102 lines
3.7 KiB
Python
102 lines
3.7 KiB
Python
#!/usr/bin/env python3
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# VMConsoleWatcherInstance.py - Class implementing a console log watcher for PVC domains
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# Part of the Parallel Virtual Cluster (PVC) system
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#
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# Copyright (C) 2018-2021 Joshua M. Boniface <joshua@boniface.me>
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, version 3.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <https://www.gnu.org/licenses/>.
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#
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###############################################################################
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import os
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import time
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from threading import Thread, Event
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from collections import deque
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class VMConsoleWatcherInstance(object):
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# Initialization function
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def __init__(self, domuuid, domname, zkhandler, config, logger, this_node):
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self.domuuid = domuuid
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self.domname = domname
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self.zkhandler = zkhandler
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self.config = config
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self.logfile = '{}/{}.log'.format(config['console_log_directory'], self.domname)
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self.console_log_lines = config['console_log_lines']
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self.logger = logger
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self.this_node = this_node
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# Try to append (create) the logfile and set its permissions
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open(self.logfile, 'a').close()
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os.chmod(self.logfile, 0o600)
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try:
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self.logdeque = deque(open(self.logfile), self.console_log_lines)
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except UnicodeDecodeError:
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# There is corruption in the log file; overwrite it
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self.logger.out('Failed to decode console log file; clearing existing file', state='w', prefix='Domain {}'.format(self.domuuid))
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with open(self.logfile, 'w') as lfh:
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lfh.write('\n')
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self.logdeque = deque(open(self.logfile), self.console_log_lines)
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self.stamp = None
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self.cached_stamp = None
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# Set up the deque with the current contents of the log
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self.last_loglines = None
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self.loglines = None
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# Thread options
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self.thread = None
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self.thread_stopper = Event()
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# Start execution thread
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def start(self):
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self.thread_stopper.clear()
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self.thread = Thread(target=self.run, args=(), kwargs={})
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self.logger.out('Starting VM log parser', state='i', prefix='Domain {}'.format(self.domuuid))
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self.thread.start()
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# Stop execution thread
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def stop(self):
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if self.thread and self.thread.is_alive():
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self.logger.out('Stopping VM log parser', state='i', prefix='Domain {}'.format(self.domuuid))
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self.thread_stopper.set()
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# Do one final flush
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self.update()
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# Main entrypoint
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def run(self):
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# Main loop
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while not self.thread_stopper.is_set():
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self.update()
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time.sleep(0.5)
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def update(self):
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self.stamp = os.stat(self.logfile).st_mtime
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if self.stamp != self.cached_stamp:
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self.cached_stamp = self.stamp
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self.fetch_lines()
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# Update Zookeeper with the new loglines if they changed
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if self.loglines != self.last_loglines:
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self.zkhandler.write([
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(('domain.console.log', self.domuuid), self.loglines)
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])
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self.last_loglines = self.loglines
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def fetch_lines(self):
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self.logdeque = deque(open(self.logfile), self.console_log_lines)
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self.loglines = ''.join(self.logdeque)
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