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authorChris St. Pierre <chris.a.st.pierre@gmail.com>2012-07-18 15:08:28 -0400
committerChris St. Pierre <chris.a.st.pierre@gmail.com>2012-07-18 15:08:38 -0400
commit14dc1773ce6cd110869d4957b2b9d4e3c2afd965 (patch)
tree4f4c987c1ab090230afd62d6fcff13f39b0c242b /src/lib/Bcfg2/Server/FileMonitor
parent4a9b9f9420ccdcbd5a0e79ca493ea85e4683f41e (diff)
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made inotify FAM work. i think.
Diffstat (limited to 'src/lib/Bcfg2/Server/FileMonitor')
-rw-r--r--src/lib/Bcfg2/Server/FileMonitor/Inotify.py95
-rw-r--r--src/lib/Bcfg2/Server/FileMonitor/Pseudo.py4
-rw-r--r--src/lib/Bcfg2/Server/FileMonitor/__init__.py14
3 files changed, 86 insertions, 27 deletions
diff --git a/src/lib/Bcfg2/Server/FileMonitor/Inotify.py b/src/lib/Bcfg2/Server/FileMonitor/Inotify.py
index 50c724279..bf540a1c6 100644
--- a/src/lib/Bcfg2/Server/FileMonitor/Inotify.py
+++ b/src/lib/Bcfg2/Server/FileMonitor/Inotify.py
@@ -1,7 +1,7 @@
""" Inotify driver for file alteration events """
import os
-import stat
+import sys
import logging
import operator
import pyinotify
@@ -12,16 +12,20 @@ logger = logging.getLogger(__name__)
class Inotify(Pseudo, pyinotify.ProcessEvent):
__priority__ = 1
- mask = pyinotify.IN_CREATE | pyinotify.IN_DELETE | pyinotify.IN_MODIFY
action_map = {pyinotify.IN_CREATE: 'created',
pyinotify.IN_DELETE: 'deleted',
- pyinotify.IN_MODIFY: 'changed'}
+ pyinotify.IN_MODIFY: 'changed',
+ pyinotify.IN_MOVED_FROM: 'deleted',
+ pyinotify.IN_MOVED_TO: 'created'}
+ mask = reduce(lambda x, y: x | y, action_map.keys())
def __init__(self, ignore=None, debug=False):
Pseudo.__init__(self, ignore=ignore, debug=debug)
self.wm = pyinotify.WatchManager()
self.notifier = pyinotify.ThreadedNotifier(self.wm, self)
self.notifier.start()
+ self.event_filter = dict()
+ self.watches_by_path = dict()
def fileno(self):
return self.wm.get_fd()
@@ -32,33 +36,88 @@ class Inotify(Pseudo, pyinotify.ProcessEvent):
if ievent.mask & amask:
action = aname
break
+ try:
+ watch = self.wm.watches[ievent.wd]
+ except KeyError:
+ err = sys.exc_info()[1]
+ logger.error("Error handling event for %s: Watch %s not found" %
+ (ievent.pathname, ievent.wd))
+ return
# FAM-style file monitors return the full path to the parent
# directory that is being watched, relative paths to anything
- # contained within the directory
- watch = self.wm.watches[ievent.wd]
- if watch.path == ievent.pathname:
+ # contained within the directory. since we can't use inotify
+ # to watch files directly, we have to sort of guess at whether
+ # this watch was actually added on a file (and thus is in
+ # self.event_filter because we're filtering out other events
+ # on the directory) or was added directly on a directory.
+ if (watch.path == ievent.pathname or ievent.wd in self.event_filter):
path = ievent.pathname
else:
# relative path
path = os.path.basename(ievent.pathname)
- evt = Event(ievent.wd, path, action)
- self.events.append(evt)
+ # figure out the handleID. start with the path of the event;
+ # that should catch events on files that are watched directly.
+ # (we have to watch the directory that a file is in, so this
+ # lets us handle events on different files in the same
+ # directory -- and thus under the same watch -- with different
+ # objects.) If the path to the event doesn't have a handler,
+ # use the path of the watch itself.
