[Fab-user] Issues with an external "is this host online" detection routine

[Samuli Seppänen]

Hi,

I'm having issues with external host exclusion list generation. The idea
is that an external routine generates the env.excludehosts list based on
real availability based on ping tests. Current code is here:

<http://pastebin.com/85jRdw0C>

The controlling thread is hostexcluder.py: It launches a number of
pingthread.py instances, each of which

- uses the subprocess module to launch a "ping" process
- waits until ping has finished
- depending on ping's return value, adds the host to excluded host list

This works great if I call hostexcluder.py directly ("python
hostexcluder.py"). However, when I try to call the same hostexcluder.py
methods from within fabfile.py (lines 111-112), it stalls at
subprocess.Popen (line 86).

Any clues why this is happening and how do I fix it?

Samuli

PS. Initially, I was using the pre-release parallel execution branch,
but upgraded to 1.3.2, which did not help. In both cases Fabric was
built from sources on Ubuntu 11.04.