+################################
+# Media processing initial steps
+################################
+
+class ProcessMedia(Task):
+ """
+ Pass this entry off for processing.
+ """
+ def run(self, media_id):
+ """
+ Pass the media entry off to the appropriate processing function
+ (for now just process_image...)
+ """
+ entry = mgg.database.MediaEntry.one(
+ {'_id': ObjectId(media_id)})
+
+ # Try to process, and handle expected errors.
+ try:
+ process_image(entry)
+ except BaseProcessingFail, exc:
+ mark_entry_failed(entry[u'_id'], exc)
+ return
+
+ entry['state'] = u'processed'
+ entry.save()
+
+ def on_failure(self, exc, task_id, args, kwargs, einfo):
+ """
+ If the processing failed we should mark that in the database.
+
+ Assuming that the exception raised is a subclass of BaseProcessingFail,
+ we can use that to get more information about the failure and store that
+ for conveying information to users about the failure, etc.
+ """
+ entry_id = args[0]
+ mark_entry_failed(entry_id, exc)
+
+
+process_media = registry.tasks[ProcessMedia.name]
+
+
+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.