[#418] Better exception handling for finding user in the db

CHANGELOG.md

@@ -7,10 +7,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [Unreleased] - YYYY-MM-DD
 ### Added
 - /health endpoint [@wujuu]
+- pid for services [@wujuu]
 ### Changed
 - **BREAKING CHANGE**: Adjust user actions handling to the new user action schema [@JanKapala]
 ### Fixed
 - engine_version in the recommendations response [@Michal-Kolomanski]
+- better exception handling for finding user in the DB [@Michal-Kolomanski]
 ### Removed
 
 ## [4.0.0] - 2022-10-26

README.md

@@ -166,6 +166,13 @@ To specify from which engine the recommendations are requested, provide an `engi
 It is possible to define which algorithm should be used by default in the absence of the `engine_version` parameter by modifying the `DEFAULT_RECOMMENDATION_ALG` parameter from .env file
 (look into [ENV variables](#env-variables) section).
 
+### Engines
+List of available engines (after training):
+- `NCF` - returns `K` recommendations from the given context.
+- `RL` - returns `K` recommendations from the given context.
+- `Random` - returns `K` random recommendations from the given context.
+- `NCFRanking` - used for sort by relevance.
+
 ### Seeding database
 Note: Only available in development and testing environment.
 

recommender/engines/base/base_inference_component.py

@@ -121,16 +121,17 @@ def _get_user(context: Dict[str, Any]) -> User:
         """
 
         user_id, aai_uid = context.get("user_id"), context.get("aai_uid")
-
-        if not (user_id or aai_uid):
-            raise UserCannotBeIdentified()
-
-        return (
+        user = (
             User.objects(id=user_id).first()
             if user_id
             else User.objects(aai_uid=aai_uid).first()
         )
 
+        if user is None:
+            raise UserCannotBeIdentified()
+
+        return user
+
     @abstractmethod
     def _generate_recommendations(
         self, user: User, candidates: Tuple[int], search_data: SearchData