sintonia/python_apps/media-monitor2/media/monitor/events.py

302 lines
10 KiB
Python

# -*- coding: utf-8 -*-
import os
import abc
import re
import media.monitor.pure as mmp
import media.monitor.owners as owners
from media.monitor.pure import LazyProperty
from media.monitor.metadata import Metadata
from media.monitor.log import Loggable
from media.monitor.exceptions import BadSongFile
class PathChannel(object):
"""
Simple struct to hold a 'signal' string and a related 'path'. Basically
used as a named tuple
"""
def __init__(self, signal, path):
self.signal = signal
self.path = path
# TODO : Move this to it's file. Also possible unsingleton and use it as a
# simple module just like m.m.owners
class EventRegistry(object):
"""
This class's main use is to keep track all events with a cookie attribute.
This is done mainly because some events must be 'morphed' into other events
because we later detect that they are move events instead of delete events.
"""
registry = {}
@staticmethod
def register(evt): EventRegistry.registry[evt.cookie] = evt
@staticmethod
def unregister(evt): del EventRegistry.registry[evt.cookie]
@staticmethod
def registered(evt): return evt.cookie in EventRegistry.registry
@staticmethod
def matching(evt):
event = EventRegistry.registry[evt.cookie]
# Want to disallow accessing the same event twice
EventRegistry.unregister(event)
return event
def __init__(self,*args,**kwargs):
raise Exception("You can instantiate this class. Must only use class \
methods")
class EventProxy(Loggable):
"""
A container object for instances of BaseEvent (or it's subclasses) used for
event contractor
"""
def __init__(self, orig_evt):
self.orig_evt = orig_evt
self.evt = orig_evt
self.reset_hook()
if hasattr(orig_evt, 'path'): self.path = orig_evt.path
def set_pack_hook(self, l):
self._pack_hook = l
def reset_hook(self):
self._pack_hook = lambda : None
def run_hook(self):
self._pack_hook()
def safe_pack(self):
self.run_hook()
# make sure that cleanup hook is never called twice for the same event
self.reset_hook()
return self.evt.safe_pack()
def merge_proxy(self, proxy):
self.evt = proxy.evt
def is_event(self, real_event):
return isinstance(self.evt, real_event)
def same_event(self, proxy):
return self.evt.__class__ == proxy.evt.__class__
class HasMetaData(object):
"""
Any class that inherits from this class gains the metadata attribute that
loads metadata from the class's 'path' attribute. This is done lazily so
there is no performance penalty to inheriting from this and subsequent
calls to metadata are cached
"""
__metaclass__ = abc.ABCMeta
@LazyProperty
def metadata(self): return Metadata(self.path)
class BaseEvent(Loggable):
__metaclass__ = abc.ABCMeta
def __init__(self, raw_event):
# TODO : clean up this idiotic hack
# we should use keyword constructors instead of this behaviour checking
# bs to initialize BaseEvent
if hasattr(raw_event,"pathname"):
self._raw_event = raw_event
self.path = os.path.normpath(raw_event.pathname)
else: self.path = raw_event
self.owner = owners.get_owner(self.path)
owner_re = re.search('stor/imported/(?P<owner>\d+)/', self.path)
if owner_re:
self.logger.info("matched path: %s" % self.path)
self.owner = owner_re.group('owner')
else:
self.logger.info("did not match path: %s" % self.path)
self._pack_hook = lambda: None # no op
# into another event
# TODO : delete this method later
def reset_hook(self):
"""
Resets the hook that is called after an event is packed. Before
resetting the hook we execute it to make sure that whatever cleanup
operations were queued are executed.
"""
self._pack_hook()
self._pack_hook = lambda: None
def exists(self): return os.path.exists(self.path)
@LazyProperty
def cookie(self): return getattr( self._raw_event, 'cookie', None )
def __str__(self):
return "Event(%s). Path(%s)" % ( self.path, self.__class__.__name__)
# TODO : delete this method later
def add_safe_pack_hook(self,k):
"""
adds a callable object (function) that will be called after the event
has been "safe_packed"
"""
self._pack_hook = k
def proxify(self):
return EventProxy(self)
# As opposed to unsafe_pack...
def safe_pack(self):
"""
returns exceptions instead of throwing them to be consistent with
events that must catch their own BadSongFile exceptions since generate
a set of exceptions instead of a single one
"""
try:
self._pack_hook()
ret = self.pack()
# Remove owner of this file only after packing. Otherwise packing
# will not serialize the owner correctly into the airtime request
owners.remove_file_owner(self.path)
return ret
except BadSongFile as e: return [e]
except Exception as e:
self.unexpected_exception(e)
return[e]
# nothing to see here, please move along
def morph_into(self, evt):
self.logger.info("Morphing %s into %s" % ( str(self), str(evt) ) )
self._raw_event = evt._raw_event
self.path = evt.path
self.__class__ = evt.__class__
# Clean up old hook and transfer the new events hook
self.reset_hook()
self.add_safe_pack_hook( evt._pack_hook )
return self
def assign_owner(self,req):
"""
Packs self.owner to req if the owner is valid. I.e. it's not -1. This
method is used by various events that would like to pass owner as a
parameter. NewFile for example.
"""
if self.owner != -1: req['MDATA_KEY_OWNER_ID'] = self.owner
class FakePyinotify(object):
"""
sometimes we must create our own pyinotify like objects to
instantiate objects from the classes below whenever we want to turn
a single event into multiple events
"""
def __init__(self, path): self.pathname = path
class OrganizeFile(BaseEvent, HasMetaData):
"""
The only kind of event that does support the pack protocol. It's used
internally with mediamonitor to move files in the organize directory.
"""
def __init__(self, *args, **kwargs):
super(OrganizeFile, self).__init__(*args, **kwargs)
def pack(self):
raise AttributeError("You can't send organize events to airtime!!!")
class NewFile(BaseEvent, HasMetaData):
"""
NewFile events are the only events that contain MDATA_KEY_OWNER_ID metadata
in them.
"""
def __init__(self, *args, **kwargs):
super(NewFile, self).__init__(*args, **kwargs)
def pack(self):
"""
packs turns an event into a media monitor request
"""
req_dict = self.metadata.extract()
req_dict['mode'] = u'create'
req_dict['is_record'] = self.metadata.is_recorded()
self.assign_owner(req_dict)
req_dict['MDATA_KEY_FILEPATH'] = unicode( self.path )
return [req_dict]
class DeleteFile(BaseEvent):
"""
DeleteFile event only contains the path to be deleted. No other metadata
can be or is included. (This is because this event is fired after the
deletion occurs).
"""
def __init__(self, *args, **kwargs):
super(DeleteFile, self).__init__(*args, **kwargs)
def pack(self):
req_dict = {}
req_dict['mode'] = u'delete'
req_dict['MDATA_KEY_FILEPATH'] = unicode( self.path )
return [req_dict]
class MoveFile(BaseEvent, HasMetaData):
"""
Path argument should be the new path of the file that was moved
"""
def __init__(self, *args, **kwargs):
super(MoveFile, self).__init__(*args, **kwargs)
def old_path(self):
return self._raw_event.src_pathname
def pack(self):
req_dict = {}
req_dict['mode'] = u'moved'
req_dict['MDATA_KEY_ORIGINAL_PATH'] = self.old_path()
req_dict['MDATA_KEY_FILEPATH'] = unicode( self.path )
req_dict['MDATA_KEY_MD5'] = self.metadata.extract()['MDATA_KEY_MD5']
return [req_dict]
class ModifyFile(BaseEvent, HasMetaData):
def __init__(self, *args, **kwargs):
super(ModifyFile, self).__init__(*args, **kwargs)
def pack(self):
req_dict = self.metadata.extract()
req_dict['mode'] = u'modify'
# path to directory that is to be removed
req_dict['MDATA_KEY_FILEPATH'] = unicode( self.path )
return [req_dict]
def map_events(directory, constructor):
"""
Walks 'directory' and creates an event using 'constructor'. Returns a list
of the constructed events.
"""
# -unknown-path should not appear in the path here but more testing
# might be necessary
for f in mmp.walk_supported(directory, clean_empties=False):
try:
for e in constructor( FakePyinotify(f) ).pack(): yield e
except BadSongFile as e: yield e
class DeleteDir(BaseEvent):
"""
A DeleteDir event unfolds itself into a list of DeleteFile events for every
file in the directory.
"""
def __init__(self, *args, **kwargs):
super(DeleteDir, self).__init__(*args, **kwargs)
def pack(self):
return map_events( self.path, DeleteFile )
class MoveDir(BaseEvent):
"""
A MoveDir event unfolds itself into a list of MoveFile events for every
file in the directory.
"""
def __init__(self, *args, **kwargs):
super(MoveDir, self).__init__(*args, **kwargs)
def pack(self):
return map_events( self.path, MoveFile )
class DeleteDirWatch(BaseEvent):
"""
Deleting a watched directory is different from deleting any other
directory. Hence we must have a separate event to handle this case
"""
def __init__(self, *args, **kwargs):
super(DeleteDirWatch, self).__init__(*args, **kwargs)
def pack(self):
req_dict = {}
req_dict['mode'] = u'delete_dir'
req_dict['MDATA_KEY_FILEPATH'] = unicode( self.path + "/" )
return [req_dict]