Add validate function, fix flake8 issues

Author: Ran Isenberg

aws_lambda_powertools/utilities/validation/__init__.py

@@ -1,6 +1,14 @@
 """Validation utility
 """
 from .envelopes import DynamoDBEnvelope, EventBridgeEnvelope, SnsEnvelope, SqsEnvelope, UserEnvelope
-from .validator import validator
+from .validator import validate, validator
 
-__all__ = ["UserEnvelope", "DynamoDBEnvelope", "EventBridgeEnvelope", "SnsEnvelope", "SqsEnvelope", "validator"]
+__all__ = [
+    "UserEnvelope",
+    "DynamoDBEnvelope",
+    "EventBridgeEnvelope",
+    "SnsEnvelope",
+    "SqsEnvelope",
+    "validate",
+    "validator",
+]

aws_lambda_powertools/utilities/validation/envelopes/__init__.py

@@ -4,11 +4,4 @@
 from .sns import SnsEnvelope
 from .sqs import SqsEnvelope
 
-
-__all__ = [
-    "UserEnvelope",
-    "DynamoDBEnvelope",
-    "EventBridgeEnvelope",
-    "SqsEnvelope",
-    "SnsEnvelope"
-]
+__all__ = ["UserEnvelope", "DynamoDBEnvelope", "EventBridgeEnvelope", "SqsEnvelope", "SnsEnvelope"]

aws_lambda_powertools/utilities/validation/envelopes/event_bridge.py

@@ -6,7 +6,6 @@
 from aws_lambda_powertools.utilities.validation.envelopes.base import BaseEnvelope
 from aws_lambda_powertools.utilities.validation.schemas import EventBridgeSchema
 
-
 logger = logging.getLogger(__name__)
 
 

aws_lambda_powertools/utilities/validation/envelopes/sns.py

@@ -12,9 +12,8 @@
 class SnsEnvelope(BaseEnvelope):
     def parse(self, event: Dict[str, Any], inbound_schema_model: BaseModel) -> Any:
         try:
-            parsed_envelope = SnsSchema(**event)
+            SnsSchema(**event)
         except (ValidationError, TypeError):
             logger.exception("Validation exception received from input sqs event")
             raise
-        ## TODO
         return None

aws_lambda_powertools/utilities/validation/schemas/sqs.py

@@ -57,4 +57,4 @@ class SqsRecordSchema(BaseModel):
 
 
 class SqsSchema(BaseModel):
-    Records: List[SqsRecordSchema]
+    Records: List[SqsRecordSchema]

aws_lambda_powertools/utilities/validation/validator.py

@@ -9,6 +9,16 @@
 logger = logging.getLogger(__name__)
 
 
+def validate(
+    event: Dict[str, Any], schema_model: BaseModel, envelope: BaseEnvelope, return_parsed_event: bool = False
+) -> Any:
+    logger.debug("Validating schema")
+    parsed_event_model = envelope.parse(event=event, inbound_schema_model=schema_model)
+    if return_parsed_event:
+        return parsed_event_model
+    return None
+
+
 @lambda_handler_decorator
 def validator(
     handler: Callable[[Dict, Any], Any],

tests/functional/test_validator.py

@@ -1,4 +1,3 @@
-import io
 from http import HTTPStatus
 from typing import Any, Dict, Optional
 
@@ -12,10 +11,79 @@
     EventBridgeEnvelope,
     SqsEnvelope,
     UserEnvelope,
-    validator
+    validate,
+    validator,
 )
 
 
+class MyMessage(BaseModel):
+    message: str
+    messageId: int
+
+
+def test_validate_function():
+    eventbridge_event = {
+        "version": "0",
+        "id": "553961c5-5017-5763-6f21-f88d5f5f4b05",
+        "detail-type": "my func stream event json",
+        "source": "arn:aws:lambda:eu-west-1:88888888:function:my_func",
+        "account": "88888888",
+        "time": "2020-02-11T08:18:09Z",
+        "region": "eu-west-1",
+        "resources": ["arn:aws:dynamodb:eu-west-1:88888888:table/stream/2020-02"],
+        "detail": {"message": "hello", "messageId": 8},
+    }
+    parsed_event = validate(eventbridge_event, MyMessage, EventBridgeEnvelope(), True)
+    assert parsed_event.dict() == {"message": "hello", "messageId": 8}
+
+
+def test_validate_function_no_return_value():
+    eventbridge_event = {
+        "version": "0",
+        "id": "553961c5-5017-5763-6f21-f88d5f5f4b05",
+        "detail-type": "my func stream event json",
+        "source": "arn:aws:lambda:eu-west-1:88888888:function:my_func",
+        "account": "88888888",
+        "time": "2020-02-11T08:18:09Z",
+        "region": "eu-west-1",
+        "resources": ["arn:aws:dynamodb:eu-west-1:88888888:table/stream/2020-02"],
+        "detail": {"message": "hello", "messageId": 8},
+    }
+    parsed_event = validate(eventbridge_event, MyMessage, EventBridgeEnvelope())
+    assert parsed_event is None
+
+
+def test_validate_function_fail_envelope():
+    eventbridge_event = {
+        "version": "0",
+        "id": "553961c5-5017-5763-6f21-f88d5f5f4b05",
+        "detail-type": "my func stream event json",
+        "source": "arn:aws:lambda:eu-west-1:88888888:function:my_func",
+        "time": "2020-02-11T08:18:09Z",
+        "region": "eu-west-1",
+        "resources": ["arn:aws:dynamodb:eu-west-1:88888888:table/stream/2020-02"],
+        "detail": {"message": "hello", "messageId": 8},
+    }
+    with pytest.raises(ValidationError):
+        validate(eventbridge_event, MyMessage, EventBridgeEnvelope())
+
+
+def test_validate_function_fail_user_schema():
+    eventbridge_event = {
+        "version": "0",
+        "id": "553961c5-5017-5763-6f21-f88d5f5f4b05",
+        "detail-type": "my func stream event json",
+        "source": "arn:aws:lambda:eu-west-1:88888888:function:my_func",
+        "account": "88888888",
+        "time": "2020-02-11T08:18:09Z",
+        "region": "eu-west-1",
+        "resources": ["arn:aws:dynamodb:eu-west-1:88888888:table/stream/2020-02"],
+        "detail": {"mess11age": "hello", "messageId": 8},
+    }
+    with pytest.raises(ValidationError):
+        validate(eventbridge_event, MyMessage, EventBridgeEnvelope())
+
+
 class OutboundSchema(BaseModel):
     response_code: HTTPStatus
     message: str
@@ -25,11 +93,6 @@ class InboundSchema(BaseModel):
     greeting: str
 
 
-@pytest.fixture
-def stdout():
-    return io.StringIO()
-
-
 @validator(inbound_schema_model=InboundSchema, outbound_schema_model=OutboundSchema, envelope=UserEnvelope())
 def my_handler(event: Dict[str, Any], context: LambdaContext) -> Dict[str, Optional[Any]]:
     assert event["custom"]
@@ -58,11 +121,6 @@ def test_fail_inbound_validation():
         my_handler({"this_fails": "hello"}, LambdaContext())
 
 
-class MyMessage(BaseModel):
-    message: str
-    messageId: int
-
-
 @validator(inbound_schema_model=MyMessage, outbound_schema_model=OutboundSchema, envelope=DynamoDBEnvelope())
 def dynamodb_handler(event: Dict[str, Any], context: LambdaContext) -> Dict[str, Optional[Any]]:
     assert event["custom"]