Memleak debugging

[Mathieu Duponchelle]

Oh I see, nice! Also note that you may want to use python's weak refs
eventually, if you end up having reference loops you need to break :)

On Wed, 2022-09-07 at 08:08 +0200, Florian Echtler wrote:
> OK, found it: there was still a reference to the data channels and
> the WebSocket 
> connection object. Now it's finally cleaned up properly.
> 
> Thanks again and best, Florian
> 
> On 06.09.22 15:01, Mathieu Duponchelle wrote:
> > You're probably still leaking WebRTCBin itself :)
> > 
> > On Tue, 2022-09-06 at 14:40 +0200, Florian Echtler wrote:
> > > P.S. Seems my code is still leaking one each of the following
> > > objects
> > > per
> > > connection: GstWebRTCDTLSTransport, GstWebRTCICEStream,
> > > GstWebRTCNiceTransport,
> > > GstWebRTCSCTPTransport, GstSctpEnc, GstSctpDec, GstAppSink,
> > > GstAppSrc.
> > > 
> > > However, all of these are definitely created internally by
> > > WebRTCBin,
> > > so I can't
> > > be holding any more references to them - suggestions for getting
> > > rid
> > > of them as
> > > well?
> > > 
> > > Thanks again and best, Florian
> > > 
> > > On 06.09.22 13:07, Florian Echtler via gstreamer-devel wrote:
> > > > Oh wow, so obvious in hindsight 🤦
> > > > 
> > > > Thank you, I entirely forgot about the Python references. Seems
> > > > to
> > > > work.
> > > > 
> > > > Best, Florian
> > > > 
> > > > On 06.09.22 11:14, Mathieu Duponchelle wrote:
> > > > > Hey Florian,
> > > > > 
> > > > > You need to make sure to release all references to elements,
> > > > > for
> > > > > instance clear self.mixers, self.outputs etc :)
> > > > > 
> > > > > Hope that helps
> > > > > 
> > > > > On Tue, 2022-09-06 at 08:39 +0200, Florian Echtler via
> > > > > gstreamer-
> > > > > devel
> > > > > wrote:
> > > > > > Hi everyone,
> > > > > > 
> > > > > > I noticed a resource leak in my Python-based WebRTC
> > > > > > application
> > > > > > after
> > > > > > extended
> > > > > > runtime; it hangs with the repeated error message
> > > > > > "gst_poll_read_control:
> > > > > > assertion 'set != NULL' failed". AFAICT this likely means
> > > > > > that
> > > > > > too
> > > > > > many GstBus
> > > > > > objects or bus watches are still hanging around.
> > > > > > 
> > > > > > I've taken care to cleanup all resources when a client
> > > > > > disconnects
> > > > > > and I've
> > > > > > verified this via the debug dot graph; there are no
> > > > > > unexpected
> > > > > > elements or pads
> > > > > > hanging around anymore.
> > > > > > 
> > > > > > However, when I use the leak tracer, then it complains
> > > > > > about a
> > > > > > huge
> > > > > > amount of
> > > > > > leaks, including all the elements I supposedly removed
> > > > > > (e.g.
> > > > > > after 4
> > > > > > clients
> > > > > > have connected and disconnected, the leak tracer shows 4
> > > > > > leaked
> > > > > > GstWebRTCBin
> > > > > > objects).
> > > > > > 
> > > > > > Here's a snippet from the code I use to tidy up after a
> > > > > > client
> > > > > > disconnects:
> > > > > > 
> > > > > >            # pause the bin
> > > > > >            self.wrb.bin.set_state(Gst.State.NULL)
> > > > > > 
> > > > > >            # pause, unlink, and remove the output buffers
> > > > > >            logging.debug("  Removing outputs...")
> > > > > >            for i in self.outputs:
> > > > > >                out_tee = self.outputs[i]
> > > > > >                out_tee.set_state(Gst.State.NULL)
> > > > > >                for p in out_tee.srcpads:
> > > > > >                    p.unlink(p.get_peer())
> > > > > >                remove_element(out_tee)
> > > > > > 
> > > > > >            # remove the bin
> > > > > >            logging.debug("  Removing main bin...")
> > > > > >            remove_element(self.wrb.bin)
> > > > > > 
> > > > > > AFAICT, if I stop and remove a bin, then it should deal
> > > > > > with
> > > > > > its
> > > > > > internal
> > > > > > components on its own, correct? Is there something I'm
> > > > > > missing?
> > > > > > I did
> > > > > > not use
> > > > > > blocking pad probes here because I don't care about buffers
> > > > > > getting
> > > > > > lost at this
> > > > > > point.
> > > > > > 
> > > > > > Any hints welcome!
> > > > > > 
> > > > > > For reference, the full code is here:
> > > > > > https://github.com/floe/surfacestreams/blob/main/client.py#L84-L140
> > > > > > 
> > > > > > Thanks and best, Florian
> > > > > > -- 
> > > > > > SENT FROM MY DEC VT50 TERMINAL
> > > > 
> > > > 
> > > 
> > > 
> > > -- 
> > > SENT FROM MY DEC VT50 TERMINAL
> 
> 
> -- 
> SENT FROM MY DEC VT50 TERMINAL