2879: Improve sorting in Collection.uuids_for_docker_image.

[arvados.git] / services / api / app / models / collection.rb

diff --git a/services/api/app/models/collection.rb b/services/api/app/models/collection.rb
index 64a6bb05304b84877bb4f6d55231c3e561bc8ee6..24e4ccc0ab744e32dcf1027c171251b7ae6455a7 100644 (file)
--- a/services/api/app/models/collection.rb
+++ b/services/api/app/models/collection.rb
@@ -148,7 +148,7 @@ class Collection < ArvadosModel
     [hash_part, size_part].compact.join '+'
   end
 
-  def self.for_latest_docker_image(search_term, search_tag=nil, readers=nil)
+  def self.uuids_for_docker_image(search_term, search_tag=nil, readers=nil)
     readers ||= [Thread.current[:user]]
     base_search = Link.
       readable_by(*readers).
@@ -161,7 +161,7 @@ class Collection < ArvadosModel
     coll_matches = base_search.
       where(link_class: "docker_image_hash", collections: {uuid: search_term})
     if match = coll_matches.first
-      return find_by_uuid(match.head_uuid)
+      return [match.head_uuid]
     end
 
     # Find Collections with matching Docker image repository+tag pairs.
@@ -176,20 +176,24 @@ class Collection < ArvadosModel
               "docker_image_hash", "#{search_term}%")
     end
 
-    # Select the image that was created most recently.  Note that the
-    # SQL search order and fallback timestamp values are chosen so
-    # that if image timestamps are missing, we use the image with the
-    # newest link.
-    latest_image_link = nil
-    latest_image_timestamp = "1900-01-01T00:00:00Z"
+    # Generate an order key for each result.  We want to order the results
+    # so that anything with an image timestamp is considered more recent than
+    # anything without; then we use the link's created_at as a tiebreaker.
+    uuid_timestamps = {}
     matches.find_each do |link|
-      link_timestamp = link.properties.fetch("image_timestamp",
-                                             "1900-01-01T00:00:01Z")
-      if link_timestamp > latest_image_timestamp
-        latest_image_link = link
-        latest_image_timestamp = link_timestamp
-      end
+      uuid_timestamps[link.head_uuid] =
+        [(-link.properties["image_timestamp"].to_datetime.to_i rescue 0),
+         -link.created_at.to_i]
+    end
+    uuid_timestamps.keys.sort_by { |uuid| uuid_timestamps[uuid] }
+  end
+
+  def self.for_latest_docker_image(search_term, search_tag=nil, readers=nil)
+    image_uuid = uuids_for_docker_image(search_term, search_tag, readers).last
+    if image_uuid.nil?
+      nil
+    else
+      find_by_uuid(image_uuid)
     end
-    latest_image_link.nil? ? nil : find_by_uuid(latest_image_link.head_uuid)
   end
 end