feat(data-classes): decorator to instantiate data_classes and docs updates (#442)

Author: Michael Brewer

aws_lambda_powertools/utilities/data_classes/__init__.py

@@ -10,6 +10,7 @@
 from .connect_contact_flow_event import ConnectContactFlowEvent
 from .dynamo_db_stream_event import DynamoDBStreamEvent
 from .event_bridge_event import EventBridgeEvent
+from .event_source import event_source
 from .kinesis_stream_event import KinesisStreamEvent
 from .s3_event import S3Event
 from .ses_event import SESEvent
@@ -31,4 +32,5 @@
     "SESEvent",
     "SNSEvent",
     "SQSEvent",
+    "event_source",
 ]

aws_lambda_powertools/utilities/data_classes/alb_event.py

@@ -6,6 +6,7 @@
 class ALBEventRequestContext(DictWrapper):
     @property
     def elb_target_group_arn(self) -> str:
+        """Target group arn for your Lambda function"""
         return self["requestContext"]["elb"]["targetGroupArn"]
 
 
@@ -15,6 +16,7 @@ class ALBEvent(BaseProxyEvent):
     Documentation:
     --------------
     - https://docs.aws.amazon.com/lambda/latest/dg/services-alb.html
+    - https://docs.aws.amazon.com/elasticloadbalancing/latest/application/lambda-functions.html
     """
 
     @property

aws_lambda_powertools/utilities/data_classes/event_source.py

@@ -0,0 +1,39 @@
+from typing import Any, Callable, Dict, Type
+
+from aws_lambda_powertools.middleware_factory import lambda_handler_decorator
+from aws_lambda_powertools.utilities.data_classes.common import DictWrapper
+from aws_lambda_powertools.utilities.typing import LambdaContext
+
+
+@lambda_handler_decorator
+def event_source(
+    handler: Callable[[Any, LambdaContext], Any],
+    event: Dict[str, Any],
+    context: LambdaContext,
+    data_class: Type[DictWrapper],
+):
+    """Middleware to create an instance of the passed in event source data class
+
+    Parameters
+    ----------
+    handler: Callable
+        Lambda's handler
+    event: Dict
+        Lambda's Event
+    context: Dict
+        Lambda's Context
+    data_class: Type[DictWrapper]
+        Data class type to instantiate
+
+    Example
+    --------
+
+    **Sample usage**
+
+        from aws_lambda_powertools.utilities.data_classes import S3Event, event_source
+
+        @event_source(data_class=S3Event)
+        def handler(event: S3Event, context):
+             return {"key": event.object_key}
+    """
+    return handler(data_class(event), context)

aws_lambda_powertools/utilities/idempotency/persistence/base.py

@@ -224,6 +224,7 @@ def _generate_hash(self, data: Any) -> str:
             Hashed representation of the provided data
 
         """
+        data = getattr(data, "raw_event", data)  # could be a data class depending on decorator order
         hashed_data = self.hash_function(json.dumps(data, cls=Encoder).encode())
         return hashed_data.hexdigest()