Github Actions 中 Service Container 的使用

jobs:
  # Label of the runner job
  runner-job:
    # You must use a Linux environment when using service containers or container jobs
    runs-on: ubuntu-latest

    # Service containers to run with `runner-job`
    services:
      # Label used to access the service container
      redis:
        # Docker image
        image: redis:alpine
        # Set health checks to wait until redis has started
        options: >-
          --health-cmd "redis-cli ping"
          --health-interval 10s
          --health-timeout 5s
          --health-retries 5
        ports:
          # Maps port 6379 on service container to the host
          - 6379:6379

上面是一个 redis service container 配置示例的一部分，需要注意的是使用 service container 的时候必须要使用 Linux 环境，因为 service container 的本质就是 docker run 了一个 container，通过一定的规则配置来实现在跑 CI 的环境可以访问的这个 service。

上面的示例配置了一个 redis 的 service container，并将容器服务的 6379 端口映射到 host 的 6379 端口，这样 host 上的服务就可以通过 127.0.0.1:6379/localhost:6379 访问到使用 docker 跑起来的 redis 服务(redis service container)了。

steps:
  # Downloads a copy of the code in your repository before running CI tests
  - name: Check out repository code
    uses: actions/checkout@v2

  # Performs a clean installation of all dependencies in the `package.json` file
  # For more information, see https://docs.npmjs.com/cli/ci.html
  - name: Install dependencies
    run: npm ci

  - name: Connect to Redis
    # Runs a script that creates a Redis client, populates
    # the client with data, and retrieves data
    run: node client.js
    # Environment variable used by the `client.js` script to create
    # a new Redis client.
    env:
      # The hostname used to communicate with the Redis service container
      REDIS_HOST: localhost
      # The default Redis port
      REDIS_PORT: 6379

上面的这种形式是在 host 上跑的，也就是直接在跑 CI 的服务器上跑的，有些情况下环境的配置比较麻烦的情况下也可以直接在指定的 docker 镜像为基础的 docker container 里跑 CI，需要注意的是 docker container 里跑 CI 的时候和直接在 host 上跑 CI 网络上有区别， host 可能就是直接访问 localhost，container 访问就是 service 名称，来看下面的 container 的一个示例：

jobs:
  # Label of the container job
  container-job:
    # Containers must run in Linux based operating systems
    runs-on: ubuntu-latest
    # Docker Hub image that `container-job` executes in
    container: node:10.18-jessie

    # Service containers to run with `container-job`
    services:
      # Label used to access the service container
      redis:
        # Docker Hub image
        image: redis
        # Set health checks to wait until redis has started
        options: >-
          --health-cmd "redis-cli ping"
          --health-interval 10s
          --health-timeout 5s
          --health-retries 5

可以看到大部分是一样的，只是多了一个 container 的配置，这样实际的 CI 就是在这个 container 里执行的，创建的执行 CI 的 container 和 service container 是在同一个 network 下，可以直接通过服务名称来访问

steps:
  # Downloads a copy of the code in your repository before running CI tests
  - name: Check out repository code
    uses: actions/checkout@v2

  # Performs a clean installation of all dependencies in the `package.json` file
  # For more information, see https://docs.npmjs.com/cli/ci.html
  - name: Install dependencies
    run: npm ci

  - name: Connect to Redis
    # Runs a script that creates a Redis client, populates
    # the client with data, and retrieves data
    run: node client.js
    # Environment variable used by the `client.js` script to create a new Redis client.
    env:
      # The hostname used to communicate with the Redis service container
      REDIS_HOST: redis
      # The default Redis port
      REDIS_PORT: 6379

提供一个我目前在用的一个 service container，和上面的示例基本是类似的，有需要的可以参考一下：

name: dotnetcore

on: [push]

jobs:
  # Label of the container job
  redis-integration-test:
    # Containers must run in Linux based operating systems
    runs-on: ubuntu-latest
    # # Docker image that `job` executes in
    # container: mcr.microsoft.com/dotnet/sdk:5.0

    # Service containers to run with `container-job`
    # https://docs.github.com/en/free-pro-team@latest/actions/guides/creating-redis-service-containers
    services:
      # Label used to access the service container
      redis:
        # Docker Hub image
        image: redis:alpine
        # Set health checks to wait until redis has started
        options: >-
          --health-cmd "redis-cli ping"
          --health-interval 10s
          --health-timeout 5s
          --health-retries 5
        ports:
          # Maps port 6379 on service container to the host
          - 6379:6379

    steps:
    - uses: actions/checkout@v1
    - name: Setup .NET Core
      uses: actions/setup-dotnet@v1
      with:
        dotnet-version: 5.0.x
    - name: dotnet info
      run: dotnet --info
    - name: build
      run: bash build.sh --target=test

CI 执行日志：

从日志上我们可以看出来比普通的 CI 执行会多出两个步骤，一个是初始化 container，一个是清理 container

完整的CI 日志可以在这里看到：https://github.com/WeihanLi/WeihanLi.Redis/runs/1400006789?check_suite_focus=true

虽然我的场景是 redis，但是不仅仅是 redis，很多应用外的依赖比如说数据库，甚至MQ等都是可以通过 service container 来做一个完善的集成测试，没有尝试过的快去试试吧~~