Feature: Add sns notification support to Parser utility #206

Author: Ran Isenberg

aws_lambda_powertools/utilities/parser/envelopes/__init__.py

@@ -1,6 +1,7 @@
 from .base import BaseEnvelope
 from .dynamodb import DynamoDBStreamEnvelope
 from .event_bridge import EventBridgeEnvelope
+from .sns import SnsEnvelope
 from .sqs import SqsEnvelope
 
-__all__ = ["DynamoDBStreamEnvelope", "EventBridgeEnvelope", "SqsEnvelope", "BaseEnvelope"]
+__all__ = ["DynamoDBStreamEnvelope", "EventBridgeEnvelope", "SnsEnvelope", "SqsEnvelope", "BaseEnvelope"]

aws_lambda_powertools/utilities/parser/envelopes/sns.py

@@ -0,0 +1,42 @@
+import logging
+from typing import Any, Dict, List, Optional, Union
+
+from ..models import SnsModel
+from ..types import Model
+from .base import BaseEnvelope
+
+logger = logging.getLogger(__name__)
+
+
+class SnsEnvelope(BaseEnvelope):
+    """SNS Envelope to extract array of Records
+
+    The record's body parameter is a string, though it can also be a JSON encoded string.
+    Regardless of its type it'll be parsed into a BaseModel object.
+
+    Note: Records will be parsed the same way so if model is str,
+    all items in the list will be parsed as str and npt as JSON (and vice versa)
+    """
+
+    def parse(self, data: Optional[Union[Dict[str, Any], Any]], model: Model) -> List[Optional[Model]]:
+        """Parses records found with model provided
+
+        Parameters
+        ----------
+        data : Dict
+            Lambda event to be parsed
+        model : Model
+            Data model provided to parse after extracting data using envelope
+
+        Returns
+        -------
+        List
+            List of records parsed with model provided
+        """
+        logger.debug(f"Parsing incoming data with SNS model {SnsModel}")
+        parsed_envelope = SnsModel.parse_obj(data)
+        output = []
+        logger.debug(f"Parsing SNS records in `body` with {model}")
+        for record in parsed_envelope.Records:
+            output.append(self._parse(data=record.Sns.Message, model=model))
+        return output

aws_lambda_powertools/utilities/parser/models/__init__.py

@@ -1,12 +1,16 @@
 from .dynamodb import DynamoDBStreamChangedRecordModel, DynamoDBStreamModel, DynamoDBStreamRecordModel
 from .event_bridge import EventBridgeModel
+from .sns import SnsModel, SnsNotificationModel, SnsRecordModel
 from .sqs import SqsModel, SqsRecordModel
 
 __all__ = [
     "DynamoDBStreamModel",
     "EventBridgeModel",
     "DynamoDBStreamChangedRecordModel",
     "DynamoDBStreamRecordModel",
+    "SnsModel",
+    "SnsNotificationModel",
+    "SnsRecordModel",
     "SqsModel",
     "SqsRecordModel",
 ]

aws_lambda_powertools/utilities/parser/models/sns.py

@@ -0,0 +1,36 @@
+from datetime import datetime
+from typing import Dict, List, Optional
+
+from pydantic import BaseModel
+from pydantic.networks import HttpUrl
+from typing_extensions import Literal
+
+
+class SqsMsgAttributeModel(BaseModel):
+    Type: str
+    Value: str
+
+
+class SnsNotificationModel(BaseModel):
+    Subject: Optional[str]
+    TopicArn: str
+    UnsubscribeUrl: HttpUrl
+    Type: Literal["Notification"]
+    MessageAttributes: Dict[str, SqsMsgAttributeModel]
+    Message: str
+    MessageId: str
+    SigningCertUrl: HttpUrl
+    Signature: str
+    Timestamp: datetime
+    SignatureVersion: str
+
+
+class SnsRecordModel(BaseModel):
+    EventSource: Literal["aws:sns"]
+    EventVersion: str
+    EventSubscriptionArn: str
+    Sns: SnsNotificationModel
+
+
+class SnsModel(BaseModel):
+    Records: List[SnsRecordModel]

