fix: Correct HTTP response status for subscription (#334)

* Correct HTTP response status for subscription

Signed-off-by: Deepanshu Agarwal <[email protected]>

* Remove commented code

Signed-off-by: Deepanshu Agarwal <[email protected]>

* Addressing comments

Signed-off-by: Deepanshu Agarwal <[email protected]>

Signed-off-by: Deepanshu Agarwal <[email protected]>

Author: DeepanshuA

src/enum/SubscribedMessageHttpResponse.enum.ts

@@ -0,0 +1,24 @@
+/*
+Copyright 2022 The Dapr Authors
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+    http://www.apache.org/licenses/LICENSE-2.0
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+/**
+ * Http Response Status to be sent back to dapr runtime as subscription response, as per 
+ * https://docs.dapr.io/reference/api/pubsub_api/#expected-http-response
+ */
+export enum SubscribedMessageHttpResponse {
+    SUCCESS = "SUCCESS",  // Message is processed successfully
+    RETRY = "RETRY", // Message to be retried by Dapr
+    DROP = "DROP", // Warning is logged and message is dropped
+  }
+  
+  export default SubscribedMessageHttpResponse;

src/implementation/Server/HTTPServer/pubsub.ts

@@ -15,6 +15,7 @@ import { TypeDaprPubSubCallback } from '../../../types/DaprPubSubCallback.type';
 import IServerPubSub from '../../../interfaces/Server/IServerPubSub';
 import HTTPServer from './HTTPServer';
 import { Logger } from '../../../logger/Logger';
+import SubscribedMessageHttpResponse from '../../../enum/SubscribedMessageHttpResponse.enum';
 
 // https://docs.dapr.io/reference/api/pubsub_api/
 export default class HTTPServerPubSub implements IServerPubSub {
@@ -45,13 +46,13 @@ export default class HTTPServerPubSub implements IServerPubSub {
       try {
         await cb(data);
       } catch (e) {
-        this.logger.error(`subscribe failed: ${e}`);
-        return res.send({ success: false });
+        this.logger.error(`[route-${topic}] Message processing failed, dropping: ${e}`);
+        return res.send({ status: SubscribedMessageHttpResponse.DROP });
       }
 
       // Let Dapr know that the message was processed correctly
       this.logger.debug(`[route-${topic}] Ack'ing the message`);
-      return res.send({ success: true });
+      return res.send({ status: SubscribedMessageHttpResponse.SUCCESS });
     });
   }
 }