1. Logging
and why it’s the shit.

2. You are going to love logging!

3. Ever had to debug a live issue and had no
information to go on?

4. The aim of logging is to tell the story
of what the application is doing

5. You tell the story to ILog

6. private static readonly ILog _log =
LogManager.GetLogger(typeof(Foo));

7. There are 4 different log levels

8. Info

9. High level user activity

10. _log.InfoFormat(
"User {0} has just logged in",
user.Id
);

11. Debug

12. Details of the internal logic of a method

13. _log.DebugFormat(
"User {0} needs to pay {2} bills",
user.Id, user.Bills.Count
);

14. Warn

15. Something suspicious has happened from
which we have recovered but...
if this happens a lot, we need to investigate

16. _log.WarnFormat(
"User {0} tried to hack our servers",
user.Id
);

17. Error

18. Something went seriously wrong - this requires
investigation because it means we have a bug.

19. _log.ErrorFormat(
"Could not find User {0}’s bills",
user.Id
);

20. Where the hell are the logs a
and how do we use them?

21. tail -f is your friend

22. Adding an identifier (e.g. user id) to your logs
makes it easier to grep

23. Some do’s & don’ts

24. DO create a logger in
every class you use

25. DON’T be afraid
of doing LOTS of
logging

26. Questions?

27. Thanks to
Ed Devlin (Who initially came up with these guidelines)
David Padbury (Who I stole these slides from)
Images
Good Friends by Juliana Coutinho, http://www.flickr.com/photos/ngmmemuda/4166182931/
Four Colors by by Tambako the Jaguar http://www.flickr.com/photos/tambako/2390708966/
Engineering Information by Calistobreeze http://www.flickr.com/photos/callisto/2172555529/
Swat by fengschwing http://www.flickr.com/photos/fengschwing/4931950933/
Comments and faves by bumblesweet http://www.flickr.com/photos/bumblesweet/4253655700/
Ahhhhhhh by kennymatic http://www.flickr.com/photos/kwl/4678498113/in/set-72157623544311963/
What is going on? by SAN_DRINO, http://www.flickr.com/photos/san_drino/1454922072/
The Simple Life by kennymatic http://www.flickr.com/photos/kwl/4574642827/in/set-72157623544311963/
the_dos_and_donts_with_babies_001 by DrJohnBullas http://www.flickr.com/photos/johnbullas/2247403198/
What the wut? by kennymatic http://www.flickr.com/photos/kwl/4514986410/in/set-72157623544311963/