python2.7实现websocket服务器，可以在web实时显示远程服务器日志

一、开始的话

　　使用python实现websocket服务器，可以在浏览器上实时显示远程服务器的日志。

　　之前写了一个发布系统，每次发布版本后，为了了解发布情况（进度、是否有错误）都会登录到服务器上查看日志，有点麻烦，如果发布的服务器比较多，难道要登录到每台服务器去看日志吗？作为新时代的运维，太不能接收这种重复操作的体力劳动了，于是一个看日志的功能就这么诞生了。下面是效果图，页面丑陋不堪，将就着吧。

二、行动

　　打开页面时，自动连接websocket服务器，完成握手，并发送ip和type给服务端，所以可以看不同类型，不同机器上的日志，websocket服务器接收到信息后，去数据库查找对应的日志路径和主机账号密码，然后起一个线程ssh登录到远程服务器上tail查看日志，再推送给浏览器，代码如下：

# coding:utf-8
import os
import struct
import base64
import hashlib
import socket
import threading
import paramiko


def get_ssh(ip, user, pwd):
    try:
        ssh = paramiko.SSHClient()
        ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
        ssh.connect(ip, 22, user, pwd, timeout=15)
        return ssh
    except Exception, e:
        print e
        return "False"


def recv_data(conn):    # 服务器解析浏览器发送的信息
    try:
        all_data = conn.recv(1024)
        if not len(all_data):
            return False
    except:
        pass
    else:
        code_len = ord(all_data[1]) & 127
        if code_len == 126:
            masks = all_data[4:8]
            data = all_data[8:]
        elif code_len == 127:
            masks = all_data[10:14]
            data = all_data[14:]
        else:
            masks = all_data[2:6]
            data = all_data[6:]
        raw_str = ""
        i = 0
        for d in data:
            raw_str += chr(ord(d) ^ ord(masks[i % 4]))
            i += 1
        return raw_str


def send_data(conn, data):   # 服务器处理发送给浏览器的信息
    if data:
        data = str(data)
    else:
        return False
    token = "x81"
    length = len(data)
    if length < 126:
        token += struct.pack("B", length)    # struct为Python中处理二进制数的模块，二进制流为C，或网络流的形式。
    elif length <= 0xFFFF:
        token += struct.pack("!BH", 126, length)
    else:
        token += struct.pack("!BQ", 127, length)
    data = '%s%s' % (token, data)
    conn.send(data)
    return True


def handshake(conn, address, thread_name):    # 握手建立连接
    headers = {}
    shake = conn.recv(1024)
    if not len(shake):
        return False

    print ('%s : Socket start handshaken with %s:%s' % (thread_name, address[0], address[1]))
    header, data = shake.split('

', 1)
    for line in header.split('
')[1:]:
        key, value = line.split(': ', 1)
        headers[key] = value

    if 'Sec-WebSocket-Key' not in headers:
        print ('%s : This socket is not websocket, client close.' % thread_name)
        conn.close()
        return False

    MAGIC_STRING = '258EAFA5-E914-47DA-95CA-C5AB0DC85B11'
    HANDSHAKE_STRING = "HTTP/1.1 101 Switching Protocols
" 
                       "Upgrade:websocket
" 
                       "Connection: Upgrade
" 
                       "Sec-WebSocket-Accept: {1}
" 
                       "WebSocket-Origin: {2}
" 
                       "WebSocket-Location: ws://{3}/

"

    sec_key = headers['Sec-WebSocket-Key']
    res_key = base64.b64encode(hashlib.sha1(sec_key + MAGIC_STRING).digest())
    str_handshake = HANDSHAKE_STRING.replace('{1}', res_key).replace('{2}', headers['Origin']).replace('{3}', headers['Host'])
    conn.send(str_handshake)                 # 发送建立连接的信息
    print ('%s : Socket handshaken with %s:%s success' % (thread_name, address[0], address[1]))
    print 'Start transmitting data...'
    print '- - - - - - - - - - - - - - - - - - - - - - - - - - - - - -'
    return True


def dojob(conn, address, thread_name):
    handshake(conn, address, thread_name)     # 握手
    conn.setblocking(0)                       # 设置socket为非阻塞

    ssh = get_ssh('192.168.1.1', 'root', '123456')   # 连接远程服务器（日志所在的服务器）
    ssh_t = ssh.get_transport()
    chan = ssh_t.open_session()
    chan.setblocking(0)          # 设置非阻塞
    chan.exec_command('tail -f /var/log/messages')   # 执行查看日志命令

