Empty responses support

Author: tzununbekov

node10/bootstrap

@@ -123,7 +123,7 @@ async function invokeResponse(result, context) {
   const res = await request({
     method: 'POST',
     path: `${RUNTIME_PATH}/invocation/${context.awsRequestId}/response`,
-    body: JSON.stringify(result),
+    body: result === null ? '' : JSON.stringify(result),
   })
   if (res.statusCode !== 202) {
     throw new Error(`Unexpected /invocation/response response: ${JSON.stringify(res)}`)

python37/bootstrap.py

@@ -149,7 +149,8 @@ def handle_event_request(lambda_runtime_client, request_handler, invoke_id, even
         context = LambdaContext(invoke_id, client_context, cloudevents_context, cognito_identity, epoch_deadline_time_in_ms, invoked_function_arn)
         json_input = try_or_raise(lambda: json.loads(event_body.decode()), "Unable to parse input as json")
         result = request_handler(json_input, context)
-        result = try_or_raise(lambda: to_json(result), "An error occurred during JSON serialization of response")
+        if result is not None:
+            result = try_or_raise(lambda: to_json(result), "An error occurred during JSON serialization of response")
     except FaultException as e:
         error_result = make_error(e.msg, None, None)
         error_result = to_json(error_result)

ruby25/Dockerfile

@@ -15,7 +15,7 @@ ENV LAMBDA_TASK_ROOT "/opt"
 
 COPY --from=downloader /opt/aws-custom-runtime /opt/
 COPY --from=lambda /var/runtime/lib /opt
-COPY lambda_context.rb /opt/
+COPY lambda_context.rb lambda_handler.rb /opt/
 
 RUN mv /opt/runtime.rb /opt/bootstrap
 RUN sed -i /opt/lambda_server.rb -e 's|http://127.0.0.1:9001/2018-06-01|http://127.0.0.1/2018-06-01|'

ruby25/lambda_handler.rb

@@ -0,0 +1,42 @@
+# Copyright 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+
+class LambdaHandler
+    attr_reader :handler_file_name, :handler_method_name
+  
+    def initialize(env_handler:)
+      handler_split = env_handler.split('.')
+      if handler_split.size == 2
+        @handler_file_name, @handler_method_name = handler_split
+      elsif handler_split.size == 3
+        @handler_file_name, @handler_class, @handler_method_name = handler_split
+      else
+        raise ArgumentError.new("Invalid handler #{handler_split}, must be of form FILENAME.METHOD or FILENAME.CLASS.METHOD where FILENAME corresponds with an existing Ruby source file FILENAME.rb, CLASS is an optional module/class namespace and METHOD is a callable method. If using CLASS, METHOD must be a class-level method.")
+      end
+    end
+  
+    def call_handler(request:, context:)
+      begin
+        opts = {
+          event: request,
+          context: context
+        }
+        if @handler_class
+          response = Kernel.const_get(@handler_class).send(@handler_method_name, opts)
+        else
+          response = __send__(@handler_method_name, opts)
+        end
+        # serialization can be a part of user code
+        response.nil? ? response : AwsLambda::Marshaller.marshall_response(response)
+      rescue NoMethodError => e
+        # This is a special case of standard error that we want to hard-fail for
+        raise LambdaErrors::LambdaHandlerCriticalException.new(e)
+      rescue NameError => e
+        # This is a special case error that we want to wrap
+        raise LambdaErrors::LambdaHandlerCriticalException.new(e)
+      rescue StandardError => e
+        raise LambdaErrors::LambdaHandlerError.new(e)
+      rescue Exception => e
+        raise LambdaErrors::LambdaHandlerCriticalException.new(e)
+      end
+    end
+  end