[lttng-dev] Human read-writeable format for CTF traces

[Geneviève Bastien]

Ok, I'll wait for Jérémie's answer for more details. As I said, my 
concern is to have something fully standalone in TMF. But if one has 
access to babeltrace and eventual plugins to read-write a CTF trace to 
XML, then all the better. We could then import an XML generated by a 
python script into TMF, edit it there and then use it to test analyses.

All we have to settle on is the intermediate format that should be used. 
I'd go for XML because of the possibility to validate it and have visual 
editors.


On 02/03/2014 11:00 AM, Michel Dagenais wrote:
>> I would expect that the ctf writer API recently added to babeltrace
>> (currently in master branch), along with the Python bindings that cover
>> trace read and write APIs, should allow you to implement things like:
>>
>> - A plugin to read a CTF trace, and output it in an intermediate format
>>    to facilitate edits (e.g. XML as you propose),
>> - A plugin to read this XML format and output a CTF trace.
> Yes, this would indeed be extremely helpful, in XML and/or JSON.
>
>> You could also generate the XML trace completely by hand if you like, and
>> then convert it to CTF with the second plugin I'm relating to above.
> The likely scenario is to add a few events by hand.
>
>> Another possibility is that the XML description also allows
>> describing what the trace contains at a slightly higher level. For instance, if you
>> have a periodic event happening for a certain amount of time, it would
>> be described in XML, and then "generated" by the XML-to-CTF
>> converter.
> Do we want to describe this in XML or in Python? We could have "CTF" to "Python statements" generating XML. Then we could add loops by hand. We could also have CTF to XML, with hooks to merge Python generated events.
Indeed being able to script a trace would be extremely helpful and 
convert it either directly to CTF or to the intermediate format. Some 
scenarios for unit test would be to script a custom trace then change a 
few events for the test purpose, then either import it in TMF or convert 
it to CTF.

Thanks,
Geneviève
>
> In addition, TMF may also want to offer similar functionality, an XML dump of events and an XML events reader. Indeed, TMF supports a few formats other than CTF.