581 lines
12 KiB
Markdown
581 lines
12 KiB
Markdown
# 数据库迁移工具 - 完整指南
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## 📌 核心特点
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- ✅ **独立工具，零耦合** - 与应用代码完全分离
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- ✅ **生产就绪** - 编译成二进制，无需Go环境
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- ✅ **灵活配置** - 支持命令行参数、环境变量、配置文件
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- ✅ **Docker友好** - 挂载配置，修改无需重启容器
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---
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## 🚀 快速开始（3步）
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> **黑盒模式**：迁移工具内部调用 `migration.RunMigrationsFromConfig()` 方法，自动处理配置加载、数据库连接、迁移执行等所有细节。你只需要提供配置文件和SQL文件即可。
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### 1. 复制迁移工具模板
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```bash
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mkdir -p cmd/migrate
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cp /path/to/go-common/templates/migrate/main.go cmd/migrate/
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```
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### 2. 创建迁移文件
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```bash
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mkdir -p migrations
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```
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创建 `migrations/20240101000001_create_users.sql`：
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```sql
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CREATE TABLE users (
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id BIGINT PRIMARY KEY AUTO_INCREMENT,
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username VARCHAR(255) NOT NULL,
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email VARCHAR(255) NOT NULL,
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created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
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);
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```
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### 3. 编译和使用
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```bash
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# 编译（生产环境推荐）
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go build -o bin/migrate cmd/migrate/main.go
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# 使用
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./bin/migrate up # 使用默认配置
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./bin/migrate up -config /path/to/config.json # 指定配置
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./bin/migrate status # 查看状态
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./bin/migrate -help # 查看帮助
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```
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---
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## 💻 本地使用
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### 开发环境
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```bash
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# 直接运行（需要Go环境）
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go run cmd/migrate/main.go up
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go run cmd/migrate/main.go up -config dev.json
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# 编译后运行（推荐）
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go build -o bin/migrate cmd/migrate/main.go
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./bin/migrate up
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./bin/migrate up -config config.prod.json
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./bin/migrate up -c prod.json -d db/migrations
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```
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### 命令说明
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```bash
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./bin/migrate -help
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# 输出：
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# 用法: migrate [命令] [选项]
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#
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# 命令:
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# up 执行所有待执行的迁移（默认）
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# down 回滚最后一个迁移
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# status 查看迁移状态
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#
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# 选项:
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# -config, -c 配置文件路径（默认: config.json）
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# -dir, -d 迁移文件目录（默认: migrations）
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# -help, -h 显示帮助信息
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```
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### 配置方式
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#### 方式1：配置文件（推荐开发环境）
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`config.json`:
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```json
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{
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"database": {
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"type": "mysql",
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"host": "localhost",
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"port": 3306,
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"user": "root",
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"password": "password",
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"database": "mydb"
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}
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}
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```
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#### 方式2：环境变量指定配置文件路径（推荐生产环境）
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```bash
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# 使用环境变量指定配置文件路径
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export CONFIG_FILE="/etc/app/config.json"
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export MIGRATIONS_DIR="/opt/app/migrations"
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./bin/migrate up
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```
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#### 配置优先级（从高到低）
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1. 命令行参数 `-config` 和 `-dir`（最高）
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2. 环境变量 `CONFIG_FILE` 和 `MIGRATIONS_DIR`
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3. 默认值 `config.json` 和 `migrations`
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---
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## 🐳 Docker 使用
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### 方式1：挂载配置文件（推荐）⭐
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**优势**：修改配置无需重启容器！
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#### docker-compose.yml
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```yaml
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version: '3.8'
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services:
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app:
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build: .
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ports:
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- "8080:8080"
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volumes:
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# 挂载配置文件（推荐：修改配置无需重启容器）
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- ./config.json:/app/config.json:ro
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# 启动时先执行迁移，再启动应用
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command: sh -c "./migrate up && ./server"
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```
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#### 使用方式
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```bash
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# 1. 启动服务
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docker-compose up -d
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# 2. 修改配置文件
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vim config.json
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# 3. 手动执行迁移（无需重启容器！）
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docker-compose exec app ./migrate up
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# 4. 查看状态
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docker-compose exec app ./migrate status
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```
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### 方式2：指定配置文件路径
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适用于多环境部署：
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```yaml
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services:
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app:
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build: .
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volumes:
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# 挂载不同环境的配置文件
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- ./config.prod.json:/app/config.json:ro
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command: sh -c "./migrate up -config /app/config.json && ./server"
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```
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```bash
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# 手动切换环境（修改挂载的配置文件后）
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docker-compose exec app ./migrate up
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```
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### 方式3：使用环境变量指定配置文件路径
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适用于多环境部署，通过环境变量指定不同环境的配置文件：
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```yaml
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services:
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app:
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build: .
