Extend router to accept List of events. Add functional test

Author: Michal Ploski

aws_lambda_powertools/event_handler/appsync.py

@@ -1,10 +1,9 @@
 import logging
-from typing import Any, Callable, Optional, Type, TypeVar, List, Union
+from itertools import groupby
+from typing import Any, Callable, List, Optional, Type, TypeVar, Union
 
 from aws_lambda_powertools.utilities.data_classes import AppSyncResolverEvent
 from aws_lambda_powertools.utilities.typing import LambdaContext
-from itertools import groupby
-from operator import itemgetter
 
 logger = logging.getLogger(__name__)
 
@@ -155,6 +154,8 @@ def lambda_handler(event, context):
         """
         # Maintenance: revisit generics/overload to fix [attr-defined] in mypy usage
 
+        BaseRouter.lambda_context = context
+
         # If event is a list it means that AppSync sent batch request
         if isinstance(event, list):
             event_groups = [
@@ -164,15 +165,15 @@ def lambda_handler(event, context):
             if len(event_groups) > 1:
                 ValueError("batch with different field names. It shouldn't happen!")
 
-            BaseRouter.current_event = [data_model(event) for event in event_groups[0]["events"]]
-
-            resolver = self._get_resolver(BaseRouter.current_event[0].type_name, event_groups[0]["field_name"])
+            appconfig_events = [data_model(event) for event in event_groups[0]["events"]]
+            BaseRouter.current_event = appconfig_events
+            resolver = self._get_resolver(appconfig_events[0].type_name, event_groups[0]["field_name"])
             response = resolver()
         else:
-            BaseRouter.current_event = data_model(event)
-            resolver = self._get_resolver(BaseRouter.current_event.type_name, BaseRouter.current_event.field_name)
-            response = resolver(**BaseRouter.current_event.arguments)
-        BaseRouter.lambda_context = context
+            appconfig_event = data_model(event)
+            BaseRouter.current_event = appconfig_event
+            resolver = self._get_resolver(appconfig_event.type_name, appconfig_event.field_name)
+            response = resolver(**appconfig_event.arguments)
 
         self.clear_context()
 

tests/e2e/event_handler/handlers/appsync_handler.py

@@ -0,0 +1,100 @@
+from typing import List
+
+
+from aws_lambda_powertools.event_handler import AppSyncResolver
+from aws_lambda_powertools.utilities.typing import LambdaContext
+from pydantic import BaseModel
+
+app = AppSyncResolver()
+
+
+posts = {
+    "1": {
+        "id": "1",
+        "title": "First book",
+        "author": "Author1",
+        "url": "https://amazon.com/",
+        "content": "SAMPLE TEXT AUTHOR 1 SAMPLE TEXT AUTHOR 1 SAMPLE TEXT AUTHOR 1 SAMPLE TEXT AUTHOR 1 SAMPLE TEXT AUTHOR 1 SAMPLE TEXT AUTHOR 1",
+        "ups": "100",
+        "downs": "10",
+    },
+    "2": {
+        "id": "2",
+        "title": "Second book",
+        "author": "Author2",
+        "url": "https://amazon.com",
+        "content": "SAMPLE TEXT AUTHOR 2 SAMPLE TEXT AUTHOR 2 SAMPLE TEXT",
+        "ups": "100",
+        "downs": "10",
+    },
+    "3": {
+        "id": "3",
+        "title": "Third book",
+        "author": "Author3",
+        "url": None,
+        "content": None,
+        "ups": None,
+        "downs": None,
+    },
+    "4": {
+        "id": "4",
+        "title": "Fourth book",
+        "author": "Author4",
+        "url": "https://www.amazon.com/",
+        "content": "SAMPLE TEXT AUTHOR 4 SAMPLE TEXT AUTHOR 4 SAMPLE TEXT AUTHOR 4 SAMPLE TEXT AUTHOR 4 SAMPLE TEXT AUTHOR 4 SAMPLE TEXT AUTHOR 4 SAMPLE TEXT AUTHOR 4 SAMPLE TEXT AUTHOR 4",
+        "ups": "1000",
+        "downs": "0",
+    },
+    "5": {
+        "id": "5",
+        "title": "Fifth book",
+        "author": "Author5",
+        "url": "https://www.amazon.com/",
+        "content": "SAMPLE TEXT AUTHOR 5 SAMPLE TEXT AUTHOR 5 SAMPLE TEXT AUTHOR 5 SAMPLE TEXT AUTHOR 5 SAMPLE TEXT",
+        "ups": "50",
+        "downs": "0",
+    },
+}
+
+posts_related = {
+    "1": [posts["4"]],
+    "2": [posts["3"], posts["5"]],
+    "3": [posts["2"], posts["1"]],
+    "4": [posts["2"], posts["1"]],
+    "5": [],
+}
+
+
+class Post(BaseModel):
+    id: str
+    author: str
+    title: str
+    url: str
+    content: str
+    ups: str
+    downs: str
+
+
+@app.resolver(type_name="Query", field_name="getPost")
+def get_post(id: str = "") -> dict:
+    post = Post(**posts[id]).dict()
+    return post
+
+
+@app.resolver(type_name="Query", field_name="allPosts")
+def all_posts() -> List[dict]:
+    parsed_posts = [post for post in posts.values()]
+    return parsed_posts
+
+
+@app.resolver(type_name="Post", field_name="relatedPosts")
+def related_posts() -> List[dict]:
+    posts = []
+    for resolver_event in app.current_event:
+        if resolver_event.source:
+            posts.append(posts_related[resolver_event.source["id"]])
+    return posts
+
+
+def lambda_handler(event, context: LambdaContext) -> dict:
+    return app.resolve(event, context)

tests/functional/event_handler/test_appsync.py

@@ -164,6 +164,59 @@ def create_something(id: str):  # noqa AA03 VNE003
     assert app.current_event.country_viewer == "US"
 
 
+def test_resolve_batch_processing():
+    event = [
+        {
+            "typeName": "Query",
+            "info": {
+                "fieldName": "listLocations",
+                "parentTypeName": "Post",
+            },
+            "fieldName": "listLocations",
+            "arguments": {},
+            "source": {
+                "id": "1",
+            },
+        },
+        {
+            "typeName": "Query",
+            "info": {
+                "fieldName": "listLocations",
+                "parentTypeName": "Post",
+            },
+            "fieldName": "listLocations",
+            "arguments": {},
+            "source": {
+                "id": "2",
+            },
+        },
+        {
+            "typeName": "Query",
+            "info": {
+                "fieldName": "listLocations",
+                "parentTypeName": "Post",
+            },
+            "fieldName": "listLocations",
+            "arguments": {},
+            "source": {
+                "id": "3",
+            },
+        },
+    ]
+
+    app = AppSyncResolver()
+
+    @app.resolver(field_name="listLocations")
+    def create_something():  # noqa AA03 VNE003
+        return [event.source["id"] for event in app.current_event]
+
+    # Call the implicit handler
+    result = app.resolve(event, LambdaContext())
+    assert result == ["1", "2", "3"]
+
+    assert len(app.current_event) == len(event)
+
+
 def test_resolver_include_resolver():
     # GIVEN
     app = AppSyncResolver()