feat: support if-none-match for the extension list endpoint

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+## (next)
+
+- Support if-none-match for the extension list endpoint
+
 ## v1.0.15
 
 - Update alpine packages in Docker image to address CVEs

main.go

@@ -5,6 +5,8 @@
 package main
 
 import (
+	"time"
+
 	_ "github.com/KimMachineGun/automemlimit" // By default, it sets `GOMEMLIMIT` to 90% of cgroup's memory limit.
 	"github.com/rs/zerolog"
 	"github.com/steadybit/action-kit/go/action_kit_api/v2"
@@ -21,6 +23,8 @@ import (
 	"github.com/steadybit/extension-kit/extsignals"
 )
 
+var startedAt = time.Now().Format(time.RFC3339)
+
 func main() {
 	// Most Steadybit extensions leverage zerolog. To encourage persistent logging setups across extensions,
 	// you may leverage the extlogging package to initialize zerolog. Among others, this package supports
@@ -48,13 +52,13 @@ func main() {
 
 	// This call registers a handler for the extension's root path. This is the path initially accessed
 	// by the Steadybit agent to obtain the extension's capabilities.
-	exthttp.RegisterHttpHandler("/", exthttp.GetterAsHandler(getExtensionList))
-
 	// This is a section you will most likely want to change: The registration of HTTP handlers
 	// for your extension. You might want to change these because the names do not fit, or because
 	// you do not have a need for all of them.
 	action_kit_sdk.RegisterAction(extdebug.NewDebugAction())
 
+	exthttp.RegisterHttpHandler("/", exthttp.IfNoneMatchHandler(func() string { return startedAt }, exthttp.GetterAsHandler(getExtensionList)))
+
 	//This will install a signal handlder, that will stop active actions when receiving a SIGURS1, SIGTERM or SIGINT
 	extsignals.ActivateSignalHandlers()