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

[gbastien+lttng@versatic.net (Geneviève Bastien)]

Hello all,

Short question:

As we develop analyses in TMF for LTTng traces, we'd like to unit test 
them with very specific sequences of events, something no real-life 
trace can provide. We'd like to build our own traces manually.

Does a human read-writeable format already exist to work with CTF traces 
or convert from/to CTF traces? I heard of a few CTF trace generators, 
some which haven't been rebased in a while. What's their status? 
Anything that answers our need there?

Thanks,

==================
Detailed specification of what I'm looking for and why:

* In TMF, analyses use event requests and they handle events. It does 
not matter at all whether the event came from a CTF binary stream or 
from a text file, as long as they have the same name and fields, it will 
be handled the same.

* Also, while we may want to hand make a full test trace, we may also 
wish to take (part of) a real life CTF trace, convert it to a human 
read-writeable format, tweak it to our needs and... as far as TMF is 
concerned, we'll be perfectly happy with this format, but it may 
eventually be desirable to convert it back to a CTF trace.

* XML-defined analyses are about to make it into TMF master. That means 
users will be able to develop in XML their own state providers, but 
eventually also their own views, filters, analyses, etc. Before trying 
them on real traces, it must be possible to test them on controlled 
hand-made traces. So that trace format is not just a feature for unit 
tests, it should be made available in the main TMF for users to use.

* We must keep in mind that users of this format may not have access to 
the complete LTTng toolchain, or even to a linux command line as they 
may be working... on Windows! That's even more true now that work is 
being done to convert Windows traces to CTF format. So the solution must 
be completely standalone in TMF.

* In a quick prototype last week, I came up with this format for the 
human read-writeable test traces:

<trace>
<event>
<timestamp value="1" />
<eventName value="A" />
<source value="0" /> /** the cpu */
<field name="b" value="1" type="int" />
<field name="c" value="abcdef" type="string" />
</event>
</trace>

Why XML? Because it's easy to validate with a XSD and we can use 
existing tool to automatically generate from this XSD a user interface 
to edit the events. But that's just a suggestion.

* Lastly and not least, whatever we end up implementing in TMF must use 
or at least play nice with other tools around CTF that do more or less 
the same thing. I wouldn't want to reinvent the wheel here.

Any thoughts?  Any thing I should look at?

Thanks,
Genevi?ve