action.yaml

# Copyright (c) 2023 The Jaeger Authors.
# SPDX-License-Identifier: Apache-2.0

name: 'Verify Metric Snapshot and Upload Metrics'
description: 'Upload or cache the metrics data after verification'
inputs:
  snapshot:
    description: 'Path to the metric file'
    required: true
  artifact_key:
    description: 'Artifact key used for uploading and fetching artifacts'
    required: true
runs:
  using: 'composite'
  steps:
    - name: Upload current metrics snapshot
      uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6.0.0
      with:
        name: ${{ inputs.artifact_key }}
        path: ./.metrics/${{ inputs.snapshot }}.txt
        retention-days: 7

      # The github cache restore successfully restores when cache saved has same key and same path.
      # Hence to restore release metric with name relese_{metric_name} , the name must be changed to the same.
    - name: Change file name before caching
      if: github.ref_name == 'main'
      shell: bash
      run: |
        mv ./.metrics/${{ inputs.snapshot }}.txt ./.metrics/baseline_${{ inputs.snapshot }}.txt

    - name: Cache metrics snapshot on main branch for longer retention
      if: github.ref_name == 'main'
      uses: actions/cache/save@1bd1e32a3bdc45362d1e726936510720a7c30a57
      with:
        path: ./.metrics/baseline_${{ inputs.snapshot }}.txt
        key: ${{ inputs.artifact_key }}_${{ github.run_id }}

    # Use restore keys to match prefix and fetch the latest cache
    # Here , restore keys is an ordered list of prefixes that need to be matched
    - name: Download the cached tagged metrics
      id: download-release-snapshot
      if: github.ref_name != 'main'
      uses: actions/cache/restore@1bd1e32a3bdc45362d1e726936510720a7c30a57
      with:
        path: ./.metrics/baseline_${{ inputs.snapshot }}.txt
        key: ${{ inputs.artifact_key }}
        restore-keys: |
          ${{ inputs.artifact_key }}

    # Create an empty stub so the diff artifact is always uploaded on PRs.
    # The fan-in uses 1-to-1 presence of diff artifacts to detect infra failures
    # (a missing diff_* artifact means this action never ran for that snapshot).
    # The stub is overwritten by the compare step when a baseline exists.
    - name: Create diff file stub
      if: github.ref_name != 'main'
      shell: bash
      run: touch ./.metrics/diff_${{ inputs.snapshot }}.txt

    - name: Calculate diff between the snapshots
      id: compare-snapshots
      if: ${{ (github.ref_name != 'main') && (steps.download-release-snapshot.outputs.cache-matched-key != '')  }}
      continue-on-error: true
      shell: bash
      run: |
        python3 -m pip install prometheus-client
        if python3 ./scripts/e2e/compare_metrics.py --file1 ./.metrics/${{ inputs.snapshot }}.txt --file2 ./.metrics/baseline_${{ inputs.snapshot }}.txt --output ./.metrics/diff_${{ inputs.snapshot }}.txt; then
          echo "No differences found in metrics"
        else
          echo "🛑 Differences found in metrics"
          echo "has_diff=true" >> $GITHUB_OUTPUT
        fi

    # Always upload the diff artifact on PRs (even when empty / no baseline yet).
    # Presence of this artifact in the fan-in proves this action ran for the snapshot.
    - name: Upload the diff artifact
      if: github.ref_name != 'main'
      uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6.0.0
      with:
        name: diff_${{ inputs.artifact_key }}
        path: ./.metrics/diff_${{ inputs.snapshot }}.txt
        retention-days: 7