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confluent/confluent_server/confluent/shellmodule.py
Jarrod Johnson 87700d6d3d Fix filehandles leaking on shell modules
When shell module plugins failed and exited,
confluent was failing to release the filehandle.  This
would ultimately lead to unreasonable exhaustion of
filehandles.
2014-06-12 14:42:09 -04:00

119 lines
4.3 KiB
Python

# vim: tabstop=4 shiftwidth=4 softtabstop=4
# Copyright 2014 IBM Corporation
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# This implements a plugin factory to produce plugin objects from shell scripts
# For now, this only is intended to support scripts to implement console
# Special comment fields shall be used to request anything like config
# data and config data will be passed in as environment variables.
# at least in linux, this is a safe enough practice since environ is readable
# only by the process owner and such an owner would be able to read a file
# anyway. Regardless, it is advisable to 'unset'
import confluent.interface.console as conapi
import eventlet
import eventlet.green.select as select
import eventlet.green.subprocess as subprocess
import fcntl
import os
import pty
import random
import subprocess
class ExecConsole(conapi.Console):
def __init__(self, executable, node):
self.subproc = None
self._master = None
self._datacallback = None
self.readerthread = None
self.executable = executable
self.subenv = {
'TERM': 'xterm',
'CONFLUENT_NODE': node,
}
def relaydata(self):
while self.subproc is not None:
rdylist, _, _ = select.select(
(self._master, self.subproc.stderr), (), (),
3600 + (random.random() * 120))
if self._master in rdylist:
try:
somedata = os.read(self._master, 128)
while somedata:
self._datacallback(somedata)
eventlet.sleep(0)
somedata = os.read(self._master, 128)
except OSError as e:
if e.errno != 11:
raise
if self.subproc.stderr in rdylist:
try:
somedata = self.subproc.stderr.read()
while somedata:
self._datacallback(somedata)
eventlet.sleep(0)
somedata = self.subproc.stderr.read()
except IOError as e:
if e.errno != 11:
raise
childstate = self.subproc.poll()
if childstate is not None:
self._datacallback(conapi.ConsoleEvent.Disconnect)
self.subproc = None
def connect(self, callback):
self._datacallback = callback
master, slave = pty.openpty()
self._master = master
self.subproc = subprocess.Popen(
[self.executable], env=self.subenv,
stdin=slave, stdout=slave,
stderr=subprocess.PIPE, close_fds=True)
os.close(slave)
fcntl.fcntl(master, fcntl.F_SETFL, os.O_NONBLOCK)
fcntl.fcntl(self.subproc.stderr.fileno(), fcntl.F_SETFL, os.O_NONBLOCK)
self.readerthread = eventlet.spawn(self.relaydata)
def write(self, data):
os.write(self._master, data)
def close(self):
os.close(self._master)
if self.subproc is None or self.subproc.poll() is not None:
return
self.subproc.terminate()
waittime = 10
while self.subproc is not None and self.subproc.poll() is None:
eventlet.sleep(1)
waittime -= 1
if waittime == 0:
break
if self.subproc is not None and self.subproc.poll() is None:
self.subproc.kill()
class Plugin(object):
def __init__(self, filename):
self.filename = filename
def create(self, nodes, element, configmanager, inputdata):
if element != ['_console', 'session']:
raise NotImplementedError("Shell plugins only do console")
if len(nodes) != 1:
raise NotImplementedError("_console/session is only single node")
return ExecConsole(self.filename, nodes[0])