grpc/grpc-go/blob/v1.35.1/codes/codes.go#L32-L33
+     */
     public const OK = 0;
 
-    // Canceled indicates the operation was canceled (typically by the caller).
+    /**
+     * Indicates the operation was canceled (typically by the caller).
+     *
+     * @see https://github.com/grpc/grpc-go/blob/v1.35.1/codes/codes.go#L35-L39
+     */
     public const CANCELLED = 1;
 
-    // Unknown error. An example of where this error may be returned is
-    // if a Status value received from another address space belongs to
-    // an error-space that is not known in this address space. Also
-    // errors raised by APIs that do not return enough error information
-    // may be converted to this error.
+    /**
+     * Unknown error. An example of where this error may be returned is
+     * if a Status value received from another address space belongs to
+     * an error-space that is not known in this address space. Also
+     * errors raised by APIs that do not return enough error information
+     * may be converted to this error.
+     *
+     * @see https://github.com/grpc/grpc-go/blob/v1.35.1/codes/codes.go#L41-L49
+     */
     public const UNKNOWN = 2;
 
-    // InvalidArgument indicates client specified an invalid argument.
-    // Note that this differs from FailedPrecondition. It indicates arguments
-    // that are problematic regardless of the state of the system
-    // (e.g., a malformed file name).
+    /**
+     * Indicates client specified an invalid argument.
+     *
+     * Note that this differs from {@see FAILED_PRECONDITION}. It indicates
+     * arguments that are problematic regardless of the state of the system
+     * (e.g., a malformed file name).
+     *
+     * @see https://github.com/grpc/grpc-go/blob/v1.35.1/codes/codes.go#L51-L57
+     */
     public const INVALID_ARGUMENT = 3;
 
-    // DeadlineExceeded means operation expired before completion.
-    // For operations that change the state of the system, this error may be
-    // returned even if the operation has completed successfully. For
-    // example, a successful response from a server could have been delayed
-    // long enough for the deadline to expire.
+    /**
+     * Means operation expired before completion.
+     *
+     * For operations that change the state of the system, this error may be
+     * returned even if the operation has completed successfully. For
+     * example, a successful response from a server could have been delayed
+     * long enough for the deadline to expire.
+     *
+     * @see https://github.com/grpc/grpc-go/blob/v1.35.1/codes/codes.go#L59-L67
+     */
     public const DEADLINE_EXCEEDED = 4;
 
-    // NotFound means some requested entity (e.g., file or directory) was
-    // not found.
+    /**
+     * Means some requested entity (e.g., file or directory) was not found.
+     *
+     * @see https://github.com/grpc/grpc-go/blob/v1.35.1/codes/codes.go#L69-L73
+     */
     public const NOT_FOUND = 5;
 
-    // AlreadyExists means an attempt to create an entity failed because one
-    // already exists.
+    /**
+     * Means an attempt to create an entity failed because one already exists.
+     *
+     * @see https://github.com/grpc/grpc-go/blob/v1.35.1/codes/codes.go#L75-L79
+     */
     public const ALREADY_EXISTS = 6;
 
-    // PermissionDenied indicates the caller does not have permission to
-    // execute the specified operation. It must not be used for rejections
-    // caused by exhausting some resource (use ResourceExhausted
-    // instead for those errors). It must not be
-    // used if the caller cannot be identified (use Unauthenticated
-    // instead for those errors).
+    /**
+     * Indicates the caller does not have permission to execute the specified
+     * operation. It must not be used for rejections caused by exhausting some
+     * resource (use {@see RESOURCE_EXHAUSTED} instead for those errors).
+     * It must not be used if the caller cannot be identified
+     * (use {@see UNAUTHENTICATED} instead for those errors).
+     *
+     * @see https://github.com/grpc/grpc-go/blob/v1.35.1/codes/codes.go#L81-L90
+     */
     public const PERMISSION_DENIED = 7;
 
-    // ResourceExhausted indicates some resource has been exhausted, perhaps
-    // a per-user quota, or perhaps the entire file system is out of space.
+    /**
+     * Indicates some resource has been exhausted, perhaps a per-user quota,
+     * or perhaps the entire file system is out of space.
+     *
+     * @see https://github.com/grpc/grpc-go/blob/v1.35.1/codes/codes.go#L92-L98
+     */
     public const RESOURCE_EXHAUSTED = 8;
 
-    // FailedPrecondition indicates operation was rejected because the
-    // system is not in a state required for the operation's execution.
-    // For example, directory to be deleted may be non-empty, an rmdir
-    // operation is applied to a non-directory, etc.
-    //
-    // A litmus test that may help a service implementor in deciding
-    // between FailedPrecondition, Aborted, and Unavailable:
-    //  (a) Use Unavailable if the client can retry just the failing call.
-    //  (b) Use Aborted if the client should retry at a higher-level
-    //      (e.g., restarting a read-modify-write sequence).
-    //  (c) Use FailedPrecondition if the client should not retry until
-    //      the system state has been explicitly fixed. E.g., if an "rmdir"
-    //      fails because the directory is non-empty, FailedPrecondition
-    //      should be returned since the client should not retry unless
-    //      they have first fixed up the directory by deleting files from it.
-    //  (d) Use FailedPrecondition if the client performs conditional
-    //      REST Get/Update/Delete on a resource and the resource on the
-    //      server does not match the condition. E.g., conflicting
-    //      read-modify-write on the same resource.
+    /**
+     * Indicates operation was rejected because the system is not in a state
+     * required for the operation's execution.
+     *
+     * For example, directory to be deleted may be non-empty, an {@see rmdir}
+     * operation is applied to a non-directory, etc.
+     *
+     * A litmus test that may help a service implementor in deciding
+     * between {@see FAILED_PRECONDITION}, {@see ABORTED},
+     * and {@see UNAVAILABLE}:
+     *
+     * - Use {@see UNAVAILABLE} if the client can retry just the failing call.
+     *
+     * - Use {@see ABORTED} if the client should retry at a higher-level
+     *   (e.g., restarting a read-modify-write sequence).
+     *
+     * - Use {@see FAILED_PRECONDITION} if the client should not retry until
+     *   the system state has been explicitly fixed. E.g., if an {@see rmdir}
+     *   fails because the directory is non-empty, {@see FAILED_PRECONDITION}
+     *   should be returned since the client should not retry unless
+     *   they have first fixed up the directory by deleting files from it.
+     *
+     * - Use {@see FAILED_PRECONDITION} if the client performs conditional
+     *   REST GET/UPDATE/DELETE on a resource and the resource on the
+     *   server does not match the condition. E.g., conflicting
+     *   read-modify-write on the same resource.
+     *
+     * This error code will not be generated by the gRPC framework.
+     *
+     * @see https://github.com/grpc/grpc-go/blob/v1.35.1/codes/codes.go#L100-L120
+     */
     public const FAILED_PRECONDITION = 9;
 
-    // Aborted indicates the operation was aborted, typically due to a
-    // concurrency issue like sequencer check failures, transaction aborts,
-    // etc.
-    //
-    // See litmus test above for deciding between FailedPrecondition,
-    // Aborted, and Unavailable.
+    /**
+     * Indicates the operation was aborted, typically due to a concurrency
+     * issue like sequencer check failures, transaction aborts, etc.
+     *
+     * See litmus test above for deciding between:
+     *  - {@see FAILED_PRECONDITION}
+     *  - {@see ABORTED}
+     *  - {@see UNAVAILABLE}
+     *
+     * @see https://github.com/grpc/grpc-go/blob/v1.35.1/codes/codes.go#L123-L131
+     */
     public const ABORTED = 10;
 
