feat: add OTel

[janishorsts]

Description

The implementation conforms to OTel autoexport configuration with the environment variables.

Opt-in

By default, the user is opted out of the telemetry (unlike the autoexport default opt-in).

To enable a specific exporter, set at least one of the following environment variables.

environment variables	exporters
OTEL_EXPORTER_OTLP_ENDPOINT	traces, metrics, logs
OTEL_TRACES_EXPORTER, OTEL_EXPORTER_OTLP_TRACES_ENDPOINT	traces
OTEL_METRICS_EXPORTER, OTEL_EXPORTER_OTLP_METRICS_ENDPOINT	metrics
OTEL_LOGS_EXPORTER, OTEL_EXPORTER_OTLP_LOGS_ENDPOINT	logs

Parent span

The TRACEPARENT environment variable defines the parent span. The value must conform to the W3C Trace Context format.

TODO

These may or may not be part of this feat.

• Do not send telemetry by default.
• Make phases (Init, Build, Output) as parent spans? Or remove the phases? REMOVED
• Read span parent from the environment

Screenshot

[github-actions]

➖ Are we earthbuild yet?

No change in "earthly" occurrences

📈 Overall Progress

Branch	Total Count
main	5625
This PR	5625
Difference	+0

---

Keep up the great work migrating from Earthly to Earthbuild! 🚀

💡 Tips for finding more occurrences

Run locally to see detailed breakdown:

./.github/scripts/count-earthly.sh

Note that the goal is not to reach 0.
There is anticipated to be at least some occurences of earthly in the source code due to backwards compatibility with config files and language constructs.

[gemini-code-assist]

Summary of Changes

Hello @janishorsts, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request lays the groundwork for enhanced observability within the EarthBuild project by integrating OpenTelemetry. It establishes a robust framework for collecting and exporting telemetry data, including traces, metrics, and logs, from critical application workflows. This foundational change will provide developers with deeper insights into the application's runtime behavior and performance characteristics, facilitating debugging and optimization efforts.

Highlights

• OpenTelemetry Integration: Introduced OpenTelemetry for comprehensive observability, enabling distributed tracing, metrics collection, and structured logging across key components of the application.
• Centralized Telemetry Setup: A new internal/telemetry package has been added to centralize the configuration and management of the OpenTelemetry pipeline, including tracer, meter, and logger providers with auto-export capabilities.
• Automated Tracing of Core Operations: Key build phases (PhaseBuild, PhaseOutput, PhaseInit) and the main application execution (main function) are now automatically instrumented with OpenTelemetry spans to capture performance data.
• Dependency Updates: Numerous Go module dependencies have been added or updated, primarily to support the OpenTelemetry integration and ensure compatibility with the latest versions of related libraries.

Changelog

• builder/builder.go
  • Imported internal/telemetry package.
  • Added OpenTelemetry tracing spans for PhaseBuild and PhaseOutput within the convertAndBuild function.
• cmd/earthly/main.go
  • Imported internal/telemetry and go.opentelemetry.io/otel/semconv.
  • Initialized the OpenTelemetry pipeline and configured a shutdown hook in the run function.
  • Added a main OpenTelemetry span for the application's execution and set the process exit code as an attribute.
  • Refactored error variable declarations to reuse err for f.Apply and godotenv.Load calls.
  • Simplified the return statement for earthly.Run.
• cmd/earthly/subcmd/build_cmd.go
  • Imported internal/telemetry package.
  • Added an OpenTelemetry tracing span for builder.PhaseInit within the ActionBuildImp function.
• earthfile2llb/converter.go
  • Removed context.Context from the NewConverter function signature.
• earthfile2llb/earthfile2llb.go
  • Imported internal/telemetry package.
  • Added an OpenTelemetry tracing span for the Earthfile2LLB function, dynamically named after the target.
  • Updated the call to NewConverter to reflect the modified function signature.
• go.mod
  • Added core OpenTelemetry modules (go.opentelemetry.io/otel, go.opentelemetry.io/otel/sdk, go.opentelemetry.io/otel/sdk/log, go.opentelemetry.io/otel/sdk/metric, go.opentelemetry.io/otel/log).
  • Added OpenTelemetry contrib modules (go.opentelemetry.io/contrib/exporters/autoexport, go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc, go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp, go.opentelemetry.io/contrib/bridges/prometheus).
  • Updated google.golang.org/grpc and google.golang.org/protobuf versions.
  • Updated various indirect dependencies including github.com/felixge/httpsnoop, github.com/grpc-ecosystem/grpc-gateway/v2, github.com/klauspost/compress, github.com/prometheus/*, golang.org/x/exp, golang.org/x/net, golang.org/x/time.
• go.sum
  • Updated checksums for all modified and newly added Go modules to reflect changes in go.mod.
• internal/telemetry/telemetry.go
  • New file: Implemented the core OpenTelemetry setup logic.
  • Defined Tracer() to provide the application's tracer instance.
  • Implemented Setup() to initialize the OpenTelemetry pipeline, including propagator, tracer provider, meter provider, and logger provider.
  • Configured resource attributes for the service, process command, PID, and executable path.
  • Provided helper functions (newTracerProvider, newMeterProvider, newLoggerProvider) for configuring specific OpenTelemetry providers with auto-export capabilities.

Activity

• The pull request is currently marked as 'Work In Progress' (WIP).
• A TODO item exists to implement a mechanism to prevent telemetry from being sent by default.
• A screenshot has been provided, likely demonstrating the initial telemetry output or integration.

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[gemini-code-assist]

Code Review

This pull request introduces OpenTelemetry to the project, which is a great step towards better observability. The implementation in the new internal/telemetry package is a solid foundation, especially with the use of autoexport for flexible configuration. However, I've found a few critical issues related to span management that could lead to incorrect traces, such as leaked spans and double-ending spans. There are also a couple of minor points in the new telemetry package concerning error handling and logging that could be improved. Please see the detailed comments for specifics.

[janishorsts]

/gemini review

[gemini-code-assist]

Code Review

This pull request introduces OpenTelemetry support, which is a great addition for observability. The implementation correctly uses auto-export for traces and metrics, and makes telemetry opt-out by default as intended.

I've found a few areas for improvement in the new internal/telemetry/telemetry.go file:

• There's an inconsistency in the semconv library version being used.
• The logger provider is hardcoded to use a stdout exporter, instead of using the auto-exporter like traces and metrics.
• There's some duplicated code for resource creation that could be refactored.
• A minor violation of a project coding standard regarding if statements with initializers.

My detailed comments provide suggestions to address these points. Overall, this is a solid implementation.

[janishorsts]

/gemini review

[gemini-code-assist]

Code Review

This pull request introduces OpenTelemetry (OTel) support for tracing, metrics, and logging, which is a great addition for observability. The implementation is opt-out by default, which is a sensible choice. My review focuses on improving the robustness and correctness of the OTel setup. I've identified a few areas for improvement: ensuring the correct executable path is reported in telemetry data, making HTTP client instrumentation more robust, and directing setup errors to the standard error stream. These changes will help ensure the telemetry data is accurate and the setup process follows best practices.