    while True:            # 下面这个逻辑是在看日志时能停止或继续，写的有点混乱，还没想到优化的方案
        clientdata = recv_data(conn)
        if clientdata is not None and 'quit' in clientdata:    # 当浏览器点击stop按钮或close按钮时，断开连接
            print ('%s : Socket close with %s:%s' % (thread_name, address[0], address[1]))
            send_data(conn, 'close connect')
            conn.close()
            break
        while True:
            while chan.recv_ready():
                clientdata1 = recv_data(conn)
                if clientdata1 is not None and 'quit' in clientdata1:
                    print ('%s : Socket close with %s:%s' % (thread_name, address[0], address[1]))
                    send_data(conn, 'close connect')
                    conn.close()
                    break
                log_msg = chan.recv(10000).strip()    # 接收日志信息
                print log_msg
                send_data(conn, log_msg)
            if chan.exit_status_ready():
                break
            clientdata2 = recv_data(conn)
            if clientdata2 is not None and 'quit' in clientdata2:
                print ('%s : Socket close with %s:%s' % (thread_name, address[0], address[1]))
                send_data(conn, 'close connect')
                conn.close()
                break
        break


def ws_service():

    index = 1
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    sock.bind(("127.0.0.1", 12345))
    sock.listen(100)

    print ('

Websocket server start, wait for connect!')
    print '- - - - - - - - - - - - - - - - - - - - - - - - - - - - - -'
    while True:
        connection, address = sock.accept()
        thread_name = 'thread_%s' % index
        print ('%s : Connection from %s:%s' % (thread_name, address[0], address[1]))
        t = threading.Thread(target=dojob, args=(connection, address, thread_name))
        t.start()
        index += 1


ws_service()

页面代码如下:

<!DOCTYPE html>
<html>
<head>
    <title>WebSocket</title>

    <style>
    #log {
         440px;
        height: 200px;
        border: 1px solid #7F9DB9;
        overflow: auto;
    }
    pre {
        margin: 0 0 0;
        padding: 0;
        border: hidden;
        background-color: #0c0c0c;
        color: #00ff00;
    }
    #btns {
        text-align: right;
    }
    </style>

    <script>
        var socket;
        function init() {
            var host = "ws://127.0.0.1:12345/";

            try {
                socket = new WebSocket(host);
                socket.onopen = function () {
                    log('Connected');
                };
                socket.onmessage = function (msg) {
                    log(msg.data);
                    var obje = document.getElementById("log");   //日志过多时清屏
                    var textlength = obje.scrollHeight;
                    if (textlength > 10000) {
                        obje.innerHTML = '';
                    }
                };
                socket.onclose = function () {
                    log("Lose Connection!");
                    $("#start").attr('disabled', false);
                    $("#stop").attr('disabled', true);
                };
                $("#start").attr('disabled', true);
                $("#stop").attr('disabled', false);
            }
            catch (ex) {
                log(ex);
            }
        }
        window.onbeforeunload = function () {
            try {
                socket.send('quit');
                socket.close();
                socket = null;
            }
            catch (ex) {
                log(ex);
            }
        };
        function log(msg) {
            var obje = document.getElementById("log");
            obje.innerHTML += '<pre><code>' + msg + '</code></pre>';
            obje.scrollTop = obje.scrollHeight;   //滚动条显示最新数据
        }
        function stop() {
            try {
                log('Close connection!');
                socket.send('quit');
                socket.close();
                socket = null;
                $("#start").attr('disabled', false);
                $("#stop").attr('disabled', true);
            }
            catch (ex) {
                log(ex);
            }
        }
        function closelayer() {
            try {
                log('Close connection!');
                socket.send('quit');
                socket.close();
                socket = null;
            }
            catch (ex) {
                log(ex);
            }
            var index = parent.layer.getFrameIndex(window.name); //先得到当前iframe层的索引
            parent.layer.close(index); //再执行关闭
        }
    </script>

</head>


<body onload="init()">
    <div class="row">
        <div class="col-lg-12">
            <div id="log" style=" 100%;height:440px;background-color: #0c0c0c;overflow:scroll;overflow-x: auto;"></div>
            <br>
        </div>
    </div>
    <div class="row">
        <div class="col-lg-12">
            <div id="btns">
                <input disabled="disabled" type="button" class="btn btn-primary btn-sm" value="start" id="start" onclick="init()">
                <input disabled="disabled" type="button" class="btn btn-primary btn-sm" value="stop" id="stop" onclick="stop()" >
                <input type="button" class="btn btn-primary btn-sm" value="close" id="close" onclick="closelayer()" >
            </div>
        </div>
    </div>
</body>

</html>