-    // OutOfRange means operation was attempted past the valid range.
-    // E.g., seeking or reading past end of file.
-    //
-    // Unlike InvalidArgument, this error indicates a problem that may
-    // be fixed if the system state changes. For example, a 32-bit file
-    // system will generate InvalidArgument if asked to read at an
-    // offset that is not in the range [0,2^32-1], but it will generate
-    // OutOfRange if asked to read from an offset past the current
-    // file size.
-    //
-    // There is a fair bit of overlap between FailedPrecondition and
-    // OutOfRange. We recommend using OutOfRange (the more specific
-    // error) when it applies so that callers who are iterating through
-    // a space can easily look for an OutOfRange error to detect when
-    // they are done.
+    /**
+     * Means operation was attempted past the valid range.
+     *
+     * E.g., seeking or reading past end of file.
+     *
+     * Unlike {@see INVALID_ARGUMENT}, this error indicates a
+     * problem that may be fixed if the system state changes. For example,
+     * a 32-bit file system will generate {@see INVALID_ARGUMENT}
+     * if asked to read at an offset that is not in the range from `0`
+     * to `2 ** 32 - 1`, but it will generate {@see OUT_OF_RANGE}
+     * if asked to read from an offset past the current file size.
+     *
+     * There is a fair bit of overlap between {@see FAILED_PRECONDITION}
+     * and {@see OUT_OF_RANGE}. We recommend using {@see OUT_OF_RANGE}
+     * (the more specific error) when it applies so that callers who are
+     * iterating through a space can easily look for an {@see OUT_OF_RANGE}
+     * error to detect when they are done.
+     *
+     * @see https://github.com/grpc/grpc-go/blob/v1.35.1/codes/codes.go#L133-L150
+     */
     public const OUT_OF_RANGE = 11;
 
-    // Unimplemented indicates operation is not implemented or not
-    // supported/enabled in this service.
+    /**
+     * Indicates operation is not implemented or not supported/enabled in
+     * this service.
+     *
+     * @see https://github.com/grpc/grpc-go/blob/v1.35.1/codes/codes.go#L152-L160
+     */
     public const UNIMPLEMENTED = 12;
 
-    // Internal errors. Means some invariants expected by underlying
-    // system has been broken. If you see one of these errors,
-    // something is very broken.
+    /**
+     * Means some invariants expected by underlying system has been broken.
+     * If you see one of these errors, something is very broken.
+     *
+     * @see https://github.com/grpc/grpc-go/blob/v1.35.1/codes/codes.go#L162-L168
+     */
     public const INTERNAL = 13;
 
-    // Unavailable indicates the service is currently unavailable.
-    // This is a most likely a transient condition and may be corrected
-    // by retrying with a backoff.
-    //
-    // See litmus test above for deciding between FailedPrecondition,
-    // Aborted, and Unavailable.
+    /**
+     * Indicates the service is currently unavailable.
+     *
+     * This is a most likely a transient condition and may be corrected
+     * by retrying with a backoff.
+     *
+     * See litmus test above for deciding between:
+     *  - {@see FAILED_PRECONDITION}
+     *  - {@see ABORTED}
+     *  - {@see UNAVAILABLE}
+     *
+     * @see https://github.com/grpc/grpc-go/blob/v1.35.1/codes/codes.go#L170-L180
+     */
     public const UNAVAILABLE = 14;
 
-    // DataLoss indicates unrecoverable data loss or corruption.
+    /**
+     * Indicates unrecoverable data loss or corruption.
+     *
+     * @see https://github.com/grpc/grpc-go/blob/v1.35.1/codes/codes.go#L182-L185
+     */
     public const DATA_LOSS = 15;
 
-    // Unauthenticated indicates the request does not have valid
-    // authentication credentials for the operation.
+    /**
+     * Indicates the request does not have valid authentication credentials
+     * for the operation.
+     *
+     * @see https://github.com/grpc/grpc-go/blob/v1.35.1/codes/codes.go#L187-L193
+     */
     public const UNAUTHENTICATED = 16;
 }
diff --git a/tests/GRPC/InvokerTest.php b/tests/GRPC/InvokerTest.php
index 249af2f..880e667 100644
--- a/tests/GRPC/InvokerTest.php
+++ b/tests/GRPC/InvokerTest.php
@@ -27,12 +27,7 @@ public function testInvoke(): void
 
         $i = new Invoker();
 
-        $out = $i->invoke(
-            $s,
-            $m,
-            new Context([]),
-            $this->packMessage('hello')
-        );
+        $out = $i->invoke($s, $m, new Context([]), $this->packMessage('hello'));
 
         $m = new Message();
         $m->mergeFromString($out);
@@ -40,22 +35,16 @@ public function testInvoke(): void
         $this->assertSame('hello', $m->getMsg());
     }
 
-    /**
-     * @expectedException \Spiral\GRPC\Exception\InvokeException
-     */
     public function testInvokeError(): void
     {
+        $this->expectException(\Spiral\GRPC\Exception\InvokeException::class);
+
         $s = new TestService();
         $m = Method::parse(new \ReflectionMethod($s, 'Echo'));
 
         $i = new Invoker();
 
-        $i->invoke(
-            $s,
-            $m,
-            new Context([]),
-            'invalid-message'
-        );
+        $i->invoke($s, $m, new Context([]), 'invalid-message');
     }
 
     private function packMessage(string $message): string
diff --git a/tests/GRPC/MethodTest.php b/tests/GRPC/MethodTest.php
index 6a782d4..7491e84 100644
--- a/tests/GRPC/MethodTest.php
+++ b/tests/GRPC/MethodTest.php
@@ -19,11 +19,10 @@
 
 class MethodTest extends TestCase
 {
-    /**
-     * @expectedException \Spiral\GRPC\Exception\GRPCException
-     */
     public function testInvalidParse(): void
     {
+        $this->expectException(\Spiral\GRPC\Exception\GRPCException::class);
+
         Method::parse(new \ReflectionMethod($this, 'testInvalidParse'));
     }
 
diff --git a/tests/GRPC/ServiceWrapperTest.php b/tests/GRPC/ServiceWrapperTest.php
index 5032a51..bae551b 100644
--- a/tests/GRPC/ServiceWrapperTest.php
+++ b/tests/GRPC/ServiceWrapperTest.php
@@ -55,11 +55,10 @@ public function testMethods(): void
         $this->assertCount(5, $w->getMethods());
     }
 
-    /**
-     * @expectedException \Spiral\GRPC\Exception\NotFoundException
-     */
     public function testInvokeNotFound(): void
     {
+        $this->expectException(\Spiral\GRPC\Exception\NotFoundException::class);
+
         $w = new ServiceWrapper(
             new Invoker(),
             TestInterface::class,
@@ -85,11 +84,10 @@ public function testInvoke(): void
         $this->assertSame('hello world', $m->getMsg());
     }
 
-    /**
-     * @expectedException \Spiral\GRPC\Exception\ServiceException
-     */
     public function testNotImplemented(): void
     {
+        $this->expectException(\Spiral\GRPC\Exception\ServiceException::class);
+
         $w = new ServiceWrapper(
             new Invoker(),
             TestInterface::class,
@@ -97,11 +95,10 @@ public function testNotImplemented(): void
         );
     }
 
-    /**
-     * @expectedException \Spiral\GRPC\Exception\ServiceException
-     */
     public function testInvalidInterface(): void
     {
+        $this->expectException(\Spiral\GRPC\Exception\ServiceException::class);
+
         $w = new ServiceWrapper(
             new Invoker(),
             InvalidInterface::class,
@@ -109,11 +106,10 @@ public function testInvalidInterface(): void
         );
     }
 
-    /**
-     * @expectedException \Spiral\GRPC\Exception\ServiceException
-     */
     public function testInvalidInterface2(): void
     {
+        $this->expectException(\Spiral\GRPC\Exception\ServiceException::class);
+
         $w = new ServiceWrapper(
             new Invoker(),
             'NotFound',

From 3ac8f789e3deddcad34ed5e1d804a107ccd6dc1c Mon Sep 17 00:00:00 2001
From: SerafimArts <nesk@xakep.ru>
Date: Thu, 25 Mar 2021 21:34:14 +0300
Subject: [PATCH 10/29] Remove phpunit cache

