#!/usr/bin/env python

from email.mime.text import MIMEText
import os
import re
import socket
import sys
import subprocess
import time
import threading

# Add the email address to be notified here.
EMAIL_TO = ', '.join([
    'Root <root@localhost>',
])

class Matcher(object):
    def __init__(self):
        self.lastseen = 0
        self.regexp = re.compile(r'\((\d+): (.*?)\)')
        self.timeframe = 20

    def __call__(self, line):
        now = time.time()
        if (now - self.lastseen) > self.timeframe:
            if ('104: Connection reset by peer' in line) or \
               ('111: Connection refused' in line):
                match = self.regexp.search(line)
                if match:
                   # sendmail(self.get_message(match))
                    self.lastseen = time.time()
                    return match

    def get_message(self, match):
        hostname = socket.gethostname()
        message = 'PHP/FastCGI instance on %s is detected dead.\n\n%s' % \
            (hostname, match.group(0))
            
        message = MIMEText(message)
        message['From'] = 'Root <root@%s>' % (hostname, hostname)
        message['To'] = EMAIL_TO
        message['Subject'] = 'Broken PHP detected - %s' % hostname

        return message



class Processor(object):
    def __init__(self):
        self.thread = None
        self.restart = None

    def __call__(self, matched):
        if self.thread is None:
            self.thread = threading.Thread(target=self.run)
            self.thread.setDaemon(True)
            self.thread.start()

    def get_message(self):
        hostname = socket.gethostname()
        message = 'PHP/FastCGI instance on %s has been restarted.' % hostname
            
        message = MIMEText(message)
        message['From'] = 'Root <root@%s>' % (hostname, hostname)
        message['To'] = EMAIL_TO
        message['Subject'] = 'PHP restarted - %s' % hostname

        return message

    def run(self):
        initscript = '/etc/init.d/php-fastcgi/'
        if not os.path.exists(initscript):
            initscript = '/etc/init.d/php-fastcgi'

        try:
            try:
                subprocess.call(['killall', '-9', 'php5-cgi'])
                time.sleep(1)
                subprocess.call([initscript, 'start'])
               # sendmail(self.get_message())
            except Exception, ex:
                pass
        finally:
            self.thread = None


def call_devnull(args):
    proc = subprocess.Popen(args, stderr=subprocess.STDOUT,
        stdout=subprocess.STDOUT)
    return proc.wait()


def daemonize():
    pid = os.fork()
    if pid == 0:
        os.setsid()
        pid = os.fork()
        if pid == 0:
            os.chdir('/')
            os.umask(0)
        else:
            os._exit(0)
    else:
        os._exit(0)

    import resource
    maxfd = resource.getrlimit(resource.RLIMIT_NOFILE)[1]
    if maxfd == resource.RLIM_INFINITY:
        maxfd = 1024
    for fd in range(0, maxfd):
        try:
            os.close(fd)
        except OSError:
            pass

    os.open(os.devnull, os.O_RDWR)
    os.dup2(0, 1)
    os.dup2(0, 2)


#def sendmail(message):
#    proc = subprocess.Popen(['/usr/lib/sendmail', '-t'], stdin=subprocess.PIPE)
#    proc.stdin.write(message.as_string())
#    proc.stdin.close()
#    proc.wait()


def main(filename, match, action):
    try:
        for line in tailf(filename):
            matchobj = match(line)
            if matchobj:
                action(matchobj)
    except KeyboardInterrupt:
        pass


def tailf(filename):
    import cStringIO
    import os
    import time

    lastsize = os.path.getsize(filename)
    while True:
        size = os.path.getsize(filename)
        if size > lastsize:
            fobj = open(filename, 'r')
            fobj.seek(lastsize)
            data = fobj.read(size - lastsize)
            fobj.close()

            data = cStringIO.StringIO(data)
            for line in data:
                yield line

            lastsize = size

        if size < lastsize:
            lastsize = 0

        else:
            time.sleep(2.0)


if __name__ == '__main__':
    daemonize()
    filename = sys.argv[1] if len(sys.argv) > 1 else '/var/log/nginx/error.log'
    main(filename, Matcher(), Processor())