Logging - Revision history

Admin: /* References */

2018-09-04T05:10:36Z

References

← Older revision		Revision as of 05:10, 4 September 2018
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	=References=		=References=

	Logging documentation on Python.org: https://docs.python.org/2/library/logging.html		Logging documentation on Python.org: https://docs.python.org/3/library/logging.html

			Good practice logging: https://fangpenlin.com/posts/2012/08/26/good-logging-practice-in-python/

	[[Category:Python]]		[[Category:Python]]

Admin: /* Separating Code */

2018-09-04T02:52:16Z

Separating Code

← Older revision		Revision as of 02:52, 4 September 2018
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	I set up all of my logging-related variables in a single file, which I can then import wherever I need to append information to the log. This ensures that everyone has access to the same logs, that all changes are propagated, and that code stays fresh and clean.		I set up all of my logging-related variables in a single file, which I can then import wherever I need to append information to the log. This ensures that everyone has access to the same logs, that all changes are propagated, and that code stays fresh and clean.

			==Printing Exceptions==

			My pattern is to handle exceptions with a call to logging.error() or logger.error(). When you call this function, you can also pass the <code>exc_info</code> argument to include exception information:

			<pre>
			try:
			open('/path/to/does/not/exist', 'rb')
			except (SystemExit, KeyboardInterrupt):
			raise
			except Exception, e:
			logger.error('Failed to open file', exc_info=True)
			</pre>

	==Signing Log Messages==		==Signing Log Messages==

Admin: /* Logging Multiple Levels */

2018-09-02T20:08:18Z

Logging Multiple Levels

← Older revision		Revision as of 20:08, 2 September 2018
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	CRITICAL 50		CRITICAL 50
	ERROR 40		ERROR 40
	WARNING 30		WARNING 30
	INFO 20		INFO 20
	DEBUG 10		DEBUG 10

Admin: /* Logging Multiple Levels */

2018-09-02T20:08:09Z

Logging Multiple Levels

← Older revision		Revision as of 20:08, 2 September 2018
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	</source>		</source>

	~~and so on. All listed on the logging documentation's main page (~~https://docs.python.org/3/library/logging.html).		List of log levels: https://docs.python.org/3/library/logging.html#levels

			<pre>
			Level Numeric value
			CRITICAL 50
			ERROR 40
			WARNING 30
			INFO 20
			DEBUG 10
			NOTSET 0
			</pre>

	=References=		=References=

Admin: /* Logging Multiple Levels */

2018-09-02T20:07:15Z

Logging Multiple Levels

← Older revision		Revision as of 20:07, 2 September 2018
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	</source>		</source>

	and so on. All listed on the logging documentation's main page (https://docs.python.org/2/library/logging.html).		and so on. All listed on the logging documentation's main page (https://docs.python.org/3/library/logging.html).

	=References=		=References=

Admin: /* Strategies for Using Logging */

2015-02-23T15:01:52Z

Strategies for Using Logging

← Older revision		Revision as of 15:01, 23 February 2015
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	</pre>		</pre>

			=Logging Multiple Levels=

			You may have a need to log at multiple levels. The examples above mainly just use INFO, but what about DEBUG or WARN or others?

			Well, it's dead simple. Whereas before you would be logging INFO level messages:

			<source lang="python">
			import logging
			# set up your logging...

			message1 = "Hello cruel world!"
			logging.info(message1)
			</source>

			to log a debug message, you would say:

			<source lang="python">
			message1 = "Hello cruel world!"
			logging.debug(message1)
			</source>

			and to log a warning message, you would say:

			<source lang="python">
			message1 = "Hello cruel world!"
			logging.warn(message1)
			</source>

			and so on. All listed on the logging documentation's main page (https://docs.python.org/2/library/logging.html).

			=References=

			Logging documentation on Python.org: https://docs.python.org/2/library/logging.html

	[[Category:Python]]		[[Category:Python]]

Admin: /* Signing Log Messages */

2015-02-22T21:07:29Z

Signing Log Messages

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	So the string "Encountered an exception" would become "[bot1] Encountered an exception". This, combined with logging's timestamp capabilities, will allow you to determine exactly what's happening and when.		So the string "Encountered an exception" would become "[bot1] Encountered an exception". This, combined with logging's timestamp capabilities, will allow you to determine exactly what's happening and when.

