logging exceptions

[Alexandru Mosoi]

why doesn't logging throw any exception when it should? how do I
configure logging to throw exceptions?
.... logging.fatal('asdf %d', '123')
.... except:
.... print 'this line is never printed'
....
Traceback (most recent call last):
File "/Library/Frameworks/Python.framework/Versions/2.5/lib/
python2.5/logging/__init__.py", line 744, in emit
msg = self.format(record)
File "/Library/Frameworks/Python.framework/Versions/2.5/lib/
python2.5/logging/__init__.py", line 630, in format
return fmt.format(record)
File "/Library/Frameworks/Python.framework/Versions/2.5/lib/
python2.5/logging/__init__.py", line 418, in format
record.message = record.getMessage()
File "/Library/Frameworks/Python.framework/Versions/2.5/lib/
python2.5/logging/__init__.py", line 288, in getMessage
msg = msg % self.args
TypeError: int argument required

 

[Rob Wolfe]

Alexandru Mosoi napisa³(a):

why doesn't logging throw any exception when it should? how do I
configure logging to throw exceptions?

... logging.fatal('asdf %d', '123')
... except:
... print 'this line is never printed'
...

[...]

You need to subclass your handler and redefine `handleError` method.
See: http://docs.python.org/lib/node409.html

HTH,
Rob

 

[Vinay Sajip]

why doesn'tloggingthrow any exception when it should? how do I
configureloggingto throw exceptions?


... logging.fatal('asdf %d', '123')
... except:
... print 'this line is never printed'
...
Traceback (most recent call last):
File "/Library/Frameworks/Python.framework/Versions/2.5/lib/
python2.5/logging/__init__.py", line 744, in emit
msg = self.format(record)
File "/Library/Frameworks/Python.framework/Versions/2.5/lib/
python2.5/logging/__init__.py", line 630, in format
return fmt.format(record)
File "/Library/Frameworks/Python.framework/Versions/2.5/lib/
python2.5/logging/__init__.py", line 418, in format
record.message = record.getMessage()
File "/Library/Frameworks/Python.framework/Versions/2.5/lib/
python2.5/logging/__init__.py", line 288, in getMessage
msg = msg % self.args
TypeError: int argument required

Was your traceback from the snippet you posted? If it was, then the
exception (a TypeError) *is* being raised from logging. So I don't
understand your question "why doesn't logging throw any exception when
it should?", because logging is raising an exception here.

To cause logging to *not* raise exceptions, set
logging.raiseExceptions to 0 (default is 1). The raiseExceptions
variable would normally be set to 0 in a production environment, where
you don't want logging-related exceptions to bring an application
down.

Regards,

Vinay Sajip

 

[Rob Wolfe]

Vinay Sajip napisa³(a):

Was your traceback from the snippet you posted? If it was, then the
exception (a TypeError) *is* being raised from logging. So I don't
understand your question "why doesn't logging throw any exception when
it should?", because logging is raising an exception here.

No, it isn't.
This traceback is *printed* in `Handler.handleError` method:

<code from logging>
__version__ = "0.5.0.2"

[...]

def handleError(self, record):
"""
Handle errors which occur during an emit() call.

This method should be called from handlers when an exception
is
encountered during an emit() call. If raiseExceptions is
false,
exceptions get silently ignored. This is what is mostly wanted
for a logging system - most users will not care about errors
in
the logging system, they are more interested in application
errors.
You could, however, replace this with a custom handler if you
wish.
The record which was being processed is passed in to this
method.
"""
if raiseExceptions:
ei = sys.exc_info()
traceback.print_exception(ei[0], ei[1], ei[2], None,
sys.stderr)
del ei

To cause logging to *not* raise exceptions, set
logging.raiseExceptions to 0 (default is 1). The raiseExceptions
variable would normally be set to 0 in a production environment, where
you don't want logging-related exceptions to bring an application
down.

Well, I think that it will not help. The exception will be printed
not raised. The only solution is to redefine `handleError` method
or maybe I've missed something?

Br,
Rob

 

[Vinay Sajip]

Vinay Sajip napisa³(a):





No, it isn't.
This traceback is *printed* in `Handler.handleError` method:

You're right - silly me. I wasn't paying attention :-(

Well, I think that it will not help. The exception will be printed
not raised. The only solution is to redefine `handleError` method
or maybe I've missed something?

No, you're right. To do custom handling of exceptions, handleError
needs to be overridden.

Regards,

Vinay