feat(rabbitmq): cleanup for error handlers

golevelup · Apr 16, 2020 · ddd4707 · ddd4707
1 parent 85b1b67
commit ddd4707
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Showing 8 changed files with 132 additions and 122 deletions.
diff --git a/integration/rabbitmq/e2e/subscribe.e2e-spec.ts b/integration/rabbitmq/e2e/subscribe.e2e-spec.ts
@@ -93,22 +93,4 @@ describe('Rabbit Subscribe', () => {
       done();
     }, 50);
   });
-
-  // it('should receive undefined argument when subscriber allows non-json messages and message is empty', async (done) => {
-
-  //   setTimeout(() => {
-  //     expect(testHandler).toHaveBeenCalledTimes(1);
-  //     expect(testHandler).toHaveBeenCalledWith(undefined);
-  //     done();
-  //   }, 50);
-  // });
-
-  // it('should receive undefined argument when subscriber allows non-json messages and message is unparseable by JSON', async (done) => {
-
-  //   setTimeout(() => {
-  //     expect(testHandler).toHaveBeenCalledTimes(1);
-  //     expect(testHandler).toHaveBeenCalledWith(undefined);
-  //     done();
-  //   }, 50);
-  // });
 });
diff --git a/integration/rabbitmq/src/rpc/reply.error.callback.ts b/integration/rabbitmq/src/rpc/reply.error.callback.ts
@@ -16,5 +16,6 @@ export function ReplyErrorCallback(
     error = Buffer.from(JSON.stringify({ status: 'error', message: error }));
 
     channel.publish('', replyTo, error, { correlationId });
+    channel.ack(msg);
   }
 }
diff --git a/integration/rabbitmq/src/rpc/rpc.service.ts b/integration/rabbitmq/src/rpc/rpc.service.ts
@@ -1,10 +1,10 @@
 import {
-  RabbitRPC,
   MessageHandlerErrorBehavior,
+  RabbitRPC,
 } from '@golevelup/nestjs-rabbitmq';
 import { Injectable, UseInterceptors } from '@nestjs/common';
-import { TransformInterceptor } from '../transform.interceptor';
 import { RpcException } from '@nestjs/microservices';
+import { TransformInterceptor } from '../transform.interceptor';
 import { ReplyErrorCallback } from './reply.error.callback';
 
 @Injectable()
@@ -37,7 +37,7 @@ export class RpcService {
     exchange: 'exchange1',
     queue: 'error-reply-rpc',
     errorBehavior: MessageHandlerErrorBehavior.ACK,
-    errorCallbacks: [ReplyErrorCallback],
+    errorHandler: ReplyErrorCallback,
   })
   errorReplyRpc(message: object) {
     throw new RpcException(message);

diff --git a/packages/rabbitmq/README.md b/packages/rabbitmq/README.md
@@ -6,29 +6,28 @@
 <img alt="license" src="https://img.shields.io/npm/l/@golevelup/nestjs-rabbitmq.svg">
 </p>
 
-Table of Contents
-=================
-
-  * [Description](#description)
-  * [Motivation](#motivation)
-  * [Connection Management](#connection-management)
-  * [Usage](#usage)
-      * [Install](#install)
-      * [Module Initialization](#module-initialization)
-  * [Receiving Messages](#receiving-messages)
-      * [Exposing RPC Handlers](#exposing-rpc-handlers)
-      * [Exposing Pub/Sub Handlers](#exposing-pubsub-handlers)
-      * [Message Handling](#message-handling)
-      * [Conditional Handler Registration](#conditional-handler-registration)
-  * [Sending Messages](#sending-messages)
-      * [Inject the AmqpConnection](#inject-the-amqpconnection)
-      * [Publising Messages (Fire and Forget)](#publising-messages-fire-and-forget)
-      * [Requesting Data from an RPC](#requesting-data-from-an-rpc)
-        * [Type Inference](#type-inference)
-        * [Interop with other RPC Servers](#interop-with-other-rpc-servers)
-  * [Advanced Patterns](#advanced-patterns)
-      * [Competing Consumers](#competing-consumers)
-  * [TODO](#todo)
+# Table of Contents
+
+- [Description](#description)
+- [Motivation](#motivation)
+- [Connection Management](#connection-management)
+- [Usage](#usage)
+  - [Install](#install)
+  - [Module Initialization](#module-initialization)
+- [Receiving Messages](#receiving-messages)
+  - [Exposing RPC Handlers](#exposing-rpc-handlers)
+  - [Exposing Pub/Sub Handlers](#exposing-pubsub-handlers)
+  - [Message Handling](#message-handling)
+  - [Conditional Handler Registration](#conditional-handler-registration)
+- [Sending Messages](#sending-messages)
+  - [Inject the AmqpConnection](#inject-the-amqpconnection)
+  - [Publising Messages (Fire and Forget)](#publising-messages-fire-and-forget)
+  - [Requesting Data from an RPC](#requesting-data-from-an-rpc)
+    - [Type Inference](#type-inference)
+    - [Interop with other RPC Servers](#interop-with-other-rpc-servers)
+- [Advanced Patterns](#advanced-patterns)
+  - [Competing Consumers](#competing-consumers)
+- [TODO](#todo)
 
