I'm only concerned with the difference in treatment.<br><br> public class CrashFreeSWITCH : ILoadNotificationPlugin<br> {<br> public bool Load()<br> {<br> ThreadPool.QueueUserWorkItem((o) => { throw new NotImplementedException(); });<br>
return true;<br> }<br> }<br><div><span class="Apple-style-span" style="font-family: arial, sans-serif; font-size: 13px; border-collapse: collapse; color: rgb(80, 0, 80); "><div>Crashes the entire switch, terminating all calls and disconnecting from the PSTN.<p>
<span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: arial; font-size: small; ">public class CrashFreeSWITCH : ILoadNotificationPlugin<br> {<br> public bool Load()<br>
{<br> throw new NotImplementedException();<br> return true;<br> }<br> }</span></p></div></span>Logs a message to the console and doesn't load the module, while leaving the switch operating.</div>
<div><br></div><div>In my experience, exceptions in multi-threaded code: a) happen, b) are hard to diagnose. Is the best behavior for the environment to crash, providing no diagnostic information? That's hard in development, and even harder in production. I suppose 'terminate switch on fault' should be an option, to allow the operating system to restart the whole process on fault conditions, but if that is the intended result, shouldn't any fault do the same thing? What if the billing was happening in my second code block?</div>
<div><br></div><div>Normally, I'd trap the ThreadException and UnhandledExceptions in my application, so that my code could choose the correct actions to perform should the application get into an unknown state. This can include terminating the whole application, but also logging diagnostic information, trying to save uncommitted data, and sending notifications of the failure.</div>
<div><br></div><div>Is 'crash if it's a thread, but not if it's not' good because it's the way the module works now, or is it a better design for a reason I'm not understanding?</div><div> </div><div>
<div class="gmail_quote">On Wed, Sep 9, 2009 at 11:09 PM, Michael Giagnocavo <span dir="ltr"><<a href="mailto:mgg@giagnocavo.net">mgg@giagnocavo.net</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div lang="EN-US" link="blue" vlink="purple">
<div>
<p><span style="font-size:11.0pt;color:#1F497D">Well, a segfault in voicemail would do the same thing.</span></p>
<p><span style="font-size:11.0pt;color:#1F497D"> </span></p>
<p><span style="font-size:11.0pt;color:#1F497D">Suppose your plugin runs a thread that does something important,
like billing or so on. That thread fails – do you really want it to go on?</span></p>
<p><span style="font-size:11.0pt;color:#1F497D"> </span></p>
<p><span style="font-size:11.0pt;color:#1F497D">Anyways, the solution is simple enough, handle your exceptions </span><span style="font-size:11.0pt;font-family:Wingdings;color:#1F497D">J</span><span style="font-size:11.0pt;color:#1F497D">.
Every plugin can decide what it wants to do here.</span></p>
<p><span style="font-size:11.0pt;color:#1F497D"> </span></p>
<p><span style="font-size:11.0pt;color:#1F497D">-Michael</span></p>
<p><span style="font-size:11.0pt;color:#1F497D"> </span></p>
<div style="border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in">
<p><b><span style="font-size:10.0pt">From:</span></b><span style="font-size:10.0pt">
<a href="mailto:freeswitch-users-bounces@lists.freeswitch.org" target="_blank">freeswitch-users-bounces@lists.freeswitch.org</a>
