Apologies, did not mean for the message to be private. Thank you for all your assistance, for now I think compiling with the flag to disable cli is the way to go.
Regards, Mosleh On Wed, Apr 3, 2019 at 4:00 PM Jonathan Rajotte-Julien < jonathan.rajotte-jul...@efficios.com> wrote: > Hi Mosleh, > > I just saw this was a private email. > > As you will understand based on my previous email, this is slowly starting > the > be out of scope of our public support effort. > > Note that we do offer commercial support if it is something you would be > interested in. You would be able to talk openly of the requirements, more > importantly of the project you are working on and how to integrate lttng > with > it. > > Cheers > > On Wed, Apr 03, 2019 at 02:15:55PM -0400, Mosleh Uddin wrote: > > I apologize, I will give the bigger picture of what I am trying to do. > > > > So the restraint I have is that I can't install lttng-tools and lttng-ust > > libraries as part of the yocto build, mostly because we have release > > software (for the public) and we don't want these CLI features available > to > > the public (if they were to somehow access the CLI). > > > > I have compiled a userspace application using the 'lttng-ust' compile > flag > > with lttng tracepoints distributed throughout the code. I am creating a > > separate custom lttng application (compiled with lttng-ctl) which will > > communicate with the application (via domain socket) in order to dictate > > when to start/stop sessions. I want the this custom application to have > the > > ability to not only start/stop sessions but also spawn the session > daemon. > > > > From my description, you see that the system we are building for will not > > any have lttng libraries installed, I will be cross-compiling the > > applications with the libraries that are needed. I know you said > lttng-ctl > > doesn't expose spawning sessiond, so I was curious how I could get this > > functionality for my custom lttng application. > > > > Regards, > > Mosleh > > > > On Wed, Apr 3, 2019 at 11:55 AM Jonathan Rajotte-Julien < > > jonathan.rajotte-jul...@efficios.com> wrote: > > > > > On Wed, Apr 03, 2019 at 11:04:19AM -0400, Mosleh Uddin wrote: > > > > Hello, > > > > > > > > It is a limitation for both size and some security measures. We want > to > > > > ensure that we can set limits controlled by our custom application. > > > > > > What security measure? What limits? Unless you provide clear > requirement > > > it is > > > quite hard to understand where you are going and how we can help you > get > > > there. > > > > > > > > > > > For testing purposes, I did initially have lttng-tools and lttng-ust > > > added > > > > to the build image but again for the limitations described it cannot > go > > > > into the final 'production' rootfs. So it's nice that the service > file > > > > exists, but without the tools installed I do not think I can make > use of > > > > it, unless there is a way to strip out everything from lttng-tools > except > > > > for the sessiond functionality. > > > > > > Well the biggest part of lttng-tools project is lttng-sessiond and > > > lttng-consumerd. If the cli is the problem you can pass > > > "--disable-bin-lttng" at > > > configure time to simply exclude it from being built and installed. > > > > > > As for lttng-sessiond executable, you can limit the user able to use > it via > > > regular user/group permissions. > > > > > > > > > > > My guess from everything you are saying is that I will have to > create a > > > > custom method for spawning a session daemon without having > lttng-tools > > > > available, however I am unsure where to start. > > > > > > No, you will need lttng-tools (in the sense of the project, no the > > > executable) to > > > be present on the system if you want to trace at all. > > > > > > > From way lttng-tools does > > > > it, I see it call the executable 'lttng-sessiond', but I cannot find > a > > > > reference to when or how that executable is getting built. > > > > > > Take a look at the src/bin folder (git tree). The "lttng" subfolder is > > > only the > > > CLI. The meat of lttng is lttng-sessiond/relayd/consumerd. > > > > > > > > > > > Thanks again for quick responses. > > > > > > > > Regards, > > > > Mosleh > > > > > > > > > > > > > > > > On Wed, Apr 3, 2019 at 10:25 AM Jonathan Rajotte-Julien < > > > > jonathan.rajotte-jul...