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[mgg at giagnocavo.net]

“ ThreadPool.QueueUserWorkItem((o) =>”
That starts a lambda, which is compiled to a delegate, same as anonymous methods.
Guess I’ll wait for him to respond on the crash he gets.


From: freeswitch-users-bounces@lists.freeswitch.org [mailto:freeswitch-users-bounces@lists.freeswitch.org] On Behalf Of Raffaele P. Guidi
Sent: Tuesday, September 08, 2009 12:22 PM
To: freeswitch-users@lists.freeswitch.org
Subject: Re: [Freeswitch-users] Subscribing to events in managed C# / .NET


Well, I can't see any delegate in josh sample, just a ThreadPool.QueueUserWorkItem. Here is an example that, at least on my system (I reached my home pc in the meanwhile), works fine.


public class LoadPluginDemo : ILoadNotificationPlugin {

delegate void Listener();

private void EventListener() {

EventConsumer con = new EventConsumer("all", null);

while (true){

Event ev = con.pop(1);

Log.WriteLine(LogLevel.Notice, "Got event " + ev.GetHeader("Event-Name"));

}

}

public bool Load() {

Log.WriteLine(LogLevel.Notice, "LoadDemo running.");

new Listener(EventListener).BeginInvoke(null,null);

return true;

}

}






On Tue, Sep 8, 2009 at 18:43, Michael Giagnocavo <mgg@giagnocavo.net (mgg@giagnocavo.net)> wrote:
That’s what his sample does, but he says it crashes.

From: freeswitch-users-bounces@lists.freeswitch.org (freeswitch-users-bounces@lists.freeswitch.org) [mailto:freeswitch-users-bounces@lists.freeswitch.org (freeswitch-users-bounces@lists.freeswitch.org)] On Behalf Of Raffaele P. Guidi
Sent: Tuesday, September 08, 2009 10:08 AM

To: freeswitch-users@lists.freeswitch.org (freeswitch-users@lists.freeswitch.org)
Subject: Re: [Freeswitch-users] Subscribing to events in managed C# / .NET



Hi, you just have to use delegates to asynchronously call the function containing the loop and return back the control to the calling thread. Here an example (don't have my code at hand, hope it doesn't contain typos).



Regards,

Raffaele



public class TestLoop : ILoadNotificationPlugin

{


Delegate void DoStuffDelegate();



public void doStuff()

{

EventConsumer con = new EventConsumer("all", "");


while (true)

{

Event ev = con.pop(0);


Log.WriteLine(LogLevel.Notice, "Event: " + ev.serialized_string);

freeswitch.msleep(100);

}

}

public bool Load()

{

DoStuffDelegate dsdlg = new DoStuffDelegate(doStuff);

dsdlg.BeginInvoke();

}


}


On Tue, Sep 8, 2009 at 08:21, Josh Rivers <josh@radianttiger.com (josh@radianttiger.com)> wrote:
Thanks for the response!


I have tried putting a long-running loop here, but then it blocks anything else managed from happening:



public class TestLoop : ILoadNotificationPlugin

{

public bool Load()

{

EventConsumer con = new EventConsumer("all", "");


while (true)

{

Event ev = con.pop(0);


Log.WriteLine(LogLevel.Notice, "Event: " + ev.serialized_string);

freeswitch.msleep(100);

}

}

}



However, if I fork off a thread here, freeswitch crashes:

public class TestLoop : ILoadNotificationPlugin

{

public bool Load()

{

ThreadPool.QueueUserWorkItem((o) =>

{

Log.WriteLine(LogLevel.Notice, "Thread Starting. ");

EventConsumer con = new EventConsumer("all", "");


while (true)

{

Event ev = con.pop(0);


Log.WriteLine(LogLevel.Notice, "Event: " + ev.serialized_string);

freeswitch.msleep(100);

}

});

return true;

}

}



It doesn't look like this is a good place to start a long-running process?



Thanks!