---
 .gitignore            | 3 ++-
 .phpunit.result.cache | 1 -
 2 files changed, 2 insertions(+), 2 deletions(-)
 delete mode 100644 .phpunit.result.cache

diff --git a/.gitignore b/.gitignore
index 42dc51b..bd558f8 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,4 +6,5 @@ vendor/
 clover.xml
 example/vendor/
 go.sum
-builds/
\ No newline at end of file
+builds/
+.phpunit.result.cache
diff --git a/.phpunit.result.cache b/.phpunit.result.cache
deleted file mode 100644
index c23c558..0000000
--- a/.phpunit.result.cache
+++ /dev/null
@@ -1 +0,0 @@
-C:37:"PHPUnit\Runner\DefaultTestResultCache":2131:{a:2:{s:7:"defects";a:0:{}s:5:"times";a:35:{s:43:"Spiral\GRPC\Tests\ContextTest::testGetValue";d:0.004;s:47:"Spiral\GRPC\Tests\ContextTest::testGetNullValue";d:0;s:44:"Spiral\GRPC\Tests\ContextTest::testGetValues";d:0;s:44:"Spiral\GRPC\Tests\ContextTest::testWithValue";d:0;s:52:"Spiral\GRPC\Tests\ContextTest::testGetOutgoingHeader";d:0;s:53:"Spiral\GRPC\Tests\ContextTest::testGetOutgoingHeaders";d:0;s:44:"Spiral\GRPC\Tests\ExceptionTest::testDefault";d:0.001;s:45:"Spiral\GRPC\Tests\ExceptionTest::testNotFound";d:0;s:43:"Spiral\GRPC\Tests\ExceptionTest::testInvoke";d:0;s:52:"Spiral\GRPC\Tests\ExceptionTest::testUnauthenticated";d:0;s:50:"Spiral\GRPC\Tests\ExceptionTest::testUnimplemented";d:0;s:41:"Spiral\GRPC\Tests\InvokerTest::testInvoke";d:0.014;s:46:"Spiral\GRPC\Tests\InvokerTest::testInvokeError";d:0.001;s:46:"Spiral\GRPC\Tests\MethodTest::testInvalidParse";d:0;s:39:"Spiral\GRPC\Tests\MethodTest::testMatch";d:0;s:41:"Spiral\GRPC\Tests\MethodTest::testNoMatch";d:0;s:42:"Spiral\GRPC\Tests\MethodTest::testNoMatch2";d:0;s:42:"Spiral\GRPC\Tests\MethodTest::testNoMatch3";d:0;s:42:"Spiral\GRPC\Tests\MethodTest::testNoMatch4";d:0;s:42:"Spiral\GRPC\Tests\MethodTest::testNoMatch5";d:0;s:44:"Spiral\GRPC\Tests\MethodTest::testMethodName";d:0;s:49:"Spiral\GRPC\Tests\MethodTest::testMethodInputType";d:0;s:50:"Spiral\GRPC\Tests\MethodTest::testMethodOutputType";d:0;s:40:"Spiral\GRPC\Tests\ServerTest::testInvoke";d:0.003;s:42:"Spiral\GRPC\Tests\ServerTest::testNotFound";d:0;s:43:"Spiral\GRPC\Tests\ServerTest::testNotFound2";d:0;s:59:"Spiral\GRPC\Tests\ServerTest::testServerDebugModeNotEnabled";d:0;s:46:"Spiral\GRPC\Tests\ServiceWrapperTest::testName";d:0;s:49:"Spiral\GRPC\Tests\ServiceWrapperTest::testService";d:0;s:49:"Spiral\GRPC\Tests\ServiceWrapperTest::testMethods";d:0;s:56:"Spiral\GRPC\Tests\ServiceWrapperTest::testInvokeNotFound";d:0;s:48:"Spiral\GRPC\Tests\ServiceWrapperTest::testInvoke";d:0;s:56:"Spiral\GRPC\Tests\ServiceWrapperTest::testNotImplemented";d:0;s:58:"Spiral\GRPC\Tests\ServiceWrapperTest::testInvalidInterface";d:0;s:59:"Spiral\GRPC\Tests\ServiceWrapperTest::testInvalidInterface2";d:0;}}}
\ No newline at end of file

From 96ce30fc27b8fc5fa8978b64f5b6603293fc8274 Mon Sep 17 00:00:00 2001
From: SerafimArts <nesk@xakep.ru>
Date: Thu, 25 Mar 2021 21:41:45 +0300
Subject: [PATCH 11/29] Implement "Context::offsetSet" method

---
 src/Context.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Context.php b/src/Context.php
index 07d876f..3c9dab7 100644
--- a/src/Context.php
+++ b/src/Context.php
@@ -91,7 +91,7 @@ public function offsetSet($offset, $value): void
     {
         assert(\is_string($offset), 'Offset argument must be a type of string');
 
-        throw new \LogicException(__METHOD__ . ' not implemented yet');
+        $this->values[$offset] = $value;
     }
 
     /**

From 02b2e56e48c8496eb72fcff1de2610bb6f3c399c Mon Sep 17 00:00:00 2001
From: SerafimArts <nesk@xakep.ru>
Date: Tue, 30 Mar 2021 21:40:52 +0300
Subject: [PATCH 12/29] Improve Server code

---
 src/Internal/Json.php   |  77 +++++++++++++++++++++
 src/ResponseHeaders.php |  26 +-------
 src/Server.php          | 144 +++++++++++++++++++++++-----------------
 3 files changed, 162 insertions(+), 85 deletions(-)
 create mode 100644 src/Internal/Json.php

diff --git a/src/Internal/Json.php b/src/Internal/Json.php
new file mode 100644
index 0000000..8727b5a
--- /dev/null
+++ b/src/Internal/Json.php
@@ -0,0 +1,77 @@
+<?php
+
+/**
+ * This file is part of RoadRunner GRPC package.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace Spiral\GRPC\Internal;
+
+/**
+ * @internal Json is an internal library class, please do not use it in your code.
+ * @psalm-internal Spiral\GRPC
+ */
+final class Json
+{
+    /**
+     * @var positive-int
+     */
+    public const DEFAULT_JSON_DEPTH = 512;
+
+    /**
+     * @return positive-int|0
+     */
+    private static function getFlags(): int
+    {
+        return \defined('\\JSON_THROW_ON_ERROR')
+            // Avoid PHP DCE constant inlining
+            ? \constant('\\JSON_THROW_ON_ERROR')
+            : 0;
+    }
+
+    /**
+     * @param mixed $payload
+     * @return string
+     * @throws \JsonException
+     */
+    public static function encode($payload): string
+    {
+        /** @var string $result */
+        $result = @\json_encode($payload, self::getFlags(), self::DEFAULT_JSON_DEPTH);
+
+        self::assertJsonErrors();
+
+        return $result;
+    }
+
+    /**
+     * @param string $payload
+     * @return array
+     * @throws \JsonException
+     */
+    public static function decode(string $payload): array
+    {
+        /** @var array $result */
+        $result = @\json_decode($payload, true, self::DEFAULT_JSON_DEPTH, self::getFlags());
+
+        self::assertJsonErrors();
+
+        return $result;
+    }
+
+    /**
+     * @throws \JsonException
+     */
+    private static function assertJsonErrors(): void
+    {
+        $code = \json_last_error();
+
+        if ($code !== \JSON_ERROR_NONE) {
+            throw new \JsonException(\json_last_error_msg(), $code);
+        }
+    }
+}
diff --git a/src/ResponseHeaders.php b/src/ResponseHeaders.php
index a15cb94..c1ee345 100644
--- a/src/ResponseHeaders.php
+++ b/src/ResponseHeaders.php
@@ -11,6 +11,8 @@
 
 namespace Spiral\GRPC;
 
+use Spiral\GRPC\Internal\Json;
+
 /**
  * @template-implements \IteratorAggregate<string, string>
  */
@@ -78,28 +80,6 @@ public function packHeaders(): string
             return '{}';
         }
 