@efficios.com> wrote: > > > > > > > > > On Wed, Apr 03, 2019 at 09:08:45AM -0400, Mosleh Uddin wrote: > > > > > > Hello, > > > > > > > > > > > > Sorry, I should be more specific. I am creating a custom yocto > > > build. I > > > > > > have seen some examples where systemd is utilized to start the > > > sessiond > > > > > as > > > > > > a service. The limitation I have is that I don't want to include > the > > > > > whole > > > > > > lttng-tools librray in my build. I understand that the sessiond > is an > > > > > > > > > > You will have to if you plan on tracing any applications on your > > > resulting > > > > > image. Why is it a limitation? Size constraint? > > > > > > > > > > lttng-tools is already part of OE-core (the meta/ layer). Use this > > > recipe > > > > > to > > > > > build it [1] or as a base for a custom one. > > > > > > > > > > [1] > > > > > > > > > https://git.yoctoproject.org/cgit/cgit.cgi/poky/tree/meta/recipes-kernel/lttng/lttng-tools_2.10.6.bb > > > > > > > > > > You can add the following to your local.conf file to build only > > > lttng-ust > > > > > and > > > > > lttng-tools. > > > > > > > > > > CORE_IMAGE_EXTRA_INSTALL += "lttng-ust lttng-tools" > > > > > PACKAGECONFIG_pn-lttng-tools_append = " lttng-ust" > > > > > > > > > > By default a systemd service file is installed but is not activated > > > (which > > > > > seems > > > > > to be what you want). > > > > > > > > > > Cheers > > > > > > > > > > > > > > > > executable, I am just unsure how I could build or get this in my > > > build. > > > > > > Moving forward from this I could use fork/exec to daemonize which > > > would > > > > > be > > > > > > simple. > > > > > > Is there perhaps a existing recipe? > > > > > > > > > > > > Regards, > > > > > > Mosleh > > > > > > > > > > > > On Tue, Apr 2, 2019 at 6:01 PM Mosleh Uddin < > mosleh1...@gmail.com> > > > > > wrote: > > > > > > > > > > > > > Hi, > > > > > > > > > > > > > > That makes complete sense. I was more curious about the > sessiond > > > > > > > executable. I'm guessing this is something I will have to > create > > > along > > > > > with > > > > > > > my build? > > > > > > > > > > > > > > Regards, > > > > > > > Mosleh > > > > > > > > > > > > > > On Tue, Apr 2, 2019 at 5:18 PM Jonathan Rajotte-Julien < > > > > > > > jonathan.rajotte-jul...@efficios.com> wrote: > > > > > > > > > > > > > >> On Tue, Apr 02, 2019 at 04:54:00PM -0400, Mosleh Uddin wrote: > > > > > > >> > 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. > > > > > > >> > > > > > > >> Normally lttng-sessiond is treated as a > "server/service/daemon" > > > (think > > > > > > >> http > > > > > > >> server as apache) and is *normally* launched as a daemon > > > > > > >> (systemd/sysVinit) at > > > > > > >> boot time. > > > > > > >> > > > > > > >> Managing manually the lifetime of a lttng-sessiond process is > > > done the > > > > > > >> same way > > > > > > >> as any other process. You can manage it via the command line > > > > > > >> (./lttng-sessiond), via a > > > > > > >> service manager (systemd/upstart etc.) or with a custom > service > > > > > manager (a > > > > > > >> python script/c etc.). > > > > > > >> > > > > > > >> You could spawn a lttng-sessiond from your application with > the > > > > > > >> appropriate > > > > > > >> parameters set to isolate it if you need. LTTNG_HOME is an > > > important > > > > > one. > > > > > > >> The > > > > > > >> output directory also can be manipulated. See man > lttng-sessiond > > > for > > > > > more > > > > > > >> details. You will need to manage the process or leave it to a > > > system > > > > > > >> administrator and only active tracing when a sessiond is > present > > > for > > > > > > >> example. > > > > > > >> > > > > > > >> Cheers > > > > > > >> > > > > > > >> > > > > > > > >> > Regards, > > > > > > >> > Mosleh > > > > > > >> > > > > > > > >> > On Wed, Mar 27, 2019 at 1:52 PM Jonathan Rajotte-Julien < > > > > > > >> > jonathan.rajotte-jul...@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-jul...@efficios.com> wrote: > > > > > > >> > > > > > > > > > >> > > > > > > > > >> > > > > > > >> -- > > > > > > >> Jonathan Rajotte-Julien > > > > > > >> EfficiOS > > > > > > >> > > > > > > > > > > > > > > > > > -- > > > > > Jonathan Rajotte-Julien > > > > > EfficiOS > > > > > > > > > > > -- > > > Jonathan Rajotte-Julien > > > EfficiOS > > > > > -- > Jonathan Rajotte-Julien > EfficiOS >
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