Josh





On Mon, Sep 7, 2009 at 11:05 PM, Raffaele P. Guidi <raffaele.p.guidi@gmail.com (raffaele.p.guidi@gmail.com)> wrote:
Yes!


public class LoadDemo : ILoadNotificationPlugin {

public bool Load() {

Log.WriteLine(LogLevel.Notice, "LoadDemo running.");

return true;

}

}



this example is from Michael Giagnocavo's Demo.csx which you can find into the mod_managed svn.



And let me add that works like a charm



Ciao,

Raffaele


On Sun, Sep 6, 2009 at 22:50, Josh Rivers <josh@radianttiger.com (josh@radianttiger.com)> wrote:

[raffaele.p.guidi at gm...]

Oh, I see... all those years wasted doing java stuff!

On Tue, Sep 8, 2009 at 22:46, Michael Giagnocavo <mgg@giagnocavo.net (mgg@giagnocavo.net)> wrote:

[pjintheusa at gmail.com]

I build this out.

This seems to work fine:

ThreadPool.QueueUserWorkItem((o) =>
            {
                Log.WriteLine(LogLevel.Notice, "Thread Starting. ");
                EventConsumer con = new EventConsumer("all", "");
                while (true)
                {
                    Event ev = con.pop(1);
                    Log.WriteLine(LogLevel.Alert, "Event: " + ev.GetHeader("Event-Name"));
                    //freeswitch.msleep(100);
                }
            });

With
            Event ev = con.pop(0) however FS crashes with a System.NullReferenceException (attached)










On Tue, Sep 8, 2009 at 5:20 PM, Raffaele P. Guidi <raffaele.p.guidi@gmail.com (raffaele.p.guidi@gmail.com)> wrote:

[mgg at giagnocavo.net]

I’m not sure how EventConsumer is supposed to work – maybe one of the real devs can explain how pop works and if it should fail on pop 0 or not.

From: freeswitch-users-bounces@lists.freeswitch.org [mailto:freeswitch-users-bounces@lists.freeswitch.org] On Behalf Of Phillip Jones
Sent: Tuesday, September 08, 2009 3:50 PM
To: freeswitch-users@lists.freeswitch.org
Subject: Re: [Freeswitch-users] Subscribing to events in managed C# / .NET


I build this out.

This seems to work fine:

ThreadPool.QueueUserWorkItem((o) =>
{
Log.WriteLine(LogLevel.Notice, "Thread Starting. ");
EventConsumer con = new EventConsumer("all", "");
while (true)
{
Event ev = con.pop(1);
Log.WriteLine(LogLevel.Alert, "Event: " + ev.GetHeader("Event-Name"));
//freeswitch.msleep(100);
}
});

With
Event ev = con.pop(0) however FS crashes with a System.NullReferenceException (attached)










On Tue, Sep 8, 2009 at 5:20 PM, Raffaele P. Guidi <raffaele.p.guidi@gmail.com (raffaele.p.guidi@gmail.com)> wrote:
Oh, I see... all those years wasted doing java stuff!

On Tue, Sep 8, 2009 at 22:46, Michael Giagnocavo <mgg@giagnocavo.net (mgg@giagnocavo.net)> wrote:
“ ThreadPool.QueueUserWorkItem((o) =>”
That starts a lambda, which is compiled to a delegate, same as anonymous methods.
Guess I’ll wait for him to respond on the crash he gets.


From: freeswitch-users-bounces@lists.freeswitch.org (freeswitch-users-bounces@lists.freeswitch.org) [mailto:freeswitch-users-bounces@lists.freeswitch.org (freeswitch-users-bounces@lists.freeswitch.org)] On Behalf Of Raffaele P. Guidi
Sent: Tuesday, September 08, 2009 12:22 PM

To: freeswitch-users@lists.freeswitch.org (freeswitch-users@lists.freeswitch.org)
Subject: Re: [Freeswitch-users] Subscribing to events in managed C# / .NET




Well, I can't see any delegate in josh sample, just a ThreadPool.QueueUserWorkItem. Here is an example that, at least on my system (I reached my home pc in the meanwhile), works fine.


public class LoadPluginDemo : ILoadNotificationPlugin {

delegate void Listener();

private void EventListener() {

EventConsumer con = new EventConsumer("all", null);

while (true){

Event ev = con.pop(1);

Log.WriteLine(LogLevel.Notice, "Got event " + ev.GetHeader("Event-Name"));

}

}

public bool Load() {

Log.WriteLine(LogLevel.Notice, "LoadDemo running.");

new Listener(EventListener).BeginInvoke(null,null);

return true;

}

}






On Tue, Sep 8, 2009 at 18:43, Michael Giagnocavo <mgg@giagnocavo.net (mgg@giagnocavo.net)> wrote:
That’s what his sample does, but he says it crashes.

