Collection of Sage specific functions used with Buildkite

The lib/code_coverage_checker.sh script implements a coverage gate that validates PR coverage against a baseline branch.

The coverage gate script performs the following steps:

1. Resolves Baseline Build ID

   • Queries the Buildkite API for the latest passed build on the configured baseline branch (BASE_BRANCH).

2. Downloads Baseline Coverage Artifact

   • Fetches coverage metrics from the baseline build using pagination.
   • Stores the artifact list in base_artifacts.json.
   • Downloads the baseline coverage file (default: base-coverage-metrics.json).
   • Extracts the line coverage percentage from the baseline.

3. Downloads Current PR Coverage Artifact

   • Fetches coverage metrics from the current build (PR/branch build).
   • Stores the artifact list in patch_artifacts.json.
   • Downloads the current coverage file (default: current-coverage-metrics.json).
   • Extracts the line coverage percentage from the PR.

4. Compares Coverage Metrics

   • Compares current PR coverage against baseline coverage.
   • Fails (exit 1) if PR coverage is below baseline
   • Passes (exit 0) if PR coverage is equal to or above baseline.

5. Annotates Buildkite

   • Posts a success annotation if coverage passes.
   • Posts an error annotation if coverage fails.

Environment variables to customize behavior:

- label: ':bar_chart: Code coverage regression'
  retry:
    automatic:
      signal_reason: agent_stop
  plugins:
    - ecr#v2.9.0:
        login: true
        account-ids: '522104923602'
        region: 'eu-west-1'
        assume_role:
        role_arn: 'arn:aws:iam::522104923602:role/CI.Integration'
    - ssh://git@github.com/Sage/sbc-shared-buildkite-plugin.git#2.9.0:
        action: coverage_metrics