Docker环境下Gin应用本地无法访问及调试失败问题求助

我使用Go语言和Gin框架开发Web应用，希望通过Docker容器运行并实现调试功能，但本地8080端口访问无响应，VS Code启动调试也报错。以下是我的配置和运行日志：

Dockerfile #

FROM golang:1.21.6

WORKDIR /go/src/gitlab.com/main/server

COPY go.mod .
COPY go.sum .

RUN go mod download

RUN go install github.com/cosmtrek/air@latest
RUN go install github.com/swaggo/swag/cmd/swag@latest
RUN go install github.com/go-delve/delve/cmd/dlv@latest

EXPOSE 2345
EXPOSE 80

docker-compose配置 #

version: "3.2"
services:
  service-influxdb:
    image: go-time-series
    build:
      context: ..
      dockerfile: docker/Dockerfile
    command: air -c .air.toml
    volumes:
      - ../:/go/src/gitlab.com/main/server
    ports:
      - 8080:80
      - 10000:2345
    environment:
      - WEB_APP_VERSION=0.0.1
      - WEP_APP_TITLE=Thori influx-DB
      - WEP_APP_DESCRIPTION=Micro service for the manage of the influx-db services
      - ENVIRONMENT=dev
      - HOST=localhost:8080
      - INFLUX_URL=http://localhost:8086
      - INFLUX_TOKEN=1234
      - INFLUX_ORG=Abc
      - INFLUX_MINIMUN_DATE=1677-09-21 00:12:44
      - INFLUX_MAXIMUN_DATE=2100-01-01 00:00:00

    network_mode: host

VS Code调试配置 #

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Debug in Docker",
            "type": "go",
            "request": "attach",
            "mode": "remote",
            "remotePath": "/go/src/gitlab.com/main/server",
            "port": 10000,
            "host": "127.0.0.1",
            "showLog": true,
            "trace": "log",
            "logOutput": "rpc"
        },
    ]
}

.air.toml配置 #

root = "."
testdata_dir = "testdata"
tmp_dir = "tmp"

[build]
  args_bin = []
  bin = "./tmp/main"
  full_bin = "dlv exec --accept-multiclient --headless --listen :2345 --api-version 2 ./tmp/main"
  pre_cmd = ["swag init -g ./cmd/main.go"]
  cmd = "go build -o ./tmp/main ./cmd/main.go"
  post_cmd = []
  delay = 0
  exclude_dir = ["assets", "tmp", "vendor", "testdata", "docs"]
  exclude_file = []
  exclude_regex = ["_test.go"]
  exclude_unchanged = true
  follow_symlink = true
  include_dir = []
  include_ext = ["go", "tpl", "tmpl", "html"]
  include_file = []
  kill_delay = "0s"
  log = "build-errors.log"
  poll = false
  poll_interval = 0
  rerun = false
  rerun_delay = 500
  send_interrupt = false
  stop_on_error = false

[color]
  app = ""
  build = "yellow"
  main = "magenta"
  runner = "green"
  watcher = "cyan"

[log]
  main_only = false
  time = true

[misc]
  clean_on_exit = true

[screen]
  clear_on_rebuild = true
  keep_scroll = true

应用main函数代码 #

func main() {
    port := flag.Int("port", 80, "Listening port")
    flag.Parse()

    if config.Cfg.Environment == "prod" {
        gin.ForceConsoleColor()
        gin.SetMode(gin.ReleaseMode)
    }

    router := gin.Default()
    loadSwagger(router)
    loadAPI(router)
    router.Run(fmt.Sprintf(":%d", *port))
}

func loadSwagger(router *gin.Engine) {
    //  @securityDefinitions.apikey ApiKeyAuth
    //  @in                         Header
    //  @name                       Authorization

    docs.SwaggerInfo.Title = config.Cfg.WebAppTitle
    docs.SwaggerInfo.Version = config.Cfg.WebAppVersion
    docs.SwaggerInfo.Description = config.Cfg.WebAppDescription
    docs.SwaggerInfo.Host = config.Cfg.Host