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environment:
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CONFIG_FILE: /app/config.prod.json
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MIGRATIONS_DIR: /app/migrations
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volumes:
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- ./config.prod.json:/app/config.prod.json:ro
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command: sh -c "./migrate up && ./server"
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```
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### Dockerfile
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```dockerfile
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FROM golang:1.21 as builder
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WORKDIR /app
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COPY go.mod go.sum ./
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RUN go mod download
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COPY . .
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# 编译应用和迁移工具
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RUN go build -o bin/server cmd/server/main.go
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RUN go build -o bin/migrate cmd/migrate/main.go
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FROM debian:bookworm-slim
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WORKDIR /app
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RUN apt-get update && apt-get install -y ca-certificates && rm -rf /var/lib/apt/lists/*
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# 复制二进制文件和迁移文件
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COPY --from=builder /app/bin/migrate .
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COPY --from=builder /app/bin/server .
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COPY --from=builder /app/migrations ./migrations
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EXPOSE 8080
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# 启动：先迁移，再启动应用
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CMD ["sh", "-c", "./migrate up && ./server"]
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# 注意：配置文件通过 volumes 挂载，不打包进镜像
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```
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---
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## ☸️ Kubernetes 部署
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### 使用 Job 执行迁移
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```yaml
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# k8s-job-migrate.yaml
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apiVersion: batch/v1
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kind: Job
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metadata:
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name: db-migrate
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spec:
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template:
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spec:
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containers:
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- name: migrate
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image: myapp:latest
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command: ["./migrate", "up", "-config", "/etc/config/database.json"]
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volumeMounts:
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- name: config
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mountPath: /etc/config
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readOnly: true
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volumes:
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- name: config
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configMap:
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name: app-config
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restartPolicy: OnFailure
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```
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### 部署流程
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```bash
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# 1. 创建 ConfigMap
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kubectl create configmap app-config --from-file=config.json
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# 2. 执行迁移
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kubectl apply -f k8s-job-migrate.yaml
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kubectl wait --for=condition=complete job/db-migrate
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# 3. 部署应用
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kubectl apply -f k8s-deployment.yaml
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```
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---
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## 🔧 CI/CD 集成
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### GitLab CI
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```yaml
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# .gitlab-ci.yml
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stages:
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- build
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- migrate
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- deploy
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build:
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stage: build
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script:
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- go build -o bin/migrate cmd/migrate/main.go
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- go build -o bin/server cmd/server/main.go
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artifacts:
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paths:
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- bin/
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migrate:
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stage: migrate
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script:
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- ./bin/migrate up -config config.prod.json
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environment:
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name: production
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deploy:
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stage: deploy
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script:
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- ./bin/server
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```
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### GitHub Actions
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```yaml
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# .github/workflows/deploy.yml
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name: Deploy
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on:
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push:
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branches: [main]
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jobs:
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deploy:
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runs-on: ubuntu-latest
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steps:
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- uses: actions/checkout@v3
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- name: Set up Go
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uses: actions/setup-go@v4
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with:
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go-version: '1.21'
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- name: Build
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run: |
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go build -o bin/migrate cmd/migrate/main.go
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go build -o bin/server cmd/server/main.go
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- name: Create Config File
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run: |
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echo '${{ secrets.CONFIG_JSON }}' > config.json
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- name: Run Migrations
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run: ./bin/migrate up -config config.json
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- name: Deploy
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run: ./bin/server
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```
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---
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## 📁 迁移文件管理
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### 文件命名规则
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```
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migrations/
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├── 20240101000001_create_users.sql # Up 迁移
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├── 20240101000001_create_users.down.sql # Down 回滚（可选）
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├── 20240102000001_add_posts.sql
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└── 20240102000001_add_posts.down.sql
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```
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格式：`{时间戳}_{描述}.sql`
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### 创建迁移文件
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```bash
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# 获取时间戳
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date +%Y%m%d%H%M%S
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# 输出：20240101120000
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# 创建迁移文件
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vim migrations/20240101120000_create_posts.sql
