Type Checking workflow (seapagan/fastapi-template)

The Type Checking workflow from seapagan/fastapi-template, explained and optimized by Latchkey.

What it does

This is the Type Checking workflow from the seapagan/fastapi-template repository, a real project running GitHub Actions. It is shown here with attribution under its MIT license.

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

The workflow

name: Type Checking

on: [push, pull_request, workflow_dispatch]

jobs:
  mypy:
    # uncomment the line before to disable this job if needed.
    # if: false
    name: mypy
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v6

      - name: Install uv
        uses: astral-sh/setup-uv@v8.2.0
        with:
          enable-cache: true
          cache-dependency-glob: "uv.lock"

      - name: Set up Python
        run: uv python install 3.12

      - name: Run mypy
        run: uv run --all-extras mypy . --strict

The same workflow, on Latchkey

Removes redundant runs and caps runaway jobs. Added and changed lines are highlighted.

name: Type Checking
 
on: [push, pull_request, workflow_dispatch]
 
concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true
 
jobs:
  mypy:
    timeout-minutes: 30
    # uncomment the line before to disable this job if needed.
    # if: false
    name: mypy
    runs-on: latchkey-small
    steps:
      - uses: actions/checkout@v6
 
      - name: Install uv
        uses: astral-sh/setup-uv@v8.2.0
        with:
          enable-cache: true
          cache-dependency-glob: "uv.lock"
 
      - name: Set up Python
        run: uv python install 3.12
 
      - name: Run mypy
        run: uv run --all-extras mypy . --strict
 

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• Cancel superseded runs when a branch or PR gets a newer push.
• Add a job timeout so a hung step cannot burn hours of runner time.

1 third-party action is referenced by a movable tag. Pin it to the commit SHA (Latchkey resolves and applies this automatically) so a repointed tag cannot change what runs.

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