optimize-test-sharding.yml

name: Optimize Test Sharding

on:
  schedule:
    # Runs at 0700 UTC daily
    - cron: "0 7 * * *"
  workflow_dispatch: # Allow manual trigger

permissions:
  contents: read

env:
  SALT_FILE: tests/testcore/shard_salt.txt
  BRANCH: auto/optimize-test-sharding

jobs:
  update-salts:
    runs-on: ubuntu-latest

    steps:
      - name: Generate GitHub token
        id: generate-token
        uses: actions/create-github-app-token@v2
        with:
          app-id: ${{ secrets.TEMPORAL_CICD_APP_ID }}
          private-key: ${{ secrets.TEMPORAL_CICD_PRIVATE_KEY }}
          owner: temporalio

      - name: Checkout code
        uses: actions/checkout@v6
        with:
          ref: main
          token: ${{ steps.generate-token.outputs.token }}

      - name: Set up Go
        uses: actions/setup-go@v6
        with:
          go-version-file: go.mod
          cache: true

      - name: Optimize functional test sharding
        run: |
          # NOTE: shard count must match shards in run-tests.yml
          go run ./cmd/tools/optimize-test-sharding \
            -shards 3 \
            -workflow run-tests.yml \
            -artifact-pattern 'junit-xml--*shard*--functional-test' \
            -file "${{ env.SALT_FILE }}" \
            -threshold 0.05
        env:
          GH_TOKEN: ${{ steps.generate-token.outputs.token }}

      - name: Create pull request
        run: |
          if git diff --quiet; then
            echo "No changes to shard salt"
            exit 0
          fi

          # Delete remote branch if it exists from a previous run.
          # This will also close a previous, stuck PR if it exists.
          git push origin --delete ${{ env.BRANCH }} 2>/dev/null || true

          git config --local user.name 'Temporal Data'
          git config --local user.email 'commander-data@temporal.io'

          git checkout -b ${{ env.BRANCH }}
          git add "${{ env.SALT_FILE }}"
          git commit -m "Update test shard salt"
          git push origin ${{ env.BRANCH }}

          gh pr create \
            --title "Update test shard salt" \
            --body "Automatically generated by the optimize-test-sharding workflow."

          gh pr merge ${{ env.BRANCH }} --auto --squash
        env:
          GH_TOKEN: ${{ steps.generate-token.outputs.token }}