hasura graphql-engine &&patroni docker-compose 环境运行

patroni 是一个很不错的pg ha 解决方案，graphql-engine 是一个很好的graphql 工具，为了方便使用
参考patroni官方的文档，使用docker-compose 将应用集成在一起，方便进行测试

环境准备

github 代码 https://github.com/rongfengliang/graphql-engine-patroni

• docker-compose 文件

version: "3"
services:
  patroni_etcd:
    container_name: patroni_etcd
    image: dalongrong/patroni
    command: --etcd
  dbnode1:
    image: dalongrong/patroni
    hostname: dbnode1
    ports:
    - "5432:5432"
    - "8008:8008"
    links:
        - patroni_etcd:patroni_etcd
    volumes:
        - ./patroni:/patroni
    env_file: docker/patroni-secrets.env
    environment:
        PATRONI_ETCD_URL: http://patroni_etcd:2379
        PATRONI_NAME: dbnode1
        PATRONI_SCOPE: testcluster

  dbnode2:
    image: dalongrong/patroni
    hostname: dbnode2
    ports:
    - "5433:5432"
    - "8009:8008"
    links:
        - patroni_etcd:patroni_etcd
    volumes:
        - ./patroni:/patroni
    env_file: docker/patroni-secrets.env
    environment:
        PATRONI_ETCD_URL: http://patroni_etcd:2379
        PATRONI_NAME: dbnode2
        PATRONI_SCOPE: testcluster

  dbnode3:
    image: dalongrong/patroni
    hostname: dbnode3
    ports:
    - "5434:5432"
    - "8010:8008"
    links:
        - patroni_etcd:patroni_etcd
    volumes:
        - ./patroni:/patroni
    env_file: docker/patroni-secrets.env      
    environment:
        PATRONI_ETCD_URL: http://patroni_etcd:2379
        PATRONI_NAME: dbnode3
        PATRONI_SCOPE: testcluster

  haproxy:
    image: dalongrong/patroni
    links:
        - patroni_etcd:patroni_etcd
    ports:
        - "5000:5000"
        - "5001:5001"
        - "7000:7000"
    environment:
        PATRONI_ETCD_URL: http://patroni_etcd:2379
        PATRONI_SCOPE: testcluster
    command: --confd
  graphql-engine:
    image: hasura/graphql-engine:v1.0.0-alpha30
    ports:
    - "8080:8080"
    environment:
    - "POSTGRES_PASSWORD:postgres"
    command: >
      /bin/sh -c "
      graphql-engine --database-url postgres://postgres:postgres@haproxy:5000/postgres serve --enable-console;
      "

• 说明
  挂在的数据卷： 很简单，主要是pg 状态的http server 代码，以及一些环境变量的配置
  系统的访问通过haproxy进行，同时haproxy 集成了confd使用etcd 动态进行负载均衡的处理
  基础镜像：镜像使用了patroni官方的代码进行了构建，参考https://github.com/rongfengliang/patroni

启动&&测试

• 启动

docker-compose up -d

• haproxy 界面
  http://localhost:7000/，通过界面可以快速的看出master 以及replicas 节点的信息，同时基于haproxy 提供了读写分离的处理
  
• pg server 状态信息
  http://localhost:80XX ,实际参考docker-compose 文件
  
  
  
• graphql 引擎界面
  
• 故障模拟
  因为目前dbnode3 为master，尝试stop 掉，看看切换效果,很清晰，可以看到3剔除了，同时2成为master，grarphql 引擎基本不会影响
  （haproxy的作用）

docker-compose stop dbnode3

重新启动3
从haproxy的界面可以看出，会有一个选举的过程，但是还是很不错的，都是自动的

docker-compose start dbnode3

master rest 接口的信息

参考资料

https://github.com/rongfengliang/patroni
https://github.com/zalando/patroni
https://github.com/rongfengliang/graphql-engine-patroni
https://github.com/hasura/graphql-engine
https://docs.hasura.io/1.0/graphql/manual/index.html