#!/usr/bin/python env
from optparse import OptionParser
import os, sys, socket, re
import json, memcache
import logging as log
from contextlib import closing
'''
desc: flushing memcache instance when it ejected in twemproxy cache pool
author: ugur engin
usage: tw_eject_memcache [options]
Options:
-h, --help show this help message and exit
-H HOST Twemproxy host address
-P PORT Twemproxy port
Also you should define the "cache pool name" in this script where is set in twemproxy service.
'''
def opt():
parser = OptionParser()
parser.add_option("-H", dest="host", help="Twemproxy host address")
parser.add_option("-P", dest="port", type='int', help="Twemproxy port")
(options, args) = parser.parse_args()
return options, args
# logging function
def log_script():
log.basicConfig(
format="%(asctime)s %(levelname)s %(filename)s %(message)s",
filename = "/var/log/messages",
filemode = 'a',
level = log.DEBUG)
if __name__ == "__main__":
log_script()
log_script()
# checking first requirements to connect twemproxy.
def check_opt(host, port):
if not host:
print "Unknown: Twemproxy host address is required."
raise SystemExit, 3
elif port is None:
print "Unknown: Twemproxy port number is required."
raise SystemExit, 3
# checking twemproxy statistics socket port.
def twemproxy_socket(host, port, timeout=3):
s = socket.socket()
s.settimeout(timeout)
try:
s.connect((host, port))
return True
except socket.error, e:
msg = "Connection to %s on port %s failed: %s" % (host, port, e)
print msg
log.debug(msg)
return False
# get hostname of local memcache
def memcache_host():
h = socket.gethostname()
try:
hsfx = ".int.pkgms.net"
name = '.'.join(h.split('.')[0:1]) + hsfx
return name
except ImportError, e:
msg= "cannot to take memcache hostname!"
print msg
log.debug(msg)
raise SystemExit, 1
# flushing local memcache
def mc_clean():
try:
mc = memcache.Client(["localhost:11211"], debug=1)
return mc.flush_all()
except Exception as m:
log.Exception(m)
raise SystemExit, 1
# validating json data which returned twemproxy statistic socket.
def validate_ejected_ts(host, port, name):
s = socket.socket()
char=[];
ts_file = "/var/log/tw_ejected_timestamp"
try:
s.connect((host, port))
jrecv = s.recv(10240) # data lenght
char.append(jrecv)
jobjc = json.loads(jrecv)
ts_key = jobjc['<pool-name>'][name]['server_ejected_at']
if ts_key is not None:
if (not os.path.exists(ts_file) or os.stat(ts_file).st_size == 0) and ts_key != 0:
mc_clean()
write_ts_a = open(ts_file,"a")
write_ts_a.write(str(ts_key) + "\n")
write_ts_a.close()
msg = "mc_flush_1: memcache is flushed due to ejected in twemproxy!"
print msg
log.debug(msg)
elif os.stat(ts_file).st_size != 0 and ts_key != 0:
with open(ts_file) as f_ts:
ts_r = int((list(f_ts)[-1]).strip())
if ts_r != ts_key:
mc_clean()
write_ts_b = open(ts_file,"a")
write_ts_b.write(str(ts_key) + "\n")
write_ts_b.close()
msg = "mc_flush_2: memcache is flushed due to ejected in twemproxy!"
print msg
log.debug(msg)
else:
print "OK2: Memcache server is not ejected from twemproxy."
else:
print "OK1: Memcache server is not ejected from twemproxy."
except socket.error, e:
print "Failed to load json data" % (host, port, e)
log.debug(e)
return False
def check_main():
options, args = opt()
host = memcache_host()
check_opt(options.host, options.port)
twemproxy_socket(options.host, options.port)
validate_ejected_ts(options.host,options.port,host)
if __name__ == "__main__":
check_main()
