[Buildbot-devel] Per-build temp directory

[Greg Ward]

Hi all --

I'm wrestling with a bizarre Visual Studio problem -- every so often
it dies claiming "Permission denied" on a file in %TEMP%.  (Naturally
it doesn't say if it's trying to read or write the file.)  Since it's
intermittent, I strongly suspect that "Permission denied" is a secret
Microsoft codeword for "too many files in this directory" or "disk
full" or "pffft, I'm just not going to work today, and you can't make
me, nyahh nyahh".  And of course I cannot reproduce it; it only seems
to affect builds that are needed by QA *right now*.

As a possible workaround, I came up with the idea of using a per-build
temporary directory.  (We run each build in a brand-new directory,
since we're using BuildBot for full production builds, not
incrementals.)  But I can't think of a good way to do this.  I have a
global constant in my master.cfg for the workdir:

  DEFAULT_WORKDIR = WithProperties("%s", "ims_build_id")

(ims_build_id is a custom build property that's different for each
build.) But that's relative to the builder's directory, which is
relative to the slave directory.  So in reality,

  workdir = <slave dir> + <builder dir> + <ims_build_id>
          = "e:\slave" + "build.windows" + "7342"
          = "e:\slave\build.windows\7342"

but of course that computation happens on the slave, rather late in
the game.  I want to be able to do

  factory.addStep(ShellCommand(
    command="windows-build"
    env={ 'TEMPDIR': <slave dir> + <builder dir> + <ims_build_id> + "tmp" })

I don't see how to do it with WithProperties, since <slave dir> and
<builder dir> do not seem to be exposed as build properties.  And I'm
pretty sure that %TEMPDIR% really needs to be an absolute path.

Ideas?

Oh yeah, I'm using BuildBot 0.7.12.  Upgrading to 0.8.x will be a bit
of a bother, so I'll do it when I have to.

Thanks --

Greg