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```
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### 迁移文件示例
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**Up 文件**：
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```sql
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-- migrations/20240101000001_create_users.sql
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CREATE TABLE users (
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id BIGINT PRIMARY KEY AUTO_INCREMENT,
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username VARCHAR(255) NOT NULL UNIQUE,
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email VARCHAR(255) NOT NULL UNIQUE,
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created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
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);
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CREATE INDEX idx_users_email ON users(email);
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```
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**Down 文件**（可选）：
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```sql
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-- migrations/20240101000001_create_users.down.sql
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DROP INDEX idx_users_email ON users;
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DROP TABLE IF EXISTS users;
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```
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### 兼容性建议
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使用条件语句确保迁移可重复执行：
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```sql
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-- 创建表
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CREATE TABLE IF NOT EXISTS users (...);
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-- 添加列
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ALTER TABLE posts ADD COLUMN IF NOT EXISTS author_id BIGINT;
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-- 创建索引
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CREATE INDEX IF NOT EXISTS idx_posts_author ON posts(author_id);
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```
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---
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## 🔍 常见问题
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### Q: 为什么不直接在应用代码中调用？
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**A**: **耦合度太高！** 独立工具的优势：
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- ✅ 应用和迁移完全解耦
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- ✅ 可以独立部署和执行
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- ✅ 更灵活的部署策略
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- ✅ 符合单一职责原则
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### Q: 生产环境没有Go怎么办？
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**A**: **编译成二进制文件**！
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```bash
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# 本地或CI中编译
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go build -o bin/migrate cmd/migrate/main.go
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# 部署二进制文件（不需要Go环境）
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scp bin/migrate server:/app/
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ssh server "/app/migrate up"
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```
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### Q: Docker中修改配置需要重启吗？
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**A**: **不需要！** 使用挂载方式：
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```yaml
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volumes:
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- ./config.json:/app/config.json:ro
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```
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修改后直接执行：
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```bash
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docker-compose exec app ./migrate up
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```
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### Q: 如何指定不同的配置文件？
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**A**: 使用命令行参数：
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```bash
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# 开发环境
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./migrate up -config config.dev.json
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# 测试环境
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./migrate up -config config.test.json
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# 生产环境
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./migrate up -config /etc/app/config.prod.json
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```
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### Q: 多个实例同时启动会有问题吗？
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**A**: 不会。数据库会保证只有一个实例能执行迁移（通过版本号主键）。
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### Q: Docker连不上数据库？
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**A**: 注意主机名：
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- ❌ `localhost`（容器内无法访问宿主机）
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- ✅ `db`（docker-compose 服务名）
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- ✅ `host.docker.internal`（Mac/Windows 访问宿主机）
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---
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## 💡 最佳实践
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### 1. 开发环境
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- 使用 `go run` 快速迭代
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- 使用配置文件管理不同环境
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```bash
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go run cmd/migrate/main.go up -config config.dev.json
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```
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### 2. 测试环境
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- 编译后部署，模拟生产环境
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- 使用独立的数据库
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|
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```bash
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go build -o bin/migrate cmd/migrate/main.go
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./bin/migrate up -config config.test.json
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```
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### 3. 生产环境
|
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|
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- 编译后部署，先执行迁移再启动应用
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- 使用配置文件管理敏感信息
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|
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```bash
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go build -o bin/migrate cmd/migrate/main.go
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./bin/migrate up -config config.json
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./bin/server
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```
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### 4. Docker 部署
|
||
|
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- 多阶段构建，只包含二进制文件
|
||
- 挂载配置文件，灵活修改
|
||
|
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```dockerfile
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FROM golang:1.21 as builder
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RUN go build -o bin/migrate cmd/migrate/main.go
|
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|
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FROM debian:bookworm-slim
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COPY --from=builder /app/bin/migrate .
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CMD ["sh", "-c", "./migrate up && ./server"]
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```
|
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### 5. CI/CD
|
||
|
||
- 在构建阶段编译
|
||
- 部署前执行迁移
|
||
|
||
```yaml
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- build: go build -o bin/migrate cmd/migrate/main.go
|
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- migrate: ./bin/migrate up
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- deploy: ./bin/server
|
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```
|
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|
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---
|
||
|
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## 📊 推荐的项目结构
|
||
|
||
```
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your-project/
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├── cmd/
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│ ├── migrate/
|
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│ │ └── main.go # 迁移工具（独立）
|
||
│ └── server/
|
||
│ └── main.go # 应用主程序
|
||
├── migrations/ # 迁移SQL文件
|
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│ ├── 20240101000001_create_users.sql
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│ └── 20240101000001_create_users.down.sql
|
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├── config.json # 配置文件
|
||
├── Dockerfile
|
||
├── docker-compose.yml
|
||
├── Makefile # 常用命令
|
||
└── go.mod
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||
```
|
||
|
||
---
|
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|
||
## 📚 更多资源
|
||
|
||
- [模板文件](./templates/) - 可直接复制的模板
|
||
- [完整文档](./docs/migration.md) - 详细功能文档
|
||
- [配置文档](./docs/config.md) - 配置说明
|
||
|
||
---
|
||
|
||
## 🎯 总结
|
||
|
||
使用 GoCommon 的迁移工具，你可以：
|
||
|
||
1. ✅ 复制一个模板文件到 `cmd/migrate/main.go`
|
||
2. ✅ 创建 SQL 迁移文件到 `migrations/`
|
||
3. ✅ 编译：`go build -o bin/migrate cmd/migrate/main.go`
|
||
4. ✅ 使用：`./bin/migrate up`
|
||
|
||
**核心优势**：
|
||
- 独立工具，零耦合
|
||
- 生产就绪，无需Go环境
|
||
- 灵活配置，支持多环境
|
||
- Docker友好，修改配置无需重启
|
||
|
||
**开箱即用，灵活强大！** 🎉
|
||
|