-        $flags = \defined('\\JSON_THROW_ON_ERROR')
-            // Avoid PHP DCE constant inlining
-            ? \constant('\\JSON_THROW_ON_ERROR')
-            : 0;
-
-        return $this->toJsonString($this->headers, $flags);
-    }
-
-    /**
-     * @param array $payload
-     * @param int $flags
-     * @return string
-     * @throws \JsonException
-     */
-    private function toJsonString(array $payload, int $flags = 0): string
-    {
-        $result = @\json_encode($payload, $flags);
-
-        if (($code = \json_last_error()) !== \JSON_ERROR_NONE) {
-            throw new \JsonException(\json_last_error_msg(), $code);
-        }
-
-        return $result;
+        return Json::encode($this->headers);
     }
 }
diff --git a/src/Server.php b/src/Server.php
index f2265e8..f01689b 100644
--- a/src/Server.php
+++ b/src/Server.php
@@ -13,33 +13,53 @@
 
 use Google\Protobuf\Any;
 use Google\Protobuf\Internal\Message;
+use JetBrains\PhpStorm\ArrayShape;
 use Spiral\GRPC\Exception\GRPCException;
 use Spiral\GRPC\Exception\NotFoundException;
 use Spiral\GRPC\Exception\ServiceException;
+use Spiral\GRPC\Internal\Json;
 use Spiral\RoadRunner\Worker;
 
 /**
  * Manages group of services and communication with RoadRunner server.
+ *
+ * @psalm-type ServerOptions = array {
+ *  debug?: bool
+ * }
+ *
+ * @psalm-type ContextResponse = array {
+ *  service: string,
+ *  method:  string,
+ *  context: array<string, array<string>>
+ * }
  */
 final class Server
 {
-    /** @var InvokerInterface */
+    /**
+     * @var InvokerInterface
+     */
     private $invoker;
 
-    /** @var ServiceWrapper[] */
+    /**
+     * @var ServiceWrapper[]
+     */
     private $services = [];
 
     /**
-     * @var array
+     * @var ServerOptions
      */
+    #[ArrayShape(['debug' => 'bool'])]
     private $options;
 
     /**
      * @param InvokerInterface|null $invoker
-     * @param array $options
+     * @param ServerOptions $options
      */
-    public function __construct(InvokerInterface $invoker = null, array $options = [])
-    {
+    public function __construct(
+        InvokerInterface $invoker = null,
+        #[ArrayShape(['debug' => 'bool'])]
+        array $options = []
+    ) {
         $this->invoker = $invoker ?? new Invoker();
         $this->options = $options;
     }
@@ -47,63 +67,72 @@ public function __construct(InvokerInterface $invoker = null, array $options = [
     /**
      * Register new GRPC service.
      *
-     * Example: $server->registerService(EchoServiceInterface::class, new EchoService());
+     * For example:
+     * <code>
+     *  $server->registerService(EchoServiceInterface::class, new EchoService());
+     * </code>
      *
-     * @param string           $interface Generated service interface.
+     * @param string $interface Generated service interface.
      * @param ServiceInterface $service Must implement interface.
-     *
      * @throws ServiceException
      */
     public function registerService(string $interface, ServiceInterface $service): void
     {
         $service = new ServiceWrapper($this->invoker, $interface, $service);
+
         $this->services[$service->getName()] = $service;
     }
 
+    /**
+     * @param string $body
+     * @param ContextResponse $data
+     * @return array{ 0: string, 1: string }
+     * @throws \JsonException
+     * @throws \Throwable
+     */
+    private function tick(string $body, array $data): array
+    {
+        $context = (new Context($data['context']))
+            ->withValue(ResponseHeaders::class, new ResponseHeaders())
+        ;
+
+        $response = $this->invoke($data['service'], $data['method'], $context, $body);
+
+        /** @var ResponseHeaders|null $responseHeaders */
+        $responseHeaders = $context->getValue(ResponseHeaders::class);
+        $responseHeadersString = $responseHeaders ? $responseHeaders->packHeaders() : '{}';
+
+        return [$response, $responseHeadersString];
+    }
+
     /**
      * Serve GRPC over given RoadRunner worker.
      *
-     * @param Worker        $worker
+     * @param Worker $worker
      * @param callable|null $finalize
      */
     public function serve(Worker $worker, callable $finalize = null): void
     {
-        while (true) {
+        try {
             $body = $worker->receive($ctx);
-            if (empty($body) && empty($ctx)) {
+
+            if (!$body && !$ctx) {
                 return;
             }
 
-            try {
-                $ctx = json_decode($ctx, true);
-                $grpcCtx = new Context(
-                    $ctx['context'] + [ResponseHeaders::class => new ResponseHeaders([])]
-                );
-
-                $resp = $this->invoke(
-                    $ctx['service'],
-                    $ctx['method'],
-                    $grpcCtx,
-                    $body
-                );
-
-                /** @var ResponseHeaders|null $responseHeaders */
-                $responseHeaders = $grpcCtx->getValue(ResponseHeaders::class);
-                $worker->send($resp, $responseHeaders ? $responseHeaders->packHeaders() : '{}');
-            } catch (GRPCException $e) {
-                $worker->error($this->packError($e));
-            } catch (\Throwable $e) {
-                if ($this->isDebugMode()) {
-                    $errorText = $e->__toString();
-                } else {
-                    $errorText = $e->getMessage();
-                }
-
-                $worker->error($errorText);
-            } finally {
-                if ($finalize !== null) {
-                    call_user_func($finalize, $e ?? null);
-                }
+            /** @var ContextResponse $context */
+            $context = Json::decode((string)$ctx);
+
+            [$answerBody, $answerHeaders] = $this->tick((string)$body, $context);
+
+            $worker->send($answerBody, $answerHeaders);
+        } catch (GRPCException $e) {
+            $worker->error($this->packError($e));
+        } catch (\Throwable $e) {
+            $worker->error($this->isDebugMode() ? (string)$e : $e->getMessage());
+        } finally {
+            if ($finalize !== null) {
+                isset($e) ? $finalize($e) : $finalize();
             }
         }
     }
@@ -111,22 +140,16 @@ public function serve(Worker $worker, callable $finalize = null): void
     /**
      * Invoke service method with binary payload and return the response.
      *
-     * @param string  $service
-     * @param string  $method
-     * @param Context $context
-     * @param string|null  $body
+     * @param string $service
+     * @param string $method
+     * @param ContextInterface $context
+     * @param string $body
      * @return string
-     *
      * @throws GRPCException
-     * @throws \Throwable
      */
-    protected function invoke(
-        string $service,
-        string $method,
-        Context $context,
-        ?string $body
-    ): string {
-        if (!isset($this->services[$service])) {
+    protected function invoke(string $service, string $method, ContextInterface $context, string $body): string
+    {
+        if (! isset($this->services[$service])) {
             throw NotFoundException::create("Service `{$service}` not found.", StatusCode::NOT_FOUND);
         }
 
@@ -138,8 +161,8 @@ protected function invoke(
      *
      * Internal agreement:
      *
-     * Details will be sent as serialized google.protobuf.Any messages after code and exception message
-     * separated with |:| delimeter.
+     * Details will be sent as serialized google.protobuf.Any messages after
+     * code and exception message separated with |:| delimiter.
      *
      * @param GRPCException $e
      * @return string
@@ -149,9 +172,6 @@ private function packError(GRPCException $e): string
         $data = [$e->getCode(), $e->getMessage()];
 
         foreach ($e->getDetails() as $detail) {
-            /**
-             * @var Message $detail
-             */
             $anyMessage = new Any();
 
             $anyMessage->pack($detail);
@@ -159,7 +179,7 @@ private function packError(GRPCException $e): string
             $data[] = $anyMessage->serializeToString();
         }
 
-        return implode('|:|', $data);
+        return \implode('|:|', $data);
     }
 
     /**
@@ -172,7 +192,7 @@ private function isDebugMode(): bool
         $debug = false;
 
         if (isset($this->options['debug'])) {
-            $debug = filter_var($this->options['debug'], FILTER_VALIDATE_BOOLEAN);
+            $debug = \filter_var($this->options['debug'], \FILTER_VALIDATE_BOOLEAN);
         }
 
         return $debug;

From 7bffa8ea4b08ed8b5e04c63a12486a17a426a0c4 Mon Sep 17 00:00:00 2001
From: SerafimArts <nesk@xakep.ru>
Date: Tue, 30 Mar 2021 21:54:07 +0300
Subject: [PATCH 13/29] Add base support of RoadRunner 2.x

