[lttng-dev] Writing a babeltrace output plugin

[Mathieu Desnoyers]

* Oestman, Fredrik (Fredrik_Oestman at mentor.com) wrote:
> Hello,
> 
> 
> I've fairly easily manged to add a new text-based output format to babeltrace by cloning the existing ctf-text code and making changes to it. Thanks to the registration mechanism it was also easy to get the program to recognize the new format on the command line.
> 
> Now, the problem I have with my new text format is that it completely lacks metadata.
> 
> What would be the intended way to provide an output format with metadata, or from where should I preferably collect metadata when writing a trace log in a new format?
> 
> Thanks in advance for any advice!

You'll have to either use the public API (see which files are installed
by babeltrace into your system): this is the preferred solution,
although there might be some missing metadata information (it's made to
support a trace reader, not a trace converter that would have to
regenerate the entire metadata).

The second solution is to look at include/babeltrace/ctf-ir/metadata.h
in-tree, and include/babeltrace/types.h (also in-tree). Those files
contain almost all the metadata of the CTF trace read, so you should be
able to extract your own metadata from those.

Hoping this helps,

Best regards,

Mathieu

> 
> 
> Cheers,
> 
> Fredrik Östman
> 
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-- 
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com