Normal vs. Debug Mode

rpspringuel · 04-14-2016, 05:10 PM

I've been having a bug with a plugin-which-shall-not-be-named recently which only shows up when calibre is in normal mode. When I restart in debug mode in order to generate the log file needed for a proper bug report, the process that failed before works fine. Is there anything in the debug infrastructure of calibre itself which would change the way the program works (besides the generation of the log file)? Further, is there some way that I can "backdoor" the debug mode so that calibre generates the debug log but "thinks" its in normal mode?

I realize that the actual problem is not one which can be addressed here, but I'm hoping for some insight into the difference between normal and debug mode so that I can extract the needed diagnostic information to addressed the problem in a more appropriate forum.

kovidgoyal · 04-14-2016, 10:10 PM

The main difference is that print statement are redirected to NUL in normal mode and a file in DEBUG mode. There are also a lot more print statements that become active -- this in turn can change the timing of various operations, which can cause timing/threading sensitive bugs to change their behavior.

davidfor · 04-15-2016, 12:04 AM

rpspringuel: What OS? I've had some reports on problems with a plugin I changed on Macs. They are getting "IOError: [Errno 32] Broken pipe" errors and the lines work out to print statements I left in the code. Most of the debug logging doesn't happen when not in debug mode, but I think I had three lines that would still execute/

rpspringuel · 04-15-2016, 10:10 AM

I am on a Mac (10.10.4) and running calibre 2.54.0.

kovidgoyal · 04-15-2016, 10:34 AM

On OS X the stdout and stderr streams get redirected to the ASL logging service for GUI apps. If you see errors happening in print statements, that usually implies the service is down/malfunctioning.

rpspringuel · 04-16-2016, 12:01 AM

Is there a way that I could capture the statements being directed to NULL in normal mode without turning on the full debug mode? I'm not terribly familiar with redirection and am not sure what's possible here, but presumably if this was possible it wouldn't change any timing (since the additional print statements wouldn't be activated) but it would give at least some diagnostic information.

If this sort of redirection isn't possible, could I make a change in the code and run from the git repository that would do something like this?

kovidgoyal · 04-16-2016, 12:41 AM

In normal mode all print statements got to the ASL service, which usually is available via Console.app

rpspringuel · 04-17-2016, 09:03 PM

Thank you. I found the "log" and have passed it along to the plugin author.

04-14-2016, 05:10 PM	#1
rpspringuel Enthusiast Posts: 40 Karma: 10 Join Date: Feb 2014 Device: Kindle 4	Normal vs. Debug Mode I've been having a bug with a plugin-which-shall-not-be-named recently which only shows up when calibre is in normal mode. When I restart in debug mode in order to generate the log file needed for a proper bug report, the process that failed before works fine. Is there anything in the debug infrastructure of calibre itself which would change the way the program works (besides the generation of the log file)? Further, is there some way that I can "backdoor" the debug mode so that calibre generates the debug log but "thinks" its in normal mode? I realize that the actual problem is not one which can be addressed here, but I'm hoping for some insight into the difference between normal and debug mode so that I can extract the needed diagnostic information to addressed the problem in a more appropriate forum.

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04-14-2016, 10:10 PM	#2
kovidgoyal creator of calibre Posts: 45,259 Karma: 27110894 Join Date: Oct 2006 Location: Mumbai, India Device: Various	The main difference is that print statement are redirected to NUL in normal mode and a file in DEBUG mode. There are also a lot more print statements that become active -- this in turn can change the timing of various operations, which can cause timing/threading sensitive bugs to change their behavior.

04-15-2016, 12:04 AM	#3
davidfor Grand Sorcerer Posts: 24,905 Karma: 47303824 Join Date: Jul 2011 Location: Sydney, Australia Device: Kobo:Touch,Glo, AuraH2O, GloHD,AuraONE, ClaraHD, Libra H2O; tolinoepos	rpspringuel: What OS? I've had some reports on problems with a plugin I changed on Macs. They are getting "IOError: [Errno 32] Broken pipe" errors and the lines work out to print statements I left in the code. Most of the debug logging doesn't happen when not in debug mode, but I think I had three lines that would still execute/

04-15-2016, 10:10 AM	#4
rpspringuel Enthusiast Posts: 40 Karma: 10 Join Date: Feb 2014 Device: Kindle 4	I am on a Mac (10.10.4) and running calibre 2.54.0.

04-15-2016, 10:34 AM	#5
kovidgoyal creator of calibre Posts: 45,259 Karma: 27110894 Join Date: Oct 2006 Location: Mumbai, India Device: Various	On OS X the stdout and stderr streams get redirected to the ASL logging service for GUI apps. If you see errors happening in print statements, that usually implies the service is down/malfunctioning.

04-16-2016, 12:01 AM	#6
rpspringuel Enthusiast Posts: 40 Karma: 10 Join Date: Feb 2014 Device: Kindle 4	Is there a way that I could capture the statements being directed to NULL in normal mode without turning on the full debug mode? I'm not terribly familiar with redirection and am not sure what's possible here, but presumably if this was possible it wouldn't change any timing (since the additional print statements wouldn't be activated) but it would give at least some diagnostic information. If this sort of redirection isn't possible, could I make a change in the code and run from the git repository that would do something like this?

04-16-2016, 12:41 AM	#7
kovidgoyal creator of calibre Posts: 45,259 Karma: 27110894 Join Date: Oct 2006 Location: Mumbai, India Device: Various	In normal mode all print statements got to the ASL service, which usually is available via Console.app

04-17-2016, 09:03 PM	#8
rpspringuel Enthusiast Posts: 40 Karma: 10 Join Date: Feb 2014 Device: Kindle 4	Thank you. I found the "log" and have passed it along to the plugin author.

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