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import logging
import os
import stat
from time import sleep, time
logger = logging.getLogger('Bcfg2.Server.FileMonitor')
def ShouldIgnore(event):
'''Test if the event should be suppresed'''
# FIXME should move event suppression out of the core
if event.filename.split('/')[-1] == '.svn':
return True
if event.filename.endswith('~') or \
event.filename.startswith('#') or event.filename.startswith('.#'):
#logger.error("Suppressing event for file %s" % (event.filename))
return True
return False
class Event(object):
def __init__(self, request_id, filename, code):
self.requestID = request_id
self.filename = filename
self.action = code
def code2str(self):
'''return static code for event'''
return self.action
class GaminEvent(Event):
'''
This class provides an event analogous to
python-fam events based on gamin sources
'''
def __init__(self, request_id, filename, code):
Event.__init__(self, request_id, filename, code)
action_map = {GAMCreated: 'created', GAMExists: 'exists',
GAMChanged: 'changed', GAMDeleted: 'deleted',
GAMEndExist: 'endExist', GAMMoved: 'moved'}
if code in action_map:
self.action = action_map[code]
class FileMonitor(object):
'''File Monitor baseclass'''
def __init__(self, debug=False):
object.__init__(self)
self.debug = debug
self.handles = dict()
def fileno(self):
return 0
def handle_one_event(self, event):
if ShouldIgnore(event):
return
if event.requestID not in self.handles:
logger.info("Got event for unexpected id %s, file %s" %
(event.requestID, event.filename))
return
if self.debug:
logger.info("Dispatching event %s %s to obj %s" \
% (event.code2str(), event.filename,
self.handles[event.requestID]))
try:
self.handles[event.requestID].HandleEvent(event)
except:
logger.error("error in handling of gamin event for %s" % \
(event.filename), exc_info=1)
def handle_event_set(self, lock=None):
count = 1
event = self.get_event()
start = time()
if lock:
lock.acquire()
try:
self.handle_one_event(event)
while self.pending():
self.handle_one_event(self.get_event())
count += 1
except:
pass
if lock:
lock.release()
end = time()
logger.info("Handled %d events in %.03fs" % (count, (end-start)))
def handle_events_in_interval(self, interval):
start = time()
end = start + interval
while time() < end:
if self.pending():
self.handle_event_set()
else:
sleep(0.5)
class Fam(FileMonitor):
'''
The fam object is a set of callbacks for
file alteration events (FAM support)
'''
def __init__(self, debug=False):
FileMonitor.__init__(self, debug)
self.fm = _fam.open()
def fileno(self):
return self.fm.fileno()
def AddMonitor(self, path, obj):
'''add a monitor to path, installing a callback to obj.HandleEvent'''
mode = os.stat(path)[stat.ST_MODE]
if stat.S_ISDIR(mode):
handle = self.fm.monitorDirectory(path, None)
else:
handle = self.fm.monitorFile(path, None)
if obj != None:
self.handles[handle.requestID()] = obj
return handle.requestID()
def pending(self):
return self.fm.pending()
def get_event(self):
return self.fm.nextEvent()
class Gamin(FileMonitor):
'''
The fam object is a set of callbacks for
file alteration events (Gamin support)
'''
def __init__(self, debug=False):
FileMonitor.__init__(self, debug)
self.mon = WatchMonitor()
self.counter = 0
self.events = []
def fileno(self):
return self.mon.get_fd()
def queue(self, path, action, request_id):
'''queue up the event for later handling'''
self.events.append(GaminEvent(request_id, path, action))
def AddMonitor(self, path, obj):
'''add a monitor to path, installing a callback to obj.HandleEvent'''
handle = self.counter
self.counter += 1
mode = os.stat(path)[stat.ST_MODE]
if stat.S_ISDIR(mode):
self.mon.watch_directory(path, self.queue, handle)
else:
self.mon.watch_file(path, self.queue, handle)
self.handles[handle] = obj
return handle
def pending(self):
return self.mon.event_pending()
def get_event(self):
self.mon.handle_one_event()
return self.events.pop()
class Pseudo(FileMonitor):
'''
The fam object is a set of callbacks for
file alteration events (static monitor support)
'''
def __init__(self, debug=False):
FileMonitor.__init__(self, debug=False)
self.pending_events = []
def pending(self):
return len(self.pending_events) != 0
def get_event(self):
return self.pending_events.pop()
def AddMonitor(self, path, obj):
'''add a monitor to path, installing a callback to obj.HandleEvent'''
handleID = len(self.handles.keys())
mode = os.stat(path)[stat.ST_MODE]
handle = GaminEvent(handleID, path, 'exists')
if stat.S_ISDIR(mode):
dirList = os.listdir(path)
self.pending_events.append(handle)
for includedFile in dirList:
self.pending_events.append(Event(handleID, includedFile, 'exists'))
self.pending_events.append(Event(handleID, path, 'endExist'))
else:
self.pending_events.append(Event(handleID, path, 'exists'))
if obj != None:
self.handles[handleID] = obj
return handleID
available = {}
try:
from gamin import WatchMonitor, GAMCreated, GAMExists, GAMEndExist, GAMChanged, GAMDeleted, GAMMoved
available['gamin'] = Gamin
except ImportError:
# fall back to _fam
pass
try:
import _fam
available['fam'] = Fam
except ImportError:
pass
available['pseudo'] = Pseudo
for fdrv in ['gamin', 'fam', 'pseudo']:
if fdrv in available:
available['default'] = available[fdrv]
break
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