[Buildbot-devel] Where did my stdout go?

[Greg Ward]

Hi -- I recently made a small change to my BB config so that some
shell commands that were formerly run directly as ShellCommand build
steps were moved into a standalone Python script which is run by BB.
This is all on a Windows buildslave, which matters.  (If it were a
Unix build slave, everything would work fine.  And even if it didn't,
I'd be able to figure it out myself!)

To illustrate, I used to do something like this in master.cfg:
  factory.addStep(ShellCommand(command=["build", "app1"]))
  factory.addStep(ShellCommand(command=["build", "app2"]))
  factory.addStep(ShellCommand(command=["build", "app3"]))

This has been replaced by:
  factory.addStep(ShellCommand(command=["build-all-apps.py"]))

where build-all-apps.py boils down to
  for app in ["app1", "app2", "app3"]:
    subprocess.call(["build", app])

(My main reason for factoring out the script, incidentally, is that
the set of apps to build might change from branch to branch, and I
don't want that knowledge in master.cfg.  Also, the build command is
just a *tad* more complex than I've shown, and having the code to
generate it in master.cfg bugged me.)

Anyways, the problem is that the stdout of commands run by
build-all-apps.py disappears.  When that long hairy build command that
I have approximated as "build <app>" was run directly by BB on the
slave, all of its output appeared in the log file available through
the master.  No more.  Now I get the output of build-all-apps.py
itself (it logs the commands it runs to its stdout), but not of its
child processes.  So if compiling one of our Windows apps fails, I
won't have the error message!

Finally, when I run build-all-apps.py manually on the Windows console,
it's fine: the stdout of the child processes appears on the console as
expected.

Any clues?  All hints, tips, suggestions welcome.  Thanks --

Greg