postgresql - GoLang 服务无法使用 docker compose 访问 Postgres

Question

我有一个用 Go 编写的 HTML 服务。它使用 Postgres，但是当使用 docker compose 将它们组合在一起时，我得到“dial tcp 0.0.0.0:5432: connect: connection refused”

在仅使用 docker 并引用 Postgres 的运行图像构建启动服务时工作

来自 go 的调用片段

    psqlInfo := fmt.Sprintf("host=%s port=%s user=%s password=%s dbname=%s sslmode=disable", host, port, user, password, dbname)

    db, err := sql.Open("postgres", psqlInfo)
    if err != nil {
        fmt.Println(err)
        return nil, err
    }

调试时自己确认

    host = os.Getenv("pgHost")
    port = os.Getenv("pgPort")
    user = os.Getenv("pgUser")
    password = os.Getenv("pgPassword")
    dbname = os.Getenv("pgDbName")

    fmt.Println("host = ", host)
    fmt.Println("port = ", port)
    fmt.Println("user = ", user)
    fmt.Println("password = ", password)
    fmt.Println("dbname = ", dbname)

docker 文件

FROM golang as builder

ENV GO111MODULE=on

WORKDIR /app

COPY go.mod .
COPY go.sum .

RUN go mod download

COPY . .

RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -o /app/doggos


FROM scratch
COPY --from=builder /app/doggos /app/
EXPOSE 7000
ENTRYPOINT ["/app/doggos"]

docker-compose.yml

version: '3.5'
services:
    app:
      build: .
      ports:
        - "7000:7000"
      environment:
        pgHost: "0.0.0.0"
        pgPort: 5432
        pgUser: "postgres"
        pgPassword: "postgres_docker"
        pgDbName: "postgres"      
        dbType: "POSTGRES"
      depends_on:
        - postgres-db
      links:
        - postgres-db

    postgres-db:
      image: postgres:latest
      restart: always
      environment:
        POSTGRES_PASSWORD: "postgres_docker"
        POSTGRES_DB: "postgres"
        POSTGRES_USER: "postgres"
        POSTGRES_HOST: "0.0.0.0"
        POSTGRES_PORT: 5432
        PGDATA: /var/lib/postgresql/data/pg_data
      ports:
        - "5432:5432"
      volumes:
        - ./scripts/postgres/schema.sql:/docker-entrypoint-initdb.d/1-schema.sql
        - ./scripts/postgres/table.sql:/docker-entrypoint-initdb.d/2-table.sql

volumes:
  pg_data:

postgres-db_1  | 2019-07-12 19:43:36.172 UTC [1] LOG:  listening on IPv4 address "0.0.0.0", port 5432
postgres-db_1  | 2019-07-12 19:43:36.172 UTC [1] LOG:  listening on IPv6 address "::", port 5432
postgres-db_1  | 2019-07-12 19:43:36.175 UTC [1] LOG:  listening on Unix socket "/var/run/postgresql/.s.PGSQL.5432"
postgres-db_1  | 2019-07-12 19:43:36.189 UTC [72] LOG:  database system was shut down at 2019-07-12 19:43:36 UTC
postgres-db_1  | 2019-07-12 19:43:36.195 UTC [1] LOG:  database system is ready to accept connections
app_1          | host =  0.0.0.0
app_1          | port =  5432
app_1          | user =  postgres
app_1          | password =  postgres_docker
app_1          | dbname =  postgres
app_1          | dial tcp 0.0.0.0:5432: connect: connection refused
app_1          | 2019/07/12 19:44:36 http: panic serving 192.168.0.1:56494: runtime error: invalid memory address or nil pointer dereference
app_1          | goroutine 3 [running]:
app_1          | net/http.(*conn).serve.func1(0xc0000b7180)
app_1          |    /usr/local/go/src/net/http/server.go:1769 +0x139
app_1          | panic(0x8b8780, 0xd75170)

Answer 1

你应该使用postgres-db(最好是给它一个不带破折号的简单名称，例如db)来设置数据库主机，而不是0.0.0.0

容器是使用postgres-db 的配置创建的。它以名称 postgres-db 加入网络。

每个容器都可以查找主机名 app 或 postgres-db 并取回相应容器的 IP 地址。例如，app 的应用程序代码可以连接到 URL postgres://postgres-db:5432 并开始使用 Postgres 数据库。

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