[libvirt] [PATCH 5/5] Add "syslog/json" log output format.

[Daniel P. Berrange]

On Wed, Oct 17, 2012 at 08:17:18PM +0200, Miloslav Trmač wrote:
> This is independent from the rest of the series, sending it anyway for
> consideration; this makes the metadata available to users on non-systemd
> platforms.  I believe the technical objections (primarily
> async-signal-safety) have been resolved; the question of whether the
> project wants to support this or not is still open, of course.
> 
> Add a "syslog/json" output format, which uses a JSON representation
> (as specified in Lumberjack project, and planned for the CEE standard)
> to format individual components, making the result easy to parse without
> writing custom code or using unreliable regexps.
> 
> Example message (line-wrapped for readability, the actual output is a
> single line):
> 
> Oct 17 16:29:56 kulicka libvirt: @cee: {"msg":"Domain not found",
>     "LIBVIRT_SOURCE":"error","priority":"err",
>     "CODE_FILE":"../../src/test/test_driver.c","CODE_LINE":1405,
>     "CODE_FUNC":"testLookupDomainByName",
>     "timestamp":"2012-10-17 14:29:56.683+0000","DOMAIN":12,"CODE":42,
>     "STR1":"Domain not found","STR2":""}
> 
> None of the existing log output formats (e.g. "syslog" or "file") is
> affected.
> 
> Async-signal-safety is preserved by
> a) providing a custom allocation function to yajl, and
> b) using a custom print function.
> Both use memory allocated within the stack frame.

I appreciate that you were able to re-work this to be async
safe. Personally though I would prefer not to have this in
libvirt, because I feel that syslog json support is really
bad approach to the problem and I don't want to validate
it in the eyes of others as a good solution by including it
in libvirt.

Regards,
Daniel
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