将go和postgres与docker-compose连接

Question

我正在尝试使用docker-compose连接go和postgres容器。

这是我的docker-compose.yml：

version: '2'
services:
    postgres:
        image: postgres
        ports:
            - "5432"
        environment:
            - POSTGRES_PASSWORD=postgres
    server:
        build: ./server
        command: gin
        volumes:
            - ./server:/go/src/app
        ports:
            - "8080:3000"

刚开始，我尝试使用docker-compose.yml中的links命令，但这并没有在服务器容器中创建任何env变量，因此让我非常困惑。（应该创建SOMETHINGSOMETHING_PORT_5432_TCP_ADDR和SOMETHINGSOMETHING_5432_TCP_PORT，不是吗？）

然后，我在某处阅读，可以只使用http：// postgres作为主机，所以我尝试了一下。所以现在这就是我的main.go的样子（注意：我正在将Gorp用于“ ORM”）：

func main() {

    dbinfo := fmt.Sprintf("user=%s password=%s host=%s dbname=%s sslmode=disable",
        "postgres",
        os.Getenv("DB_ENV_POSTGRES_PASSWORD"),
        "http://postgres",
        DB_NAME,
    )

    db, err := sql.Open("postgres", dbinfo)

    checkErr(err, "sql.Open failed")


    // construct a gorp DbMap
    dbmap := &gorp.DbMap{Db: db, Dialect: gorp.PostgresDialect{}}

    // add a table, setting the table name to 'posts' and
    // specifying that the Id property is an auto incrementing PK
    dbmap.AddTableWithName(Todo{}, "todos").SetKeys(true, "Id")

    // create the table. in a production system you'd generally
    // use a migration tool, or create the tables via scripts
    err = dbmap.CreateTablesIfNotExists()
    checkErr(err, "Create tables failed")

