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

• Fly.io GitHub Actions
• Fly.io Machines API
• GitHub Actions Secrets

Next Steps

For deployment strategies, see flyio-deploy-integration.