向docker镜像中传递变量的两种方式

测试用到的python文件：

#!/usr/bin/env python3

#conding: utf-8

from http.server import HTTPServer, BaseHTTPRequestHandler

import json

import sys

import socket

def hostname():

    return socket.gethostname()

def ipa():

    return socket.gethostbyname(hostname())

data = {hostname(): ipa()}

def httpserver(ipadd='127.0.0.1',sport=8888):

    host = (ipadd, sport)

    server = HTTPServer(host, Resquest)

    server.serve_forever()

class Resquest(BaseHTTPRequestHandler):

    def do_GET(self):

        self.send_response(200)

        self.send_header('Content-type', 'application/json')

        self.end_headers()

        self.wfile.write(json.dumps(data).encode())

if len(sys.argv) == 1:

    httpserver()

elif len(sys.argv) == 3:

    httpserver(sys.argv[1],eval(sys.argv[2]))

方式一

1、方式一所用到的Dockerfile文件

FROM centos:7

MAINTAINER "1072051214@qq.com"

COPY CentOS-Base.repo epel.repo /etc/yum.repos.d/

RUN yum install python3 net-tools -y && \

    yum clean all

COPY ["app.py","/tmp"]

ENTRYPOINT ["python3","/tmp/app.py"]

CMD ["localhost","8888"]

　　在该Dockerfile文件中，ENTRYPOINT中定义了需要在镜像中执行的py文件；而CMD定义了py文件所需要的默认参数；

2、构建镜像

　　在Dockerfile存在的同级目录下放入构建所需的app.py、CentOS-Base.repo、epel.repo文件；

　　在Dockerfile目录下执行构建命令

docker build -t zhang/python:v0.3 ./

3、测试效果

#查看镜像

[root@master dockerfile]# docker images

REPOSITORY                           TAG                 IMAGE ID            CREATED             SIZE

zhang/python                         v0.3                ef2f8644ab79        6 hours ago         278 MB

#前台运行，先测试默认值是否生效

[root@master dockerfile]# docker run --rm zhang/python:v0.3

#再开一个终端

[root@master ~]# docker ps

CONTAINER ID        IMAGE                           COMMAND                  CREATED             STATUS              PORTS                    NAMES

cb38dedce26d        zhang/python:v0.3               "python3 /tmp/app...."   2 minutes ago       Up 2 minutes                                 reverent_kowalevski

[root@master ~]# docker exec -it cb38dedce26d /bin/bash

[root@cb38dedce26d /]# netstat -ntl

Active Internet connections (only servers)

Proto Recv-Q Send-Q Local Address           Foreign Address         State

tcp        0      0 127.0.0.1:8888          0.0.0.0:*               LISTEN

#前台运行，测试传递参数进去是否生效

[root@master dockerfile]# docker run --rm zhang/python:v0.3 172.17.0.3 8080

#再开一个终端

[root@master ~]# docker ps

CONTAINER ID        IMAGE                           COMMAND                  CREATED             STATUS              PORTS                    NAMES

f43e54f80660        zhang/python:v0.3               "python3 /tmp/app...."   24 seconds ago      Up 24 seconds                                laughing_torvalds

[root@master ~]# docker exec -it f43e54f80660 /bin/bash

[root@f43e54f80660 /]# netstat -ntl

Active Internet connections (only servers)

Proto Recv-Q Send-Q Local Address           Foreign Address         State

tcp        0      0 172.17.0.3:8080         0.0.0.0:*               LISTEN

方式二

1、方式二所用到的Dockerfile文件

FROM centos:7

MAINTAINER "1072051214@qq.com"

COPY CentOS-Base.repo epel.repo /etc/yum.repos.d/

RUN yum install python3 net-tools -y && \

    yum clean all

COPY ["app.py","/tmp"]

ENV HOST="localhost"

ENV PORT="8888"

CMD python3 /tmp/app.py $HOST $PORT

　　在该Dockerfile文件中，用ENV定义变量默认值；用CMD定义要运行的py文件；