如何使用docker-compose运行golang-migrate？

Question

In golang-migrate's documentation, it is stated that you can run this command to run all the migrations in one folder.

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

How would you do this to fit the syntax of the new docker-compose, which discourages the use of --network?

And more importantly: How would you connect to a database in another container instead to one running in your localhost?

Answer 1

Adding this to your docker-compose.yml will do the trick:

    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:

Instead of using the --network host option of docker run you set up a network called new. All the services inside that network gain access to each other through a defined alias (in the above example, you can access the db service through the database alias). Then, you can use that alias just like you would use localhost, that is, in place of an IP address. That explains this connection string:

"postgres://mydbuser:mydbpwd@database:5432/mydbname?sslmode=disable"