[Buildbot-devel] How to execute two shell commands from a source buildstep

[Casey Dahlin]

Brian Warner wrote:
> On Thu, 25 Oct 2007 12:12:38 -0400
> Casey Dahlin <cdahlin at redhat.com> wrote:
>
>   
>> I am trying to rewrite the Git interface to buildbot so that it doesn't 
>> rely on cogito and is a bit more flexible. I need to tell the buildslave 
>> to execute two shell commands in sequence when it checks out the project 
>> for the first time. How do I do this?  
>>     
>
> To make a single BuildStep execute multiple shell commands, there are two
> approaches. The first is to do all the work on the buildmaster side, the
> second is to do the work on the buildslave side.
>
> The first approach has the advantage of not requiring buildslave changes,
> which means you can use old buildslaves. Each BuildStep can trigger zero or
> more RemoteCommands, and RemoteShellCommand is a kind of RemoteCommand.
> Unfortunately, I don't know if we have any examples of this sort of thing in
> there right now. I am planning to clean up the way RemoteCommands are started
> (the goal is to make it behave just like regular twisted Deferred chains),
> but the changes got too destabilizing to make it into 0.7.6 .
>
> The second approach (which is currently used by all the source-checkout
> commands) takes advantage of the fact that each RemoteCommand (on the
> buildslave side) can trigger zero or more actual shell commands. This
> approach gives you better access (you can os.stat() files directly, for
> example) and offers marginally faster operations (fewer roundtrips), at the
> expense of only working with a buildslave that's new enough to have your new
> code. All of the Source steps use this, so look at those for examples, like
> buildbot.slave.commands.SourceBase and .SVN .
>
> The SourceBase class has methods for doing a full checkout and for doing an
> update: the VC-specific subclasses fill in those methods. SourceBase tries to
> do an update, and if that fails it triggers the full-checkout method.
>
> I'd recommand doing it on the slave side, and have the Git full-checkout
> method do a chain of shell commands. I think the old Arch/Baz classes need to
> do something like this, so check them out for some hints.
>
> cheers,
>  -Brian
>   

Thanks for the reply. Currently I am doing it by running bash and using 
that to run a two-command shell line. Ugly but effective. With these 
methods I should be able to do it cleanly enough to actually submit this 
stuff back upstream :)

--CJD