Docker Compose 经典示例： Example Voting App 示例投票App

GitHub地址：https://github.com/dockersamples/example-voting-app

网络不好的同学，我已经把源码下载，地址：https://download.csdn.net/download/weixin_48447848/77354937

Example Voting App 示例投票App

跨多个Docker容器运行的简单分布式应用程序。

前期准备

下载适用于Mac或Windows的Docker Desktop。Docker Compose将自动安装。在Linux上，确保您拥有最新版本的Compose。

Linux 容器示例

Linux 堆栈使用 Python、Node.js、.NET Core（或可选的 Java），使用 Redis 进行消息传递，使用 Postgres 进行存储。

在这个目录下运行：

docker-compose up

该应用程序将在http://localhost:5000运行，结果将在http://localhost:5001。

或者，如果你想在Docker Swarm上运行它，首先确保你有一个 swarm。如果没有，请运行：

docker swarm init

一旦你有了你的 swarm，在这个目录中运行：

docker stack deploy --compose-file docker-stack.yml vote

上手操作一遍

下载源代码：https://download.csdn.net/download/weixin_48447848/77354937

查看并讲解

example-voting-app/docker-compose.yml

分析内容：
总共有5个要创建的容器：

vote 投票服务
result 后台查看投票结果
worker 消耗选票服务
redis 用于消息队列
db 数据库

volumes：挂载存储空间 db-data

networks: 2个 docker 网络，front-tier，back-tier

# version is now using "compose spec"
# v2 and v3 are now combined!
# docker-compose v1.27+ required

services:
  vote:
    build: ./vote
    # use python rather than gunicorn for local dev
    command: python app.py
    depends_on:
      redis:
        condition: service_healthy  # vote服务 依赖redis healthy状态
    volumes:
     - ./vote:/app
    ports:
      - "5000:80"
    networks:
      - front-tier
      - back-tier

  result:
    build: ./result
    # use nodemon rather than node for local dev
    command: nodemon server.js
    depends_on:
      db:
        condition: service_healthy  # result服务 依赖db数据库 healthy状态
    volumes:
      - ./result:/app
    ports:
      - "5001:80"
      - "5858:5858"
    networks:
      - front-tier
      - back-tier

  worker:
    build:
      context: ./worker
    depends_on:
      redis: # worker服务 依赖 redis和db healthy状态
        condition: service_healthy  
      db:
        condition: service_healthy 
    networks:
      - back-tier

  redis:
    image: redis:5.0-alpine3.10
    volumes:
      - "./healthchecks:/healthchecks"
    healthcheck:
      test: /healthchecks/redis.sh # 检测脚本，每五秒执行一下
      interval: "5s"
    ports: ["6379"]
    networks:
      - back-tier

  db:
    image: postgres:9.4
    environment:
      POSTGRES_USER: "postgres"
      POSTGRES_PASSWORD: "postgres"
    volumes:
      - "db-data:/var/lib/postgresql/data"
      - "./healthchecks:/healthchecks"
    healthcheck:
      test: /healthchecks/postgres.sh # 健康检测脚本
      interval: "5s"
    networks:
      - back-tier

volumes:
  db-data:

networks:
  front-tier:
  back-tier:

example-voting-app/vote/Dockerfile

前台投票服务

# Using official python runtime base image
FROM python:3.9-slim

# add curl for healthcheck
RUN apt-get update \
    && apt-get install -y --no-install-recommends \
    curl \
    && rm -rf /var/lib/apt/lists/*

# Set the application directory
WORKDIR /app

# Install our requirements.txt
COPY requirements.txt /app/requirements.txt
RUN pip install -r requirements.txt

# Copy our code from the current folder to /app inside the container 将代码从当前文件夹复制到容器内的/app
COPY . .

# Make port 80 available for links and/or publish
EXPOSE 80

# Define our command to be run when launching the container 定义启动容器时要运行的命令
CMD ["gunicorn", "app:app", "-b", "0.0.0.0:80", "--log-file", "-", "--access-logfile", "-", "--workers", "4", "--keep-alive", "0"]

example-voting-app/result/Dockerfile

后台查看投票结果，node.js服务的Dockerfile

FROM node:10-slim

# add curl for healthcheck
RUN apt-get update \
    && apt-get install -y --no-install-recommends \
    curl \
    && rm -rf /var/lib/apt/lists/*

# Add Tini for proper init of signals
ENV TINI_VERSION v0.19.0
ADD https://github.com/krallin/tini/releases/download/${TINI_VERSION}/tini /tini
RUN chmod +x /tini

WORKDIR /app # 进入app目录

# have nodemon available for local dev use (file watching)
RUN npm install -g nodemon

COPY package*.json ./

RUN npm ci \
 && npm cache clean --force \
 && mv /app/node_modules /node_modules

COPY . .  # 将代码从当前文件夹复制到容器内的/app

ENV PORT 80

EXPOSE 80

CMD ["/tini", "--", "node", "server.js"]

example-voting-app/worker/Dockerfile

FROM mcr.microsoft.com/dotnet/core/sdk:3.1 as builder

WORKDIR /Worker
COPY src/Worker/Worker.csproj .
RUN dotnet restore

COPY src/Worker/ .
RUN dotnet publish -c Release -o /out Worker.csproj

# app image
FROM mcr.microsoft.com/dotnet/core/runtime:3.1

WORKDIR /app
ENTRYPOINT ["dotnet", "Worker.dll"]

COPY --from=builder /out .

健康检测脚本 example-voting-app/healthchecks/

postgres.sh 数据库服务检测脚本

#!/bin/bash
set -eo pipefail

host="$(hostname -i || echo '127.0.0.1')"
user="${POSTGRES_USER:-postgres}"
db="${POSTGRES_DB:-$POSTGRES_USER}"
export PGPASSWORD="${POSTGRES_PASSWORD:-}"

args=(
	# force postgres to not use the local unix socket (test "external" connectibility)
	--host "$host"
	--username "$user"
	--dbname "$db"
	--quiet --no-align --tuples-only
)

if select="$(echo 'SELECT 1' | psql "${args[@]}")" && [ "$select" = '1' ]; then
	exit 0
fi

exit 1

redis.sh 检测脚本

#!/bin/sh
set -eo pipefail

host="$(hostname -i || echo '127.0.0.1')"

if ping="$(redis-cli -h "$host" ping)" && [ "$ping" = 'PONG' ]; then
	exit 0
fi

exit 1

执行

选择docker-compose.yml文件

docker-compose -f .\docker-compose.yml up -d

等待拉取和构建，上百行输入，省略……

查看容器创建情况

PS C:\Users\柏杉\Downloads\example-voting-app-master> docker-compose ps
               Name                             Command                  State                      Ports               
------------------------------------------------------------------------------------------------------------------------
example-voting-app-master_db_1       docker-entrypoint.sh postgres    Up (healthy)   5432/tcp                           
example-voting-app-master_redis_1    docker-entrypoint.sh redis ...   Up (healthy)   0.0.0.0:3161->6379/tcp             
example-voting-app-master_result_1   docker-entrypoint.sh nodem ...   Up             0.0.0.0:5858->5858/tcp,            
                                                                                     0.0.0.0:5001->80/tcp               
example-voting-app-master_vote_1     python app.py                    Up             0.0.0.0:5000->80/tcp               
example-voting-app-master_worker_1   dotnet Worker.dll                Up                                                
PS C:\Users\柏杉\Downloads\example-voting-app-master>