move get dsm context logic into lambda layer code

Author: michael-zhao459

datadog_lambda/dsm.py

@@ -1,21 +1,33 @@
+import json
+import base64
+
+from ddtrace.internal.logger import get_logger
 from datadog_lambda import logger
 from datadog_lambda.trigger import EventTypes
 
+log = get_logger(__name__)
 
-def set_dsm_context(event, event_source):
 
+def set_dsm_context(event, event_source):
     if event_source.equals(EventTypes.SQS):
         _dsm_set_sqs_context(event)
 
 
-def _dsm_set_sqs_context(event):
+def _dsm_set_context_helper(
+    event, service_type, arn_extractor, payload_size_calculator
+):
+    """
+    Common helper function for setting DSM context.
+
+    Args:
+        event: The Lambda event containing records
+        service_type: The service type string (example: sqs', 'sns')
+        arn_extractor: Function to extract the ARN from the record
+        payload_size_calculator: Function to calculate payload size
+    """
     from datadog_lambda.wrapper import format_err_with_traceback
     from ddtrace.internal.datastreams import data_streams_processor
     from ddtrace.internal.datastreams.processor import DsmPathwayCodec
-    from ddtrace.internal.datastreams.botocore import (
-        get_datastreams_context,
-        calculate_sqs_payload_size,
-    )
 
     records = event.get("Records")
     if records is None:
@@ -24,15 +36,88 @@ def _dsm_set_sqs_context(event):
 
     for record in records:
         try:
-            queue_arn = record.get("eventSourceARN", "")
-
-            contextjson = get_datastreams_context(record)
-            payload_size = calculate_sqs_payload_size(record)
+            arn = arn_extractor(record)
+            context_json = _get_dsm_context_from_lambda(record)
+            payload_size = payload_size_calculator(record, context_json)
 
-            ctx = DsmPathwayCodec.decode(contextjson, processor)
+            ctx = DsmPathwayCodec.decode(context_json, processor)
             ctx.set_checkpoint(
-                ["direction:in", f"topic:{queue_arn}", "type:sqs"],
+                ["direction:in", f"topic:{arn}", f"type:{service_type}"],
                 payload_size=payload_size,
             )
         except Exception as e:
             logger.error(format_err_with_traceback(e))
+
+
+def _dsm_set_sqs_context(event):
+    from ddtrace.internal.datastreams.botocore import calculate_sqs_payload_size
+
+    def sqs_payload_calculator(record, context_json):
+        return calculate_sqs_payload_size(record)
+
+    def sqs_arn_extractor(record):
+        return record.get("eventSourceARN", "")
+
+    _dsm_set_context_helper(event, "sqs", sqs_arn_extractor, sqs_payload_calculator)
+
+
+def _get_dsm_context_from_lambda(message):
+    """
+    Lambda-specific message formats:
+        - message.messageAttributes._datadog.stringValue (SQS -> lambda)
+        - message.Sns.MessageAttributes._datadog.Value.decode() (SNS -> lambda)
+        - message.messageAttributes._datadog.binaryValue.decode() (SNS -> SQS -> lambda, raw)
+        - message.body.MessageAttributes._datadog.Value.decode() (SNS -> SQS -> lambda)
+        - message.kinesis.data.decode()._datadog (Kinesis -> lambda)
+    """
+    context_json = None
+    message_body = message
+
+    if "kinesis" in message:
+        try:
+            kinesis_data = json.loads(
+                base64.b64decode(message["kinesis"]["data"]).decode()
+            )
+            return kinesis_data.get("_datadog")
+        except (ValueError, TypeError, KeyError):
+            log.debug("Unable to parse kinesis data for lambda message")
+            return None
+    elif "Sns" in message:
+        message_body = message["Sns"]
+    else:
+        try:
+            body = message.get("body")
+            if body:
+                message_body = json.loads(body)
+        except (ValueError, TypeError):
+            log.debug("Unable to parse lambda message body as JSON, treat as non-json")
+
+    message_attributes = message_body.get("MessageAttributes") or message_body.get(
+        "messageAttributes"
+    )
+    if not message_attributes:
+        log.debug("DataStreams skipped lambda message: %r", message)
+        return None
+
+    if "_datadog" not in message_attributes:
+        log.debug("DataStreams skipped lambda message: %r", message)
+        return None
+
+    datadog_attr = message_attributes["_datadog"]
+
+    if message_body.get("Type") == "Notification":
+        # SNS -> lambda notification
+        if datadog_attr.get("Type") == "Binary":
+            context_json = json.loads(base64.b64decode(datadog_attr["Value"]).decode())
+    elif "stringValue" in datadog_attr:
+        # SQS -> lambda
+        context_json = json.loads(datadog_attr["stringValue"])
+    elif "binaryValue" in datadog_attr:
+        # SNS -> SQS -> lambda, raw message delivery
+        context_json = json.loads(
+            base64.b64decode(datadog_attr["binaryValue"]).decode()
+        )
+    else:
+        log.debug("DataStreams did not handle lambda message: %r", message)
+
+    return context_json

tests/test_dsm.py

@@ -1,11 +1,17 @@
 import unittest
+import json
+import base64
 from unittest.mock import patch, MagicMock
 
