lambda function CORS controlled by environment variable

serverless/aws/lambda_function.py

@@ -79,9 +79,11 @@ def lambda_handler(event, context):
 
     headers = {
         "Content-Type": "application/protobuf",
-        "Access-Control-Allow-Origin": "*",
     }
 
+    if "CORS" in os.environ:
+        headers["Access-Control-Allow-Origin"] = os.environ.get("CORS")
+
     if reader.header().metadata.get("compression") == "gzip":
         if is_api_gateway:
             # API Gateway requires a compressed response to correctly return binary data