			Here's an example of this strategy from a log file for a Twitter bot flock. With lots of Twitter bots in a given Twitter bot flock, I don't want to have a separate log for each bot - I want each bot to print to the same log file. But I don't want hundreds of messages from who knows what bots! Here's an example of a "signed" log file, each bot prepending with its twitter handle:

			<pre>
			02-22-2015 13:04 Hello darling! I am the Lumberjack logger.
			02-22-2015 13:04 [@charlesreid1] Finished populating a new tweet queue with 5 tweets.
			02-22-2015 13:04 [@charlesreid2] Finished populating a new tweet queue with 5 tweets.
			02-22-2015 13:04 [@charlesreid3] Finished populating a new tweet queue with 5 tweets.
			02-22-2015 13:04 [@charlesreid1] Hello world! That's number 1 of 5.
			02-22-2015 13:04 [@charlesreid2] Hello world! That's number 1 of 5.
			02-22-2015 13:04 [@charlesreid3] Hello world! That's number 1 of 5.
			02-22-2015 13:04 [@charlesreid1] Hello world! That's number 2 of 5.
			02-22-2015 13:04 [@charlesreid2] Hello world! That's number 2 of 5.
			02-22-2015 13:04 [@charlesreid3] Hello world! That's number 2 of 5.
			02-22-2015 13:04 [@charlesreid1] Hello world! That's number 3 of 5.
			02-22-2015 13:04 [@charlesreid2] Hello world! That's number 3 of 5.
			02-22-2015 13:04 [@charlesreid3] Hello world! That's number 3 of 5.
			02-22-2015 13:04 [@charlesreid1] Hello world! That's number 4 of 5.
			02-22-2015 13:04 [@charlesreid2] Hello world! That's number 4 of 5.
			02-22-2015 13:04 [@charlesreid3] Hello world! That's number 4 of 5.
			02-22-2015 13:04 [@charlesreid1] Hello world! That's number 5 of 5.
			02-22-2015 13:04 [@charlesreid2] Hello world! That's number 5 of 5.
			02-22-2015 13:04 [@charlesreid3] Hello world! That's number 5 of 5.
			</pre>



	[[Category:Python]]		[[Category:Python]]

Admin: /* =Signing Log Messages */

2015-02-22T20:40:37Z

=Signing Log Messages

← Older revision		Revision as of 20:40, 22 February 2015
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	I set up all of my logging-related variables in a single file, which I can then import wherever I need to append information to the log. This ensures that everyone has access to the same logs, that all changes are propagated, and that code stays fresh and clean.		I set up all of my logging-related variables in a single file, which I can then import wherever I need to append information to the log. This ensures that everyone has access to the same logs, that all changes are propagated, and that code stays fresh and clean.

	==Signing Log Messages=		==Signing Log Messages==

	Sometimes it is good to know which file, module, or process is logging particular information. A good case in point is if you have multithreaded code - different threads are writing different information, and you want each to sign their log messages differently.		Sometimes it is good to know which file, module, or process is logging particular information. A good case in point is if you have multithreaded code - different threads are writing different information, and you want each to sign their log messages differently.

Admin: /* Separating Code */

2015-02-22T20:40:28Z

Separating Code

← Older revision		Revision as of 20:40, 22 February 2015
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	I set up all of my logging-related variables in a single file, which I can then import wherever I need to append information to the log. This ensures that everyone has access to the same logs, that all changes are propagated, and that code stays fresh and clean.		I set up all of my logging-related variables in a single file, which I can then import wherever I need to append information to the log. This ensures that everyone has access to the same logs, that all changes are propagated, and that code stays fresh and clean.

			==Signing Log Messages=

			Sometimes it is good to know which file, module, or process is logging particular information. A good case in point is if you have multithreaded code - different threads are writing different information, and you want each to sign their log messages differently.

			In this case, you can create a sign_message() method, which is passed a plain string and which returns a string prepended with an identifying piece of information.

			So the string "Encountered an exception" would become "[bot1] Encountered an exception". This, combined with logging's timestamp capabilities, will allow you to determine exactly what's happening and when.


	[[Category:Python]]		[[Category:Python]]

Admin: /* Strategies for Using Logging */

2015-02-22T20:37:27Z

Strategies for Using Logging

← Older revision		Revision as of 20:37, 22 February 2015
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	=Strategies for Using Logging=		=Strategies for Using Logging=

	Here's how I use logging:		Here's some info on how I use logging.

			==Separating Code==

	I set up all of my logging-related variables in a single file, which I can then import wherever I need to append information to the log. This ensures that everyone has access to the same logs, that all changes are propagated, and that code stays fresh and clean.		I set up all of my logging-related variables in a single file, which I can then import wherever I need to append information to the log. This ensures that everyone has access to the same logs, that all changes are propagated, and that code stays fresh and clean.

	[[Category:Python]]		[[Category:Python]]