[Python-Dev] Logging enhancements (original) (raw)

Mark Hammond mhammond at skippinet.com.au
Tue Jan 10 09:10:06 CET 2006

Shane:

Vinay Sajip wrote:

> I'd be interested in your approach to solve this.

To be compatible with an external tool like logrotate, all a daemon needs to do is close and reopen log files at about the same time log rotation happens. To handle this use case, I suggest the logging module needs a function named reopen(), which daemons can call upon receipt of a signal. The reopen function will find all handlers with open files and ask them to reopen.

FWIW, such an operation is generally useless on a Windows system, as a file can not be renamed while it is in use.

zope-dev went through this discussion recently, and in the interests of still allowing an external tool (similar to logrotate) to have the rotation logic instead of Python or Zope, we came up with a slightly different scheme for Windows; when requested, Zope will temporarily close the file and rename it to the original name + ".last" (ignoring any errors.) It then reopens the original name. In most cases, this will leave a .last file around which can be processed by an external tool, but is also safe in the face of failure.

IMO, we should consider implementing something like the above; it is still preferable to have a standard solution for Windows, even if different than other platforms, rather than requiring everyone to solve this problem themselves. I'd even suggest sticking with the name 'reopen()' is still OK, noting the differences in the documentation, but that is a secondary issue.

Cheers,

Mark

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