[Buildbot-devel] buildbot try and virtualenv

[Doug Latornell]

I have recently updated a buildbot installation from 0.7.10 to 0.8.1
and things went very smoothly, for the most part. Thanks to all of the
developers and contributors!

In the course of the upgrade I put 0.8.1 in a virtualenv and all is
well for our Nightly and commit-driven schedulers. We also use
"buildbot try" to trigger a particular kind of build on demand with
special properties set. The try builds use ssh to connect and were
failing with the message:

    Failure: exceptions.RuntimeError: remote 'buildbot tryserver'
failed: sig=None, rc=1

I realized that was happening because
.virtualenvs/buildbot-0.8.1/bin/buildbot was not on the default path
for the user named by --username. So, my immediate fix was to add that
path component, but that feels a little non-robust because virtualenvs
are so changeable.

Looking at the source, it seems to be that it would be pretty straight
forward to add a --tryremotecmd argument that could be used to specify
more details of the buildbot command to run when they are necessary.
The idea is pretty much identical to the "hg clone --remotecmd"
option. The result would be a command something like:

    buildbot try --tryhost=foo at example.com
--tryremotecmd=~/.virtualenvs/buildbot-0.8.1/bin/buildbot ...

If anyone thinks this is a worthwhile idea, I'm willing to have a go
at implementing it.

Doug