fabric elocal - "local" command that raises an exception

fab.py

#!/usr/bin/env python
from fabric.api import task, local, settings

class CommandFailed(Exception):
    def __init__(self, message, result):
        Exception.__init__(self, message)
        self.result = result

def elocal(*args, **kwargs):
    with settings(warn_only=True):
        result = local(*args, **kwargs)
    if result.failed:
        raise CommandFailed("args: %r, kwargs: %r, error code: %r" % (args, kwargs, result.return_code), result)
    return result

###############################################################################

@task
def main():
    """Do the thing, with elocal."""
    try:
        elocal("ls -al yabbadababa", capture=True)
    except CommandFailed, e:
        print "command failed yo"
        print repr(e)
        print str(e)
        print e.result.stderr

if __name__ == "__main__":
    import fabric.main
    import sys
    sys.argv.pop(0)
    if not sys.argv or '--help' in sys.argv:
        sys.argv = ['--list']

    new_argv = ['fab', '-f', __file__] + sys.argv
    sys.argv = new_argv
    fabric.main.main()

"""
$ ./fab.py main
[localhost] local: ls -al yabbadababa

Warning: local() encountered an error (return code 2) while executing 'ls -al yabbadababa'

command failed yo
CommandFailed("args: ('ls -al yabbadababa',), kwargs: {'capture': True}, error code: 2",)
args: ('ls -al yabbadababa',), kwargs: {'capture': True}, error code: 2
ls: cannot access yabbadababa: No such file or directory

Done.
"""