Simon
121 lines
2.7 KiB
Markdown
121 lines
2.7 KiB
Markdown
# 502 Bad Gateway - 后端启动失败
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> 日期：2026-07-05
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> 问题：坐席端登录失败，返回 502 Bad Gateway
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---
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## 一、问题现象
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用户访问 `https://itsupport.servyou.com.cn/itagent/` 时提示登录失败：
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```
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Failed to load resource: the server responded with a status of 502 (Bad Gateway)
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AxiosError: Request failed with status code 502
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```
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---
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## 二、诊断过程
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### 2.1 检查容器状态
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```bash
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docker ps -a
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```
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发现后端容器状态为 `unhealthy`：
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```
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CONTAINER ID IMAGE STATUS
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656f7696d4e5 wecom-it-desk-backend:latest Up 8 minutes (unhealthy)
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```
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### 2.2 检查后端日志
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```bash
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docker logs 656f7696d4e5 --tail 30
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```
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发现错误：
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```
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ModuleNotFoundError: No module named 'aioredis'
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```
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### 2.3 原因分析
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- 旧版镜像中代码使用 `import aioredis`
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- 但 `aioredis` 包与 Python 3.12 不兼容
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- 报错：`TypeError: duplicate base class TimeoutError`
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---
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## 三、解决方案
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### 3.1 尝试修复（失败）
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尝试在容器内安装 `aioredis` 包，但发现：
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- `aioredis` 与 Python 3.12 不兼容
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- 安装后仍报错：`TypeError: duplicate base class TimeoutError`
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### 3.2 最终方案
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删除旧容器，使用正确的环境变量重新启动：
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```bash
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# 1. 删除旧容器
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docker stop 656f7696d4e5
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docker rm 656f7696d4e5
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# 2. 使用正确的 PYTHONPATH 重新启动
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cd /opt/wecom-it-desk
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PYTHONPATH=/app docker compose up -d backend
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```
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关键点：**必须设置 `PYTHONPATH=/app`**，否则会报错 `ModuleNotFoundError: No module named 'app.core'`
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---
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## 四、验证结果
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```bash
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# 检查容器状态
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docker ps
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# 输出：
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# 2ec80dee024c wecom-it-desk-backend:latest Up 5 minutes (healthy)
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# e147524342fa redis:7-alpine Up 11 hours (healthy)
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# 8a2265864f34 nginx:1.27-alpine Up 11 hours
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# 433ef922c8d8 postgres:16-alpine Up 11 hours (healthy)
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# 测试 API
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curl http://localhost:8000/health
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# 输出：{"status":"ok"}
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# 测试页面
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curl -sk https://localhost/itdesk/
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# 输出：HTML 页面正常返回
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```
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---
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## 五、根因总结
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| 问题 | 原因 |
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|------|------|
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| 后端容器 unhealthy | 旧镜像使用 `import aioredis`，与 Python 3.12 不兼容 |
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| 启动失败 | 需要设置 `PYTHONPATH=/app` 环境变量 |
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---
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## 六、预防措施
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1. **更新镜像**：在 Dockerfile 中将所有 `import aioredis` 改为 `import redis.asyncio as aioredis`
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2. **环境变量**：确保 docker-compose.yml 中设置 `PYTHONPATH=/app`
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3. **健康检查**：定期检查容器健康状态
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---
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## 七、相关文件
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- 部署配置：`/opt/wecom-it-desk/docker-compose.yml`
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- Nginx 配置：`/opt/wecom-it-desk/nginx/nginx.conf`
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- 后端代码：`/opt/wecom-it-desk/backend/`
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