From ce88b52295881a3dd1bc0efec8e72b1d3a235e87 Mon Sep 17 00:00:00 2001 From: Ivan Alejandro Date: Tue, 22 Jul 2014 11:33:09 -0300 Subject: Add frontend alive check to the backend. Stop the backend if the frontend process does not exist any more and backend is not a daemon. --- src/leap/bitmask/backend/backend.py | 24 +++++++++++++++++++++++- 1 file changed, 23 insertions(+), 1 deletion(-) (limited to 'src/leap/bitmask/backend/backend.py') diff --git a/src/leap/bitmask/backend/backend.py b/src/leap/bitmask/backend/backend.py index c895f8f5..67ffe35a 100644 --- a/src/leap/bitmask/backend/backend.py +++ b/src/leap/bitmask/backend/backend.py @@ -18,6 +18,8 @@ import json import threading import time +import psutil + from twisted.internet import defer, reactor, threads import zmq @@ -39,12 +41,16 @@ class Backend(object): PORT = '5556' BIND_ADDR = "tcp://127.0.0.1:%s" % PORT - def __init__(self): + PING_INTERVAL = 2 # secs + + def __init__(self, frontend_pid=None): """ Backend constructor, create needed instances. """ self._signaler = Signaler() + self._frontend_pid = frontend_pid + self._do_work = threading.Event() # used to stop the worker thread. self._zmq_socket = None @@ -81,6 +87,8 @@ class Backend(object): Note: we use a simple while since is less resource consuming than a Twisted's LoopingCall. """ + pid = self._frontend_pid + check_wait = 0 while self._do_work.is_set(): # Wait for next request from client try: @@ -93,6 +101,20 @@ class Backend(object): raise time.sleep(0.01) + check_wait += 0.01 + if pid is not None and check_wait > self.PING_INTERVAL: + check_wait = 0 + self._check_frontend_alive() + + def _check_frontend_alive(self): + """ + Check if the frontend is alive and stop the backend if it is not. + """ + pid = self._frontend_pid + if pid is not None and not psutil.pid_exists(pid): + logger.critical("The frontend is down!") + self.stop() + def _stop_reactor(self): """ Stop the Twisted reactor, but first wait a little for some threads to -- cgit v1.2.3