---
 src/Server.php | 53 ++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 47 insertions(+), 6 deletions(-)

diff --git a/src/Server.php b/src/Server.php
index f01689b..cd7d7ad 100644
--- a/src/Server.php
+++ b/src/Server.php
@@ -18,6 +18,7 @@
 use Spiral\GRPC\Exception\NotFoundException;
 use Spiral\GRPC\Exception\ServiceException;
 use Spiral\GRPC\Internal\Json;
+use Spiral\RoadRunner\Payload;
 use Spiral\RoadRunner\Worker;
 
 /**
@@ -105,6 +106,44 @@ private function tick(string $body, array $data): array
         return [$response, $responseHeadersString];
     }
 
+    /**
+     * @param Worker $worker
+     * @param string $body
+     * @param string $headers
+     */
+    private function workerSend(Worker $worker, string $body, string $headers): void
+    {
+        // RoadRunner 1.x
+        if (\method_exists($worker, 'send')) {
+            $worker->send($body, $headers);
+
+            return;
+        }
+
+        // RoadRunner 2.x
+        $worker->respond(new Payload($body, $headers));
+    }
+
+    /**
+     * @param Worker $worker
+     * @param string $message
+     */
+    private function workerError(Worker $worker, string $message): void
+    {
+        $worker->error($message);
+    }
+
+    /**
+     * @param Worker $worker
+     * @return array { 0: string, 1: string } | null
+     */
+    private function workerReceive(Worker $worker): ?array
+    {
+        $body = $worker->receive($ctx);
+
+        return [(string)$body, (string)$ctx];
+    }
+
     /**
      * Serve GRPC over given RoadRunner worker.
      *
@@ -114,22 +153,24 @@ private function tick(string $body, array $data): array
     public function serve(Worker $worker, callable $finalize = null): void
     {
         try {
-            $body = $worker->receive($ctx);
+            $request = $this->workerReceive($worker);
 
-            if (!$body && !$ctx) {
+            if (! $request) {
                 return;
             }
 
+            [$body, $headers] = $request;
+
             /** @var ContextResponse $context */
-            $context = Json::decode((string)$ctx);
+            $context = Json::decode((string)$headers);
 
             [$answerBody, $answerHeaders] = $this->tick((string)$body, $context);
 
-            $worker->send($answerBody, $answerHeaders);
+            $this->workerSend($worker, $answerBody, $answerHeaders);
         } catch (GRPCException $e) {
-            $worker->error($this->packError($e));
+            $this->workerError($worker, $this->packError($e));
         } catch (\Throwable $e) {
-            $worker->error($this->isDebugMode() ? (string)$e : $e->getMessage());
+            $this->workerError($worker, $this->isDebugMode() ? (string)$e : $e->getMessage());
         } finally {
             if ($finalize !== null) {
                 isset($e) ? $finalize($e) : $finalize();

From 3617397fbd1ada4e97236a91c7f99d3b36affa14 Mon Sep 17 00:00:00 2001
From: SerafimArts <nesk@xakep.ru>
Date: Tue, 30 Mar 2021 21:54:45 +0300
Subject: [PATCH 14/29] Improve example worker code

---
 example/server/worker.php | 27 ++++++++++++++++++---------
 1 file changed, 18 insertions(+), 9 deletions(-)

diff --git a/example/server/worker.php b/example/server/worker.php
index b089ed5..683a234 100644
--- a/example/server/worker.php
+++ b/example/server/worker.php
@@ -3,15 +3,24 @@
  * Sample GRPC PHP server.
  */
 
-use Spiral\Goridge;
-use Spiral\RoadRunner;
+use Service\EchoInterface;
+use Spiral\Goridge\StreamRelay;
+use Spiral\GRPC\Server;
+use Spiral\RoadRunner\Worker;
 
-ini_set('display_errors', 'stderr');
-require "vendor/autoload.php";
+require __DIR__ . '/vendor/autoload.php';
 
-//To run server in debug mode - new \Spiral\GRPC\Server(null, ['debug' => true]);
-$server = new \Spiral\GRPC\Server();
-$server->registerService(\Service\EchoInterface::class, new EchoService());
+$server = new Server(null, [
+    'debug' => false, // optional (default: false)
+]);
 
-$w = new RoadRunner\Worker(new Goridge\StreamRelay(STDIN, STDOUT));
-$server->serve($w);
\ No newline at end of file
+$server->registerService(EchoInterface::class, new EchoService());
+
+$worker = \method_exists(Worker::class, 'create')
+    // RoadRunner >= 2.x
+    ? Worker::create()
+    // RoadRunner 1.x
+    : new Worker(new StreamRelay(STDIN, STDOUT))
+;
+
+$server->serve($worker);

From 67578c87011d74925dcf16c5a59de45c35b0e19b Mon Sep 17 00:00:00 2001
From: SerafimArts <nesk@xakep.ru>
Date: Tue, 30 Mar 2021 21:55:02 +0300
Subject: [PATCH 15/29] Improve example composer

---
 example/server/composer.json | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/example/server/composer.json b/example/server/composer.json
index bdcd633..b630329 100644
--- a/example/server/composer.json
+++ b/example/server/composer.json
@@ -1,12 +1,23 @@
 {
     "name": "app/example-grpc-server",
     "description": "Example GRPC Server",
+    "repositories": [
+        {
+            "type": "path",
+            "url": "../.."
+        }
+    ],
     "require": {
-        "spiral/php-grpc": "^1.0"
+        "spiral/php-grpc": "*"
+    },
+    "require-dev": {
+        "grpc/grpc": "^1.36"
     },
     "autoload": {
         "psr-4": {
             "": "src"
         }
-    }
+    },
+    "minimum-stability": "dev",
+    "prefer-stable": true
 }

From 23f74d40b200b5ce1f8b16e25bc6d1971aecc61f Mon Sep 17 00:00:00 2001
From: SerafimArts <nesk@xakep.ru>
Date: Tue, 30 Mar 2021 22:00:21 +0300
Subject: [PATCH 16/29] Rollback test paths

---
 phpunit.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/phpunit.xml b/phpunit.xml
index fbd70dd..384daa4 100644
--- a/phpunit.xml
+++ b/phpunit.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<phpunit bootstrap="vendor/autoload.php"
+<phpunit bootstrap="tests/bootstrap.php"
          backupGlobals="false"
          backupStaticAttributes="false"
          colors="true"

From dc5c51b464aa6272f8ae706c264d17c8dc8e1e19 Mon Sep 17 00:00:00 2001
From: SerafimArts <nesk@xakep.ru>
Date: Tue, 30 Mar 2021 22:06:13 +0300
Subject: [PATCH 17/29] Add php 8.0 CI tests and increase phpunit version

---
 .travis.yml | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/.travis.yml b/.travis.yml
index d948824..d89e169 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -22,7 +22,7 @@ script:
   - go test -race -v -coverprofile=grpc.txt -covermode=atomic
   - go test ./parser -race -v -coverprofile=parser.txt -covermode=atomic
   - go test -race -v -coverprofile=protoc-gen-php-grpc.txt ./cmd/protoc-gen-php-grpc -covermode=atomic
-  - composer require phpunit/phpunit:~7.0 --ignore-platform-reqs
+  - composer require phpunit/phpunit:^8.5 --ignore-platform-reqs
   - vendor/bin/spiral-cs check src tests/GRPC
   - vendor/bin/phpunit --coverage-clover=coverage.xml
   - go build cmd/protoc-gen-php-grpc/main.go
@@ -62,3 +62,12 @@ jobs:
       - sudo cp `which php7.4` `which php`
       - php -v
       - composer self-update
+  - stage: Test
+    env: "PHP=8.0"
+    before_install:
+      - sudo add-apt-repository -y ppa:ondrej/php
+      - sudo apt-get update
+      - sudo apt-get install -y php8.0-cli php8.0-xml php8.0-xdebug
+      - sudo cp `which php8.0` `which php`
+      - php -v
+      - composer self-update