[mailto:<a href="mailto:freeswitch-users-bounces@lists.freeswitch.org" target="_blank">freeswitch-users-bounces@lists.freeswitch.org</a>] <b>On Behalf Of </b>Josh
Rivers<br>
<b>Sent:</b> Wednesday, September 09, 2009 10:41 PM</span></p><div><div></div><div class="h5"><br>
<b>To:</b> <a href="mailto:freeswitch-users@lists.freeswitch.org" target="_blank">freeswitch-users@lists.freeswitch.org</a><br>
<b>Subject:</b> Re: [Freeswitch-users] Subscribing to events in managed C# /
.NET</div></div><p></p>
</div><div><div></div><div class="h5">
<p> </p>
<p style="margin-bottom:12.0pt">The question is whether the CLR
should take down the whole phone server due to an unhandled
exception...definitely the CLR should terminate...but shouldn't it just log the
exception to the console, not crash the core?</p>
<div>
<p>On Wed, Sep 9, 2009 at 6:30 PM, Michael Giagnocavo <<a href="mailto:mgg@giagnocavo.net" target="_blank">mgg@giagnocavo.net</a>> wrote:</p>
<div>
<div>
<p><span style="font-size:11.0pt;color:#1F497D">That’s by design. If a thread
fails, and there’s no handler, then the application could be in a corrupted
state, so the CLR takes down the process.</span></p>
<p><span style="font-size:11.0pt;color:#1F497D"> </span></p>
<p><span style="font-size:11.0pt;color:#1F497D">I think there is a .NET 1.0
compat switch you can enable in the config if you like exceptions to be
silently ignored </span><span style="font-size:11.0pt;font-family:Wingdings;color:#1F497D">J</span><span style="font-size:11.0pt;color:#1F497D">.</span></p>
<p><span style="font-size:11.0pt;color:#1F497D"> </span></p>
<p><span style="font-size:11.0pt;color:#1F497D">-Michael</span></p>
<p><span style="font-size:11.0pt;color:#1F497D"> </span></p>
<div style="border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in">
<p><b><span style="font-size:10.0pt">From:</span></b><span style="font-size:10.0pt"> <a href="mailto:freeswitch-users-bounces@lists.freeswitch.org" target="_blank">freeswitch-users-bounces@lists.freeswitch.org</a> [mailto:<a href="mailto:freeswitch-users-bounces@lists.freeswitch.org" target="_blank">freeswitch-users-bounces@lists.freeswitch.org</a>]
<b>On Behalf Of </b>Josh Rivers<br>
<b>Sent:</b> Wednesday, September 09, 2009 6:39 PM</span></p>
<div>
<div>
<p><br>
<b>To:</b> <a href="mailto:freeswitch-users@lists.freeswitch.org" target="_blank">freeswitch-users@lists.freeswitch.org</a><br>
<b>Subject:</b> Re: [Freeswitch-users] Subscribing to events in managed C# /
.NET</p>
</div>
</div>
</div>
<div>
<div>
<p> </p>
<p>I have a new thought on the crashes...I'm able to crash FreeSWITCH any time
I like, just by having an exception in a thread.</p>
<div>
<p> </p>
<div>
<p> public class CrashFreeSWITCH : ILoadNotificationPlugin</p>
</div>
<div>
<p> {</p>
</div>
<div>
<p> public bool Load()</p>
</div>
<div>
<p> {</p>
</div>
<div>
<p>
ThreadPool.QueueUserWorkItem((o) => { throw new
NotImplementedException(); });</p>
</div>
<div>
<p> return true;</p>
</div>
<div>
<p> }</p>
</div>
<div>
<p> }</p>
</div>
<div>
<p> </p>
</div>
<div>
<p>Perhaps Application.ThreadException
or AppDomain.UnhandledException need to be trapped?</p>
</div>
<div>
<p> </p>
</div>
<div>
<p>On Wed, Sep 9, 2009 at 4:51 PM, Michael Giagnocavo <<a href="mailto:mgg@giagnocavo.net" target="_blank">mgg@giagnocavo.net</a>> wrote:</p>
<div>
<div>
<div>
<p>>Looks like the event object goes straight to pinvokes, so a null result
just crashes?</p>
<p> </p>
</div>
<p>If it’s null, you should get a NullReferenceException. The C# compiler
should callvirt the property getter and that’ll do a null check. If that isn’t
