docker - 进入 Dockerfile。我找不到包错误

Question

我在“docker-compose”期间添加了RUN go get 来安装包。但是，当我运行 go build 时，出现了以下 cannot find package 错误。我发现软件包保存在 /go/pkg/linux_amd64/ 中。

运行 docker-compose 并开始构建

$ docker-compose up -d
$ docker exec -it explorer-cli /bin/bash
# pwd
/go
# ls     
bin  pkg  src
# echo $GOPATH
/go
# ls /go/pkg/linux_amd64/github.com/
go-sql-driver
# go build -i -o /go/bin/explorer-cli src/main.go 
src/main.go:6:2: cannot find package "github.com/go-sql-driver/mysql" in any of:
    /usr/local/go/src/github.com/go-sql-driver/mysql (from $GOROOT)
    /go/src/github.com/go-sql-driver/mysql (from $GOPATH)

(it worked if I run "go get" manually)
# go get github.com/go-sql-driver/mysql
# ls src/
github.com  main.go
# go build -i -o /go/bin/explorer-cli src/main.go

docker-compose.yml

version: '3.4'

services:
  mysql:
    image: mysql:latest
    container_name: database
    volumes:
      - ./docker/:/etc/mysql/conf.d
      - ./docker/:/docker-entrypoint-initdb.d
    environment:
      - MYSQL_RANDOM_ROOT_PASSWORD=true
      - MYSQL_DATABASE=explorer
      - MYSQL_USER=admin
      - MYSQL_PASSWORD=12dlql*41
  app:
    build: .
    tty: true
    image: explorer-cli:latest
    container_name: explorer-cli
    volumes:
      - ./src:/go/src
    external_links:
      - database

Dockerfile

FROM golang:latest

RUN apt-get update
RUN apt-get upgrade -y

ENV GOBIN /go/bin

RUN go get github.com/go-sql-driver/mysql

ma​​in.go

package main

import (
    "database/sql"

    _ "github.com/go-sql-driver/mysql"
)

func main() {
    db, err := sql.Open("mysql", "XUSER:XXXX@(database:3306)/explorer")
    if err != nil {
        panic(err.Error())
    }
    defer db.Close()
}

---

更新 1

我注意到以下目录之间存在很大差异。

# ls /go/pkg/linux_amd64/github.com/go-sql-driver/
mysql.a

# ls /go/src/github.com/go-sql-driver/mysql/
AUTHORS                 connection_go18_test.go packets.go
CHANGELOG.md            connection_test.go      packets_test.go
CONTRIBUTING.md         const.go                result.go
LICENSE                 driver.go               rows.go
README.md               driver_go18_test.go     statement.go
appengine.go            driver_test.go          statement_test.go
benchmark_go18_test.go  dsn.go                  transaction.go
benchmark_test.go       dsn_test.go             utils.go
buffer.go               errors.go               utils_go17.go
collations.go           errors_test.go          utils_go18.go
connection.go           fields.go               utils_go18_test.go
connection_go18.go      infile.go               utils_test.go

---

更新 2

正如@aerokite 所说，“卷”覆盖了下载的包。我进行了如下更改并且有效。

Dockerfile

version: '3.4'

FROM golang:latest

RUN apt-get update
RUN apt-get upgrade -y

ENV GOBIN /go/bin

RUN go get github.com/go-sql-driver/mysql

RUN mkdir /go/src/explorer-cli

docker-compose

services:
  mysql:
    image: mysql:latest
    container_name: database
    volumes:
      - ./docker/:/etc/mysql/conf.d
      - ./docker/:/docker-entrypoint-initdb.d
    environment:
      - MYSQL_RANDOM_ROOT_PASSWORD=true
      - MYSQL_DATABASE=explorer
      - MYSQL_USER=XUSER
      - MYSQL_PASSWORD=XXXX
  app:
    build: .
    tty: true
    image: explorer-cli:latest
    container_name: explorer-cli
    volumes:
      - ./src/explorer-cli:/go/src/explorer-cli
    external_links:
      - database

开始构建

go build -i -o /go/bin/explorer-cli src/explorer-cli/main.go

Answer 1

我已尝试重现您的问题。

FROM golang:latest

RUN apt-get update
RUN apt-get upgrade -y

ENV GOBIN /go/bin

RUN go get github.com/go-sql-driver/mysql

您已经提供了这个 Dockerfile。我建好了

$ docker build -t test .

现在我执行此图像以运行您的 go build 命令。

$ docker run -it test bash

然后我在 /go/src 目录中创建了您提供的 main.go。

最后，我构建成功，没有任何错误

$ go build -i -o /go/bin/explorer-cli src/main.go

我想我已经找到了你的问题。我从未使用过docker-compose。但你会明白的。

问题在这里:

  app:
    build: .
    tty: true
    image: explorer-cli:latest
    container_name: explorer-cli
    volumes:
      - ./src:/go/src  <-- problem is here
    external_links:
      - database

您正在将 ./src 挂载到 docker 中的 /go/src 目录中。这个过程是用你的本地 ./src 覆盖你的 docker 中的目录 /go/src。这将删除您从 go get github.com/go-sql-driver/mysql

获得的数据

你明白了吗？

但是当你运行 go get github.com/go-sql-driver/mysql 时，它现在再次获取数据。

解决方案(01):

将您的本地卷安装到其他地方。

volumes:
  - ./src:/tmp/src

并修改您的 Dockerfile 以将此 main.go 移动到 /go/src

解决方案(02):

将 main.go 复制到您的 docker 中。在 Dockerfile 中添加这一行

COPY ./src/main.go /go/src