Fix a regression in AppSyncResolver

Author: leandrodamascena

aws_lambda_powertools/event_handler/appsync.py

@@ -49,10 +49,6 @@ def __init__(self):
         super().__init__()
         self.context = {}  # early init as customers might add context before event resolution
 
-        self.current_batch_event: List[AppSyncResolverEvent] = []
-        self.current_event: Optional[AppSyncResolverEvent] = None
-        self.lambda_context: Optional[LambdaContext] = None
-
     def __call__(
         self,
         event: dict,
@@ -139,10 +135,13 @@ def lambda_handler(event, context):
         """
 
         self.lambda_context = context
+        Router.lambda_context = context
 
         if isinstance(event, list):
+            Router.current_batch_event = [data_model(e) for e in event]
             response = self._call_batch_resolver(event=event, data_model=data_model)
         else:
+            Router.current_event = data_model(event)
             response = self._call_single_resolver(event=event, data_model=data_model)
 
         self.clear_context()
@@ -162,7 +161,6 @@ def _call_single_resolver(self, event: dict, data_model: Type[AppSyncResolverEve
 
         logger.debug("Processing direct resolver event")
 
-        self.current_event = data_model(event)
         resolver = self._resolver_registry.find_resolver(self.current_event.type_name, self.current_event.field_name)
         if not resolver:
             raise ValueError(f"No resolver found for '{self.current_event.type_name}.{self.current_event.field_name}'")
@@ -309,7 +307,6 @@ def _call_batch_resolver(self, event: List[dict], data_model: Type[AppSyncResolv
         """
         logger.debug("Processing batch resolver event")
 
-        self.current_batch_event = [data_model(e) for e in event]
         type_name, field_name = self.current_batch_event[0].type_name, self.current_batch_event[0].field_name
 
         resolver = self._batch_resolver_registry.find_resolver(type_name, field_name)

aws_lambda_powertools/event_handler/graphql_appsync/router.py

@@ -1,11 +1,16 @@
-from typing import Callable, Optional
+from typing import Callable, List, Optional
 
 from aws_lambda_powertools.event_handler.graphql_appsync._registry import ResolverRegistry
 from aws_lambda_powertools.event_handler.graphql_appsync.base import BaseRouter
+from aws_lambda_powertools.utilities.data_classes.appsync_resolver_event import AppSyncResolverEvent
+from aws_lambda_powertools.utilities.typing.lambda_context import LambdaContext
 
 
 class Router(BaseRouter):
     context: dict
+    current_batch_event: List[AppSyncResolverEvent] = []
+    current_event: Optional[AppSyncResolverEvent] = None
+    lambda_context: Optional[LambdaContext] = None
 
     def __init__(self):
         self.context = {}  # early init as customers might add context before event resolution

tests/events/appSyncBatchEvent.json

@@ -0,0 +1,46 @@
+[
+  {
+    "arguments": {
+      "id": "1"
+    },
+    "identity": {
+      "sub": "192879fc-a240-4bf1-ab5a-d6a00f3063f9",
+      "username": "jdoe"
+    },
+    "prev": null,
+    "info": {
+      "selectionSetList": [
+        "id",
+        "field1",
+        "field2"
+      ],
+      "selectionSetGraphQL": "{\n  id\n  field1\n  field2\n}",
+      "parentTypeName": "Mutation",
+      "fieldName": "createSomething",
+      "variables": {}
+    },
+    "stash": {}
+  },
+  {
+    "arguments": {
+      "id": "2"
+    },
+    "identity": {
+      "sub": "192879fc-a240-4bf1-ab5a-d6a00f3063f9",
+      "username": "jdoe"
+    },
+    "prev": null,
+    "info": {
+      "selectionSetList": [
+        "id",
+        "field1",
+        "field2"
+      ],
+      "selectionSetGraphQL": "{\n  id\n  field1\n  field2\n}",
+      "parentTypeName": "Mutation",
+      "fieldName": "createSomething",
+      "variables": {}
+    },
+    "stash": {}
+  }
+]

tests/functional/event_handler/required_dependencies/appsync/test_appsync_batch_resolvers.py

