[PEAK] Stopping PEAK application on SIGINT
Alexey Smishlayev
alexey at xtech2.lv
Fri Oct 2 06:51:54 EDT 2015
Hello!
I tried using pdb today, to some degree of success. Turns out that
eventLoop.sigsrc attribute gets an instance of
"peak.events.twisted_support.Selector". eventLoop.signals attribute is
"binding.Delegate('sigsrc')", so it gets resolved to
"peak.events.twisted_support.Selector.signals", which is
"binding.Delegate('sigsrc')" - that's where recursion appears.
I've gathered some evidence using pdb:
>
/Library/Python/2.7/site-packages/peak/config/config_components.py(398)lookup()
-> for value in iterValues(component, configKey):
(Pdb) component
<peak.config.config_components.ServiceArea object at 0x108ba3390>
(Pdb) configKey
config.MultiKey(<class 'peak.binding.interfaces.IComponentFactory'>,
<class 'peak.events.interfaces.ISignalSource'>)
(Pdb) [x for x in iterValues(component, configKey)]
[<class 'peak.events.twisted_support.Selector'>, <class
'peak.events.io_events.SignalEvents'>]
--
>
/Library/Python/2.7/site-packages/peak/config/config_components.py(384)iterValues()
-> value = gcd(forObj, configKey)
(Pdb) forObj
<peak.config.config_components.ServiceArea object at 0x108ba3390>
(Pdb) configKey
config.MultiKey(<class 'peak.binding.interfaces.IComponentFactory'>,
<class 'peak.events.interfaces.ISignalSource'>)
(Pdb) gcd
<bound method ServiceArea._getConfigData of
<peak.config.config_components.ServiceArea object at 0x108ba3390>>
(Pdb) gcd(forObj, configKey)
<class 'peak.events.twisted_support.Selector'>
--
>
/Library/Python/2.7/site-packages/peak/config/config_components.py(593)_getConfigData()
-> value = rule.get()(self, configKey, forObj)
(Pdb) rule.get()
<function f at 0x1094bfcf8>
(Pdb) rule.get()(self, configKey, forObj)
<class 'peak.events.twisted_support.Selector'>
Unfortunately, my efforts stop here. I have no idea where from this
function f appeared in configuration rules, but it creates Selector
instance, which messes up the lookup.
From peak.ini: " peak.events.interfaces.ISignalSource =
io_events.SignalEvents"
I tried grepping "ISignalSource" in my project's directory, but this
gives no results.
Regards,
Alexey
On 30/09/15 02:12, PJ Eby wrote:
> The failure is in trying to retrieve the `signals()` method from the
> ISignalSource, which should be the io_events.SignalSource singleton.
> What I don't understand is why it's recursing on the attempt to
> retrieve the signals attribute. Specifically, it seems as though this
> should only be able to happen if trying to load the 'sigsrc' attribute
> results in an attempt to load the 'signals' attribute. I would
> suggest stepping through with the debugger from line 66 of
> scheduler.py and see if you can tell what's happening there.
>
> On Tue, Sep 29, 2015 at 5:56 PM, Alexey Smishlayev <alexey at xtech2.lv> wrote:
>> Hello, Phillip!
>>
>> I use binding.Obtain() on "peak.running.interfaces.IMainLoop", which seem to
>> be instantiating as "peak.running.scheduler.MainLoop" and the
>> "peak.events.interfaces.IEventLoop" is bound to
>> "peak.events.twisted_support.EventLoop". Did not go that far, looked at the
>> PEAK default event loop and couldn't figure out what's wrong (without
>> investgating links in the project's .ini file).
>>
>> Does that mean I cannot use stopOnSignals with the Twisted event loop? Do I
>> have to implement that method? I believe, it's used because Twisted handles
>> TCP communications for us.
>>
>>
>> Best regards,
>> Alexey Smishlayev
>>
>>
>> On 30/09/15 00:27, PJ Eby wrote:
>>
>> Which event loop are you using? Twisted, the PEAK default, or
>> something else? The issue here appears to be that the eventLoop
>> property of the MainLoop instance lacks a `signals()` method -- which
>> would seem to mean it doesn't fully implement IEventLoop or is the
>> wrong type of object to start with.
>>
>> On Tue, Sep 29, 2015 at 8:06 AM, Alexey Smishlayev <alexey at xtech2.lv> wrote:
>>
>> Good day everyone!
