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PODbus/GLib Main Loop, Background Thread
 

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    <p>I'm starting out with DBus and event driven programming in general. The service that I'm trying to create really consists of three parts but two are really "server" things.</p> <p>1) The actual DBus server talks to a remote website over HTTPS, manages sessions, and conveys info the clients.</p> <p>2) The other part of the service calls a keep alive page every 2 minutes to keep the session active on the external website</p> <p>3) The clients make calls to the service to retrieve info from the service.</p> <p>I found some simple example programs. I'm trying to adapt them to prototype #1 and #2. Rather than building separate programs for both. I thought I that I can run them in a single, two threaded process. </p> <p>The problem that I'm seeing is that I call time.sleep(X) in my keep alive thread. The thread goes to sleep, but won't ever wake up. I think that the GIL isn't released by the GLib main loop. </p> <p>Here's my thread code:</p> <pre><code>class Keepalive(threading.Thread): def __init__(self, interval=60): super(Keepalive, self).__init__() self.interval = interval bus = dbus.SessionBus() self.remote = bus.get_object("com.example.SampleService", "/SomeObject") def run(self): while True: print('sleep %i' % self.interval) time.sleep(self.interval) print('sleep done') reply_status = self.remote.keepalive() if reply_status: print('Keepalive: Success') else: print('Keepalive: Failure') </code></pre> <p>From the print statements, I know that the sleep starts, but I never see "sleep done."</p> <p>Here is the main code:</p> <pre><code>if __name__ == '__main__': try: dbus.mainloop.glib.DBusGMainLoop(set_as_default=True) session_bus = dbus.SessionBus() name = dbus.service.BusName("com.example.SampleService", session_bus) object = SomeObject(session_bus, '/SomeObject') mainloop = gobject.MainLoop() ka = Keepalive(15) ka.start() print('Begin main loop') mainloop.run() except Exception as e: print(e) finally: ka.join() </code></pre> <p>Some other observations:</p> <p>I see the "begin main loop" message, so I know it's getting control. Then, I see "sleep %i," and after that, nothing. </p> <p>If I ^C, then I see "sleep done." After ~20 seconds, I get an exception from self.run() that the remote application didn't respond:</p> <blockquote> <p>DBusException: org.freedesktop.DBus.Error.NoReply: Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken.</p> </blockquote> <p>What's the best way to run my keep alive code within the server?</p> <p>Thanks,</p>
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