[bitbake-devel] [PATCH 28/30] command: add CommandStarted event

[Ed Bartosh]

On Mon, Dec 07, 2015 at 05:36:57PM +0000, Richard Purdie wrote:
> Hi Ed,
> 
> On Wed, 2015-12-02 at 10:03 -0800, brian avery wrote:
> > From: Ed Bartosh <ed.bartosh at linux.intel.com>
> > 
> > This event will be used by toasterui to set BRBE build parameter
> > as soon as it's provided to bitbake server by Toaster.
> > 
> > Signed-off-by: Ed Bartosh <ed.bartosh at linux.intel.com>
> > Signed-off-by: brian avery <avery.brian at gmail.com>
> > ---
> >  lib/bb/command.py | 6 ++++++
> >  1 file changed, 6 insertions(+)
> > 
> > diff --git a/lib/bb/command.py b/lib/bb/command.py
> > index 74106d1..78ce03a 100644
> > --- a/lib/bb/command.py
> > +++ b/lib/bb/command.py
> > @@ -31,6 +31,11 @@ Commands are queued in a CommandQueue
> >  import bb.event
> >  import bb.cooker
> >  
> > +class CommandStarted(bb.event.Event):
> > +    def  __init__(self, commandline):
> > +        bb.event.Event.__init__(self)
> > +        self.commandline = commandline
> > +
> >  class CommandCompleted(bb.event.Event):
> >      pass
> >  
> > @@ -60,6 +65,7 @@ class Command:
> >          self.currentAsyncCommand = None
> >  
> >      def runCommand(self, commandline, ro_only = False):
> > +        bb.event.fire(CommandStarted(commandline), self.cooker.expanded_data)
> >          command = commandline.pop(0)
> >          if hasattr(CommandsSync, command):
> >              # Can run synchronous commands straight away
> 
> I'm not sure I like the idea of this, particularly after I've seen what
> you're using it to do. Just from a performance standpoint, adding in an
> event per command execution adds in round trips and will increase the
> time something simple like "bitbake -p" takes to do nothing when the
> cache is hot.
>
> I note in a later patch you use this to check for a command coming from
> elsewhere to modify the data store and I worry that we'll end up with
> unstructured code if we encourage people to do that too.
>
The reason of adding this event is that I wanted to introduce generic
event that can be used by other people. Less generic ones would be 'VariableSet' or
'BRBESet'. I'm not sure those are better choice than CommandStarted.

> I did briefly talk to Brian and he mentioned you needed a way to
> differentiate between events from different builds. I'd suggest you can
> could do this if you markup the events as they come through your event
> receiver, since events for a specific build should come through a
> specific socket. Worst case I'd prefer doing this internally to bitbake
> rather than the command interception above but adding data to every
> event being sent over IPC is something I'd prefer to avoid if we can
> too.
>
There were no suitable events for this purpose I'm afraid. All events I
looked at were fired late than BRBE variable is set. I wanted to know
when it's changed as soon as possible.

> Would you be able to see if there is a different way we could handle
> this?
I'll try to look again.

--
Regards,
Ed