def add_extension(self, ext):
# Do nothing if the extension doesn't check out
if not self._check_extension(ext):
return
alias = ext.get_alias()
LOG.debug(_('Loaded extension: %s'), alias)
if alias in self.extensions:
raise exception.Error("Found duplicate extension: %s" % alias)
self.extensions[alias] = ext
def execute(*cmd, **kwargs):
"""
Helper method to execute command with optional retry.
:cmd Passed to subprocess.Popen.
:process_input Send to opened process.
:check_exit_code Defaults to 0. Raise exception.ProcessExecutionError
unless program exits with this code.
:delay_on_retry True | False. Defaults to True. If set to True, wait a
short amount of time before retrying.
:attempts How many times to retry cmd.
:run_as_root True | False. Defaults to False. If set to True,
the command is prefixed by the command specified
in the root_helper kwarg.
:root_helper command to prefix all cmd's with
:raises exception.Error on receiving unknown arguments
:raises exception.ProcessExecutionError
"""
process_input = kwargs.pop('process_input', None)
check_exit_code = kwargs.pop('check_exit_code', 0)
delay_on_retry = kwargs.pop('delay_on_retry', True)
attempts = kwargs.pop('attempts', 1)
run_as_root = kwargs.pop('run_as_root', False)
root_helper = kwargs.pop('root_helper', '')
if len(kwargs):
raise exception.Error(
_('Got unknown keyword args '
'to utils.execute: %r') % kwargs)
if run_as_root:
cmd = shlex.split(root_helper) + list(cmd)
cmd = map(str, cmd)
while attempts > 0:
attempts -= 1
try:
LOG.debug(_('Running cmd (subprocess): %s'), ' '.join(cmd))
_PIPE = subprocess.PIPE # pylint: disable=E1101
obj = subprocess.Popen(cmd,
stdin=_PIPE,
stdout=_PIPE,
stderr=_PIPE,
close_fds=True)
result = None
if process_input is not None:
result = obj.communicate(process_input)
else:
result = obj.communicate()
obj.stdin.close() # pylint: disable=E1101
_returncode = obj.returncode # pylint: disable=E1101
if _returncode:
LOG.debug(_('Result was %s') % _returncode)
if (isinstance(check_exit_code, int)
and not isinstance(check_exit_code, bool)
and _returncode != check_exit_code):
(stdout, stderr) = result
raise exception.ProcessExecutionError(
exit_code=_returncode,
stdout=stdout,
stderr=stderr,
cmd=' '.join(cmd))
return result
except exception.ProcessExecutionError:
if not attempts:
raise
else:
LOG.debug(_('%r failed. Retrying.'), cmd)
if delay_on_retry:
greenthread.sleep(random.randint(20, 200) / 100.0)
finally:
# NOTE(termie): this appears to be necessary to let the subprocess
# call clean something up in between calls, without
# it two execute calls in a row hangs the second one
greenthread.sleep(0)
def bad_function_error():
raise exception.Error()