Docker Compose环境变量与配置文件管理全解析

# 项目结构
.
├── docker-compose.yml
├── .env.staging
├── .env.prod
└── config/
    ├── app-config.dev.yaml
    └── app-config.prod.yaml

# 开发环境（默认.env）
docker compose up
# 预发布环境
docker compose --env-file .env.staging up
# 生产环境
docker compose -f docker-compose.yml -f docker-compose.prod.yml up

services:
  app:
    image: myapp:${APP_VERSION:-latest}
    volumes:
      - ./config/app-config.${ENV_MODE:-dev}.yaml:/app/config.yaml
    environment:
      ENV_MODE: ${ENV_MODE}

ENV_MODE=prod docker compose up

services:
  nginx:
    image: nginx:alpine
    volumes:
      - type: bind
        source: ./nginx
        target: /etc/nginx
        consistency: delegated  # 提升Mac/Win性能
    command: [sh, -c, "nginx -g 'daemon off;' && inotifywait -m /etc/nginx | xargs -n1 nginx -s reload"]

# docker-compose.yml
version: '3.8'
secrets:
  db_password:
    file: ./secrets/db_password.txt
services:
  db:
    image: postgres:15-alpine
    environment:
      POSTGRES_PASSWORD_FILE: /run/secrets/db_password
    secrets:
      - db_password

# 生成随机密码
openssl rand -base64 32 > secrets/db_password.txt
chmod 600 secrets/db_password.txt

# 安全审查命令
docker compose config | grep -E 'password|secret|key'
# 输出示例
services:
  db:
    environment:
      POSTGRES_PASSWORD: very_strong_password

# 优先级从高到低：
# 1. Shell环境变量
# 2. --env-file指定文件
# 3 Compose文件environment定义
# 4 .env文件
services:
  app:
    environment:
      LOG_LEVEL: ${LOG_LEVEL:-info}  # 默认值语法

# base配置（docker-compose.base.yml）
x-common: &common
  logging:
    driver: json-file
    options:
      max-size: "10m"
# 环境扩展（docker-compose.prod.yml）
services:
  app:
    <<: *common
    deploy:
      replicas: 3

# 验证Compose文件语法
docker compose config
# 显示解析后完整配置
docker compose convert
# 查看环境变量实际值
docker compose run app env

# 查看运行时环境变量
docker exec -it app printenv
# 验证配置文件挂载
docker exec -it app ls -l /app/config.yaml
# 跟踪配置变更
docker compose logs -f app | grep 'Config Reloaded'

# 配置命名规范
config/
├── v1.0/
│   ├── app-config.yaml
│   └── db-config.yaml
└── v1.1/
    ├── app-config.yaml
    └── new-feature.yaml
# 版本回滚操作
docker compose -f docker-compose.yml -f config/v1.0/app-config.yml up