>> I would like my PEAK application to stop on ^C or SIGINT. Currently, in that
>> case I get an output something like
>>
>> 29.09.2015 14:56:48.179 [DEBUG] Connect.twisted Unexpected error in main
>> loop.
>> 29.09.2015 14:56:48.190 [ERROR] Connect.twisted Traceback (most recent
>> call last):
>> 29.09.2015 14:56:48.190 [ERROR] File
>> "/Users/alexey/xtech2/tester/build/lib/ank/BBS/CommandBase.py", line 38, in
>> run
>> 29.09.2015 14:56:48.190 [ERROR] self.mainLoop.run()
>> 29.09.2015 14:56:48.190 [ERROR] File
>> "/Library/Python/2.7/site-packages/peak/running/scheduler.py", line 78, in
>> run
>> 29.09.2015 14:56:48.190 [ERROR] return
>> self.eventLoop.runUntil(self.exitCode,True,idle=self.sleep)[0]
>> 29.09.2015 14:56:48.190 [ERROR] File
>> "/Library/Python/2.7/site-packages/peak/events/twisted_support.py", line
>> 186, in runUntil
>> 29.09.2015 14:56:48.190 [ERROR] self.reactor.run(False)
>> 29.09.2015 14:56:48.190 [ERROR] File
>> "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/twisted/internet/base.py",
>> line 1192, in run
>> 29.09.2015 14:56:48.190 [ERROR] self.mainLoop()
>> 29.09.2015 14:56:48.190 [ERROR] --- <exception caught here> ---
>> 29.09.2015 14:56:48.190 [ERROR] File
>> "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/twisted/internet/base.py",
>> line 1204, in mainLoop
>> 29.09.2015 14:56:48.190 [ERROR] self.doIteration(t)
>> 29.09.2015 14:56:48.190 [ERROR] File
>> "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/twisted/internet/selectreactor.py",
>> line 105, in doSelect
>> 29.09.2015 14:56:48.190 [ERROR] [], timeout)
>> 29.09.2015 14:56:48.190 [ERROR] exceptions.KeyboardInterrupt:
>>
>> in the log file. In CommandBase.py attribute self.mainloop is defined as
>>
>> from peak.api import binding
>> from peak.running import commands, interfaces
>> class CommandBase(commands.EventDriven):
>> mainLoop = binding.Obtain(interfaces.IMainLoop)
>> ...
>>
>> If I set "peak.running.mainLoop.stopOnSignals" in my project's .ini file to
>> anything else except empty tuple, on the application's startup I get the
>> following error (I tried "stopOnSignals = ('SIGINT',)")
>>
>> Traceback (most recent call last):
>> File "../ank/BBS/Assembler.py", line 370, in run
>> _exitCode = _root.run()
>> File "/Library/Python/2.7/site-packages/peak/running/commands.py", line
>> 229, in run
>> return self._run() or 0
>> File "/Library/Python/2.7/site-packages/peak/running/commands.py", line
>> 509, in _run
>> return self.invoke()
>> File "/Users/alexey/xtech2/tester/build/lib/ank/BBS/CommandBase.py",
>> line 38, in run
>> self.mainLoop.run()
>> File "/Library/Python/2.7/site-packages/peak/running/scheduler.py", line
>> 66, in run
>> handler = self.eventLoop.signals(*self.stopOnSignals)
>> File "_once.pyx", line 112, in _once.BaseDescriptor.__get__
>> File "_once.pyx", line 100, in _once.__get__
>> File "/Library/Python/2.7/site-packages/peak/binding/components.py",
>> line 682, in delegate
>> return getattr(getattr(s,delegateAttr),a)
>> File "_once.pyx", line 112, in _once.BaseDescriptor.__get__
>> File "_once.pyx", line 100, in _once.__get__
>> File "/Library/Python/2.7/site-packages/peak/binding/components.py",
>> line 682, in delegate
>> return getattr(getattr(s,delegateAttr),a)
>> File "_once.pyx", line 88, in _once.BaseDescriptor.__get__
>> AttributeError: ('Recursive attempt to compute attribute', 'signals')
>>
>> How do I do everything correctly?
>>
>>
>> Best regards,
>> Alexey Smishlayev
>>
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>>
>>
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