From 4d68ca7022f30f8cd60a352d62d6127e5cf6cbbb Mon Sep 17 00:00:00 2001
From: SerafimArts <nesk@xakep.ru>
Date: Tue, 30 Mar 2021 22:51:34 +0300
Subject: [PATCH 18/29] Remove phpunit CI installation

---
 .travis.yml | 1 -
 1 file changed, 1 deletion(-)

diff --git a/.travis.yml b/.travis.yml
index d89e169..da5e25b 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -22,7 +22,6 @@ script:
   - go test -race -v -coverprofile=grpc.txt -covermode=atomic
   - go test ./parser -race -v -coverprofile=parser.txt -covermode=atomic
   - go test -race -v -coverprofile=protoc-gen-php-grpc.txt ./cmd/protoc-gen-php-grpc -covermode=atomic
-  - composer require phpunit/phpunit:^8.5 --ignore-platform-reqs
   - vendor/bin/spiral-cs check src tests/GRPC
   - vendor/bin/phpunit --coverage-clover=coverage.xml
   - go build cmd/protoc-gen-php-grpc/main.go

From 98c420cee7b8b277e1ffd2fff7a178ff2c1829f8 Mon Sep 17 00:00:00 2001
From: SerafimArts <nesk@xakep.ru>
Date: Tue, 30 Mar 2021 22:52:59 +0300
Subject: [PATCH 19/29] Fix test worker autoload file

---
 tests/worker.php | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tests/worker.php b/tests/worker.php
index e8210bb..7a80416 100644
--- a/tests/worker.php
+++ b/tests/worker.php
@@ -7,10 +7,10 @@
 use Spiral\RoadRunner;
 
 ini_set('display_errors', 'stderr');
-require "vendor/autoload.php";
+require __DIR__ . '/../vendor/autoload.php';
 
 $server = new \Spiral\GRPC\Server();
 $server->registerService(\Service\TestInterface::class, new \Test\TestService());
 
 $w = new RoadRunner\Worker(new Goridge\StreamRelay(STDIN, STDOUT));
-$server->serve($w);
\ No newline at end of file
+$server->serve($w);

From af70c7465ebdfd910c8a2a53cb3b28aed6d1ddb0 Mon Sep 17 00:00:00 2001
From: SerafimArts <nesk@xakep.ru>
Date: Wed, 31 Mar 2021 13:55:27 +0300
Subject: [PATCH 20/29] Fix server logic

---
 src/Server.php | 50 ++++++++++++++++++++++++++++----------------------
 1 file changed, 28 insertions(+), 22 deletions(-)

diff --git a/src/Server.php b/src/Server.php
index cd7d7ad..a36cedc 100644
--- a/src/Server.php
+++ b/src/Server.php
@@ -141,6 +141,10 @@ private function workerReceive(Worker $worker): ?array
     {
         $body = $worker->receive($ctx);
 
+        if (empty($body) && empty($ctx)) {
+            return null;
+        }
+
         return [(string)$body, (string)$ctx];
     }
 
@@ -152,28 +156,30 @@ private function workerReceive(Worker $worker): ?array
      */
     public function serve(Worker $worker, callable $finalize = null): void
     {
-        try {
-            $request = $this->workerReceive($worker);
-
-            if (! $request) {
-                return;
-            }
-
-            [$body, $headers] = $request;
-
-            /** @var ContextResponse $context */
-            $context = Json::decode((string)$headers);
-
-            [$answerBody, $answerHeaders] = $this->tick((string)$body, $context);
-
-            $this->workerSend($worker, $answerBody, $answerHeaders);
-        } catch (GRPCException $e) {
-            $this->workerError($worker, $this->packError($e));
-        } catch (\Throwable $e) {
-            $this->workerError($worker, $this->isDebugMode() ? (string)$e : $e->getMessage());
-        } finally {
-            if ($finalize !== null) {
-                isset($e) ? $finalize($e) : $finalize();
+        while (true) {
+            try {
+                $request = $this->workerReceive($worker);
+
+                if (! $request) {
+                    return;
+                }
+
+                [$body, $headers] = $request;
+
+                /** @var ContextResponse $context */
+                $context = Json::decode((string)$headers);
+
+                [$answerBody, $answerHeaders] = $this->tick((string)$body, $context);
+
+                $this->workerSend($worker, $answerBody, $answerHeaders);
+            } catch (GRPCException $e) {
+                $this->workerError($worker, $this->packError($e));
+            } catch (\Throwable $e) {
+                $this->workerError($worker, $this->isDebugMode() ? (string)$e : $e->getMessage());
+            } finally {
+                if ($finalize !== null) {
+                    isset($e) ? $finalize($e) : $finalize();
+                }
             }
         }
     }

From aca633625fa30d191a830a6fe398baf9d753c491 Mon Sep 17 00:00:00 2001
From: SerafimArts <nesk@xakep.ru>
Date: Wed, 31 Mar 2021 14:16:07 +0300
Subject: [PATCH 21/29] Extract some server logic from try/catch

---
 src/Server.php | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/Server.php b/src/Server.php
index a36cedc..953566c 100644
--- a/src/Server.php
+++ b/src/Server.php
@@ -157,15 +157,15 @@ private function workerReceive(Worker $worker): ?array
     public function serve(Worker $worker, callable $finalize = null): void
     {
         while (true) {
-            try {
-                $request = $this->workerReceive($worker);
+            $request = $this->workerReceive($worker);
 
-                if (! $request) {
-                    return;
-                }
+            if (! $request) {
+                return;
+            }
 
-                [$body, $headers] = $request;
+            [$body, $headers] = $request;
 
+            try {
                 /** @var ContextResponse $context */
                 $context = Json::decode((string)$headers);
 

From 1aa9f96180164d9747cff87e257785d610d876ea Mon Sep 17 00:00:00 2001
From: SerafimArts <nesk@xakep.ru>
Date: Wed, 31 Mar 2021 14:36:51 +0300
Subject: [PATCH 22/29] Fix invoker exceptions wrapping

---
 src/Invoker.php | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/Invoker.php b/src/Invoker.php
index 2a80423..161310b 100644
--- a/src/Invoker.php
+++ b/src/Invoker.php
@@ -39,14 +39,14 @@ public function invoke(ServiceInterface $service, Method $method, ContextInterfa
         /** @var callable $callable */
         $callable = [$service, $method->getName()];
 
-        try {
-            /** @var Message $message */
-            $message = $callable($ctx, $this->makeInput($method, $input));
+        /** @var Message $message */
+        $message = $callable($ctx, $this->makeInput($method, $input));
 
-            // Note: This validation will only work if the
-            // assertions option ("zend.assertions") is enabled.
-            assert($this->assertResultType($method, $message));
+        // Note: This validation will only work if the
+        // assertions option ("zend.assertions") is enabled.
+        assert($this->assertResultType($method, $message));
 
+        try {
             return $message->serializeToString();
         } catch (\Throwable $e) {
             throw InvokeException::create($e->getMessage(), StatusCode::INTERNAL, $e);

From faca40e20722e8c891081d4359dd26c176e44d33 Mon Sep 17 00:00:00 2001
From: SerafimArts <nesk@xakep.ru>
Date: Wed, 31 Mar 2021 14:39:29 +0300
Subject: [PATCH 23/29] Improve exception handling

---
 src/Invoker.php | 15 +++++++++------
 src/Server.php  |  7 ++++---
 2 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/src/Invoker.php b/src/Invoker.php
index 161310b..7f00cb3 100644
--- a/src/Invoker.php
+++ b/src/Invoker.php
@@ -12,6 +12,7 @@
 namespace Spiral\GRPC;
 
 use Google\Protobuf\Internal\Message;
+use Spiral\GRPC\Exception\GRPCExceptionInterface;
 use Spiral\GRPC\Exception\InvokeException;
 
 final class Invoker implements InvokerInterface
@@ -39,15 +40,17 @@ public function invoke(ServiceInterface $service, Method $method, ContextInterfa
         /** @var callable $callable */
         $callable = [$service, $method->getName()];
 
-        /** @var Message $message */
-        $message = $callable($ctx, $this->makeInput($method, $input));
+        try {
+            /** @var Message $message */
+            $message = $callable($ctx, $this->makeInput($method, $input));
 
