logging and daemons

[Fernando M. Maresca]

Hello.

I'm in the process of replacing a custom logger class in one of my apps
that has several daemons. In the last step of daemonizing a program,
after closing fds, stderr and stdout are redirected to the logfile of
the program.

Now, I'm trying to use TimedRotatingFileHandler as the only channel when
the programs run in daemon mode. My problem is: I can't see a goog way
to redirect stderr/stdout both to the logger.

Note that I don't have any print statements in any of my code, but I
can't be sure about all the modules I'm importing, and I like to get any
uncached exception info that may go to stderr/stdout to show up in the
logfiles.

Any ideas?
Thanks a lot,

--
Fernando

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[Diez B. Roggisch]

Hello.

I'm in the process of replacing a custom logger class in one of my apps
that has several daemons. In the last step of daemonizing a program,
after closing fds, stderr and stdout are redirected to the logfile of
the program.

Now, I'm trying to use TimedRotatingFileHandler as the only channel when
the programs run in daemon mode. My problem is: I can't see a goog way
to redirect stderr/stdout both to the logger.

Note that I don't have any print statements in any of my code, but I
can't be sure about all the modules I'm importing, and I like to get any
uncached exception info that may go to stderr/stdout to show up in the
logfiles.

why don't you just replace the sys.stdout/sys.stdin objects with
something that is file-like (supports a write-method, that should be
enough in this case), and then simply write the data arriving to the
logger instance of your trust.

If other modules don't get overly tricky to bypass sys.stdout, that
should capture all you output, regardless of the file descriptor issues.

In the end, if a 3rd-party-module choses to open a filedescriptor itself
& write to that, there is nothing you can do about that. But usually,
they don't behave that way.

Diez