Posted in Python onAugust 12, 2019
大致思路：
1.利用tornado提供的websocket功能与浏览器建立长连接，读取实时日志并输出到浏览器
2.写一个实时读取日志的脚本，利用saltstack远程执行，并把实时日志发往redis中。
3.tornado读取redis中的信息，发往浏览器。
此过程用到了redis的发布和订阅功能。
先看一下tornado中是如何处理的：
import os
import sys
import tornado.websocket
import tornado.web
import tornado.ioloop
import redis
import salt.client
from tornado import gen
from tornado.escape import to_unicode
from logs.utility import get_last_lines
from logs import settings
class SubWebSocket(tornado.websocket.WebSocketHandler):
"""
此handler处理远程日志查看
"""
def open(self, *args, **kwargs):
print("opened")
@gen.coroutine
def on_message(self, message):
# 主机名，要查看的日志路径，运行脚本的命令这些信息从浏览器传过来
hostname, log_path, cmd = message.split("||")
local = salt.client.LocalClient()
r = redis.StrictRedis(host=settings.REDIS_HOST, port=settings.REDIS_PORT,
password=settings.REDIS_PASSWD, db=5)
# 订阅频道，服务器和日志路径确定一个频道
key = settings.LOG_KEY.format(server=hostname.strip(), log_path=log_path.strip())
channel = r.pubsub()
channel.subscribe(key)
# 异步方式执行命令，远程运行脚本
local.cmd_async(hostname, "cmd.run", [cmd])
try:
while True:
data = channel.get_message()
if not data:
# 如果读取不到消息，间隔一定时间，避免无谓的CPU消耗
yield gen.sleep(0.05)
continue
if data["type"] == "message":
line = format_line(data["data"])
self.write_message(line)
except tornado.websocket.WebSocketClosedError:
self.close()
def on_close(self):
global FLAG
FLAG = False
print("closed")
def format_line(line):
line = to_unicode(line)
if "INFO" in line:
color = "#46A3FF"
elif "WARN" in line:
color = "#FFFF37"
elif "ERROR" in line:
color = "red"
elif "CRITICAL" in line:
color = "red"
else:
color = "#FFFFFF"
return "<span style='color:{}'>{}</span>".format(color, line)
class EchoWebSocket(tornado.websocket.WebSocketHandler):
def open(self):
print("WebSocket opened")
@gen.coroutine
def on_message(self, message):
log = message
print "log file: ", log
try:
with open(log, 'r') as f:
for line in get_last_lines(f):
line1 = format_line(line)
self.write_message(line1)
while True:
line = f.readline()
if not line:
yield gen.sleep(0.05)
continue
self.write_message(format_line(line.strip()))
except tornado.websocket.WebSocketClosedError as e:
print e
self.close()
# def check_origin(self, origin):
# print origin, self.request.headers.get("Host")
# # super(EchoWebSocket, self).check_origin()
# return True
def on_close(self):
print("WebSocket closed")
class Application(tornado.web.Application):
def __init__(self):
handlers = [
(r'/log/', MainHandler), # 提供浏览页面，页面中的JS与服务器建立连接
(r'/log/local', EchoWebSocket), # 处理本地日志实时查看，比较简单
(r'/log/remote', SubWebSocket), # 处理远程日志实时查看，稍微复杂
]
settings = {
"debug": True,
"template_path": os.path.join(os.path.dirname(__file__), "templates"),
"static_path": os.path.join(os.path.dirname(__file__), "static"),
}
super(Application, self).__init__(handlers, **settings)
class MainHandler(tornado.web.RequestHandler):
def get(self):
# 要查看的日志路径
log = self.get_argument("log", None)
# hostname实际上是saltstack中这台机器对应的minion id
hostname = self.get_argument("hostname", None)
# 本地日志还是远程日志
type = self.get_argument("type", "local")
# 运行读取实时日志的脚本，参数比较多，后面会有
cmd = self.get_argument("cmd", "")
context = {
"log": log,
"hostname": hostname,
"type": type,
"cmd": cmd,
}
self.render("index.html", **context)
配置文件中主要记录了redis服务器的地址等信息
# encoding: utf-8
LOG_KEY = "logs:{server}:{log_path}"
LOG_NAME = "catalina.out"
TAIL_LINE_NUM = 20
REDIS_HOST = "127.0.0.1"
REDIS_PORT = "6379"
REDIS_PASSWD = None
REDIS_EXPIRE = 300
try:
from local_settings import *
except ImportError:
pass
index.html的内容如下：
<html>
<head>
<link href="{{ static_url('public/css/public.css') }}" rel="external nofollow" rel="stylesheet" />
<link href="{{ static_url('kylin/css/style.css') }}" rel="external nofollow" rel="stylesheet" />
</head>
<body style="background:#000000">
<div style="margin-left:10px;">
<pre id="id-content">
</pre>
<div id="id-bottom"></div>
<input type="hidden" id="id-log" value="{{ log }}" />
<input type="hidden" id="id-type" value="{{ type }}" />
<input type="hidden" id="id-hostname" value="{{ hostname }}" />
<input type="hidden" id="id-cmd" value="{{ cmd }}" />
<div class="btns btns_big">
<button type="button" class="query_btn cancle" id="id-stop">Stop</button>
<button type="button" class="query_btn commit" id="id-start">Start</button>
</div>
</div>
<script type="text/javascript" src="{{ static_url('js/jquery-1.11.3.min.js') }}"></script>
<script type="text/javascript">