-from datadog_lambda.dsm import set_dsm_context, _dsm_set_sqs_context
+from datadog_lambda.dsm import (
+    set_dsm_context,
+    _dsm_set_sqs_context,
+    _get_dsm_context_from_lambda,
+)
 from datadog_lambda.trigger import EventTypes, _EventSource
 
 
-class TestDsmSQSContext(unittest.TestCase):
+class TestDSMContext(unittest.TestCase):
     def setUp(self):
         patcher = patch("datadog_lambda.dsm._dsm_set_sqs_context")
         self.mock_dsm_set_sqs_context = patcher.start()
@@ -110,3 +116,230 @@ def test_sqs_multiple_records_process_each_record(self):
             self.assertIn(f"topic:{expected_arns[i]}", tags)
             self.assertIn("type:sqs", tags)
             self.assertEqual(kwargs["payload_size"], 100)
+
+
+class TestGetDSMContext(unittest.TestCase):
+    def test_sqs_to_lambda_string_value_format(self):
+        """Test format: message.messageAttributes._datadog.stringValue (SQS -> lambda)"""
+        trace_context = {
+            "x-datadog-trace-id": "789123456",
+            "x-datadog-parent-id": "321987654",
+            "dd-pathway-ctx": "test-pathway-ctx",
+        }
+
+        lambda_record = {
+            "messageId": "059f36b4-87a3-44ab-83d2-661975830a7d",
+            "receiptHandle": "AQEBwJnKyrHigUMZj6rYigCgxlaS3SLy0a...",
+            "body": "Test message.",
+            "attributes": {
+                "ApproximateReceiveCount": "1",
+                "SentTimestamp": "1545082649183",
+                "SenderId": "AIDAIENQZJOLO23YVJ4VO",
+                "ApproximateFirstReceiveTimestamp": "1545082649185",
+            },
+            "messageAttributes": {
+                "_datadog": {
+                    "stringValue": json.dumps(trace_context),
+                    "stringListValues": [],
+                    "binaryListValues": [],
+                    "dataType": "String",
+                },
+                "myAttribute": {
+                    "stringValue": "myValue",
+                    "stringListValues": [],
+                    "binaryListValues": [],
+                    "dataType": "String",
+                },
+            },
+            "md5OfBody": "e4e68fb7bd0e697a0ae8f1bb342846b3",
+            "eventSource": "aws:sqs",
+            "eventSourceARN": "arn:aws:sqs:us-east-2:123456789012:my-queue",
+            "awsRegion": "us-east-2",
+        }
+
+        result = _get_dsm_context_from_lambda(lambda_record)
+
+        assert result is not None
+        assert result == trace_context
+        assert result["x-datadog-trace-id"] == "789123456"
+        assert result["x-datadog-parent-id"] == "321987654"
+        assert result["dd-pathway-ctx"] == "test-pathway-ctx"
+
+    def test_sns_to_lambda_format(self):
+        """Test format: message.Sns.MessageAttributes._datadog.Value.decode() (SNS -> lambda)"""
+        trace_context = {
+            "x-datadog-trace-id": "111111111",
+            "x-datadog-parent-id": "222222222",
+            "dd-pathway-ctx": "test-pathway-ctx",
+        }
+        binary_data = base64.b64encode(
+            json.dumps(trace_context).encode("utf-8")
+        ).decode("utf-8")
+
+        sns_lambda_record = {
+            "EventSource": "aws:sns",
+            "EventSubscriptionArn": (
+                "arn:aws:sns:us-east-1:123456789012:sns-topic:12345678-1234-1234-1234-123456789012"
+            ),
+            "Sns": {
+                "Type": "Notification",
+                "MessageId": "95df01b4-ee98-5cb9-9903-4c221d41eb5e",
+                "TopicArn": "arn:aws:sns:us-east-1:123456789012:sns-topic",
+                "Subject": "Test Subject",
+                "Message": "Hello from SNS!",
+                "Timestamp": "2023-01-01T12:00:00.000Z",
+                "MessageAttributes": {
+                    "_datadog": {"Type": "Binary", "Value": binary_data}
+                },
+            },
+        }
+
+        result = _get_dsm_context_from_lambda(sns_lambda_record)
+
+        assert result is not None
+        assert result == trace_context
+        assert result["x-datadog-trace-id"] == "111111111"
+        assert result["x-datadog-parent-id"] == "222222222"
+        assert result["dd-pathway-ctx"] == "test-pathway-ctx"
+
+    def test_sns_to_sqs_to_lambda_binary_value_format(self):
+        """Test format: message.messageAttributes._datadog.binaryValue.decode() (SNS -> SQS -> lambda, raw)"""
+        trace_context = {
+            "x-datadog-trace-id": "777666555",
+            "x-datadog-parent-id": "444333222",
+            "dd-pathway-ctx": "test-pathway-ctx",
+        }
+        binary_data = base64.b64encode(
+            json.dumps(trace_context).encode("utf-8")
+        ).decode("utf-8")
+
+        lambda_record = {
+            "messageId": "test-message-id",
