feat: add driver-opts support for buildkitd environment variables

[adityamaru]

Summary

This PR adds support for driver-opts input parameter to the setup-docker-builder action, enabling users to pass environment variables to buildkitd. This brings API compatibility with Docker's setup-buildx-action for driver options.

Key Changes

• ✨ Added driver-opts input parameter to action.yml
• 📝 Parse driver-opts using Util.getInputList with ignoreComma: true and quote: false (matching Docker's approach)
• 🔧 Support env.* format for passing environment variables to buildkitd
• ✅ Added comprehensive tests for driver-opts functionality
• 🧪 Added test workflow job to verify driver-opts in CI

Use Case

This enables OpenTelemetry tracing and other environment-based configuration for buildkitd:

- name: Set up Docker Buildx with OTEL
  uses: useblacksmith/setup-docker-builder@feat/driver-opts-support
  with:
    driver-opts: |
      env.OTEL_TRACES_EXPORTER=otlp
      env.OTEL_EXPORTER_OTLP_PROTOCOL=http/protobuf
      env.OTEL_EXPORTER_OTLP_ENDPOINT=https://otel.example.com
      env.OTEL_SERVICE_NAME=buildkitd

Testing

• Added unit tests in src/driver-opts.test.ts
• Added integration test job test-driver-opts in .github/workflows/test-action.yml
• All tests passing ✅

Compatibility

This implementation closely mirrors the parsing logic from docker/setup-buildx-action to ensure compatibility while adapting to our direct buildkitd execution approach.

🤖 Generated with Claude Code

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Note

Adds driver-opts input and plumbing to pass env.* options to buildkitd, with tests, CI workflow, and usage example.

• Action inputs & parsing:
  • Add inputs.driver-opts in action.yml.
  • Parse driver-opts via Util.getInputList({ignoreComma: true, quote: false}) in src/main.ts.
• Buildkitd env propagation:
  • In src/setup_builder.ts, parse env.* entries and start buildkitd with sudo env KEY='value' ....
• Tests:
  • Add src/driver-opts.test.ts covering env parsing, quoting, and warnings.
  • Update src/main.test.ts to validate input handling for driver-opts.
• CI/Examples:
  • Add workflow job test-driver-opts in .github/workflows/test-action.yml to exercise driver options.
  • Add example examples/with-driver-opts.yml demonstrating OTEL configuration.
• Build artifacts:
  • Update dist/index.js and source map.

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