-        // Note: This validation will only work if the
-        // assertions option ("zend.assertions") is enabled.
-        assert($this->assertResultType($method, $message));
+            // Note: This validation will only work if the
+            // assertions option ("zend.assertions") is enabled.
+            assert($this->assertResultType($method, $message));
 
-        try {
             return $message->serializeToString();
+        } catch (GRPCExceptionInterface $e) {
+            throw $e;
         } catch (\Throwable $e) {
             throw InvokeException::create($e->getMessage(), StatusCode::INTERNAL, $e);
         }
diff --git a/src/Server.php b/src/Server.php
index 953566c..138d36a 100644
--- a/src/Server.php
+++ b/src/Server.php
@@ -15,6 +15,7 @@
 use Google\Protobuf\Internal\Message;
 use JetBrains\PhpStorm\ArrayShape;
 use Spiral\GRPC\Exception\GRPCException;
+use Spiral\GRPC\Exception\GRPCExceptionInterface;
 use Spiral\GRPC\Exception\NotFoundException;
 use Spiral\GRPC\Exception\ServiceException;
 use Spiral\GRPC\Internal\Json;
@@ -172,7 +173,7 @@ public function serve(Worker $worker, callable $finalize = null): void
                 [$answerBody, $answerHeaders] = $this->tick((string)$body, $context);
 
                 $this->workerSend($worker, $answerBody, $answerHeaders);
-            } catch (GRPCException $e) {
+            } catch (GRPCExceptionInterface $e) {
                 $this->workerError($worker, $this->packError($e));
             } catch (\Throwable $e) {
                 $this->workerError($worker, $this->isDebugMode() ? (string)$e : $e->getMessage());
@@ -211,10 +212,10 @@ protected function invoke(string $service, string $method, ContextInterface $con
      * Details will be sent as serialized google.protobuf.Any messages after
      * code and exception message separated with |:| delimiter.
      *
-     * @param GRPCException $e
+     * @param GRPCExceptionInterface $e
      * @return string
      */
-    private function packError(GRPCException $e): string
+    private function packError(GRPCExceptionInterface $e): string
     {
         $data = [$e->getCode(), $e->getMessage()];
 

From 781d3b16914361495e5626fd3d0c54335f49cb40 Mon Sep 17 00:00:00 2001
From: SerafimArts <nesk@xakep.ru>
Date: Wed, 31 Mar 2021 14:57:14 +0300
Subject: [PATCH 24/29] Remove JB attributes (phpcs bug)

---
 src/Server.php | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/src/Server.php b/src/Server.php
index 138d36a..79070ee 100644
--- a/src/Server.php
+++ b/src/Server.php
@@ -12,8 +12,6 @@
 namespace Spiral\GRPC;
 
 use Google\Protobuf\Any;
-use Google\Protobuf\Internal\Message;
-use JetBrains\PhpStorm\ArrayShape;
 use Spiral\GRPC\Exception\GRPCException;
 use Spiral\GRPC\Exception\GRPCExceptionInterface;
 use Spiral\GRPC\Exception\NotFoundException;
@@ -50,18 +48,14 @@ final class Server
     /**
      * @var ServerOptions
      */
-    #[ArrayShape(['debug' => 'bool'])]
     private $options;
 
     /**
      * @param InvokerInterface|null $invoker
      * @param ServerOptions $options
      */
-    public function __construct(
-        InvokerInterface $invoker = null,
-        #[ArrayShape(['debug' => 'bool'])]
-        array $options = []
-    ) {
+    public function __construct(InvokerInterface $invoker = null, array $options = [])
+    {
         $this->invoker = $invoker ?? new Invoker();
         $this->options = $options;
     }

From fdd9e82dddfed9c3addbddf6f2f875f8074942ec Mon Sep 17 00:00:00 2001
From: SerafimArts <nesk@xakep.ru>
Date: Wed, 31 Mar 2021 14:58:40 +0300
Subject: [PATCH 25/29] Fix unit tests

---
 src/Invoker.php | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/src/Invoker.php b/src/Invoker.php
index 7f00cb3..c4ca1ee 100644
--- a/src/Invoker.php
+++ b/src/Invoker.php
@@ -40,17 +40,15 @@ public function invoke(ServiceInterface $service, Method $method, ContextInterfa
         /** @var callable $callable */
         $callable = [$service, $method->getName()];
 
-        try {
-            /** @var Message $message */
-            $message = $callable($ctx, $this->makeInput($method, $input));
+        /** @var Message $message */
+        $message = $callable($ctx, $this->makeInput($method, $input));
 
-            // Note: This validation will only work if the
-            // assertions option ("zend.assertions") is enabled.
-            assert($this->assertResultType($method, $message));
+        // Note: This validation will only work if the
+        // assertions option ("zend.assertions") is enabled.
+        assert($this->assertResultType($method, $message));
 
+        try {
             return $message->serializeToString();
-        } catch (GRPCExceptionInterface $e) {
-            throw $e;
         } catch (\Throwable $e) {
             throw InvokeException::create($e->getMessage(), StatusCode::INTERNAL, $e);
         }

From 7d56393f60c0a90c1fb5ffde26dce389c64731a6 Mon Sep 17 00:00:00 2001
From: SerafimArts <nesk@xakep.ru>
Date: Wed, 31 Mar 2021 15:10:15 +0300
Subject: [PATCH 26/29] AFix psalm errors and improve types

---
 psalm.xml                                |  1 +
 src/Exception/GRPCExceptionInterface.php |  1 +
 src/Invoker.php                          |  3 +-
 src/Method.php                           |  2 ++
 src/Server.php                           | 11 ++++++--
 src/ServiceWrapper.php                   | 35 ++++++++++++------------
 6 files changed, 32 insertions(+), 21 deletions(-)

diff --git a/psalm.xml b/psalm.xml
index 0218777..9cb3de6 100644
--- a/psalm.xml
+++ b/psalm.xml
@@ -16,6 +16,7 @@
     <issueHandlers>
         <RedundantConditionGivenDocblockType errorLevel="suppress" />
         <MixedReturnStatement errorLevel="suppress" />
+        <UnusedPsalmSuppress errorLevel="suppress" />
     </issueHandlers>
     <projectFiles>
         <directory name="src" />
diff --git a/src/Exception/GRPCExceptionInterface.php b/src/Exception/GRPCExceptionInterface.php
index df9cba8..75c1894 100644
--- a/src/Exception/GRPCExceptionInterface.php
+++ b/src/Exception/GRPCExceptionInterface.php
@@ -23,6 +23,7 @@ interface GRPCExceptionInterface extends \Throwable
     /**
      * Returns GRPC exception status code.
      *
+     * @psalm-suppress MissingImmutableAnnotation
      * @psalm-return StatusCodeType
      * @return int
      */
diff --git a/src/Invoker.php b/src/Invoker.php
index c4ca1ee..706ded5 100644
--- a/src/Invoker.php
+++ b/src/Invoker.php
@@ -81,7 +81,6 @@ private function assertResultType(Method $method, $result): bool
      * @param string|null $body
      * @return Message
      * @throws InvokeException
-     * @psalm-suppress InvalidStringClass
      */
     private function makeInput(Method $method, ?string $body): Message
     {
@@ -92,7 +91,7 @@ private function makeInput(Method $method, ?string $body): Message
             // assertions option ("zend.assertions") is enabled.
             assert($this->assertInputType($method, $class));
 
-            /** @var Message $in */
+            /** @psalm-suppress UnsafeInstantiation */
             $in = new $class();
 
             if ($body !== null) {
diff --git a/src/Method.php b/src/Method.php
index 9406647..5c8e19d 100644
--- a/src/Method.php
+++ b/src/Method.php
@@ -124,6 +124,7 @@ public function getOutputType(): string
     private static function getReflectionClassByType(?\ReflectionType $type): ?\ReflectionClass
     {
         if ($type instanceof \ReflectionNamedType && ! $type->isBuiltin()) {
+            /** @psalm-suppress ArgumentTypeCoercion */
             return new \ReflectionClass($type->getName());
         }
 