var log_name = $("#id-log").val();
var type = $("#id-type").val();
var hostname = $("#id-hostname").val();
var cmd = $("#id-cmd").val();
// 初始化websocket对象
var ws = new WebSocket("ws://{{ request.host }}/log/" + type);
ws.onopen = function(){
if (type === "local"){
ws.send(log_name);
} else {
// 建立连接后把相关信息发往服务器，对应上面的SubWebSocket
ws.send(hostname + "||" + log_name + "||" + cmd);
}
};
var get_message = function(evt){
$("#id-content").append(evt.data + "\n");
document.getElementById("id-bottom").scrollIntoView()
};
ws.onmessage = get_message;
// 两个按钮控制日志的输出，如果看到需要的日志信息，可以暂停日志的输出，
// 之后可以继续启动日志的输出
$("#id-stop").click(function(){
ws.onmessage = function(){};
})
$("#id-start").click(function(){
ws.onmessage = get_message;
})
</script>
</body>
</html>
这个tornado仅仅是提供了实时日志的服务，实际项目使用的是django，django中要做的其实很简单，提供log_name,hostname,type,cmd等四个参数。
下面看一个实例：
class LogView(KylinView):
# 实时读取日志的脚本，事先使用saltstack批量传到各台服务器上
client_path = "/tmp/logtail.py"
def get(self, request):
minion_id = request.GET.get("minion_id")
context = {
"minion_id": minion_id,
"tail_log_url": settings.TAIL_LOG_URL,
}
return render(request, "cmdb/log_view.html", context)
def post(self, request):
minion_id = request.POST.get("minion_id")
log_path = request.POST.get("log_path")
if not log_path:
return JsonResponse({"success": False, "message": "请填写日志路径"})
try:
# 制定一开始读取的行数
line_count = request.POST.get("line_count")
except (TypeError, ValueError):
return JsonResponse({"success": False, "message": "请输入正确的行数"})
local = salt.client.LocalClient()
# 确保saltstack能连通并且日志文件存在
ret = local.cmd(minion_id, "file.file_exists", [log_path])
if minion_id not in ret:
return JsonResponse({"success": False, "message": "服务器无法连通"})
if not ret[minion_id]:
return JsonResponse({"success": False, "message": "日志文件不存在"})
# 组成命令的各个参数，redis信息需要和tornado配置文件中的redis信息一致
cmd = "{} {} {} {} {} {} {} {}".format(
settings.PYTHON_BIN, self.client_path, minion_id, log_path, line_count, settings.REDIS_HOST,
settings.REDIS_PORT, settings.REDIS_PASSWD)
# settings.TAIL_LOG_URL是tornado中MainHandler对应的url,把其它几个
# 参数组合成最终的URL，直接访问这个URL就可以在浏览器中实时读取日志了。
url = "{}?type=remote&log={}&hostname={}&cmd={}".format(
settings.TAIL_LOG_URL, log_path, minion_id, cmd)
# 这一步的操作确保同一个日志文件只有一个脚本在读取，避免日志信息重复，这一步
# 也很重要，必不可少
local.cmd(minion_id, "cmd.run",
["kill `ps aux|grep logtail.py|grep %s|grep -v grep|awk '{print $2}'`" % (log_path,)])
return JsonResponse({"success": True, "url": url})
下面来看看logtail.py的实现：
# encoding: utf-8
from __future__ import unicode_literals, division
import math
import time
import sys
import socket
import signal
import redis
FLAG = True
def get_last_lines(f, num=10):
"""读取文件的最后几行
"""
size = 1000
try:
f.seek(-size, 2)
except IOError: # 文件内容不足size
f.seek(0)
return f.readlines()[-num:]
data = f.read()
lines = data.splitlines()
n = len(lines)
while n < num:
size *= int(math.ceil(num / n))
try:
f.seek(-size, 2)
except IOError:
f.seek(0)
return f.readlines()[-num:]
data = f.read()
lines = data.splitlines()
n = len(lines)
return lines[-num:]
def process_line(r, channel, line):
r.publish(channel, line.strip())
def sig_handler(signum, frame):
global FLAG
FLAG = False
# 收到退出信号后，以比较优雅的方式终止脚本
signal.signal(signal.SIGTERM, sig_handler)
# 为了避免日志输出过多，浏览器承受不住，设置5分钟后脚本自动停止
signal.signal(signal.SIGALRM, sig_handler)
signal.alarm(300)
def get_hostname():
return socket.gethostname()
def force_str(s):
if isinstance(s, unicode):
s = s.encode("utf-8")
return s
def tail():
password = sys.argv[6]
if password == "None":
password = None
r = redis.StrictRedis(host=sys.argv[4], port=sys.argv[5], password=password, db=5)
log_path = sys.argv[2]
line_count = int(sys.argv[3])
# 往redis频道发送实时日志
channel = "logs:{hostname}:{log_path}".format(hostname=sys.argv[1], log_path=log_path)
with open(log_path, 'r') as f:
last_lines = get_last_lines(f, line_count)
for line in last_lines:
process_line(r, channel, force_str(line))
try:
while FLAG: # 通过信号控制这个变量，实现优雅退出循环
line = f.readline()
if not line:
time.sleep(0.05)
continue
process_line(r, channel, line)
except KeyboardInterrupt:
pass
print("Exiting...")
if __name__ == "__main__":
if len(sys.argv) < 6:
print "Usage: %s minion_id log_path host port redis_pass"
exit(1)
tail()
到此为止，整个实时读取远程日志的流程就讲完了。
github: https://github.com/tuxinhang1989/logs
以上这篇django+tornado实现实时查看远程日志的方法就是小编分享给大家的全部内容了，希望能给大家一个参考，也希望大家多多支持三水点靠木。
django+tornado实现实时查看远程日志的方法
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