happening, that’d be an interesting optimization somewhere along the line.</p>
<p> </p>
<p>-Michael </p>
<p><span style="font-size:11.0pt;color:#1F497D"> </span></p>
<p><span style="font-size:11.0pt;color:#1F497D"> </span></p>
<div style="border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in">
<p><b><span style="font-size:10.0pt">From:</span></b><span style="font-size:10.0pt"> <a href="mailto:freeswitch-users-bounces@lists.freeswitch.org" target="_blank">freeswitch-users-bounces@lists.freeswitch.org</a> [mailto:<a href="mailto:freeswitch-users-bounces@lists.freeswitch.org" target="_blank">freeswitch-users-bounces@lists.freeswitch.org</a>]
<b>On Behalf Of </b>Josh Rivers<br>
<b>Sent:</b> Wednesday, September 09, 2009 3:01 PM</span></p>
<div>
<p><br>
<b>To:</b> <a href="mailto:freeswitch-users@lists.freeswitch.org" target="_blank">freeswitch-users@lists.freeswitch.org</a></p>
</div>
<p><b>Subject:</b> Re: [Freeswitch-users] Subscribing to events in managed C# /
.NET</p>
</div>
<div>
<div>
<p> </p>
<p>A new discovery:</p>
<div>
<div>
<p> public bool Load()</p>
</div>
<div>
<p> {</p>
</div>
<div>
<p>
ThreadPool.QueueUserWorkItem((o) =></p>
</div>
<div>
<p> {</p>
</div>
<div>
<p>
Log.WriteLine(LogLevel.Notice, "Thread Starting. ");</p>
</div>
<div>
<p> EventConsumer
con = new EventConsumer("all", "");</p>
</div>
<div>
<p> while (true)</p>
</div>
<div>
<p> {</p>
</div>
<div>
<p>
Event ev = con.pop(0);</p>
</div>
<div>
<p>
if (ev == null) continue;</p>
</div>
<div>
<p>
Log.WriteLine(LogLevel.Notice, "Event: " +
ev.serialized_string);</p>
</div>
<div>
<p> }</p>
</div>
<div>
<p> });</p>
</div>
<div>
<p> return true;</p>
</div>
<div>
<p> }</p>
</div>
<div>
<p>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?</p>
</div>
<div>
<p> </p>
</div>
<div>
<p>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.</p>
</div>
<div>
<p> </p>
</div>
<div>
<p>--Josh</p>
</div>
<p> </p>
<div>
<p>On Wed, Sep 9, 2009 at 12:57 PM, Jeff Lenk <<a href="mailto:jlenk@frontiernet.net" target="_blank">jlenk@frontiernet.net</a>>
wrote:</p>
<p><br>
I think the problem here is that the loader only keeps this method in scope<br>
until completion then it drops the remoted connection. Therefore you should<br>
not use threads in this method. Michael please correct me if I am wrong<br>
here.<br>
<br>
As an example of the failure simply just put a Sleep(10000) call in the<br>
thread and you will see the failure.<br>
<br>
As Michael said this method was only designed to allow the option to opt out<br>
of being loaded.<br>
<br>
In order to support this perhaps a configuration flag simular to the lua<br>
"startup-script" should be added.</p>
<div>
<p style="margin-bottom:12.0pt"><br>
<br>
<br>
Here is the error I get with the loop I mentioned. -Josh<br>
[image: Capture.PNG]<br>
<br>
On Tue, Sep 8, 2009 at 5:05 AM, Michael Giagnocavo<br>
<<a href="mailto:mgg@giagnocavo.net" target="_blank">mgg@giagnocavo.net</a>>wrote:<br>
<br>
> Hi,<br>
><br>
><br>
><br>
> Can you please
elaborate on the crash you receive when you<br>
> queue a thread during load?<br>
><br>
><br>
><br>
> Thanks,<br>
><br>
> Michael<br>
><br>
></p>
</div>
<p><span style="color:#888888">--<br>
View this message in context: <a href="http://n2.nabble.com/Subscribing-to-events-in-managed-C-NET-tp3573619p3613195.html" target="_blank">http://n2.nabble.com/Subscribing-to-events-in-managed-C-NET-tp3573619p3613195.html</a><br>
Sent from the freeswitch-users mailing list archive at Nabble.com.</span></p>
<div>
<div>
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