From: freeswitch-users-bounces@lists.freeswitch.org (freeswitch-users-bounces@lists.freeswitch.org) [mailto:freeswitch-users-bounces@lists.freeswitch.org (freeswitch-users-bounces@lists.freeswitch.org)] On Behalf Of Raffaele P. Guidi
Sent: Tuesday, September 08, 2009 10:08 AM

To: freeswitch-users@lists.freeswitch.org (freeswitch-users@lists.freeswitch.org)
Subject: Re: [Freeswitch-users] Subscribing to events in managed C# / .NET



Hi, you just have to use delegates to asynchronously call the function containing the loop and return back the control to the calling thread. Here an example (don't have my code at hand, hope it doesn't contain typos).



Regards,

Raffaele



public class TestLoop : ILoadNotificationPlugin

{


Delegate void DoStuffDelegate();



public void doStuff()

{

EventConsumer con = new EventConsumer("all", "");


while (true)

{

Event ev = con.pop(0);


Log.WriteLine(LogLevel.Notice, "Event: " + ev.serialized_string);

freeswitch.msleep(100);

}

}

public bool Load()

{

DoStuffDelegate dsdlg = new DoStuffDelegate(doStuff);

dsdlg.BeginInvoke();

}


}


On Tue, Sep 8, 2009 at 08:21, Josh Rivers <josh@radianttiger.com (josh@radianttiger.com)> wrote:
Thanks for the response!


I have tried putting a long-running loop here, but then it blocks anything else managed from happening:



public class TestLoop : ILoadNotificationPlugin

{

public bool Load()

{

EventConsumer con = new EventConsumer("all", "");


while (true)

{

Event ev = con.pop(0);


Log.WriteLine(LogLevel.Notice, "Event: " + ev.serialized_string);

freeswitch.msleep(100);

}

}

}



However, if I fork off a thread here, freeswitch crashes:

public class TestLoop : ILoadNotificationPlugin

{

public bool Load()

{

ThreadPool.QueueUserWorkItem((o) =>

{

Log.WriteLine(LogLevel.Notice, "Thread Starting. ");

EventConsumer con = new EventConsumer("all", "");


while (true)

{

Event ev = con.pop(0);


Log.WriteLine(LogLevel.Notice, "Event: " + ev.serialized_string);

freeswitch.msleep(100);

}

});

return true;

}

}



It doesn't look like this is a good place to start a long-running process?



Thanks!

Josh





On Mon, Sep 7, 2009 at 11:05 PM, Raffaele P. Guidi <raffaele.p.guidi@gmail.com (raffaele.p.guidi@gmail.com)> wrote:
Yes!


public class LoadDemo : ILoadNotificationPlugin {

public bool Load() {

Log.WriteLine(LogLevel.Notice, "LoadDemo running.");

return true;

}

}



this example is from Michael Giagnocavo's Demo.csx which you can find into the mod_managed svn.



And let me add that works like a charm



Ciao,

Raffaele


On Sun, Sep 6, 2009 at 22:50, Josh Rivers <josh@radianttiger.com (josh@radianttiger.com)> wrote:

[mrene_lists at avgs.ca]

Click Break, then go in Window, Debug, Stack Trace (or something similar, I don't have any VS nearby), then copy paste that.
Mathieu Rene
Avant-Garde Solutions Inc
Office: + 1 (514) 664-1044 x100
Cell: +1 (514) 664-1044 x200
mrene@avgs.ca (mrene@avgs.ca)








On 8-Sep-09, at 10:30 PM, Josh Rivers wrote:

[josh at radianttiger.com]

