Question

在golang-migrate的文档中，您可以运行此命令以在一个文件夹中运行所有迁移。

docker run -v {{ migration dir }}:/migrations --network host migrate/migrate
    -path=/migrations/ -database postgres://localhost:5432/database up 2

您将如何执行此操作以适应新的docker-compose的语法，从而不鼓励使用--network？

更重要的是：如何连接到另一个容器中的数据库而不是本地主机中运行的数据库？

Answer 1

将其添加到您的docker-compose.yml即可达到目的：

    db:
        image: postgres
        networks:
            new:
                aliases:
                    - database
        environment:
            POSTGRES_DB: mydbname
            POSTGRES_USER: mydbuser
            POSTGRES_PASSWORD: mydbpwd
        ports:
            - "5432"
    migrate:
        image: migrate/migrate
        networks:
            - new
        volumes:
            - .:/migrations
        command: ["-path", "/migrations", "-database",  "postgres://mydbuser:mydbpwd@database:5432/mydbname?sslmode=disable", "up", "3"]
        links: 
            - db
networks:
      new:

您建立了一个名为--network host的网络，而不是使用docker run的{{1}}选项。该网络内的所有服务都通过定义的别名相互访问（在上例中，您可以通过new别名访问数据库服务）。然后，您可以像使用database一样使用该别名，即代替IP地址。这说明了此连接字符串：

localhost

Answer 2

从 Compose 文件格式版本 2 开始，您无需设置网络。

如 docker networking documentation 中所述，默认情况下，Compose 会为您的应用设置单个网络。服务的每个容器都加入默认网络，并且可以被该网络上的其他容器访问，并且可以在与容器名称相同的主机名上被它们发现。

因此，在您的情况下，您可以执行以下操作：

version: '3.8'
services:
   #note this databaseservice name is what we will use instead
   #of localhost when using migrate as compose assigns
   #the service name as host
   #for example if we had another container in the same compose
   #that wnated to access this service port 2000 we would have written
   # databaseservicename:2000
  databaseservicename:
    image: postgres:13.3-alpine

    restart: always

    ports:
      - "5432"

    environment:
      POSTGRES_PASSWORD: password
      POSTGRES_USER: username
      POSTGRES_DB: database

    volumes:
      - pgdata:/var/lib/postgresql/data

    #if we had another container that wanted to access migrate container at let say
    #port 1000
    #and it's in the same compose file  we would have written migrate:1000
  migrate:
    image: migrate/migrate

    depends_on:
      - databaseservicename

    volumes:
      - path/to/you/migration/folder/in/local/computer:/database
    # here instead of localhost as the host we use databaseservicename as that is the name we gave to the postgres service
    command:
      [ "-path", "/database", "-database",  "postgres://databaseusername:databasepassword@databaseservicename:5432/database?sslmode=disable", "up" ]
volumes:
  pgdata:

如何使用docker-compose运行golang-migrate？

2 个答案: