PLATFORM-1762 Create get_services_identifiers_by_tag_name method at container

src/pypendency/container.py

@@ -73,39 +73,15 @@ def set(self, identifier: str, service: object, tags: Optional[Set[Tag]] = None)
             for tag in tags:
                 self.__add_service_to_tag_group(tag, identifier)
 
+    def has(self, identifier: str) -> bool:
+        return identifier in self._service_mapping
+
     def get(self, identifier: str) -> Optional[object]:
         if self.is_resolved() is False:
             self.resolve()
 
         return self._do_get(identifier)
 
-    def get_by_tag(self, tag: Tag) -> Set[object]:
-        if self.is_resolved() is False:
-            self.resolve()
-
-        if tag not in self._tags_mapping:
-            raise exceptions.TagNotFoundInContainer(tag.identifier)
-
-        return set([self._do_get(service) for service in self._tags_mapping[tag]])
-
-    def get_by_tag_name(self, tag_identifier: str, tag_value: Optional[object] = Tag.UNSET_VALUE) -> Set[object]:
-        if self.is_resolved() is False:
-            self.resolve()
-
-        services = set()
-        for tag, tagged_services in self._tags_mapping.items():
-            if tag.identifier == tag_identifier and (tag_value == Tag.UNSET_VALUE or tag.value == tag_value):
-                for tagged_service in tagged_services:
-                    services.add(self._do_get(tagged_service))
-
-        return services
-
-    def get_service_tags(self, service_identifier: str) -> Set[Tag]:
-        if self.is_resolved() is False:
-            self.resolve()
-
-        return {tag for tag, services in self._tags_mapping.items() if service_identifier in services}
-
     def _do_get(self, identifier: str) -> Optional[object]:
         empty = object()
 
@@ -149,5 +125,43 @@ def __instance_from_fqn(self, fully_qualified_name: str, args: list, kwargs: dic
         except TypeError as e:
             raise exceptions.ServiceInstantiationFailed(fully_qualified_name) from e
 
-    def has(self, identifier: str) -> bool:
-        return identifier in self._service_mapping
+    def get_service_identifier(self, service: Union[object, Definition]) -> str:
+        if self.is_resolved() is False:
+            self.resolve()
+
+        matching_identifiers: Set[str] = {k for k, v in self._service_mapping.items() if v == service}
+
+        if len(matching_identifiers) == 0:
+            raise exceptions.ServiceNotFoundInContainer(service.__str__())
+
+        if len(matching_identifiers) > 1:
+            raise exceptions.ServiceIsRegisteredWithMultipleIdentifiers(service)
+
+        return matching_identifiers.pop()
+
+    def get_by_tag(self, tag: Tag) -> Set[object]:
+        if self.is_resolved() is False:
+            self.resolve()
+
+        if tag not in self._tags_mapping:
+            raise exceptions.TagNotFoundInContainer(tag.identifier)
+
+        return set([self._do_get(service) for service in self._tags_mapping[tag]])
+
+    def get_by_tag_name(self, tag_identifier: str, tag_value: Optional[object] = Tag.UNSET_VALUE) -> Set[object]:
+        if self.is_resolved() is False:
+            self.resolve()
+
+        services = set()
+        for tag, tagged_services in self._tags_mapping.items():
+            if tag.identifier == tag_identifier and (tag_value == Tag.UNSET_VALUE or tag.value == tag_value):
+                for tagged_service in tagged_services:
+                    services.add(self._do_get(tagged_service))
+
+        return services
+
+    def get_service_tags(self, service_identifier: str) -> Set[Tag]:
+        if self.is_resolved() is False:
+            self.resolve()
+
+        return {tag for tag, services in self._tags_mapping.items() if service_identifier in services}

src/pypendency/exceptions.py

@@ -1,3 +1,6 @@
+from typing import Union
+
+from pypendency.definition import Definition
 from pypendency.tag import Tag
 
 
@@ -34,6 +37,7 @@ def __init__(self, fully_qualified_name: str):
             f"Container can't locate any class in {fully_qualified_name}"
         )
 
+
 class ServiceInstantiationFailed(Exception):
     def __init__(self, service_fqn: str) -> None:
         self.service_fqn = service_fqn
@@ -45,6 +49,13 @@ def __init__(self, tag_identifier: str) -> None:
         self.tag_identifier = tag_identifier
         super().__init__(f"The tag '{tag_identifier}' does not exist in the container")
 
+
 class PypendencyCallbackException(Exception):
     def __init__(self) -> None:
         super().__init__(f"Exception on_resolved_callback")
+
+
+class ServiceIsRegisteredWithMultipleIdentifiers(Exception):
+    def __init__(self, service: Union[object, Definition]) -> None:
+        self.service = service
+        super().__init__(f"The service {service} is registered with multiple identifiers")

tests/test_container.py

@@ -198,6 +198,31 @@ def test_get_service_tags(self):
         self.assertEqual(1, len(tags))
         self.assertEqual(list(tags)[0], test_tag)
 
+    def test_get_service_identifier_raises_when_registered_multiple_times(self):
+        container = Container([])
+        test_service = object()
+        container.set("test_service", test_service)
+        container.set("another_test_service", test_service)
+
+        with self.assertRaises(exceptions.ServiceIsRegisteredWithMultipleIdentifiers):
+            container.get_service_identifier(test_service)
+
+    def test_get_service_identifier_raises_when_service_not_registered(self):
+        container = Container([])
+        test_service = object()
+
+        with self.assertRaises(exceptions.ServiceNotFoundInContainer):
+            container.get_service_identifier(test_service)
+
+    def test_get_service_identifier(self):
+        container = Container([])
+        test_service = object()
+        container.set("test_service", test_service)
+
+        identifier = container.get_service_identifier(test_service)
+
+        self.assertEqual("test_service", identifier)
+
     def test_has(self):
         container = Container([
             Definition("example", "example.fqn"),