+ handleID = ievent.pathname
+ if handleID not in self.handles:
+ handleID = watch.path
+ evt = Event(handleID, path, action)
+
+ if (ievent.wd not in self.event_filter or
+ ievent.pathname in self.event_filter[ievent.wd]):
+ self.events.append(evt)
def AddMonitor(self, path, obj):
- res = self.wm.add_watch(path, self.mask, quiet=False)
- if not res:
- # if we didn't get a return, but we also didn't get an
- # exception, we're already watching this directory, so we
- # need to find the watch descriptor for it
- for wd, watch in self.wm.watches.items():
- if watch.path == path:
- wd = watch.wd
+ if not os.path.isdir(path):
+ # inotify is a little wonky about watching files. for
+ # instance, if you watch /tmp/foo, and then do 'mv
+ # /tmp/bar /tmp/foo', it processes that as a deletion of
+ # /tmp/foo (which it technically _is_, but that's rather
+ # useless -- we care that /tmp/foo changed, not that it
+ # was first deleted and then created). In order to
+ # effectively watch a file, we have to watch the directory
+ # it's in, and filter out events for other files in the
+ # same directory that are not similarly watched.
+ # watch_transient_file requires a Processor _class_, not
+ # an object, so we can't have this object handle events,
+ # which is Wrong, so we can't use that function.
+ watch_path = os.path.dirname(path)
+ is_dir = False
else:
- wd = res[path]
+ watch_path = path
+ is_dir = True
+
+ # see if this path is already being watched
+ try:
+ wd = self.watches_by_path[watch_path]
+ except KeyError:
+ wd = self.wm.add_watch(watch_path, self.mask,
+ quiet=False)[watch_path]
+ self.watches_by_path[watch_path] = wd
+
+ produce_exists = True
+ if not is_dir:
+ if wd not in self.event_filter:
+ self.event_filter[wd] = [path]
+ elif path not in self.event_filter[wd]:
+ self.event_filter[wd].append(path)
+ else:
+ # we've been asked to watch a file that we're already
+ # watching, so we don't need to produce 'exists'
+ # events
+ produce_exists = False
# inotify doesn't produce initial 'exists' events, so we
# inherit from Pseudo to produce those
- return Pseudo.AddMonitor(self, path, obj, handleID=wd)
+ if produce_exists:
+ return Pseudo.AddMonitor(self, path, obj, handleID=path)
+ else:
+ self.handles[path] = obj
+ return path
def shutdown(self):
self.notifier.stop()
diff --git a/src/lib/Bcfg2/Server/FileMonitor/Pseudo.py b/src/lib/Bcfg2/Server/FileMonitor/Pseudo.py
index baff871d0..089d4cf0f 100644
--- a/src/lib/Bcfg2/Server/FileMonitor/Pseudo.py
+++ b/src/lib/Bcfg2/Server/FileMonitor/Pseudo.py
@@ -1,7 +1,6 @@
""" Pseudo provides static monitor support for file alteration events """
import os
-import stat
import logging
from Bcfg2.Server.FileMonitor import FileMonitor, Event
@@ -14,9 +13,8 @@ class Pseudo(FileMonitor):
"""add a monitor to path, installing a callback to obj.HandleEvent"""
if handleID is None:
handleID = len(list(self.handles.keys()))
- mode = os.stat(path)[stat.ST_MODE]
self.events.append(Event(handleID, path, 'exists'))
- if stat.S_ISDIR(mode):
+ if os.path.isdir(path):
dirList = os.listdir(path)
for includedFile in dirList:
self.events.append(Event(handleID, includedFile, 'exists'))
diff --git a/src/lib/Bcfg2/Server/FileMonitor/__init__.py b/src/lib/Bcfg2/Server/FileMonitor/__init__.py
index 8bd63e18d..c490acc81 100644
--- a/src/lib/Bcfg2/Server/FileMonitor/__init__.py
+++ b/src/lib/Bcfg2/Server/FileMonitor/__init__.py
@@ -44,12 +44,15 @@ class FileMonitor(object):
def __repr__(self):
return "%s (%s events, fd %s)" % (str(self), len(self.events), self.fileno)
+ def debug_log(self, msg):
+ if self.debug:
+ logger.info(msg)
+
def should_ignore(self, event):
for pattern in self.ignore:
if (fnmatch.fnmatch(event.filename, pattern) or
fnmatch.fnmatch(os.path.split(event.filename)[-1], pattern)):
- if self.debug:
- logger.info("Ignoring %s" % event)
+ self.debug_log("Ignoring %s" % event)
return True
return False
@@ -69,10 +72,9 @@ class FileMonitor(object):
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]))
+ self.debug_log("Dispatching event %s %s to obj %s" %
+ (event.code2str(), event.filename,
+ self.handles[event.requestID]))
try:
self.handles[event.requestID].HandleEvent(event)
except: