#
# Copyright (C) 2008-2015 CEA/DAM
# Copyright (C) 2015 Stephane Thiell <sthiell@stanford.edu>
#
# This file is part of ClusterShell.
#
# ClusterShell is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# ClusterShell is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with ClusterShell; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
"""
WorkerPopen
ClusterShell worker for executing local commands.
Usage example:
>>> worker = WorkerPopen("/bin/uname", key="mykernel")
>>> task.schedule(worker) # schedule worker
>>> task.resume() # run task
>>> worker.retcode() # get return code
0
>>> worker.read() # read command output
'Linux'
"""
from ClusterShell.Worker.Worker import WorkerSimple, StreamClient
from ClusterShell.Worker.Worker import _eh_sigspec_invoke_compat
[docs]
class PopenClient(StreamClient):
[docs]
def __init__(self, worker, key, stderr, timeout, autoclose):
"""PopenClient initializer"""
StreamClient.__init__(self, worker, key, stderr, timeout, autoclose)
self.popen = None
self.rc = None
# Declare writer stream to allow early buffering
self.streams.set_writer(worker.SNAME_STDIN, None, retain=False)
def _start(self):
"""Worker is starting."""
assert not self.worker.started
assert self.popen is None
self.popen = self._exec_nonblock(self.worker.command, shell=True)
task = self.worker.task
if task.info("debug", False):
task.info("print_debug")(task, "POPEN: %s" % self.worker.command)
self.worker._on_start(self.key)
return self
def _close(self, abort, timeout):
"""
Close client. See EngineClient._close().
"""
if abort:
# it's safer to call poll() first for long time completed processes
prc = self.popen.poll()
# if prc is None, process is still running
if prc is None:
try: # try to kill it
self.popen.kill()
except OSError:
pass
prc = self.popen.wait()
self.streams.clear()
self.invalidate()
if prc >= 0: # filter valid rc
self.rc = prc
self.worker._on_close(self.key, prc)
elif timeout:
assert abort, "abort flag not set on timeout"
self.worker._on_timeout(self.key)
elif not abort:
# if process was signaled, return 128 + signum (bash-like)
self.rc = 128 + -prc
self.worker._on_close(self.key, self.rc)
if self.worker.eh is not None:
_eh_sigspec_invoke_compat(self.worker.eh.ev_close, 2, self.worker,
timeout)
[docs]
class WorkerPopen(WorkerSimple):
"""
Implements the Popen Worker.
"""
[docs]
def __init__(self, command, key=None, handler=None,
stderr=False, timeout=-1, autoclose=False):
"""Initialize Popen worker."""
WorkerSimple.__init__(self, None, None, None, key, handler, stderr,
timeout, autoclose, client_class=PopenClient)
self.command = command
if not self.command:
raise ValueError("missing command parameter in WorkerPopen "
"constructor")
self.key = key
[docs]
def retcode(self):
"""Return return code or None if command is still in progress."""
return self.clients[0].rc
WORKER_CLASS = WorkerPopen