Docker 哲学 - compose.yaml 指令

compose.yaml 的 image commond working_dir 和 dockerfile的 from cmd workdir 区别在哪里 。为什么 dockerfile制定过了。compose还要再写一个。是处于个性化还是 有不同的意义

如果 dockerfile 的 from 是 node:16 ，compose.yaml 的 images 是 node:18 那么 直接 docker run 用的 就是默认 16 的node 但是 compose up启动用的就是 18的node

 depends_on：

总结 ：

depends_on 可以设置容器的启动顺序，如果一个服务依赖另一个服务 ，那么就可以自定义控制

所以来服务的状态来启动目标服务

有几种语法：

depends_on:
      - db
      - redis

short syntax

1、跟依赖服务的名字

• Compose creates services in dependency order. In the following example, db and redis are created before web.

• Compose removes services in dependency order. In the following example, web is removed before db and redis.

• Compose guarantees dependency services have been started before starting a dependent service. Compose waits for dependency services to be "ready" before starting a dependent service.

• 弊端：不会等依赖服务完全初始化完成 只是一个 ready

2、

depends_on:

         可以有三个属性：

                restart  设置为 true时 依赖服务有更新，compose自动重启

                condition:  自定义条件决定什么时候启动该服务 有三个属性

                required： 是否与依赖服务之间存在 上下文关系

      

      condition 的三个属性

           service_started ：不会等依赖服务完全初始化完成 只是一个 ready 等同直接写服务名

           service_healthy: 该属性的值 由 另一个容器的 service下字段 healthy_check 决定 

           service_completion_successfully:依赖服务完全初始化

            

介绍 

  healthy_check:

 

version: '3'

services:
  rabbitmq:
    hostname: rabbitmq_host
    container_name: 'mq'
    image: rabbitmq:3.9.11-management
    restart: always
    ports:
      - "5772:5672"  # AMQP
      - "15772:15672"  # Web UI
    networks:
      - app-network
    environment:
      RABBITMQ_DEFAULT_USER: root
      RABBITMQ_DEFAULT_PASS: pwd
      RABBITMQ_DEFAULT_VHOST: /
    volumes:
      - rabbitmq_data:/var/lib/rabbitmq/mnesia

    healthcheck:
      test: [ "CMD", "rabbitmq-diagnostics", "ping" ]
      interval: 50s
      timeout: 5s
      retries: 3


  selenium:
    container_name: 'selenium'
    image: selenium/standalone-chrome
    restart: always
    ports:
      - "4444:4444"

    networks:
      - app-network

    healthcheck:
      test: [ "CMD", "curl", "-f", "http://localhost:4444/wd/hub/status" ]
      interval: 30s
      timeout: 5s
      retries: 3


  db:
    container_name: 'mysql8'
    image: mysql:8.0.32
#    hostname: mysql_host
    user: root
    command:
      --default-authentication-plugin=mysql_native_password
      --character-set-server=utf8mb4
      --collation-server=utf8mb4_unicode_ci

    environment:
      LANG: C.UTF-8
      MYSQL_ROOT_PASSWORD: pwd
      MYSQL_DATABASE: yinlian

    ports:
      - "3306:3306"

    volumes:
      - "./data/db/data:/var/lib/mysql"
      - "./data/db/mysql-files:/var/lib/mysql-files"
      - "./build/docker/mysqldb/my.cnf:/etc/my.cnf"

    networks:
      - app-network

    healthcheck:
      test: [ "CMD", "mysqladmin", "ping", "-h", "localhost" ]
      interval: 30s
      timeout: 5s
      retries: 3

  app-producer:
    container_name: 'producer'
    build:
      context: .
      dockerfile: Dockerfile
    ports:
      - "8001:8001"

    command: ['echo','hello world, Frank']
    depends_on:
      db:
        condition: service_healthy

      rabbitmq:
        condition: service_healthy

      selenium:
        condition: service_healthy

    networks:
      - app-network


networks:
  app-network:
    driver: bridge

volumes:
  rabbitmq_data:
    driver: local