+            "receiptHandle": "test-receipt-handle",
+            "body": "Test message body",
+            "messageAttributes": {
+                "_datadog": {"binaryValue": binary_data, "dataType": "Binary"}
+            },
+            "eventSource": "aws:sqs",
+            "eventSourceARN": "arn:aws:sqs:us-west-2:123456789012:test-queue",
+        }
+
+        result = _get_dsm_context_from_lambda(lambda_record)
+
+        assert result is not None
+        assert result == trace_context
+        assert result["x-datadog-trace-id"] == "777666555"
+        assert result["x-datadog-parent-id"] == "444333222"
+        assert result["dd-pathway-ctx"] == "test-pathway-ctx"
+
+    def test_sns_to_sqs_to_lambda_body_format(self):
+        """Test format: message.body.MessageAttributes._datadog.Value.decode() (SNS -> SQS -> lambda)"""
+        trace_context = {
+            "x-datadog-trace-id": "123987456",
+            "x-datadog-parent-id": "654321987",
+            "x-datadog-sampling-priority": "1",
+            "dd-pathway-ctx": "test-pathway-ctx",
+        }
+
+        message_body = {
+            "Type": "Notification",
+            "MessageId": "test-message-id",
+            "Message": "Test message from SNS",
+            "MessageAttributes": {
+                "_datadog": {
+                    "Type": "Binary",
+                    "Value": base64.b64encode(
+                        json.dumps(trace_context).encode("utf-8")
+                    ).decode("utf-8"),
+                }
+            },
+        }
+
+        lambda_record = {
+            "messageId": "lambda-message-id",
+            "body": json.dumps(message_body),
+            "eventSource": "aws:sqs",
+            "eventSourceARN": "arn:aws:sqs:us-east-1:123456789012:sns-to-sqs-queue",
+        }
+
+        result = _get_dsm_context_from_lambda(lambda_record)
+
+        assert result is not None
+        assert result == trace_context
+        assert result["x-datadog-trace-id"] == "123987456"
+        assert result["x-datadog-parent-id"] == "654321987"
+        assert result["dd-pathway-ctx"] == "test-pathway-ctx"
+
+    def test_kinesis_to_lambda_format(self):
+        """Test format: message.kinesis.data.decode()._datadog (Kinesis -> lambda)"""
+        trace_context = {
+            "x-datadog-trace-id": "555444333",
+            "x-datadog-parent-id": "888777666",
+            "dd-pathway-ctx": "test-pathway-ctx",
+        }
+
+        # Create the kinesis data payload
+        kinesis_payload = {
+            "_datadog": trace_context,
+            "actualData": "some business data",
+        }
+        encoded_kinesis_data = base64.b64encode(
+            json.dumps(kinesis_payload).encode("utf-8")
+        ).decode("utf-8")
+
+        kinesis_lambda_record = {
+            "eventSource": "aws:kinesis",
+            "eventSourceARN": (
+                "arn:aws:kinesis:us-east-1:123456789012:stream/my-stream"
+            ),
+            "kinesis": {
+                "data": encoded_kinesis_data,
+                "partitionKey": "partition-key-1",
+                "sequenceNumber": (
+                    "49590338271490256608559692538361571095921575989136588898"
+                ),
+            },
+        }
+
+        result = _get_dsm_context_from_lambda(kinesis_lambda_record)
+
+        assert result is not None
+        assert result == trace_context
+        assert result["x-datadog-trace-id"] == "555444333"
+        assert result["x-datadog-parent-id"] == "888777666"
+        assert result["dd-pathway-ctx"] == "test-pathway-ctx"
+
+    def test_no_message_attributes(self):
+        """Test message without MessageAttributes returns None."""
+        message = {
+            "messageId": "test-message-id",
+            "body": "Test message without attributes",
+        }
+
+        result = _get_dsm_context_from_lambda(message)
+
+        assert result is None
+
+    def test_no_datadog_attribute(self):
+        """Test message with MessageAttributes but no _datadog attribute returns None."""
+        message = {
+            "messageId": "test-message-id",
+            "body": "Test message",
+            "messageAttributes": {
+                "customAttribute": {"stringValue": "custom-value", "dataType": "String"}
+            },
+        }
+
+        result = _get_dsm_context_from_lambda(message)
+        assert result is None
+
+    def test_empty_datadog_attribute(self):
+        """Test message with empty _datadog attribute returns None."""
+        message = {
+            "messageId": "test-message-id",
+            "messageAttributes": {"_datadog": {}},
+        }
+
+        result = _get_dsm_context_from_lambda(message)
+
+        assert result is None