@@ -319,6 +320,7 @@ public static function parse(\ReflectionMethod $method): Method
         /** @var \ReflectionNamedType $returnType */
         $returnType = $method->getReturnType();
 
+        /** @psalm-suppress ArgumentTypeCoercion */
         return new self($method->getName(), $inputType->getName(), $returnType->getName());
     }
 }
diff --git a/src/Server.php b/src/Server.php
index 79070ee..90886d3 100644
--- a/src/Server.php
+++ b/src/Server.php
@@ -68,8 +68,10 @@ public function __construct(InvokerInterface $invoker = null, array $options = [
      *  $server->registerService(EchoServiceInterface::class, new EchoService());
      * </code>
      *
-     * @param string $interface Generated service interface.
-     * @param ServiceInterface $service Must implement interface.
+     * @template T of ServiceInterface
+     *
+     * @param class-string<T> $interface Generated service interface.
+     * @param T $service Must implement interface.
      * @throws ServiceException
      */
     public function registerService(string $interface, ServiceInterface $service): void
@@ -105,6 +107,7 @@ private function tick(string $body, array $data): array
      * @param Worker $worker
      * @param string $body
      * @param string $headers
+     * @psalm-suppress InaccessibleMethod
      */
     private function workerSend(Worker $worker, string $body, string $headers): void
     {
@@ -131,9 +134,13 @@ private function workerError(Worker $worker, string $message): void
     /**
      * @param Worker $worker
      * @return array { 0: string, 1: string } | null
+     *
+     * @psalm-suppress UndefinedMethod
+     * @psalm-suppress PossiblyUndefinedVariable
      */
     private function workerReceive(Worker $worker): ?array
     {
+        /** @var string|\Stringable $body */
         $body = $worker->receive($ctx);
 
         if (empty($body) && empty($ctx)) {
diff --git a/src/ServiceWrapper.php b/src/ServiceWrapper.php
index 23b1ba1..77e60e6 100644
--- a/src/ServiceWrapper.php
+++ b/src/ServiceWrapper.php
@@ -34,17 +34,14 @@ final class ServiceWrapper
 
     /**
      * @param InvokerInterface $invoker
-     * @param string $interface Service interface name.
+     * @param class-string $interface Service interface name.
      * @param ServiceInterface $service
-     *
      * @throws ServiceException
      */
-    public function __construct(
-        InvokerInterface $invoker,
-        string $interface,
-        ServiceInterface $service
-    ) {
+    public function __construct(InvokerInterface $invoker, string $interface, ServiceInterface $service)
+    {
         $this->invoker = $invoker;
+
         $this->configure($interface, $service);
     }
 
@@ -76,40 +73,44 @@ public function getMethods(): array
      * @param string $method
      * @param ContextInterface $context
      * @param string|null $input
-     * @param array $metadata
      * @return string
-     *
      * @throws NotFoundException
      * @throws InvokeException
      */
-    public function invoke(string $method, ContextInterface $context, ?string $input, array &$metadata = []): string
+    public function invoke(string $method, ContextInterface $context, ?string $input): string
     {
         if (! isset($this->methods[$method])) {
             throw NotFoundException::create("Method `{$method}` not found in service `{$this->name}`.");
         }
 
-        return $this->invoker->invoke($this->service, $this->methods[$method], $context, $input, $metadata);
+        return $this->invoker->invoke($this->service, $this->methods[$method], $context, $input);
     }
 
     /**
      * Configure service name and methods.
      *
-     * @param string $interface
+     * @param class-string $interface
      * @param ServiceInterface $service
-     *
      * @throws ServiceException
      */
     protected function configure(string $interface, ServiceInterface $service): void
     {
         try {
-            $r = new \ReflectionClass($interface);
+            $reflection = new \ReflectionClass($interface);
 
-            if (! $r->hasConstant('NAME')) {
+            if (! $reflection->hasConstant('NAME')) {
                 $message = "Invalid service interface `{$interface}`, constant `NAME` not found.";
                 throw ServiceException::create($message);
             }
 
-            $this->name = $r->getConstant('NAME');
+            $name = $reflection->getConstant('NAME');
+
+            if (! \is_string($name)) {
+                $message = "Constant `NAME` of service interface `{$interface}` must be a type of string";
+                throw ServiceException::create($message);
+            }
+
+            $this->name = $name;
         } catch (\ReflectionException $e) {
             $message = "Invalid service interface `{$interface}`.";
             throw ServiceException::create($message, StatusCode::INTERNAL, $e);
@@ -127,7 +128,7 @@ protected function configure(string $interface, ServiceInterface $service): void
 
     /**
      * @param ServiceInterface $service
-     * @return array
+     * @return array<string, Method>
      */
     protected function fetchMethods(ServiceInterface $service): array
     {

From 181d7c6f4769e933a25afc9c9e95ccc69abcaa96 Mon Sep 17 00:00:00 2001
From: SerafimArts <nesk@xakep.ru>
Date: Wed, 31 Mar 2021 15:29:05 +0300
Subject: [PATCH 27/29] Using composer update command in CI instead of install

---
 .travis.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.travis.yml b/.travis.yml
index da5e25b..8b36a13 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -15,7 +15,7 @@ install:
   - popd
   - export GO111MODULE=on
   - go mod download
-  - composer install --no-interaction --prefer-source --ignore-platform-reqs
+  - composer update --no-interaction --prefer-source --ignore-platform-reqs
   - go get
 
 script:

From 9fb357ab3bb94a97fcbcd13975b8a9bdc83cf074 Mon Sep 17 00:00:00 2001
From: SerafimArts <nesk@xakep.ru>
Date: Wed, 31 Mar 2021 16:45:16 +0300
Subject: [PATCH 28/29] Remove "--ignore-platform-reqs" flag

---
 .travis.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.travis.yml b/.travis.yml
index 8b36a13..b63f434 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -15,7 +15,7 @@ install:
   - popd
   - export GO111MODULE=on
   - go mod download
-  - composer update --no-interaction --prefer-source --ignore-platform-reqs
+  - composer install --no-interaction --prefer-source
   - go get
 
 script:

From c0b8968e520f4e7c0563ca82f4faca93f48efaaa Mon Sep 17 00:00:00 2001
From: Rodrigo Chacon <rochacon@kumbuca.com>
Date: Tue, 20 Apr 2021 20:26:20 -0300
Subject: [PATCH 29/29] Add gRPC method to call metrics

Signed-off-by: Rodrigo Chacon <rochacon@kumbuca.com>
---
 cmd/rr-grpc/grpc/metrics.go | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/cmd/rr-grpc/grpc/metrics.go b/cmd/rr-grpc/grpc/metrics.go
index 51de6cb..a5510dd 100644
--- a/cmd/rr-grpc/grpc/metrics.go
+++ b/cmd/rr-grpc/grpc/metrics.go
@@ -73,14 +73,14 @@ func newCollector() *metricCollector {
 				Name: "rr_grpc_call_total",
 				Help: "Total number of handled grpc requests after server restart.",
 			},
-			[]string{"code"},
+			[]string{"code", "method"},
 		),
 		callDuration: prometheus.NewHistogramVec(
 			prometheus.HistogramOpts{
 				Name: "rr_grpc_call_duration_seconds",
 				Help: "GRPC call duration.",
 			},
-			[]string{"code"},
+			[]string{"code", "method"},
 		),
 		workersMemory: prometheus.NewGauge(
 			prometheus.GaugeOpts{
@@ -103,8 +103,12 @@ func (c *metricCollector) listener(event int, ctx interface{}) {
 			code = st.Code().String()
 		}
 
-		c.callDuration.With(prometheus.Labels{"code": code}).Observe(uc.Elapsed().Seconds())
-		c.callCounter.With(prometheus.Labels{"code": code}).Inc()
+		method := "Unknown"
+		if uc.Info != nil {
+			method = uc.Info.FullMethod
+		}
+		c.callDuration.With(prometheus.Labels{"code": code, "method": method}).Observe(uc.Elapsed().Seconds())
+		c.callCounter.With(prometheus.Labels{"code": code, "method": method}).Inc()
 	}
 }