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部署与运维

问题​

Python Web 应用如何部署到生产环境？Gunicorn、uWSGI、Uvicorn 怎么选？

答案​

部署架构​

Gunicorn 配置​

gunicorn.conf.py
import multiprocessing

# Worker 数量 = 2 * CPU核心 + 1
workers = multiprocessing.cpu_count() * 2 + 1
worker_class = "uvicorn.workers.UvicornWorker"  # 异步 Worker
bind = "0.0.0.0:8000"
timeout = 120
keepalive = 5
max_requests = 1000       # 处理 N 个请求后重启 Worker（防内存泄漏）
max_requests_jitter = 100 # 随机抖动，避免同时重启
preload_app = True        # 预加载应用（fork 后共享内存）
accesslog = "-"
errorlog = "-"
loglevel = "info"
gunicorn app:app -c gunicorn.conf.py

Docker 部署​

Dockerfile
# 多阶段构建
FROM python:3.12-slim AS builder
WORKDIR /app
COPY requirements.txt .
RUN pip install --no-cache-dir --prefix=/install -r requirements.txt

FROM python:3.12-slim
WORKDIR /app
COPY --from=builder /install /usr/local
COPY . .

# 非 root 用户
RUN useradd -m appuser
USER appuser

EXPOSE 8000
# 健康检查
HEALTHCHECK --interval=30s --timeout=5s \
    CMD curl -f http://localhost:8000/health || exit 1

CMD ["gunicorn", "app:app", "-c", "gunicorn.conf.py"]
docker-compose.yml
services:
  web:
    build: .
    ports:
      - "8000:8000"
    environment:
      - DATABASE_URL=postgresql://user:pass@db:5432/mydb
      - REDIS_URL=redis://redis:6379/0
    depends_on:
      db:
        condition: service_healthy
      redis:
        condition: service_started
    restart: unless-stopped

  db:
    image: postgres:16
    volumes:
      - pgdata:/var/lib/postgresql/data
    healthcheck:
      test: ["CMD-SHELL", "pg_isready"]
      interval: 5s

  redis:
    image: redis:7-alpine

volumes:
  pgdata:

Nginx 反向代理​

nginx.conf
upstream app {
    server 127.0.0.1:8000;
}

server {
    listen 80;
    server_name example.com;

    location / {
        proxy_pass http://app;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
    }

    location /static/ {
        alias /app/static/;
        expires 30d;
    }
}

常见面试问题​

Q1: Gunicorn vs Uvicorn vs uWSGI？​

答案：

服务器类型适用
GunicornWSGIDjango、Flask
UvicornASGIFastAPI、Starlette
Gunicorn + Uvicorn WorkerASGIFastAPI 生产部署（推荐）
uWSGIWSGIDjango（功能多但配置复杂）

Q2: Worker 数量怎么定？​

答案：

  • CPU 密集：workers = CPU核心数 + 1
  • IO 密集：workers = CPU核心数 * 2 + 1
  • 异步框架：可以用更少 Worker（async 本身有并发能力）

Q3: 如何实现零停机部署？​

答案：

  1. Gunicorn 信号：kill -USR2 <pid> 优雅重启
  2. Blue-Green 部署：两套环境切换
  3. Rolling Update：K8s 滚动更新
# Gunicorn 优雅重启
kill -HUP $(cat gunicorn.pid)   # 重新加载配置
kill -USR2 $(cat gunicorn.pid)  # 平滑升级

相关链接​