Enhance apigw-lambda-sns pattern with production-ready improvements

apigw-lambda-sns/api.yaml

@@ -17,15 +17,23 @@ paths:
             application/json:
               schema:
                 $ref: "#/components/schemas/Empty"
+        "400":
+          description: "400 response"
+        "500":
+          description: "500 response"
       x-amazon-apigateway-integration:
         httpMethod: "POST"
         uri: "arn:${AWS::Partition}:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/arn:${AWS::Partition}:lambda:${AWS::Region}:${AWS::AccountId}:function:LambdaFunctionName/invocations"
         responses:
           default:
             statusCode: "200"
+          ".*4\\d{2}.*":
+            statusCode: "400"
+          ".*5\\d{2}.*":
+            statusCode: "500"
         passthroughBehavior: "when_no_match"
         contentHandling: "CONVERT_TO_TEXT"
-        type: "aws"
+        type: "aws_proxy"
 components:
   schemas:
     Empty:

apigw-lambda-sns/src/code.py

@@ -11,23 +11,38 @@ def lambda_handler(event, context):
     logger.setLevel(logging.INFO)
     logger.info("request: " + json.dumps(event))
 
-    topic_arn = os.environ.get('TOPIC_ARN')
-
-    sns_client = boto3.client("sns")
-
     try:
+        topic_arn = os.environ.get('TOPIC_ARN')
+        if not topic_arn:
+            logger.error("Missing TOPIC_ARN environment variable")
+            return {
+                "statusCode": 500,
+                "body": json.dumps({"error": "Server configuration error"})
+            }
+
+        sns_client = boto3.client("sns")
         sent_message = sns_client.publish(
             TargetArn=topic_arn,
             Message=json.dumps({'default': json.dumps(event)})
         )
 
-        if sent_message is not None:
-            logger.info(f"Success - Message ID: {sent_message['MessageId']}")
+        logger.info(f"Success - Message ID: {sent_message['MessageId']}")
         return {
             "statusCode": 200,
-            "body": json.dumps("Success")
+            "body": json.dumps({"status": "Success", "messageId": sent_message['MessageId']})
         }
 
     except ClientError as e:
-        logger.error(e)
-        return None
+        error_code = e.response['Error']['Code']
+        error_message = e.response['Error']['Message']
+        logger.error(f"ClientError: {error_code} - {error_message}")
+        return {
+            "statusCode": 500,
+            "body": json.dumps({"error": "Failed to publish message to SNS"})
+        }
+    except Exception as e:
+        logger.error(f"Unexpected error: {str(e)}")
+        return {
+            "statusCode": 500,
+            "body": json.dumps({"error": "Internal server error"})
+        }

apigw-lambda-sns/template.yaml

@@ -28,7 +28,7 @@ Resources:
       Handler: code.lambda_handler
       MemorySize: 128
       Timeout: 3
-      Runtime: python3.8
+      Runtime: python3.13
       Environment:
         Variables:
           TOPIC_ARN: !Ref MySnsTopic
@@ -60,6 +60,6 @@ Outputs:
   SNStopicARN:
     Description: SNS topic ARN
     Value: !Ref MySnsTopic
-
+  
   apiGatewayInvokeURL:
     Value: !Sub https://${RestApi}.execute-api.${AWS::Region}.amazonaws.com/s1