#!/usr/bin/python
#authors: yeasy.github.com
#date: 2013-07-05

import sys
import BaseHTTPServer
from SimpleHTTPServer import SimpleHTTPRequestHandler
import socket
import fcntl
import struct
import pickle
from datetime import datetime
from collections import OrderedDict

class HandlerClass(SimpleHTTPRequestHandler):
    def get_ip_address(self,ifname):
        s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        return socket.inet_ntoa(fcntl.ioctl(
            s.fileno(),
            0x8915,  # SIOCGIFADDR
            struct.pack('256s', ifname[:15])
        )[20:24])
    def log_message(self, format, *args):
        if len(args) < 3 or "200" not in args[1]:
            return
        try:
            request = pickle.load(open("pickle_data.txt","r"))
        except:
            request=OrderedDict()
        time_now = datetime.now()
        ts = time_now.strftime('%Y-%m-%d %H:%M:%S')
        server = self.get_ip_address('eth0')
        host=self.address_string()
        addr_pair = (host,server)
        if addr_pair not in request:
            request[addr_pair]=[1,ts]
        else:
            num = request[addr_pair][0]+1
            del request[addr_pair]
            request[addr_pair]=[num,ts]
        file=open("index.html", "w")
        file.write("<!DOCTYPE html> <html> <body><center><h1><font color=\"blue\" face=\"Georgia, Arial\" size=8><em>HA</em></font> Webpage Visit Results</h1></center>");
        for pair in request:
            if pair[0] == host:
                guest = "LOCAL: "+pair[0]
            else:
                guest = pair[0]
            if (time_now-datetime.strptime(request[pair][1],'%Y-%m-%d %H:%M:%S')).seconds < 3:
                file.write("<p style=\"font-size:150%\" >#"+ str(request[pair][1]) +": <font color=\"red\">"+str(request[pair][0])+ "</font> requests " + "from &lt<font color=\"blue\">"+guest+"</font>&gt to WebServer &lt<font color=\"blue\">"+pair[1]+"</font>&gt</p>")
            else:
                file.write("<p style=\"font-size:150%\" >#"+ str(request[pair][1]) +": <font color=\"maroon\">"+str(request[pair][0])+ "</font> requests " + "from &lt<font color=\"navy\">"+guest+"</font>&gt to WebServer &lt<font color=\"navy\">"+pair[1]+"</font>&gt</p>")
        file.write("</body> </html>");
        file.close()
        pickle.dump(request,open("pickle_data.txt","w"))

if __name__ == '__main__':
    try:
        ServerClass  = BaseHTTPServer.HTTPServer
        Protocol     = "HTTP/1.0"
        addr = len(sys.argv) < 2 and "0.0.0.0" or sys.argv[1]
        port = len(sys.argv) < 3 and 80 or int(sys.argv[2])
        HandlerClass.protocol_version = Protocol
        httpd = ServerClass((addr, port), HandlerClass)
        sa = httpd.socket.getsockname()
        print "Serving HTTP on", sa[0], "port", sa[1], "..."
        httpd.serve_forever()
    except:
        exit()

index.html

生成一個臨時的 index.html 文件，其內(nèi)容會被 index.py 更新。

$ touch index.html

Dockerfile

生成一個 Dockerfile，內(nèi)容為

FROM python:2.7
WORKDIR /code
ADD . /code
EXPOSE 80
CMD python index.py

haproxy 目錄

在其中生成一個 haproxy.cfg 文件，內(nèi)容為

global
  log 127.0.0.1 local0
  log 127.0.0.1 local1 notice

defaults
  log global
  mode http
  option httplog
  option dontlognull
  timeout connect 5000ms
  timeout client 50000ms
  timeout server 50000ms

listen stats :70
    stats enable
    stats uri /

frontend balancer
    bind 0.0.0.0:80
    mode http
    default_backend web_backends

backend web_backends
    mode http
    option forwardfor
    balance roundrobin
    server weba weba:80 check
    server webb webb:80 check
    server webc webc:80 check
    option httpchk GET /
    http-check expect status 200

docker-compose.yml

編寫 docker-compose.yml 文件，這個是 Compose 使用的主模板文件。內(nèi)容十分簡單，指定 3 個 web 容器，以及 1 個 haproxy 容器。

weba:
    build: ./web
    expose:
        - 80

webb:
    build: ./web
    expose:
        - 80

webc:
    build: ./web
    expose:
        - 80

haproxy:
    image: haproxy:latest
    volumes:
        - haproxy:/haproxy-override
        - haproxy/haproxy.cfg:/usr/local/etc/haproxy/haproxy.cfg:ro
    links:
        - weba
        - webb
        - webc
    ports:
        - "80:80"
        - "70:70"
    expose:
        - "80"
        - "70"

運行 compose 項目

現(xiàn)在 compose-haproxy-web 目錄長成下面的樣子。

compose-haproxy-web
├── docker-compose.yml
├── haproxy
│   └── haproxy.cfg
└── web
    ├── Dockerfile
    ├── index.html
    └── index.py

在該目錄下執(zhí)行 docker-compose up 命令，會整合輸出所有容器的輸出。

$sudo docker-compose up
Recreating composehaproxyweb_webb_1...
Recreating composehaproxyweb_webc_1...
Recreating composehaproxyweb_weba_1...
Recreating composehaproxyweb_haproxy_1...
Attaching to composehaproxyweb_webb_1, composehaproxyweb_webc_1, composehaproxyweb_weba_1, composehaproxyweb_haproxy_1

此時訪問本地的 80 端口，會經(jīng)過 haproxy 自動轉(zhuǎn)發(fā)到后端的某個 web 容器上，刷新頁面，可以觀察到訪問的容器地址的變化。

訪問本地 70 端口，可以查看到 haproxy 的統(tǒng)計信息。

當然，還可以使用 consul、etcd 等實現(xiàn)服務(wù)發(fā)現(xiàn)，這樣就可以避免手動指定后端的 web 容器了，更為靈活。

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