程序准备

  • 准备一个Python文件，名字为 app.py 内容如下：

    1. from flask import Flask
    2. from redis import Redis
    3. import os
    4. import socket
    5. app = Flask(__name__)
    6. redis = Redis(host=os.environ.get('REDIS_HOST', '127.0.0.1'), port=6379)
    7. @app.route('/')
    8. def hello():
    9.   redis.incr('hits')
    10.   return f"Hello Container World! I have been seen {redis.get('hits').decode('utf-8')} times and my hostname is {socket.gethostname()}.\n"

  • 准备一个Dockerfile

    1. FROM python:3.9.5-slim
    2. RUN pip install flask redis && \
    3.   groupadd -r flask && useradd -r -g flask flask && \
    4.   mkdir /src && \
    5.   chown -R flask:flask /src
    6. USER flask
    7. COPY app.py /src/app.py
    8. WORKDIR /src
    9. ENV FLASK_APP=app.py REDIS_HOST=redis
    10. EXPOSE 5000
    11. CMD ["flask", "run", "-h", "0.0.0.0"]

    镜像准备

    构建flask镜像，准备一个redis镜像。

    1. $ docker image pull redis
    2. $ docker image build -t flask-demo .
    3. $ docker image ls
    4. REPOSITORY   TAG          IMAGE ID       CREATED              SIZE
    5. flask-demo   latest       4778411a24c5   About a minute ago   126MB
    6. python       3.9.5-slim   c71955050276   8 days ago           115MB
    7. redis        latest       08502081bff6   2 weeks ago          105MB

    创建一个docker bridge

    1. $ docker network create -d bridge demo-network
    2. 8005f4348c44ffe3cdcbbda165beea2b0cb520179d3745b24e8f9e05a3e6456d
    3. $ docker network ls
    4. NETWORK ID     NAME           DRIVER    SCOPE
    5. 2a464c0b8ec7   bridge         bridge    local
    6. 8005f4348c44   demo-network   bridge    local
    7. 80b63f711a37   host           host      local
    8. fae746a75be1   none           null      local
    9. $

    创建redis container

    创建一个叫 redis-server 的container，连到 demo-network上

    1. $ docker container run -d --name redis-server --network demo-network redis
    2. 002800c265020310231d689e6fd35bc084a0fa015e8b0a3174aa2c5e29824c0e
    3. $ docker container ls
    4. CONTAINER ID   IMAGE     COMMAND                  CREATED         STATUS         PORTS      NAMES
    5. 002800c26502   redis     "docker-entrypoint.s…"   4 seconds ago   Up 3 seconds   6379/tcp   redis-server
    6. $

    创建flask container

    1. $ docker container run -d --network demo-network --name flask-demo --env REDIS_HOST=redis-server -p 5000:5000 flask-demo

    打开浏览器访问 http://127.0.0.1:5000
    应该能看到类似下面的内容，每次刷新页面，计数加1
    Hello Container World! I have been seen 36 times and my hostname is 925ecb8d111a.

    总结

    如果把上面的步骤合并到一起，成为一个部署脚本

    1. # prepare image
    2. docker image pull redis
    3. docker image build -t flask-demo .
    4. # create network
    5. docker network create -d bridge demo-network
    6. # create container
    7. docker container run -d --name redis-server --network demo-network redis
    8. docker container run -d --network demo-network --name flask-demo --env REDIS_HOST=redis-server -p 5000:5000 flask-demo