tests/events/snsEvent.json

@@ -8,7 +8,7 @@
         "SignatureVersion": "1",
         "Timestamp": "2019-01-02T12:45:07.000Z",
         "Signature": "tcc6faL2yUC6dgZdmrwh1Y4cGa/ebXEkAi6RibDsvpi+tE/1+82j...65r==",
-        "SigningCertUrl": "https://sns.us-east-2.amazonaws.com/SimpleNotificat ...",
+        "SigningCertUrl": "https://sns.us-east-2.amazonaws.com/SimpleNotification",
         "MessageId": "95df01b4-ee98-5cb9-9903-4c221d41eb5e",
         "Message": "Hello from SNS!",
         "MessageAttributes": {
@@ -22,10 +22,10 @@
           }
         },
         "Type": "Notification",
-        "UnsubscribeUrl": "https://sns.us-east-2.amazonaws.com/?Action=Unsubscri ...",
+        "UnsubscribeUrl": "https://sns.us-east-2.amazonaws.com/?Action=Unsubscribe",
         "TopicArn": "arn:aws:sns:us-east-2:123456789012:sns-lambda",
         "Subject": "TestInvoke"
       }
     }
   ]
-}
+}

tests/functional/parser/schemas.py

@@ -8,6 +8,9 @@
     DynamoDBStreamModel,
     DynamoDBStreamRecordModel,
     EventBridgeModel,
+    SnsModel,
+    SnsNotificationModel,
+    SnsRecordModel,
     SqsModel,
     SqsRecordModel,
 )
@@ -51,3 +54,20 @@ class MyAdvancedSqsRecordModel(SqsRecordModel):
 
 class MyAdvancedSqsBusiness(SqsModel):
     Records: List[MyAdvancedSqsRecordModel]
+
+
+class MySnsBusiness(BaseModel):
+    message: str
+    username: str
+
+
+class MySnsNotificationModel(SnsNotificationModel):
+    Message: str
+
+
+class MyAdvancedSnsRecordModel(SnsRecordModel):
+    Sns: MySnsNotificationModel
+
+
+class MyAdvancedSnsBusiness(SnsModel):
+    Records: List[MyAdvancedSnsRecordModel]

tests/functional/parser/test_sns.py

@@ -0,0 +1,93 @@
+from typing import Any, List
+
+import pytest
+
+from aws_lambda_powertools.utilities.parser import ValidationError, envelopes, event_parser
+from aws_lambda_powertools.utilities.typing import LambdaContext
+from tests.functional.parser.schemas import MyAdvancedSnsBusiness, MySnsBusiness
+from tests.functional.parser.utils import load_event
+from tests.functional.validator.conftest import sns_event  # noqa: F401
+
+
+@event_parser(model=MySnsBusiness, envelope=envelopes.SnsEnvelope)
+def handle_sns_json_body(event: List[MySnsBusiness], _: LambdaContext):
+    assert len(event) == 1
+    assert event[0].message == "hello world"
+    assert event[0].username == "lessa"
+
+
+def test_handle_sns_trigger_event_json_body(sns_event):  # noqa: F811
+    handle_sns_json_body(sns_event, LambdaContext())
+
+
+def test_validate_event_does_not_conform_with_model():
+    event: Any = {"invalid": "event"}
+
+    with pytest.raises(ValidationError):
+        handle_sns_json_body(event, LambdaContext())
+
+
+def test_validate_event_does_not_conform_user_json_string_with_model():
+    event: Any = {
+        "Records": [
+            {
+                "EventVersion": "1.0",
+                "EventSubscriptionArn": "arn:aws:sns:us-east-2:123456789012:sns-la ...",
+                "EventSource": "aws:sns",
+                "Sns": {
+                    "SignatureVersion": "1",
+                    "Timestamp": "2019-01-02T12:45:07.000Z",
+                    "Signature": "tcc6faL2yUC6dgZdmrwh1Y4cGa/ebXEkAi6RibDsvpi+tE/1+82j...65r==",
+                    "SigningCertUrl": "https://sns.us-east-2.amazonaws.com/SimpleNotificat ...",
+                    "MessageId": "95df01b4-ee98-5cb9-9903-4c221d41eb5e",
+                    "Message": "not a valid JSON!",
+                    "MessageAttributes": {"Test": {"Type": "String", "Value": "TestString"}},
+                    "Type": "Notification",
+                    "UnsubscribeUrl": "https://sns.us-east-2.amazonaws.com/?Action=Unsubscri ...",
+                    "TopicArn": "arn:aws:sns:us-east-2:123456789012:sns-lambda",
+                    "Subject": "TestInvoke",
+                },
+            }
+        ]
+    }
+
+    with pytest.raises(ValidationError):
+        handle_sns_json_body(event, LambdaContext())
+
+
+@event_parser(model=MyAdvancedSnsBusiness)
+def handle_sns_no_envelope(event: MyAdvancedSnsBusiness, _: LambdaContext):
+    records = event.Records
+    record = records[0]
+
+    assert len(records) == 1
+    assert record.EventVersion == "1.0"
+    assert record.EventSubscriptionArn == "arn:aws:sns:us-east-2:123456789012:sns-la ..."
+    assert record.EventSource == "aws:sns"
+    assert record.Sns.Type == "Notification"
+    assert record.Sns.UnsubscribeUrl.scheme == "https"
+    assert record.Sns.UnsubscribeUrl.host == "sns.us-east-2.amazonaws.com"
+    assert record.Sns.UnsubscribeUrl.query == "Action=Unsubscribe"
+    assert record.Sns.TopicArn == "arn:aws:sns:us-east-2:123456789012:sns-lambda"
+    assert record.Sns.Subject == "TestInvoke"
+    assert record.Sns.SignatureVersion == "1"
+    convert_time = int(round(record.Sns.Timestamp.timestamp() * 1000))
+    assert convert_time == 1546433107000
+    assert record.Sns.Signature == "tcc6faL2yUC6dgZdmrwh1Y4cGa/ebXEkAi6RibDsvpi+tE/1+82j...65r=="
+    assert record.Sns.SigningCertUrl.host == "sns.us-east-2.amazonaws.com"
+    assert record.Sns.SigningCertUrl.scheme == "https"
+    assert record.Sns.SigningCertUrl.host == "sns.us-east-2.amazonaws.com"
+    assert record.Sns.SigningCertUrl.path == "/SimpleNotification"
+    assert record.Sns.MessageId == "95df01b4-ee98-5cb9-9903-4c221d41eb5e"
+    assert record.Sns.Message == "Hello from SNS!"
+    attrib_dict = record.Sns.MessageAttributes
+    assert len(attrib_dict) == 2
+    assert attrib_dict["Test"].Type == "String"
+    assert attrib_dict["Test"].Value == "TestString"
+    assert attrib_dict["TestBinary"].Type == "Binary"
+    assert attrib_dict["TestBinary"].Value == "TestBinary"
+
+
+def test_handle_sns_trigger_event_no_envelope():
+    event_dict = load_event("snsEvent.json")
+    handle_sns_no_envelope(event_dict, LambdaContext())

