[Python-Dev] Using logging in the stdlib and its unit tests (original) (raw)

Nick Coghlan ncoghlan at gmail.com
Thu Dec 9 06:57:16 CET 2010

On Thu, Dec 9, 2010 at 4:49 AM, Paul Moore <p.f.moore at gmail.com> wrote:

On 8 December 2010 14:52, Nick Coghlan <ncoghlan at gmail.com> wrote:

As I see it, there aren't many cases at the library level where logging errors is more appropriate than raising exceptions: On a slightly tangential note, what do you think of the idea of library code including info or debug level logging? In effect, tracing and diagnostic code built in and available simply by changing the logging level?

It's a trade-off between performance and the ability to diagnose faults and what you want to do will vary by application and problem domain. My background is in working on distributed projects where we need enough diagnostic information to debug one-off failures of the live system, so I'm in favour of the idea in general, but doing it can carry a fairly hefty speed cost (you can ameliorate that to some degree by handing off the actual I/O to a separate thread, but the system would still be faster if the log messages weren't there).

As Skip says, you definitely want to take advantage of the lazy string formatting when doing this with the Python logging module.

Cheers, Nick.

-- Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia

More information about the Python-Dev mailing list