Here is the error I get with the loop I mentioned. -Josh


On Tue, Sep 8, 2009 at 5:05 AM, Michael Giagnocavo <mgg@giagnocavo.net (mgg@giagnocavo.net)> wrote:

[josh at radianttiger.com]

You are probably right, but commenting out the msleep doesn't prevent the crash. -Josh

On Tue, Sep 8, 2009 at 11:12 AM, Phillip Jones <pjintheusa@gmail.com (pjintheusa@gmail.com)> wrote:

[josh at radianttiger.com]

I confirmed that pop(1) works for me. since it's spinning in it's own thread, that's probably the right solution. These are the relevant pieces of core code, though:


APU_DECLARE(apr_status_t) apr_queue_trypop(apr_queue_t *queue, void **data)
{
    apr_status_t rv;


    if (queue->terminated) {
        return APR_EOF; /* no more elements ever again */
    }


    rv = apr_thread_mutex_lock(queue->one_big_mutex);
    if (rv != APR_SUCCESS) {
        return rv;
    }


    if (apr_queue_empty(queue)) {
        rv = apr_thread_mutex_unlock(queue->one_big_mutex);
        return APR_EAGAIN;
    } 


    *data = queue->data[queue->out];
    queue->nelts--;


    queue->out = (queue->out + 1) % queue->bounds;
    if (queue->full_waiters) {
        Q_DBG("signal !full", queue);
        rv = apr_thread_cond_signal(queue->not_full);
        if (rv != APR_SUCCESS) {
            apr_thread_mutex_unlock(queue->one_big_mutex);
            return rv;
        }
    }


    rv = apr_thread_mutex_unlock(queue->one_big_mutex);
    return rv;
}


AND


APU_DECLARE(apr_status_t) apr_queue_pop(apr_queue_t *queue, void **data)
{
    apr_status_t rv;


    if (queue->terminated) {
        return APR_EOF; /* no more elements ever again */
    }


    rv = apr_thread_mutex_lock(queue->one_big_mutex);
    if (rv != APR_SUCCESS) {
        return rv;
    }


    /* Keep waiting until we wake up and find that the queue is not empty. */
    if (apr_queue_empty(queue)) {
        if (!queue->terminated) {
            queue->empty_waiters++;
            rv = apr_thread_cond_wait(queue->not_empty, queue->one_big_mutex);
            queue->empty_waiters--;
            if (rv != APR_SUCCESS) {
                apr_thread_mutex_unlock(queue->one_big_mutex);
                return rv;
            }
        }
        /* If we wake up and it's still empty, then we were interrupted */
        if (apr_queue_empty(queue)) {
            Q_DBG("queue empty (intr)", queue);
            rv = apr_thread_mutex_unlock(queue->one_big_mutex);
            if (rv != APR_SUCCESS) {
                return rv;
            }
            if (queue->terminated) {
                return APR_EOF; /* no more elements ever again */
            }
            else {
                return APR_EINTR;
            }
        }
    } 


    *data = queue->data[queue->out];
    queue->nelts--;


    queue->out = (queue->out + 1) % queue->bounds;
    if (queue->full_waiters) {
        Q_DBG("signal !full", queue);
        rv = apr_thread_cond_signal(queue->not_full);
        if (rv != APR_SUCCESS) {
            apr_thread_mutex_unlock(queue->one_big_mutex);
            return rv;
        }
    }


    rv = apr_thread_mutex_unlock(queue->one_big_mutex);
    return rv;
}


Is the trypop method returning without unlocking the mutex?


    rv = apr_thread_mutex_lock(queue->one_big_mutex);
    if (rv != APR_SUCCESS) {
        return rv;
    }




On Tue, Sep 8, 2009 at 7:06 PM, Michael Giagnocavo <mgg@giagnocavo.net (mgg@giagnocavo.net)> wrote:

[josh at radianttiger.com]

I'm running of the binary release, so I don't have debug symbols for the freeswitch core. I can do a build...but does somebody else already have one handy? -Josh

On Tue, Sep 8, 2009 at 10:33 PM, Mathieu Rene <mrene_lists@avgs.ca (mrene_lists@avgs.ca)> wrote:

[mrene_lists at avgs.ca]

"Is the trypop method returning without unlocking the mutex?"