@@ -8,6 +8,7 @@
 from aws_lambda_powertools.utilities.data_classes import AppSyncResolverEvent
 from aws_lambda_powertools.utilities.typing import LambdaContext
 from aws_lambda_powertools.warnings import PowertoolsUserWarning
+from tests.functional.utils import load_event
 
 
 # TESTS RECEIVING THE EVENT PARTIALLY AND PROCESS EACH RECORD PER TIME.
@@ -710,7 +711,6 @@ def create_something(event: List[AppSyncResolverEvent]) -> List:  # noqa AA03 VN
     assert result == [appsync_event["source"]["id"] for appsync_event in event]
 
     assert app.current_batch_event and len(app.current_batch_event) == len(event)
-    assert not app.current_event
 
 
 def test_resolve_async_batch_processing_with_simple_queries_with_aggregate():
@@ -772,7 +772,6 @@ async def create_something(event: List[AppSyncResolverEvent]) -> List:  # noqa A
     assert result == [appsync_event["source"]["id"] for appsync_event in event]
 
     assert app.current_batch_event and len(app.current_batch_event) == len(event)
-    assert not app.current_event
 
 
 def test_resolve_batch_processing_with_aggregate_and_returning_a_non_list():
@@ -907,3 +906,40 @@ def do_something_with_post_id(post_id): ...
     # THEN the resolver should raise a InvalidBatchResponse when processing the batch of queries
     with pytest.raises(InvalidBatchResponse):
         app.resolve(event, LambdaContext())
+
+
+def test_include_router_access_batch_current_event():
+    mock_event = load_event("appSyncBatchEvent.json")
+
+    # GIVEN An instance of AppSyncResolver, a Router instance, and a resolver function registered with the router
+    app = AppSyncResolver()
+    router = Router()
+
+    @router.batch_resolver(field_name="createSomething")
+    def get_user(event: List) -> List:
+        return [router.current_batch_event[0].identity.sub]
+
+    app.include_router(router)
+
+    # WHEN we resolve the event
+    ret = app.resolve(mock_event, {})
+
+    # THEN the resolver must be able to return a field in the batch_current_event
+    assert ret[0] == mock_event[0]["identity"]["sub"]
+
+
+def test_app_access_batch_current_event():
+    mock_event = load_event("appSyncBatchEvent.json")
+
+    # GIVEN An instance of AppSyncResolver and a resolver function registered with the app
+    app = AppSyncResolver()
+
+    @app.batch_resolver(field_name="createSomething")
+    def get_user(event: List) -> List:
+        return [app.current_batch_event[0].identity.sub]
+
+    # WHEN we resolve the event
+    ret = app.resolve(mock_event, {})
+
+    # THEN the resolver must be able to return a field in the batch_current_event
+    assert ret[0] == mock_event[0]["identity"]["sub"]

tests/functional/event_handler/required_dependencies/appsync/test_appsync_single_resolvers.py

@@ -251,3 +251,41 @@ def test_include_router_merges_context():
     app.include_router(router)
 
     assert app.context == router.context
+
+
+def test_include_router_access_current_event():
+    mock_event = load_event("appSyncDirectResolver.json")
+
+    # GIVEN An instance of AppSyncResolver, a Router instance, and a resolver function registered with the router
+    app = AppSyncResolver()
+    router = Router()
+
+    @router.resolver(field_name="createSomething")
+    def get_user(id_user: str) -> dict:
+        return router.current_event.identity.sub
+
+    app.include_router(router)
+
+    # WHEN we resolve the event
+    ret = app.resolve(mock_event, {})
+
+    # THEN the resolver must be able to return a field in the current_event
+    assert ret == mock_event["identity"]["sub"]
+
+
+def test_app_access_current_event():
+    # Check whether we can handle an example appsync direct resolver
+    mock_event = load_event("appSyncDirectResolver.json")
+
+    # GIVEN An instance of AppSyncResolver and a resolver function registered with the app
+    app = AppSyncResolver()
+
+    @app.resolver(field_name="createSomething")
+    def get_user(id_user: str) -> dict:
+        return app.current_event.identity.sub
+
+    # WHEN we resolve the event
+    ret = app.resolve(mock_event, {})
+
+    # THEN the resolver must be able to return a field in the current_event
+    assert ret == mock_event["identity"]["sub"]