[lttng-dev] Creating custom application

[Mosleh Uddin]

Hello,

Could you give me some more insight into spawning my own sessiond? Sorry
I'm not completely clear on the topic.
Thank you for all your assistance.

Regards,
Mosleh

On Wed, Mar 27, 2019 at 1:52 PM Jonathan Rajotte-Julien <
jonathan.rajotte-julien at efficios.com> wrote:

> Hi Mosleh,
>
> On Wed, Mar 27, 2019 at 12:09:54PM -0400, Mosleh Uddin wrote:
> > Hello,
> >
> > Thank you for the quick response. I was able to use the documentation you
> > provided to start a session and get tracepoint list. I do have some
> > follow-up questions:
> >
> > 1) I needed to create a session daemon before executing my custom
> > application. In the API I did see functionality to see if a daemon is
> > active, however, it is possible to spawn a session daemon in my custom
> app?
>
> liblttng-ctl does not expose a lttng-sessiond spawning function since by
> definition it is a daemon executable (think apache,mysql etc.), you will
> have to
> use system/popen/exec.. to spawn the lttng-sessiond process etc. if you
> want to
> control its lifetime using your custom application.
>
> >
> > 2) I am able to get a list of active traces lttng can see in userspace, I
> > enable all the traces and start tracing. The traces however seem to not
> be
> > written anywhere on my filesystem. Do I have to specify a location? Or
> am I
> > missing something? My current flow is:
>
> Please refer to the create command. If outputting locally you will need to
> pass
> a "file://...." url to lttng_create_session.
>
> You can check on the result for each steps using "lttng list" and "lttng
> list
> <session_name>" as you go to troubleshot your setup script.
>
> While debugging you can also start the lttng-sessiond in verbose mode to
> understand what is going on.
>
> Also note that you could also use the lttng "load" api if the session you
> are
> trying to load is "static" and always the same. You would only need to
> ship an
> xml file with your application.
>
> Cheers
>
> >
> >    - Creating a session
> >    - Specifying the domain
> >    - Creating a handle
> >    - Creating a channel (with default attributes)
> >    - Enabling the channel
> >    - Enabling event (for all traces)
> >    - Start tracing
> >
> > Thanks again for all the assistance.
> >
> > Regards,
> > Mosleh
> >
> > On Tue, Mar 26, 2019 at 11:29 AM Jonathan Rajotte-Julien <
> > jonathan.rajotte-julien at efficios.com> wrote:
> >
>
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