Fly.io CI Integration Skill

Fly.io CI Integration

Overview

Set up CI/CD for Fly.io edge deployments: run unit tests on every PR, deploy to staging on pull requests, and promote to production on merge to main. Fly.io uses Machines API for app management and deploy tokens for scoped CI authentication. CI pipelines build Docker images, deploy via flyctl, and run post-deploy health checks against the edge endpoints.

GitHub Actions Workflow

# .github/workflows/fly-ci.yml
name: Fly.io CI
on:
  pull_request:
    branches: [main]
  push:
    branches: [main]

jobs:
  unit-tests:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with: { node-version: '20' }
      - run: npm ci
      - run: npm test -- --reporter=verbose

  deploy:
    if: github.ref == 'refs/heads/main'
    needs: unit-tests
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: superfly/flyctl-actions/setup-flyctl@master
      - run: fly deploy --ha=false
        env:
          FLY_API_TOKEN: ${{ secrets.FLY_API_TOKEN }}
      - name: Health check
        run: |
          sleep 10
          curl -sf https://my-app.fly.dev/health || exit 1

Mock-Based Unit Tests

// tests/fly-service.test.ts
import { describe, it, expect, vi } from 'vitest';
import { scaleApp } from '../src/fly-service';

vi.mock('../src/fly-client', () => ({
  FlyClient: vi.fn().mockImplementation(() => ({
    listMachines: vi.fn().mockResolvedValue([
      { id: 'mch_abc', state: 'started', region: 'iad', config: { size: 'shared-cpu-1x' } },
      { id: 'mch_def', state: 'started', region: 'lhr', config: { size: 'shared-cpu-1x' } },
    ]),
    scaleMachine: vi.fn().mockResolvedValue({ id: 'mch_abc', state: 'started' }),
    getApp: vi.fn().mockResolvedValue({ name: 'my-app', status: 'deployed', hostname: 'my-app.fly.dev' }),
  })),
}));

describe('Fly.io Service', () => {
  it('scales app machines across regions', async () => {
    const result = await scaleApp('my-app', { count: 3 });
    expect(result.machines).toBeDefined();
    expect(result.status).toBe('scaled');
  });
});

Integration Tests

// tests/integration/fly.integration.test.ts
import { describe, it, expect } from 'vitest';

const hasToken = !!process.env.FLY_API_TOKEN;

describe.skipIf(!hasToken)('Fly.io Live API', () => {
  it('lists apps via Machines API', async () => {
    const res = await fetch('https://api.machines.dev/v1/apps', {
      headers: { Authorization: `Bearer ${process.env.FLY_API_TOKEN}` },
    });
    expect(res.status).toBe(200);
    const body = await res.json();
    expect(body).toHaveProperty('apps');
  });
});

Error Handling

| CI Issue | Cause | Fix | |----------|-------|-----| | FLY_API_TOKEN invalid | Token expired or revoked | Regenerate with fly tokens create deploy -a my-app | | Deploy timeout | Image build too slow | Add Docker layer caching with --build-cache | | Health check fails | App not ready after deploy | Increase sleep or use fly status --wait | | Machine stuck in replacing | Rolling deploy conflict | Run fly machines list and destroy orphaned machines | | Region unavailable | Edge region at capacity | Set primary_region in fly.toml to a different region |

Resources

Next Steps

For deployment strategies, see flyio-deploy-integration.

Agent Skills: Fly.io CI Integration

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Skill Files