Go 项目结构与工具链

// cmd/server/main.go - 入口文件示例
package main

import (
	"fmt"
	"net/http"
)

func main() {
	mux := http.NewServeMux()

	mux.HandleFunc("/health", func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusOK)
		fmt.Fprintln(w, `{"status": "ok"}`)
	})

	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		fmt.Fprintln(w, "Welcome to My Service")
	})

	addr := ":8080"
	fmt.Printf("Server starting on %s\n", addr)
	if err := http.ListenAndServe(addr, mux); err != nil {
		fmt.Printf("Server failed: %v\n", err)
	}
}

# 初始化模块
go mod init github.com/myuser/myproject

# 添加依赖
go get github.com/gin-gonic/gin@v1.9.1

# 整理依赖（移除未使用的，添加缺失的）
go mod tidy

# 查看依赖列表
go list -m all

# 查看某个依赖的可用版本
go list -m -versions github.com/gin-gonic/gin

# 升级到新版本
go get github.com/pkg/foo@v1.2.0

# 升级到最新
go get -u github.com/pkg/foo

# 降级版本
go get github.com/pkg/foo@v1.0.0

# Linux amd64
GOOS=linux GOARCH=amd64 go build -o bin/myapp-linux-amd64 ./cmd/server

# Linux arm64
GOOS=linux GOARCH=arm64 go build -o bin/myapp-linux-arm64 ./cmd/server

# macOS arm64 (Apple Silicon)
GOOS=darwin GOARCH=arm64 go build -o bin/myapp-darwin-arm64 ./cmd/server

# Windows amd64
GOOS=windows GOARCH=amd64 go build -o bin/myapp-windows-amd64.exe ./cmd/server

# 查看所有支持的平台
go tool dist list

PLATFORMS := linux/amd64 linux/arm64 darwin/amd64 darwin/arm64 windows/amd64

.PHONY: build-all
build-all:
	@for platform in $(PLATFORMS); do \
		os=$${platform%/*}; \
		arch=$${platform#*/}; \
		ext=""; \
		if [ "$$os" = "windows" ]; then ext=".exe"; fi; \
		echo "Building $$os/$$arch..."; \
		GOOS=$$os GOARCH=$$arch go build $(LDFLAGS) \
			-o bin/$(APP_NAME)-$$os-$$arch$$ext ./cmd/server; \
	done

# 格式化当前目录
go fmt ./...

# 检查是否有需要格式化的文件（CI 中使用）
gofmt -l .

go vet ./...

# 安装
go install github.com/golangci/golangci-lint/cmd/golangci-lint@latest

# 运行检查
golangci-lint run

# 使用配置文件
golangci-lint run --config .golangci.yml

linters:
  enable:
    - errcheck      # 检查未处理的错误
    - gosimple      # 简化代码建议
    - govet         # 静态分析
    - ineffassign   # 无效赋值
    - staticcheck   # 综合检查
    - unused        # 未使用的代码
    - gofmt         # 格式检查

run:
  timeout: 5m
  tests: true

# go run：编译并立即运行（不生成文件）
go run ./cmd/server

# go build：编译生成可执行文件
go build -o bin/server ./cmd/server

# go install：编译并安装到 $GOPATH/bin
go install ./cmd/server

# 查看当前配置
go env

# 常用环境变量
echo $GOROOT      # Go 安装目录
echo $GOPATH      # 工作空间目录
echo $GOPROXY     # 模块代理（国内常用）
echo $GOSUMDB     # 校验数据库
echo $GOOS        # 目标操作系统
echo $GOARCH      # 目标架构

# 设置国内代理
go env -w GOPROXY=https://goproxy.cn,direct

# 设置校验（私有仓库可能需要关闭）
go env -w GOSUMDB=off

# 设置私有仓库（如果需要）
go env -w GOPRIVATE=gitlab.mycompany.com

// internal/service/user.go
package service

import "fmt"

type User struct {
	ID   int
	Name string
}

type UserService struct{}

func NewUserService() *UserService {
	return &UserService{}
}

func (s *UserService) GetUser(id int) (*User, error) {
	if id <= 0 {
		return nil, fmt.Errorf("invalid user id: %d", id)
	}
	return &User{ID: id, Name: fmt.Sprintf("User-%d", id)}, nil
}

// internal/service/user_test.go
package service

import "testing"

func TestGetUser(t *testing.T) {
	svc := NewUserService()

	tests := []struct {
		name    string
		id      int
		wantErr bool
	}{
		{"正常用户", 1, false},
		{"无效ID", 0, true},
		{"负数ID", -1, true},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			user, err := svc.GetUser(tt.id)
			if (err != nil) != tt.wantErr {
				t.Errorf("GetUser(%d) error = %v, wantErr %v", tt.id, err, tt.wantErr)
			}
			if !tt.wantErr && user.ID != tt.id {
				t.Errorf("GetUser(%d).ID = %d, want %d", tt.id, user.ID, tt.id)
			}
		})
	}
}