    http.HandleFunc("/", handler)
    http.ListenAndServe(":3001", nil)
}

这是docker-compose up的详细日志（我在端口5432上拒绝连接）：

?[36mserver_1    |?[0m [gin] listening on port 3000
?[33mpostgres_1  |?[0m The files belonging to this database system will be owned by user "postgres".
?[33mpostgres_1  |?[0m This user must also own the server process.
?[33mpostgres_1  |?[0m
?[33mpostgres_1  |?[0m The database cluster will be initialized with locale "en_US.utf8".
?[33mpostgres_1  |?[0m The default database encoding has accordingly been set to "UTF8".
?[33mpostgres_1  |?[0m The default text search configuration will be set to "english".
?[33mpostgres_1  |?[0m
?[33mpostgres_1  |?[0m Data page checksums are disabled.
?[33mpostgres_1  |?[0m
?[33mpostgres_1  |?[0m fixing permissions on existing directory /var/lib/postgresql/data ... ok
?[33mpostgres_1  |?[0m creating subdirectories ... ok
?[33mpostgres_1  |?[0m selecting default max_connections ... 100
?[33mpostgres_1  |?[0m selecting default shared_buffers ... 128MB
?[33mpostgres_1  |?[0m selecting dynamic shared memory implementation ... posix
?[33mpostgres_1  |?[0m creating configuration files ... ok
?[33mpostgres_1  |?[0m creating template1 database in /var/lib/postgresql/data/base/1 ... ok
?[33mpostgres_1  |?[0m initializing pg_authid ... ok
?[33mpostgres_1  |?[0m initializing dependencies ... ok
?[33mpostgres_1  |?[0m creating system views ... ok
?[33mpostgres_1  |?[0m loading system objects' descriptions ... ok
?[33mpostgres_1  |?[0m creating collations ... ok
?[33mpostgres_1  |?[0m creating conversions ... ok
?[33mpostgres_1  |?[0m creating dictionaries ... ok
?[33mpostgres_1  |?[0m setting privileges on built-in objects ... ok
?[33mpostgres_1  |?[0m creating information schema ... ok
?[33mpostgres_1  |?[0m loading PL/pgSQL server-side language ... ok
?[33mpostgres_1  |?[0m vacuuming database template1 ... ok
?[33mpostgres_1  |?[0m copying template1 to template0 ... ok
?[33mpostgres_1  |?[0m copying template1 to postgres ... ok
?[33mpostgres_1  |?[0m syncing data to disk ... ok
?[33mpostgres_1  |?[0m
?[33mpostgres_1  |?[0m WARNING: enabling "trust" authentication for local connections
?[33mpostgres_1  |?[0m You can change this by editing pg_hba.conf or using the option -A, or
?[33mpostgres_1  |?[0m --auth-local and --auth-host, the next time you run initdb.
?[33mpostgres_1  |?[0m
?[33mpostgres_1  |?[0m Success. You can now start the database server using:
?[33mpostgres_1  |?[0m
?[33mpostgres_1  |?[0m     pg_ctl -D /var/lib/postgresql/data -l logfile start
?[33mpostgres_1  |?[0m
?[33mpostgres_1  |?[0m waiting for server to start....LOG:  database system was shut down at 2016-08-19 18:31:55 UTC
?[33mpostgres_1  |?[0m LOG:  MultiXact member wraparound protections are now enabled
?[33mpostgres_1  |?[0m LOG:  database system is ready to accept connections
?[33mpostgres_1  |?[0m LOG:  autovacuum launcher started
?[33mpostgres_1  |?[0m  done
?[33mpostgres_1  |?[0m server started
?[33mpostgres_1  |?[0m ALTER ROLE
?[33mpostgres_1  |?[0m
?[33mpostgres_1  |?[0m
?[33mpostgres_1  |?[0m /docker-entrypoint.sh: ignoring /docker-entrypoint-initdb.d/*
?[33mpostgres_1  |?[0m
?[33mpostgres_1  |?[0m LOG:  received fast shutdown request
?[33mpostgres_1  |?[0m LOG:  aborting any active transactions
?[33mpostgres_1  |?[0m LOG:  autovacuum launcher shutting down
?[33mpostgres_1  |?[0m LOG:  shutting down
?[33mpostgres_1  |?[0m waiting for server to shut down....LOG:  database system is shut down
?[33mpostgres_1  |?[0m  done
?[33mpostgres_1  |?[0m server stopped
?[33mpostgres_1  |?[0m
?[33mpostgres_1  |?[0m PostgreSQL init process complete; ready for start up.
?[33mpostgres_1  |?[0m
?[33mpostgres_1  |?[0m LOG:  database system was shut down at 2016-08-19 18:31:57 UTC
?[33mpostgres_1  |?[0m LOG:  MultiXact member wraparound protections are now enabled
?[33mpostgres_1  |?[0m LOG:  database system is ready to accept connections
?[33mpostgres_1  |?[0m LOG:  autovacuum launcher started
?[36mserver_1    |?[0m 2016/08/19 18:32:05 Create tables failed dial tcp [::1]:5432: getsockopt: connection refused
?[36mserver_1    |?[0m 2016/08/19 18:32:05 http: proxy error: dial tcp [::1]:3001: getsockopt: connection refused
?[36mserver_1    |?[0m 2016/08/19 18:32:05 Create tables failed dial tcp [::1]:5432: getsockopt: connection refused
?[36mserver_1    |?[0m 2016/08/19 18:32:05 http: proxy error: dial tcp [::1]:3001: getsockopt: connection refused

所以我的问题是我如何才能使它们能够互相交谈，而我在这里究竟在做什么错呢？

Answer 1

这是一个docker联网问题。您可以在此处了解更多信息。 Docker dns会进行所有艰苦的工作，因此您可以通过在撰写文件中为其指定的名称访问每个容器。

Posgres网址通常像

postgresql://user:password@ip:port/database

所以对你来说，就像是。

db, err := sql.Open("postgres", "postgresql://user:password@postgres/mydatabase)

请注意，如果postgres位于标准端口（5432）上，则不需要该端口。

Answer 2

事实证明，由于我实际上并未链接容器，因此 os.Getenv("DB_EN​​V_POSTGRES_PASSWORD") 生成了一个空字符串。在 docker-compose.yml 中向服务器容器添加了带有密码的环境变量，现在我可以连接到我的数据库。