OpenTelemetry-Go-Compile-Instrumentation

OpenTelemetry-Go-Compile-Instrumentation provides compile time OpenTelemetry instrumentation for Golang.

Getting Started

Prerequisites

• Go 1.23.0 or later
• Git

Quick Start

1. Clone the repository:

   git clone https://github.com/open-telemetry/opentelemetry-go-compile-instrumentation.git
   cd opentelemetry-go-compile-instrumentation

2. Build the instrumentation tool:

   make build

3. Run the demo with instrumentation:

   make demo

   This will:

   • Build the instrumentation tool (otel binary)
   • Run the demo with compile-time instrumentation
   • Execute the instrumented binary

How It Works

The instrumentation tool injects OpenTelemetry code at compile time using Go's -toolexec flag. The process works as follows:

1. Setup Phase: Creates .otel-build directory and initializes logging
2. Go Build Phase: Intercepts the go build command and adds -toolexec=./otel flag
3. Toolexec Phase: The Go toolchain invokes the tool for each compilation step, allowing code injection. This phase is not visible to the user.

Logging

The tool provides detailed logging to help debug instrumentation issues:

• Logs are written to .otel-build/debug.log for setup and go actions
• Toolexec action logs to stdout for immediate feedback
• All logs include structured information about the build process

Inspecting the Instrumentation

To see the result of instrumentation, navigate to the WORK directory that appears in the build output:

# Example WORK directory
cd /var/folders/x9/fddsvlt5363c0plvvw8_2mr80000gn/T/go-build2020695287

# Locate the main package under the b001 subdirectory
ls -l b001

# Inspect the modified files
cat modified.go

Contributing

See the contributing documentation.

License

OpenTelemetry Go Compile Instrumentation project is licensed under the terms of the [Apache Software License version 2.0]. See the license file for more details.