CI workflow (black-forest-labs/flux2)

The CI workflow from black-forest-labs/flux2, explained and optimized by Latchkey.

What it does

This is the CI workflow from the black-forest-labs/flux2 repository, a real project running GitHub Actions. It is shown here with attribution under its Apache-2.0 license.

Below, Latchkey shows a faster, safer version produced by its optimization engine.

The workflow

name: CI
on: push
jobs:
  lint:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
      - uses: actions/setup-python@v2
        with:
          python-version: "3.10"
      - name: Install dependencies
        run: |
          python -m pip install --upgrade pip
          pip install ruff==0.6.8
      - name: Run Ruff
        run: ruff check --output-format=github .
      - name: Check imports
        run: ruff check --select I --output-format=github .
      - name: Check formatting
        run: ruff format --check .

The same workflow, on Latchkey

Estimated ~20% faster on cache hits, plus fewer wasted runs and a safer supply chain. Added and changed lines are highlighted.

name: CI
on: push
concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true
 
jobs:
  lint:
    timeout-minutes: 30
    runs-on: latchkey-small
    steps:
      - uses: actions/checkout@v2
      - uses: actions/setup-python@v2
        with:
          cache: 'pip'
          python-version: "3.10"
      - name: Install dependencies
        run: |
          python -m pip install --upgrade pip
          pip install ruff==0.6.8
      - name: Run Ruff
        run: ruff check --output-format=github .
      - name: Check imports
        run: ruff check --select I --output-format=github .
      - name: Check formatting
        run: ruff format --check .
 

What changed

• Run on Latchkey managed runners with one line (runs-on), which apply the fixes below automatically and self-heal transient failures. This example uses latchkey-small; pick the runner size that fits the job.
• Cancel superseded runs when a branch or PR gets a newer push.
• Cache dependency installs on the setup step so they are served from cache.
• Add a job timeout so a hung step cannot burn hours of runner time.

What Latchkey heals here

This workflow has steps that commonly fail on transient issues (network, registries, flaky browsers). On Latchkey managed runners they are detected, retried, and self-healed instead of failing your build:

• Dependency installs

This workflow runs 1 job per trigger. On Latchkey the same minutes cost up to 58% less than GitHub-hosted, with zero queue time.

Actions used in this workflow