No, since the condition returns if a lock could NOT be acquired. (hence the try).

Mathieu Rene
Avant-Garde Solutions Inc
Office: + 1 (514) 664-1044 x100
Cell: +1 (514) 664-1044 x200
mrene@avgs.ca (mrene@avgs.ca)








On 8-Sep-09, at 10:46 PM, Josh Rivers wrote:

[jlenk at frontiernet.net]

I think the problem here is that the loader only keeps this method in scope
until completion then it drops the remoted connection. Therefore you should
not use threads in this method. Michael please correct me if I am wrong
here.

As an example of the failure simply just put a Sleep(10000) call in the
thread and you will see the failure.

As Michael said this method was only designed to allow the option to opt out
of being loaded.

In order to support this perhaps a configuration flag simular to the lua
"startup-script" should be added.



Here is the error I get with the loop I mentioned. -Josh
[image: Capture.PNG]

On Tue, Sep 8, 2009 at 5:05 AM, Michael Giagnocavo
<mgg@giagnocavo.net>wrote:

[josh at radianttiger.com]

  kernel32.dll!77e4bef7()
Here's that call stack.


  [Frames below may be incorrect and/or missing, no symbols loaded for kernel32.dll]
  kernel32.dll!77e4bef7()
  msvcr80.dll!78158e89()
  mscorwks.dll!79e7a17a()
  mscorwks.dll!79ea0fa8()
  mscorwks.dll!79ea0eff()
  mscorwks.dll!79e976cc()
  mscorwks.dll!79e976b3()
  mscorwks.dll!79e9e3bd()
  mscorwks.dll!79e970c8()
  mscorwks.dll!79f782f1()
  mscorwks.dll!79eaa5c5()
  mscorwks.dll!79eaad29()
  mscorwks.dll!79e9a15d()
  mscorwks.dll!79e9a15d()
  mscorwks.dll!79e7a1f1()
  mscorwks.dll!79e7a1f1()
  mscorwks.dll!79e7a17a()
  mscorwks.dll!79e88cca()
  mscorwks.dll!79e96571()
  mscorwks.dll!79e965a4()
  mscorwks.dll!79e965c2()
  mscorwks.dll!79f59330()
  mscorwks.dll!79f59492()
  mscorlib.ni.dll!792d5348()
  mscorlib.ni.dll!792d514f()
  mscorlib.ni.dll!792d4fde()
  mscorlib.ni.dll!79799714()
  mscorwks.dll!79e813e4()
  mscorwks.dll!79e813ec()

[josh at radianttiger.com]

A new discovery:        public bool Load()
        {
            ThreadPool.QueueUserWorkItem((o) =>
            {
                Log.WriteLine(LogLevel.Notice, "Thread Starting. ");
                EventConsumer con = new EventConsumer("all", "");
                while (true)
                {
                    Event ev = con.pop(0);
                    if (ev == null) continue;
                    Log.WriteLine(LogLevel.Notice, "Event: " + ev.serialized_string);
                }
            });
            return true;
        }
Does not crash. (Adding the null check prevents crash.) The backgrounded loop runs fine. Looks like the event object goes straight to pinvokes, so a null result just crashes?


I like the idea of a 'startup-script' for mod_managed. It would also be excellent if there was an event or message  informing the background code to terminate nicely when the module reloads.


--Josh

On Wed, Sep 9, 2009 at 12:57 PM, Jeff Lenk <jlenk@frontiernet.net (jlenk@frontiernet.net)> wrote:

[jlenk at frontiernet.net]

Yeah I noticed that but the thread was still terminating after a few seconds
anyway for me. Does it stay running for you?


Josh Rivers-2 wrote:

[josh at radianttiger.com]

It does from a fresh start of FreeSWITCH. I've noticed, although not really confirmed, a race condition between the unload and reload of managed code. It seems that threads started in the newly submodule are terminated along with the threads for the old, unloading submodule. Is that what you are seeing as well?

On Wed, Sep 9, 2009 at 2:38 PM, Jeff Lenk <jlenk@frontiernet.net (jlenk@frontiernet.net)> wrote: