2017-08-22 13:34:53 +05:30

450 lines
14 KiB
Python

# GNU MediaGoblin -- federated, autonomous media hosting
# Copyright (C) 2011, 2012 MediaGoblin contributors. See AUTHORS.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
# Use an ordered dict if we can. If not, we'll just use a normal dict
# later.
try:
from collections import OrderedDict
except:
OrderedDict = None
import logging
import os
import six
from mediagoblin import mg_globals as mgg
from mediagoblin.db.util import atomic_update
from mediagoblin.db.models import MediaEntry
from mediagoblin.tools.pluginapi import hook_handle
from mediagoblin.tools.translate import lazy_pass_to_ugettext as _
_log = logging.getLogger(__name__)
class ProgressCallback(object):
def __init__(self, entry):
self.entry = entry
def __call__(self, progress, default_quality_progress=None):
if progress:
if 100 - (self.entry.transcoding_progress + progress) < 0.01:
self.entry.transcoding_progress = 100
else:
self.entry.transcoding_progress += round(progress, 2)
if default_quality_progress:
self.entry.main_transcoding_progress = default_quality_progress
self.entry.save()
def create_pub_filepath(entry, filename):
return mgg.public_store.get_unique_filepath(
['media_entries',
six.text_type(entry.id),
filename])
class FilenameBuilder(object):
"""Easily slice and dice filenames.
Initialize this class with an original file path, then use the fill()
method to create new filenames based on the original.
"""
MAX_FILENAME_LENGTH = 255 # VFAT's maximum filename length
def __init__(self, path):
"""Initialize a builder from an original file path."""
self.dirpath, self.basename = os.path.split(path)
self.basename, self.ext = os.path.splitext(self.basename)
self.ext = self.ext.lower()
def fill(self, fmtstr):
"""Build a new filename based on the original.
The fmtstr argument can include the following:
{basename} -- the original basename, with the extension removed
{ext} -- the original extension, always lowercase
If necessary, {basename} will be truncated so the filename does not
exceed this class' MAX_FILENAME_LENGTH in length.
"""
basename_len = (self.MAX_FILENAME_LENGTH -
len(fmtstr.format(basename='', ext=self.ext)))
return fmtstr.format(basename=self.basename[:basename_len],
ext=self.ext)
class MediaProcessor(object):
"""A particular processor for this media type.
While the ProcessingManager handles all types of MediaProcessing
possible for a particular media type, a MediaProcessor can be
thought of as a *particular* processing action for a media type.
For example, you may have separate MediaProcessors for:
- initial_processing: the intial processing of a media
- gen_thumb: generate a thumbnail
- resize: resize an image
- transcode: transcode a video
... etc.
Some information on producing a new MediaProcessor for your media type:
- You *must* supply a name attribute. This must be a class level
attribute, and a string. This will be used to determine the
subcommand of your process
- It's recommended that you supply a class level description
attribute.
- Supply a media_is_eligible classmethod. This will be used to
determine whether or not a media entry is eligible to use this
processor type. See the method documentation for details.
- To give "./bin/gmg reprocess run" abilities to this media type,
supply both gnerate_parser and parser_to_request classmethods.
- The process method will be what actually processes your media.
"""
# You MUST override this in the child MediaProcessor!
name = None
# Optional, but will be used in various places to describe the
# action this MediaProcessor provides
description = None
def __init__(self, manager, entry):
self.manager = manager
self.entry = entry
self.entry_orig_state = entry.state
# Should be initialized at time of processing, at least
self.workbench = None
def __enter__(self):
self.workbench = mgg.workbench_manager.create()
return self
def __exit__(self, *args):
self.workbench.destroy()
self.workbench = None
# @with_workbench
def process(self, **kwargs):
"""
Actually process this media entry.
"""
raise NotImplementedError
@classmethod
def media_is_eligible(cls, entry=None, state=None):
raise NotImplementedError
###############################
# Command line interface things
###############################
@classmethod
def generate_parser(cls):
raise NotImplementedError
@classmethod
def args_to_request(cls, args):
raise NotImplementedError
##########################################
# THE FUTURE: web interface things here :)
##########################################
#####################
# Some common "steps"
#####################
def delete_queue_file(self):
# Remove queued media file from storage and database.
# queued_filepath is in the task_id directory which should
# be removed too, but fail if the directory is not empty to be on
# the super-safe side.
queued_filepath = self.entry.queued_media_file
if queued_filepath:
mgg.queue_store.delete_file(queued_filepath) # rm file
mgg.queue_store.delete_dir(queued_filepath[:-1]) # rm dir
self.entry.queued_media_file = []
class ProcessingKeyError(Exception): pass
class ProcessorDoesNotExist(ProcessingKeyError): pass
class ProcessorNotEligible(ProcessingKeyError): pass
class ProcessingManagerDoesNotExist(ProcessingKeyError): pass
class ProcessingManager(object):
"""Manages all the processing actions available for a media type
Specific processing actions, MediaProcessor subclasses, are added
to the ProcessingManager.
"""
def __init__(self):
# Dict of all MediaProcessors of this media type
if OrderedDict is not None:
self.processors = OrderedDict()
else:
self.processors = {}
def add_processor(self, processor):
"""
Add a processor class to this media type
"""
name = processor.name
if name is None:
raise AttributeError("Processor class's .name attribute not set")
self.processors[name] = processor
def list_eligible_processors(self, entry):
"""
List all processors that this media entry is eligible to be processed
for.
"""
return [
processor
for processor in self.processors.values()
if processor.media_is_eligible(entry=entry)]
def list_all_processors_by_state(self, state):
"""
List all processors that this media state is eligible to be processed
for.
"""
return [
processor
for processor in self.processors.values()
if processor.media_is_eligible(state=state)]
def list_all_processors(self):
return self.processors.values()
def gen_process_request_via_cli(self, subparser):
# Got to figure out what actually goes here before I can write this properly
pass
def get_processor(self, key, entry=None):
"""
Get the processor with this key.
If entry supplied, make sure this entry is actually compatible;
otherwise raise error.
"""
try:
processor = self.processors[key]
except KeyError:
raise ProcessorDoesNotExist(
"'%s' processor does not exist for this media type" % key)
if entry and not processor.media_is_eligible(entry):
raise ProcessorNotEligible(
"This entry is not eligible for processor with name '%s'" % key)
return processor
def workflow(self, entry, feed_url, reprocess_action, reprocess_info=None):
"""
Returns the Celery command needed to proceed with media processing
"""
return None
def request_from_args(args, which_args):
"""
Generate a request from the values of some argparse parsed args
"""
request = {}
for arg in which_args:
request[arg] = getattr(args, arg)
return request
class MediaEntryNotFound(Exception): pass
def get_processing_manager_for_type(media_type):
"""
Get the appropriate media manager for this type
"""
manager_class = hook_handle(('reprocess_manager', media_type))
if not manager_class:
raise ProcessingManagerDoesNotExist(
"A processing manager does not exist for {0}".format(media_type))
manager = manager_class()
return manager
def get_entry_and_processing_manager(media_id):
"""
Get a MediaEntry, its media type, and its manager all in one go.
Returns a tuple of: `(entry, media_type, media_manager)`
"""
entry = MediaEntry.query.filter_by(id=media_id).first()
if entry is None:
raise MediaEntryNotFound("Can't find media with id '%s'" % media_id)
manager = get_processing_manager_for_type(entry.media_type)
return entry, manager
def mark_entry_failed(entry_id, exc):
"""
Mark a media entry as having failed in its conversion.
Uses the exception that was raised to mark more information. If
the exception is a derivative of BaseProcessingFail then we can
store extra information that can be useful for users telling them
why their media failed to process.
:param entry_id: The id of the media entry
:param exc: An instance of BaseProcessingFail
"""
# Was this a BaseProcessingFail? In other words, was this a
# type of error that we know how to handle?
if isinstance(exc, BaseProcessingFail):
# Looks like yes, so record information about that failure and any
# metadata the user might have supplied.
atomic_update(mgg.database.MediaEntry,
{'id': entry_id},
{u'state': u'failed',
u'fail_error': six.text_type(exc.exception_path),
u'fail_metadata': exc.metadata})
else:
_log.warn("No idea what happened here, but it failed: %r", exc)
# Looks like no, let's record it so that admin could ask us about the
# reason
atomic_update(mgg.database.MediaEntry,
{'id': entry_id},
{u'state': u'failed',
u'fail_error': u'Unhandled exception: {0}'.format(
six.text_type(exc)),
u'fail_metadata': {}})
def get_process_filename(entry, workbench, acceptable_files):
"""
Try and get the queued file if available, otherwise return the first file
in the acceptable_files that we have.
If no acceptable_files, raise ProcessFileNotFound
"""
if entry.queued_media_file:
filepath = entry.queued_media_file
storage = mgg.queue_store
else:
for keyname in acceptable_files:
if entry.media_files.get(keyname):
filepath = entry.media_files[keyname]
storage = mgg.public_store
break
if not filepath:
raise ProcessFileNotFound()
filename = workbench.localized_file(
storage, filepath,
'source')
if not os.path.exists(filename):
raise ProcessFileNotFound()
return filename
def store_public(entry, keyname, local_file, target_name=None,
delete_if_exists=True):
if target_name is None:
target_name = os.path.basename(local_file)
target_filepath = create_pub_filepath(entry, target_name)
if keyname in entry.media_files:
_log.warn("store_public: keyname %r already used for file %r, "
"replacing with %r", keyname,
entry.media_files[keyname], target_filepath)
if delete_if_exists:
mgg.public_store.delete_file(entry.media_files[keyname])
try:
mgg.public_store.copy_local_to_storage(local_file, target_filepath)
except Exception as e:
_log.error(u'Exception happened: {0}'.format(e))
raise PublicStoreFail(keyname=keyname)
# raise an error if the file failed to copy
if not mgg.public_store.file_exists(target_filepath):
raise PublicStoreFail(keyname=keyname)
entry.media_files[keyname] = target_filepath
def copy_original(entry, orig_filename, target_name, keyname=u"original"):
store_public(entry, keyname, orig_filename, target_name)
class BaseProcessingFail(Exception):
"""
Base exception that all other processing failure messages should
subclass from.
You shouldn't call this itself; instead you should subclass it
and provide the exception_path and general_message applicable to
this error.
"""
general_message = u''
@property
def exception_path(self):
return u"%s:%s" % (
self.__class__.__module__, self.__class__.__name__)
def __init__(self, message=None, **metadata):
if message is not None:
super(BaseProcessingFail, self).__init__(message)
metadata['message'] = message
self.metadata = metadata
class BadMediaFail(BaseProcessingFail):
"""
Error that should be raised when an inappropriate file was given
for the media type specified.
"""
general_message = _(u'Invalid file given for media type.')
class PublicStoreFail(BaseProcessingFail):
"""
Error that should be raised when copying to public store fails
"""
general_message = _('Copying to public storage failed.')
class ProcessFileNotFound(BaseProcessingFail):
"""
Error that should be raised when an acceptable file for processing
is not found.
"""
general_message = _(u'An acceptable processing file was not found')