    router.GET("/docs/*any", ginSwagger.WrapHandler(swaggerFiles.Handler))
}

运行日志 #

docker-service-influxdb-1  | [21:07:26] mkdir /go/src/gitlab.com/main/server/tmp
docker-service-influxdb-1  | [21:07:26] watching .
docker-service-influxdb-1  | [21:07:26] watching app
docker-service-influxdb-1  | [21:07:26] watching app/api
docker-service-influxdb-1  | [21:07:26] watching app/api/handlers
docker-service-influxdb-1  | [21:07:26] watching app/api/handlers/healthcheck
docker-service-influxdb-1  | [21:07:26] watching app/config
docker-service-influxdb-1  | [21:07:26] watching app/domain
docker-service-influxdb-1  | [21:07:26] watching app/domain/models
docker-service-influxdb-1  | [21:07:26] watching app/domain/ports
docker-service-influxdb-1  | [21:07:26] watching app/domain/services
docker-service-influxdb-1  | [21:07:26] watching app/repositories
docker-service-influxdb-1  | [21:07:26] watching cmd
docker-service-influxdb-1  | [21:07:26] watching docker
docker-service-influxdb-1  | [21:07:26] !exclude docs
docker-service-influxdb-1  | [21:07:26] !exclude tmp
docker-service-influxdb-1  | [21:07:26] > swag init -g ./cmd/main.go
docker-service-influxdb-1  | 2024/02/07 21:07:26 Generate swagger docs....
docker-service-influxdb-1  | 2024/02/07 21:07:26 Generate general API Info, search dir:./
docker-service-influxdb-1  | 2024/02/07 21:07:26 warning: failed to get package name in dir: ./, error: execute go list command, exit status 1, stdout:, stderr:no Go files in /go/src/gitlab.com/main/server
docker-service-influxdb-1  | 2024/02/07 21:07:26 Generating models.HealthCheck
docker-service-influxdb-1  | 2024/02/07 21:07:26 create docs.go at docs/docs.go
docker-service-influxdb-1  | 2024/02/07 21:07:26 create swagger.json at docs/swagger.json
docker-service-influxdb-1  | 2024/02/07 21:07:26 create swagger.yaml at docs/swagger.yaml
docker-service-influxdb-1  | [21:07:26] building...
docker-service-influxdb-1  | [21:07:27] running...
docker-service-influxdb-1  | API server listening at: [::]:2345
docker-service-influxdb-1  | 2024-02-07T21:07:27Z warning layer=rpc Listening for remote connections (connections are not authenticated nor encrypted)

问题根源 #

1. network_mode: host 导致端口映射失效
   当docker-compose设置network_mode: host时，容器会直接使用宿主机的网络栈，此时ports配置会被完全忽略。容器内应用监听的80端口直接暴露在宿主机的80端口，而非配置的8080；Delve监听的2345端口直接暴露在宿主机2345，而非10000，这就是VS Code调试连接失败的核心原因。

2. 应用监听地址限制
   Gin默认的router.Run(":80")会监听localhost，如果不用host网络，容器外部无法访问这个地址，需要改为监听0.0.0.0来允许所有网卡的连接。

3. 环境变量拼写错误
   docker-compose里的WEP_APP_TITLE和WEP_APP_DESCRIPTION是拼写错误，应为WEB_APP_TITLE和WEB_APP_DESCRIPTION，这会导致Swagger无法正确读取标题和描述配置。

修复方案 #

方案1：移除network_mode: host（推荐） #

这是Docker容器的标准用法，通过端口映射实现外部访问：

• 修改docker-compose.yml，删除network_mode: host配置
• 修正环境变量的拼写错误
• 修改main.go中的监听地址为0.0.0.0:%d

修改后的docker-compose.yml：

version: "3.2"
services:
  service-influxdb:
    image: go-time-series
    build:
      context: ..
      dockerfile: docker/Dockerfile
    command: air -c .air.toml
    volumes:
      - ../:/go/src/gitlab.com/main/server
    ports:
      - 8080:80
      - 10000:2345
    environment:
      - WEB_APP_VERSION=0.0.1
      - WEB_APP_TITLE=Thori influx-DB
      - WEB_APP_DESCRIPTION=Micro service for the manage of the influx-db services
      - ENVIRONMENT=dev
      - HOST=localhost:8080
      - INFLUX_URL=http://localhost:8086
      - INFLUX_TOKEN=1234
      - INFLUX_ORG=Abc
      - INFLUX_MINIMUN_DATE=1677-09-21 00:12:44
      - INFLUX_MAXIMUN_DATE=2100-01-01 00:00:00

修改后的main.go监听代码：

router.Run(fmt.Sprintf("0.0.0.0:%d", *port))

方案2：保留network_mode: host #

如果必须使用host网络，调整端口配置：

• 删除docker-compose中的ports配置
• 修改VS Code调试配置中的port为2345
• 直接访问宿主机的80端口来访问应用

修改后的VS Code launch.json：

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Debug in Docker",
            "type": "go",
            "request": "attach",
            "mode": "remote",
            "remotePath": "/go/src/gitlab.com/main/server",
            "port": 2345,
            "host": "127.0.0.1",
            "showLog": true,
            "trace": "log",
            "logOutput": "rpc"
        }
    ]
}

额外说明 #

日志中的no Go files in /go/src/gitlab.com/main/server警告是因为项目根目录没有Go文件，swag仍能正常生成文档，不影响应用运行，可忽略。

内容的提问来源于stack exchange，提问作者Diego L