fix(parser): make etag optional field on S3 notification events (#4173)

Co-authored-by: Leandro Damascena <lcdama@amazon.pt>
Co-authored-by: Heitor Lessa <lessa@amazon.com>

Author: 3 people

aws_lambda_powertools/utilities/data_classes/s3_event.py

@@ -32,14 +32,14 @@ def key(self) -> str:
         return unquote_plus(self["key"])
 
     @property
-    def size(self) -> str:
-        """Object size"""
-        return self["size"]
+    def size(self) -> Optional[int]:
+        """Object size. Object deletion event doesn't contain size."""
+        return self.get("size")
 
     @property
     def etag(self) -> str:
-        """Object etag"""
-        return self["etag"]
+        """Object etag. Object deletion event doesn't contain etag; we default to empty string"""
+        return self.get("etag", "")  # type: ignore[return-value]  # false positive
 
     @property
     def version_id(self) -> str:
@@ -178,8 +178,8 @@ def size(self) -> int:
 
     @property
     def etag(self) -> str:
-        """object eTag"""
-        return self["s3"]["object"]["eTag"]
+        """Object eTag. Object deletion event doesn't contain eTag; we default to empty string"""
+        return self["s3"]["object"].get("eTag", "")
 
     @property
     def version_id(self) -> Optional[str]:

aws_lambda_powertools/utilities/parser/models/s3.py

@@ -61,7 +61,7 @@ class S3Message(BaseModel):
 class S3EventNotificationObjectModel(BaseModel):
     key: str
     size: Optional[NonNegativeFloat] = None
-    etag: str
+    etag: str = Field(default="")
     version_id: str = Field(None, alias="version-id")
     sequencer: Optional[str] = None
 

tests/events/s3EventBridgeNotificationObjectDeletedEvent.json

@@ -16,8 +16,6 @@
     },
     "object": {
         "key": "IMG_m7fzo3.jpg",
-        "size": 184662,
-        "etag": "4e68adba0abe2dc8653dc3354e14c01d",
         "sequencer": "006408CAD69598B05E"
     },
     "request-id": "0BH729840619AG5K",
@@ -26,4 +24,4 @@
     "reason": "DeleteObject",
     "deletion-type": "Delete Marker Created"
   }
-}
+}

tests/unit/data_classes/test_s3_eventbridge_notification.py

@@ -26,10 +26,10 @@ def test_s3_eventbridge_notification_detail_parsed(raw_event: Dict):
     assert parsed_event.detail.deletion_type == raw_event["detail"].get("deletion-type")
     assert parsed_event.detail.destination_access_tier == raw_event["detail"].get("destination-access-tier")
     assert parsed_event.detail.destination_storage_class == raw_event["detail"].get("destination-storage-class")
-    assert parsed_event.detail.object.etag == raw_event["detail"]["object"]["etag"]
+    assert parsed_event.detail.object.etag == raw_event["detail"]["object"].get("etag", "")
     assert parsed_event.detail.object.key == raw_event["detail"]["object"]["key"]
     assert parsed_event.detail.object.sequencer == raw_event["detail"]["object"]["sequencer"]
-    assert parsed_event.detail.object.size == raw_event["detail"]["object"]["size"]
+    assert parsed_event.detail.object.size == raw_event["detail"]["object"].get("size")
     assert parsed_event.detail.reason == raw_event["detail"].get("reason")
     assert parsed_event.detail.version == raw_event["detail"].get("version")
     assert parsed_event.detail.request_id == raw_event["detail"]["request-id"]

tests/unit/parser/test_s3_notification.py

@@ -52,8 +52,8 @@ def test_s3_eventbridge_notification_object_deleted_event():
     assert model.detail.version == raw_event["detail"]["version"]
     assert model.detail.bucket.name == raw_event["detail"]["bucket"]["name"]
     assert model.detail.object.key == raw_event["detail"]["object"]["key"]
-    assert model.detail.object.size == raw_event["detail"]["object"]["size"]
-    assert model.detail.object.etag == raw_event["detail"]["object"]["etag"]
+    assert model.detail.object.size == raw_event["detail"]["object"].get("size")
+    assert model.detail.object.etag == raw_event["detail"]["object"].get("etag", "")
     assert model.detail.object.sequencer == raw_event["detail"]["object"]["sequencer"]
     assert model.detail.request_id == raw_event["detail"]["request-id"]
     assert model.detail.requester == raw_event["detail"]["requester"]