[Twisted-Python] Log output formatting (was Re: logging question)

exarkun at twistedmatrix.com exarkun at twistedmatrix.com
Thu Nov 17 18:26:48 EST 2011

On 09:10 pm, kevin.horn at gmail.com wrote:
>On Wed, Nov 16, 2011 at 2:27 PM, Don Dwiggins 
><ddwiggins at advpubtech.com>wrote:
>>On 11/15/2011 8:57 AM, Christopher Armstrong wrote:
>>If you pass a 'system' kwarg to log.msg then it will go in that field.
>>  log.msg("hi", system="stuff") results in <date> [stuff] hi
>>This triggered me to look further into what LogPublisher.msg does, 
>>I've long wanted to customize the format of the output.  I found what 
>>wanted in
>>In msg(), the message gets added to the kwargs dictionary (along with 
>>timestamp called 'time'), and that dict is passed to LogObserver.emit,
>>which uses textFromEventDict() to create what's actually output.  This
>>dictionary has the following keys recognized by textFromEventDict:
>>    - message: A tuple of str containing messages to be logged.
>>    - system: A str which indicates the "system" which is generating 
>>    event.
>>    - isError: A bool indicating whether this event represents an 
>>    - failure: A 
>>    if the event is an error.
>>    - why: Used as header of the traceback in case of errors.
>>    - format: A string format used in place of message to customize the
>>    event. The intent is for the observer to format a message by doing
>>    something like format % eventDict.
>>So, for example, you could do log.msg(format='....', foo='stuff',
>>I suggest that this be added to the documentation string of the msg()
>>method and

`msg` doesn't really care about what you give it.  It doesn't support 
the `format` keyword in any particular way.  It's the job of a log 
observer to handle that sort of thing.  So it could certainly be 
documented, but don't mix things together that are unrelated.


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