Docker builds and services

Docker, Docker Compose and Buildx are installed on every Sengi runner. Image builds, Compose stacks and service containers work without changes.

Build an image

jobs:
  image:
    runs-on: sengi-premium-4-ubuntu-2404
    steps:
      - uses: actions/checkout@v4
      - uses: docker/setup-buildx-action@v3
      - uses: docker/build-push-action@v6
        with:
          context: .
          push: false
          cache-from: type=gha
          cache-to: type=gha,mode=max

type=gha stores layers in Sengi's own cache, so the next build reuses them. See Docker layer caching.

Run a Compose stack

      - run: docker compose up -d --wait
      - run: npm test
      - run: docker compose down

Service containers

Job services: work as they do on GitHub's runners. Map the port and connect on localhost:

jobs:
  test:
    runs-on: sengi-basic-2-ubuntu-2404
    services:
      postgres:
        image: postgres:17
        env:
          POSTGRES_PASSWORD: postgres
        ports:
          - 5432:5432
    steps:
      - uses: actions/checkout@v4
      - run: npm test

Choosing a size

Image builds are CPU and disk heavy. Premium's local NVMe and faster CPUs built our production test image about 1.9× faster than GitHub's 4 vCPU runner. Large images also need disk: see runner sizes for free space per size.