Automatically generate the docker nginx reverse proxy configuration with python

Automatically generate the docker nginx reverse proxy configuration with python

Since there are many applications deployed with docker in the test environment, and some of their ports are the same, some are different, and the number of them is quite large, it is difficult to configure when using jenkins to send version, so I want to write a script, which can automatically generate nginx reverse proxy when docker container is created and stopped, and then reload nginx

My principle is to keep it simple, lightweight, and memory footprint small

The target is clear, as long as the container start/stop event of docker can be listened for

After 1 check on the Internet, docker events can be used to monitor the docker event. After 1 try, it is found that the docker event can be basically satisfied. Therefore, a program is written using python to monitor the docker event

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('\n', '')


def get_ip(container):
  return cmd("docker inspect -f '{{.NetworkSettings.IPAddress}}' " + container).replace('\n', '')


def get_port(container):
  return cmd("docker inspect -f '{{.Config.ExposedPorts}}' " + container).replace('/tcp:{}]', '').replace('map[', '').replace('\n', '')


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 $1}'")
  containers = out.split("\n")
  servers = ''
  hosts = ''
  for con in containers:
    if con != '':
      name = get_name(con)
      ip = get_ip(con)
      port = get_port(con)
      print ip, port
      if len(port) >= 2:
        servers += tpl.replace("$name", name).replace("$ip", ip).replace("$port", port)
        hosts += "11.12.13.14 " + name + ".test.com\n"
  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

Startup command:

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

The program will run in the background, and disconnecting ssh will not end

Is mainly generated a conf file, the file to the nginx. conf introduced inside, and then have a container to start/stop every time to generate the file, and then restart the nginx, that I have put the container name and a domain name, combination is 1 is a domain name, and then the corresponding mapping relationship created a html files, through the browser can access the file, and then copy the code corresponding to the native hosts files inside, can achieve through the use of domain name, of course, only when development testing to do so, But it's enough.

Thank you for reading, I hope to help you, thank you for your support of this site!