[Webhob] task types and outcomes

Richard Purdie richard.purdie at linuxfoundation.org
Wed May 29 14:39:07 PDT 2013


On Wed, 2013-05-29 at 16:57 +0100, Paul Eggleton wrote:
> On Tuesday 28 May 2013 17:17:35 Barros Pena, Belen wrote:
> > Thanks, Paul. I guess we need to nail down what is that we are trying to
> > achieve by reporting sstate tasks vs. built tasks vs. previously built
> > tasks. From what I can remember, the main questions users need answered
> > are:
> > 
> > * Why is this a built task when I was expecting it to reuse sstate objects?
> > * Why is this an sstate task when I was expecting it to build from scratch?
> 
> These are common questions yes.
> 
> > If those are indeed the main questions we need to answer, reporting missed
> > sstate tasks and built tasks as one probably makes things easier. The
> > metaphor would be a single task with a certain life cycle, and not 2
> > separate tasks. So, "BitBake detected changes in the inputs for task x and
> > reran the task" would result in Web Hob reporting a single built task with
> > an sstate missed flag. If we report this case through 2 separate tasks
> > we'll need to link them to each other, so that users can reach one from
> > the other and get a full picture of what BitBake did during the build.
> > This is also a viable option, but it will result in a much longer table of
> > tasks, with 2 entries for a certain task + recipe combination.
> > 
> > Which way we report tasks impacts the way we structure the Web Hob tasks
> > table. From this classification of tasks:
> > 
> > * Sstate
> > ** Missed
> > ** Completed
> > ** Failed
> > 
> > * Built
> > ** Previously built
> > ** Completed
> > ** Failed
> > 
> > We would move to this one:
> > 
> > * Completed
> > ** Previously built
> > ** Sstate
> > ** Built
> > *** Sstate missed? Y/N
> > *** Sstae failed? Y/N
> > 
> > * Failed
> > ** Built
> 
> I think this is a reasonable approach. Although it does slightly obscure the 
> details of the tasks bitbake is running it's going to be a bit easier for the 
> user to follow with respect to the information they're most interested in.

Sorry about the delayed reply, as you can tell I have a bit of a backlog
today :(.

I hate to complicate things however there is a touch of added complexity
to consider. Imagine we have tasks A which depends upon B which depends
upon C.

In the no sstate available case, it builds C, then B then A, easy.

With sstate, it will try A first. If A is available, it will just
install A from sstate and skip B/C. If A is not available, it will try
B, install that and skip C. It will then build any missing pieces so it
might install B from sstate, then run C.

This means that giving the user meaningful numbers of tasks is hard for
example.

This can probably be presented in the above form fine, I just want to be
clear about the subtleties involved. Ideally we do want to try and
better convey to the user what happened too in this UI. It could be good
if for example we could show that we didn't run C as B was from sstate
and hence C wasn't needed.

I think the key concept we might also need to work into the UI is "dry
run". A mode where you run the build however rather than doing it, it
tells you what it would do (i.e. that it would need to run X tasks, Y
would be done from sstate). Combined with an indication of why something
didn't match, this would be extremely powerful/useful to most users.

I have no objection to the form you present above, the key detail is
more the dry run concept from the user perspective and start answering
questions like "what would bitbake do?".

Cheers,

Richard





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