First few changes for the image diffs feature.

data/database.py

@@ -150,10 +150,19 @@ class RepositoryTag(BaseModel):
     )
 
 
+class QueueItem(BaseMode):
+  queue_name = CharField(index=True)
+  body = TextField()
+  available_after = DateTimeField(default=datetime.now, index=True)
+  available = BooleanField(default=True, index=True)
+  processing_expires = DateTimeField(null=True, index=True)
+
+
 def initialize_db():
   create_model_tables([User, Repository, Image, AccessToken, Role,
                        RepositoryPermission, Visibility, RepositoryTag,
-                       EmailConfirmation, FederatedLogin, LoginService])
+                       EmailConfirmation, FederatedLogin, LoginService,
+                       QueueItem])
   Role.create(name='admin')
   Role.create(name='write')
   Role.create(name='read')

data/queue.py

@@ -0,0 +1,55 @@
+from datetime import datetime, timedelta
+
+from database import QueueItem
+
+
+class WorkQueue(object):
+  def __init__(self, queue_name):
+    self.queue_name = queue_name
+
+  def put(message, available_after=0):
+    """
+    Put an item, if it shouldn't be processed for some number of seconds,
+    specify that amount as available_after.
+    """
+
+    params = {
+      'queue_name': self.queue_name,
+      'body': message,
+    }
+
+    if available_after:
+      available_date = datetime.now() + timedelta(seconds=available_after)
+      params['available_after'] = available_date
+
+    QueueItem.create(**params)
+
+  def get(processing_time=300):
+    """
+    Get an available item and mark it as unavailable for the default of five
+    minutes.
+    """
+    now = datetime.now()
+    available_or_expired = (QueueItem.available == True |
+                            QueueItem.processing_expires <= now)
+
+    # TODO the query and the update should be atomic, but for now we only
+    # have one worker.
+    avaial = QueueItem.select().where(QueueItem.queue_name = self.queue_name,
+                                      QueueItem.available_after <= now,
+                                      available_or_expired)
+
+    found = list(avail.limit(1).order_by(QueueItem.available_after))
+
+    if found:
+      item = found[0]
+      item.available = False
+      item.processing_expires = now + timedelta(seconds=processing_time)
+      item.save()
+
+      return item
+
+    return None
+
+  def complete(completed_item):
+    item.delete_instance()

endpoints/api.py

@@ -360,6 +360,21 @@ def list_repository_images(namespace, repository):
   abort(403)
 
 
+@app.route('/api/repository/<path:repository>/image/<image_id>/changes',
+           methods=['GET'])
+@parse_repository_name
+def get_repository_changes(namespace, repository, image_id):
+  permission = ReadRepositoryPermission(namespace, repository)
+  if permission.can() or model.repository_is_public(namespace, repository):
+    return jsonify({
+      'added': [],
+      'changed': [],
+      'removed': []
+    })
+
+  abort(403)
+
+
 @app.route('/api/repository/<path:repository>/tag/<tag>/images',
            methods=['GET'])
 @parse_repository_name

endpoints/registry.py

@@ -312,3 +312,9 @@ def delete_repository_storage(namespace, repository):
 
   logger.debug('Recursively deleting path: %s' % repository_path)
   store.remove(repository_path)
+
+
+def process_image_changes(namespace, repository, image_id):
+  return
+  image = model.get_image_by_id(namespace, repository, image_id)
+  model.get_parent_images()

requirements-nover.txt

@@ -12,3 +12,5 @@ gunicorn
 eventlet
 mixpanel-py
 beautifulsoup4
+marisa-trie
+apscheduler

storage/__init__.py

@@ -54,6 +54,14 @@ class Storage(object):
   def repository_namespace_path(self, namespace, repository):
     return '{0}/{1}/{2}/'.format(self.images, namespace, repository)
 
+  def image_file_trie_path(self, namespace, repository, image_id):
+    return '{0}/{1}/{2}/{3}/files.trie'.format(self.images, namespace,
+                                               repository, image_id)
+
+  def image_file_diffs_trie_path(self, namespace, repository, image_id):
+    return '{0}/{1}/{2}/{3}/diffs.pkl'.format(self.images, namespace,
+                                              repository, image_id)
+
   def get_content(self, path):
     raise NotImplementedError
 

util/changes.py

@@ -0,0 +1,56 @@
+import marisa_trie
+import os
+
+
+AUFS_METADATA = u'.wh..wh.'
+
+AUFS_WHITEOUT = u'.wh.'
+AUFS_WHITEOUT_PREFIX_LENGTH = len(AUFS_WHITEOUT)
+
+
+def files_and_dirs(root_path, removed_prefix_collector):
+  for root, dirs, files in os.walk(unicode(root_path)):
+
+    rel_root = os.path.relpath(root, root_path)
+    yield rel_root
+
+    for one_file in files:
+      if one_file.startswith(AUFS_METADATA):
+        # Skip
+        continue
+
+      elif one_file.startswith(AUFS_WHITEOUT):
+        filename = one_file[AUFS_WHITEOUT_PREFIX_LENGTH:]
+        removed_prefix_collector.add(os.path.join(rel_root, filename))
+        continue
+
+      else:
+        yield os.path.join(rel_root, one_file)
+
+
+def compute_removed(base_trie, removed_prefixes):
+  for prefix in removed_prefixes:
+    for filename in base_trie.keys(prefix):
+      yield filename
+
+
+def compute_added_changed(base_trie, delta_trie):
+  added = set()
+  changed = set()
+
+  for filename in delta_trie.keys():
+    if filename not in base_trie:
+      added.add(filename)
+    else:
+      changed.add(filename)
+
+  return added, changed
+
+
+def new_fs(base_trie, added, removed):
+  for filename in base_trie.keys():
+    if filename not in removed:
+      yield filename
+
+  for filename in added:
+    yield filename

workers/image_diffs.py

@@ -0,0 +1,36 @@
+import logging
+import json
+
+from apscheduler.scheduler import Scheduler
+
+from data.queue import WorkQueue
+from endpoints.registry import process_image_changes
+
+
+logger = logging.getLogger(__name__)
+
+image_diff_queue = WorkQueue('imagediff')
+
+
+def process_work_items():
+  logger.debug('Getting work item from queue.')
+
+  item = imagediff.get()
+
+  if item:
+    logger.debug('Queue gave us some work: %s' % item.body)
+
+    request = json.loads(item.body)
+    process_image_changes(request['namepspace'], request['repository'],
+                          request['image_id'])
+  else:
+    logger.debug('No work today.')
+
+
+FORMAT = '%(asctime)-15s - %(levelname)s - %(pathname)s - %(funcName)s - %(message)s'
+logging.basicConfig(format=FORMAT, level=logging.DEBUG)
+
+sched = Scheduler()
+sched.start()
+
+sched.add_interval_job(process_work_items, seconds=10)