tests/functional/test_lambda_trigger_events.py

@@ -487,15 +487,15 @@ def test_sns_trigger_event():
     assert sns.signature_version == "1"
     assert sns.timestamp == "2019-01-02T12:45:07.000Z"
     assert sns.signature == "tcc6faL2yUC6dgZdmrwh1Y4cGa/ebXEkAi6RibDsvpi+tE/1+82j...65r=="
-    assert sns.signing_cert_url == "https://sns.us-east-2.amazonaws.com/SimpleNotificat ..."
+    assert sns.signing_cert_url == "https://sns.us-east-2.amazonaws.com/SimpleNotification"
     assert sns.message_id == "95df01b4-ee98-5cb9-9903-4c221d41eb5e"
     assert sns.message == "Hello from SNS!"
     message_attributes = sns.message_attributes
     test_message_attribute = message_attributes["Test"]
     assert test_message_attribute.get_type == "String"
     assert test_message_attribute.value == "TestString"
     assert sns.get_type == "Notification"
-    assert sns.unsubscribe_url == "https://sns.us-east-2.amazonaws.com/?Action=Unsubscri ..."
+    assert sns.unsubscribe_url == "https://sns.us-east-2.amazonaws.com/?Action=Unsubscribe"
     assert sns.topic_arn == "arn:aws:sns:us-east-2:123456789012:sns-lambda"
     assert sns.subject == "TestInvoke"
     assert event.record._data == event["Records"][0]

tests/functional/validator/conftest.py

@@ -195,8 +195,8 @@ def sns_event():
                     "Timestamp": "1970-01-01T00:00:00.000Z",
                     "SignatureVersion": "1",
                     "Signature": "EXAMPLE",
-                    "SigningCertUrl": "EXAMPLE",
-                    "UnsubscribeUrl": "EXAMPLE",
+                    "SigningCertUrl": "https://www.example.com",
+                    "UnsubscribeUrl": "https://www.example.com",
                     "MessageAttributes": {
                         "Test": {"Type": "String", "Value": "TestString"},
                         "TestBinary": {"Type": "Binary", "Value": "TestBinary"},