Basic labels support

Adds basic labels support to the registry code (V2), and the API. Note that this does not yet add any UI related support.

data/model/label.py

@@ -0,0 +1,121 @@
+import logging
+
+from data.database import Label, TagManifestLabel, MediaType, LabelSourceType, db_transaction
+from data.model import InvalidLabelKeyException, InvalidMediaTypeException, DataModelException
+from data.model._basequery import prefix_search
+from util.validation import validate_label_key
+from util.validation import is_json
+from cachetools import lru_cache
+
+logger = logging.getLogger(__name__)
+
+
+@lru_cache(maxsize=1)
+def get_label_source_types():
+  source_type_map = {}
+  for kind in LabelSourceType.select():
+    source_type_map[kind.id] = kind.name
+    source_type_map[kind.name] = kind.id
+
+  return source_type_map
+
+
+@lru_cache(maxsize=1)
+def get_media_types():
+  media_type_map = {}
+  for kind in MediaType.select():
+    media_type_map[kind.id] = kind.name
+    media_type_map[kind.name] = kind.id
+
+  return media_type_map
+
+
+def _get_label_source_type_id(name):
+  kinds = get_label_source_types()
+  return kinds[name]
+
+
+def _get_media_type_id(name):
+  kinds = get_media_types()
+  return kinds[name]
+
+
+def create_manifest_label(tag_manifest, key, value, source_type_name, media_type_name=None):
+  """ Creates a new manifest label on a specific tag manifest. """
+  if not key:
+    raise InvalidLabelKeyException()
+
+  # Note that we don't prevent invalid label names coming from the manifest to be stored, as Docker
+  # does not currently prevent them from being put into said manifests.
+  if not validate_label_key(key) and source_type_name != 'manifest':
+    raise InvalidLabelKeyException()
+
+  # Find the matching media type. If none specified, we infer.
+  if media_type_name is None:
+    media_type_name = 'text/plain'
+    if is_json(value):
+      media_type_name = 'application/json'
+
+  media_type_id = _get_media_type_id(media_type_name)
+  if media_type_id is None:
+    raise InvalidMediaTypeException
+
+  source_type_id = _get_label_source_type_id(source_type_name)
+
+  with db_transaction():
+    label = Label.create(key=key, value=value, source_type=source_type_id, media_type=media_type_id)
+    TagManifestLabel.create(annotated=tag_manifest, label=label,
+                            repository=tag_manifest.tag.repository)
+
+  return label
+
+
+def list_manifest_labels(tag_manifest, prefix_filter=None):
+  """ Lists all labels found on the given tag manifest. """
+  query = (Label.select(Label, MediaType)
+           .join(MediaType)
+           .switch(Label)
+           .join(LabelSourceType)
+           .switch(Label)
+           .join(TagManifestLabel)
+           .where(TagManifestLabel.annotated == tag_manifest))
+
+  if prefix_filter is not None:
+    query = query.where(prefix_search(Label.key, prefix_filter))
+
+  return query
+
+
+def get_manifest_label(label_uuid, tag_manifest):
+  """ Retrieves the manifest label on the tag manifest with the given ID. """
+  try:
+    return (Label.select(Label, LabelSourceType)
+            .join(LabelSourceType)
+            .where(Label.uuid == label_uuid)
+            .switch(Label)
+            .join(TagManifestLabel)
+            .where(TagManifestLabel.annotated == tag_manifest)
+            .get())
+  except Label.DoesNotExist:
+    return None
+
+
+def delete_manifest_label(label_uuid, tag_manifest):
+  """ Deletes the manifest label on the tag manifest with the given ID. """
+
+  # Find the label itself.
+  label = get_manifest_label(label_uuid, tag_manifest)
+  if label is None:
+    return None
+
+  if not label.source_type.mutable:
+    raise DataModelException('Cannot delete immutable label')
+
+  # Delete the mapping record and label.
+  deleted_count = TagManifestLabel.delete().where(TagManifestLabel.label == label).execute()
+  if deleted_count != 1:
+    logger.warning('More than a single label deleted for matching label %s', label_uuid)
+
+  label.delete_instance(recursive=False)
+  return label
+