Docker容器中Go服务部署静态React文件遇404错误

本地执行go run main.go时，8000端口可正常访问前端页面；但构建Docker镜像并运行后，访问始终返回404错误。已尝试修改router.Run监听地址、使用host网络模式，均未解决问题。

相关代码与配置 #

main.go核心代码

package main

import (
    "fmt"
    "log"
    "os"

    "github.com/gin-gonic/gin"
    "github.com/gin-contrib/cors"
    "net/http"
)

func main() {
    serveApplication()
}

func serveApplication() {
    corsConfig := cors.Config {
        AllowOrigins: []string{"*"},
        AllowMethods: []string{"GET", "POST", "PUT", "DELETE", "OPTIONS"},
        AllowHeaders: []string{"Origin", "Content-Type", "Authorization"},
        AllowCredentials: true,
    }

    router := gin.Default()
    router.Use(cors.New(corsConfig))

    router.StaticFS("/static", http.Dir("./frontend/build/static"))
    router.StaticFile("/", "./frontend/build/index.html")
    router.Run(":8000")
    fmt.Println("Server running on port 8000") // 此代码不会执行，router.Run为阻塞方法
}

Dockerfile内容

FROM node:16-alpine3.11 as build-node

WORKDIR /workdir
COPY frontend/ .
RUN yarn install
RUN yarn build

COPY .env /workdir/

FROM golang:1.21-rc-alpine3.18 as build-go
ENV GOPATH ""
RUN go env -w GOPROXY=direct
RUN apk add git

ADD go.mod go.sum ./
RUN go mod download
ADD . .
COPY --from=build-node /workdir/build ./frontend/build
RUN go build -o /main

FROM alpine:3.13
COPY --from=build-go /main /main
COPY --from=build-node /workdir/.env .env
EXPOSE 8000
ENTRYPOINT [ "/main" ]

目录结构

portal
- frontend（React应用存放目录）
- backend（后端逻辑目录）
- Dockerfile
- main.go
- go.mod

核心问题 #

容器运行时缺少前端构建文件：最终的alpine阶段仅复制了编译好的/main和.env，但未将frontend/build目录同步到容器中，导致Go程序找不到静态资源，返回404。

另外，router.Run(":8000")是阻塞方法，后续的fmt.Println永远不会执行，可调整位置让启动日志正常输出。

修正步骤 #

1. 修改Dockerfile的最终阶段，添加复制前端构建文件的命令：
   在COPY --from=build-node /workdir/.env .env后新增：

COPY --from=build-go /go/frontend/build ./frontend/build

（注：golang基础镜像默认工作目录为/go，ADD . .会将本地portal目录内容全部复制到该路径下）

若想避免路径混淆，也可在build-go阶段明确设置工作目录：

FROM golang:1.21-rc-alpine3.18 as build-go
WORKDIR /app  # 新增工作目录设置
ENV GOPATH ""
RUN go env -w GOPROXY=direct
RUN apk add git

ADD go.mod go.sum ./
RUN go mod download
ADD . .
COPY --from=build-node /workdir/build ./frontend/build
RUN go build -o /main

此时最终阶段复制路径改为：

COPY --from=build-go /app/frontend/build ./frontend/build

2. 调整main.go的日志输出位置：
   将fmt.Println("Server running on port 8000")移到router.Run(":8000")之前，确保启动信息能正常打印：

fmt.Println("Server running on port 8000")
router.Run(":8000")

3. 确认监听地址：
   router.Run(":8000")已正确监听容器内所有网卡（等价于0.0.0.0:8000），无需修改。

修正后的完整Dockerfile示例 #

FROM node:16-alpine3.11 as build-node

WORKDIR /workdir
COPY frontend/ .
RUN yarn install
RUN yarn build

COPY .env /workdir/

FROM golang:1.21-rc-alpine3.18 as build-go
WORKDIR /app
ENV GOPATH ""
RUN go env -w GOPROXY=direct
RUN apk add git

ADD go.mod go.sum ./
RUN go mod download
ADD . .
COPY --from=build-node /workdir/build ./frontend/build
RUN go build -o /main

FROM alpine:3.13
COPY --from=build-go /main /main
COPY --from=build-node /workdir/.env .env
COPY --from=build-go /app/frontend/build ./frontend/build
EXPOSE 8000
ENTRYPOINT [ "/main" ]

重新构建并运行容器：

docker build -t portal .
docker run -p 8000:8000 --name portal portal

此时容器内的Go程序可正常读取静态文件，页面访问恢复正常。

内容的提问来源于stack exchange，提问作者Alfie Danger