利用python自动生成docker nginx反向代理配置

由于在测试环境上用docker部署了多个应用，而且他们的端口有的相同，有的又不相同，数量也比较多，在使用jenkins发版本的时候，不好配置，于是想要写一个脚本，能在docker 容器创建、停止的时候，自动生成nginx反向代理，然后reload nginx

我的原则是尽量简单，轻量，内存占用少

目标很明确，只要能监听到docker的容器启动/停止事件，即可

网上查了一下可以用docker events来监听docker事件，试了一下，发现基本可以满足，于是用python写了一段程序，用来监听docker事件

python
#!/usr/bin/python
# coding: utf8
import os
import json
import re
import subprocess
 
 
def override(path, text):
  if not os.path.exists(path) and os.path.exists(path+"_temp"):
    os.rename(path+"_temp",path)
  fw = open(path+"_temp", 'wb')
  fw.write(text)
  fw.close()
  if os.path.exists(path):
    os.remove(path)
  os.rename(path+"_temp", path)
 
 
def read(path):
  try:
    fr = open(path, "rb")
  except IOError:
    print "The file don't exist, Please double check!"
    return
  lines = fr.readlines()
  ret = ''
  for line in lines:
    ret += line
  return ret
 
 
def read_jsonfile(path):
  return json.loads(read(path))
 
 
def cmd(command):
  return os.popen(command).read()
 
 
def get_name(container):
  return cmd("docker inspect -f '{{.Name}}' " + container).replace("/", "").replace('
', '')
 
 
def get_ip(container):
  return cmd("docker inspect -f '{{.NetworkSettings.IPAddress}}' " + container).replace('
', '')
 
 
def get_port(container):
  return cmd("docker inspect -f '{{.Config.ExposedPorts}}' " + container).replace('/tcp:{}]', '').replace('map[', '').replace('
', '')
 
 
def get_info(container):
  filename = "/var/lib/docker/containers/" + container + "/config.v2.json"
  config = read_jsonfile(filename)
 
  name = config['Name'].replace("/", "")
  port = config['Config']['ExposedPorts'].keys()[0].replace('/tcp', '')
  ip = cmd("docker inspect -f '{{.NetworkSettings.IPAddress}}' " + name)
  # ip = config['NetworkSettings']['Networks']['bridge']['IPAddress']
 
  ret = {'name': name, 'port': port, 'ip': ip}
  return ret
 
 
tpl = """
  server {
    listen 80;
    server_name $name.test.com;
    location / {
    proxy_set_header X-Real-IP $remote_addr;
      proxy_set_header Host $http_host;
      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
      proxy_pass http://$ip:$port;
    }
  }
"""
 
 
def generate_conf():
  print "generate_conf"
  out = cmd("docker ps | grep -v CONTAINER | awk '{print $1}'")
  containers = out.split("
")
  servers = ''
  hosts = ''
  for con in containers:
    if con != '':
      name = get_name(con)
      ip = get_ip(con)
      port = get_port(con)
      print ip, port
      if len(port) >= 2:
        servers += tpl.replace("$name", name).replace("$ip", ip).replace("$port", port)
        hosts += "11.12.13.14 " + name + ".test.com
"
  override('/usr/local/openresty/nginx/conf/vhost.conf', servers)
  override('/usr/local/openresty/nginx/html/vhost.html', "<pre>" + hosts + "</pre>")
 
 
def reload_nginx():
  print "reload nginx"
  cmd('nginx -s reload')
 
 
def auto_reload():
  generate_conf()
  reload_nginx()
 
print " ==================== docker events ==================== "
 
# auto_reload()
 
proc = subprocess.Popen(["docker", "events"],
            # shell=True,  # windows: true, linux: false
            stdout=subprocess.PIPE)
 
while 1:
  out = proc.stdout.readline()
  event = re.sub('(|)', "", out).split(" ")
  if out.find('container stop') != -1:
    auto_reload()
    print ' container stop '
  elif out.find('container start') != -1:
    auto_reload()
    print ' start container '
  if out == '':
    print "out "
    break

启动命令：

nohup ./docker.py > /dev/null 2>&1 &

程序会在后台运行，断开ssh也不会结束

主要就是生成一个 conf 文件，这个文件要在nginx.conf里面引入，然后每次有容器启动/停止都生成这个文件，然后重启nginx，我这了还把容器名加上一个域名，组合成了一个子域名，然后把对应的映射关系生成了一个html文件，通过浏览器可以访问这个文件，然后把对应的代码 复制到本机的 hosts 文件里面，可以实现通过域名访问应用，当然只是开发测试的时候会这么做，但是也足够了。