Samba debug
Andreas Schneider
asn at samba.org
Mon Nov 28 09:47:27 UTC 2016
On Monday, 28 November 2016 15:08:50 CET Martin Schwenke wrote:
> Amitay and I are in the process of moving to (more directly) use
> Samba's debug support. At the moment we are doing file and syslog
> logging using CTDB's own backends, which are hooked into debug.[ch]
> using the DEBUG_CALLBACK support.
Hey Martin,
thanks for looking into this mess!
> We have come across (at least!) a couple of idiosyncrasies in
> debug.[ch]... :-)
>
> * Headers and messages can be interleaved in file logging
>
> Header and message are written using 2 separate write() calls (via
> dbghdrclass(), dbgtext()). So, if 2 processes are writing to the same
> log file, then you can get <header1>, <header2>, <message1>,
> <message2>... or other variations.
>
> This could be improved if the above 2 functions added to the buffer
> and a single write() was then used.
>
> * When logging to syslog, header information is duplicated
>
> That is the date and time (and maybe PID, progname), are present in
> the output of dbghdrclass() and syslog adds them as well.
>
> All the backends other than file (syslog, systemd, lttng,
> GPFS) probably add their own timestamps.
>
> This could be improved by having dbghdrclass() omit these items and
> have the file backend add those that are configured.
>
> For CTDB logging we only really want single-line messages, with an
> appropriate non-redundant header. For file we want a header
> (date, time, progname, pid). For syslog we want to send just a bare
> message and have syslog do the rest.
>
> Suggestions? Ideas? :-)
Please take a look into the options:
debug prefix timestamp
timestamp logs
They are related and are totally broken.
The suggestion I have is that we need tests for the debug system. We have
features which do not work and nobody notices.
Testing debug is possible using the Mock object [1][2] support in cmocka [3].
Andreas
[1] https://lwn.net/Articles/558106/
[2] https://github.com/hpaluch/cmocka-example
[3] https://cmocka.org
--
Andreas Schneider GPG-ID: CC014E3D
Samba Team asn at samba.org
www.samba.org
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