 ## Description
 
@@ -61,13 +60,13 @@ import { RabbitMQModule } from '@golevelup/nestjs-rabbitmq';
       exchanges: [
         {
           name: 'exchange1',
-          type: 'topic'
-        }
+          type: 'topic',
+        },
       ],
       uri: 'amqp://rabbitmq:rabbitmq@localhost:5672',
-      connectionInitOptions: { wait: false }
-    })
-  ]
+      connectionInitOptions: { wait: false },
+    }),
+  ],
 })
 export class RabbitExampleModule {}
 ```
@@ -104,15 +103,15 @@ import { MessagingService } from './messaging/messaging.service';
       exchanges: [
         {
           name: 'exchange1',
-          type: 'topic'
-        }
+          type: 'topic',
+        },
       ],
-      uri: 'amqp://rabbitmq:rabbitmq@localhost:5672'
+      uri: 'amqp://rabbitmq:rabbitmq@localhost:5672',
     }),
-    RabbitExampleModule
+    RabbitExampleModule,
   ],
   providers: [MessagingService],
-  controllers: [MessagingController]
+  controllers: [MessagingController],
 })
 export class RabbitExampleModule {}
 ```
@@ -132,11 +131,11 @@ export class MessagingService {
   @RabbitRPC({
     exchange: 'exchange1',
     routingKey: 'rpc-route',
-    queue: 'rpc-queue'
+    queue: 'rpc-queue',
   })
   public async rpcHandler(msg: {}) {
     return {
-      response: 42
+      response: 42,
     };
   }
 }
@@ -155,7 +154,7 @@ export class MessagingService {
   @RabbitSubscribe({
     exchange: 'exchange1',
     routingKey: 'subscribe-route',
-    queue: 'subscribe-queue'
+    queue: 'subscribe-queue',
   })
   public async pubSubHandler(msg: {}) {
     console.log(`Received message: ${JSON.stringify(msg)}`);
@@ -194,6 +193,7 @@ export class MessagingService {
   }
 }
 ```
+
 ### Conditional Handler Registration
 
 In some scenarios, it may not be desirable for all running instances of a NestJS application to register RabbitMQ message handlers. For example, if leveraging the same application code base to expose API instances and worker roles separately it may be desirable to have only the worker instances attach handlers to manage queue subscriptions or RPC requests.
@@ -245,9 +245,9 @@ const response = await amqpConnection.request<ExpectedReturnType>({
   exchange: 'exchange1',
   routingKey: 'rpc',
   payload: {
-    request: 'val'
+    request: 'val',
   },
-  timeout = 10000 // optional timeout for how long the request
+  timeout = 10000, // optional timeout for how long the request
   // should wait before failing if no response is received
 });
 ```
@@ -281,23 +281,18 @@ export class MessagingService {
   @RabbitSubscribe({
     exchange: 'exchange1',
     routingKey: 'subscribe-route1',
-    queue: 'subscribe-queue'
+    queue: 'subscribe-queue',
   })
   public async competingPubSubHandler(msg: {}) {
     console.log(`Received message: ${JSON.stringify(msg)}`);
   }
 
   @RabbitSubscribe({
     exchange: 'exchange1',
-    routingKey: 'subscribe-route2'
+    routingKey: 'subscribe-route2',
   })
   public async messagePerInstanceHandler(msg: {}) {
     console.log(`Received message: ${JSON.stringify(msg)}`);
   }
 }
 ```
-
-## TODO
-
-- Possible validation pipeline using class-validator and class-transformer to ensure messages are well formatted
-- Integrate hooks for things like logging, metrics, or custom error handling
diff --git a/packages/rabbitmq/src/amqp/connection.ts b/packages/rabbitmq/src/amqp/connection.ts
@@ -13,11 +13,14 @@ import {
 import * as uuid from 'uuid';
 import {
   ConnectionInitOptions,
-  MessageHandlerErrorBehavior,
   MessageHandlerOptions,
   RabbitMQConfig,
   RequestOptions,
 } from '../rabbitmq.interfaces';
+import {
+  getHandlerForLegacyBehavior,
+  MessageHandlerErrorBehavior,
+} from './errorBehaviors';
 import { Nack, RpcResponse, SubscribeResponse } from './handlerResponses';
 
 const DIRECT_REPLY_QUEUE = 'amq.rabbitmq.reply-to';
@@ -274,11 +277,14 @@ export class AmqpConnection {
         if (msg == null) {
           return;
         } else {
-          const errorBehavior =
-            msgOptions.errorBehavior ||
-            this.config.defaultSubscribeErrorBehavior;
-
-          await this.handleError(channel, msgOptions, errorBehavior, msg, e);
+          const errorHandler =
+            msgOptions.errorHandler ||
+            getHandlerForLegacyBehavior(
+              msgOptions.errorBehavior ||
+                this.config.defaultSubscribeErrorBehavior
+            );
+
+          await errorHandler(channel, msg, e);
         }
       }
     });
@@ -343,10 +349,14 @@ export class AmqpConnection {
         if (msg == null) {
           return;
         } else {
-          const errorBehavior =
-            rpcOptions.errorBehavior || this.config.defaultRpcErrorBehavior;
-
-          await this.handleError(channel, rpcOptions, errorBehavior, msg, e);
+          const errorHandler =
+            rpcOptions.errorHandler ||
+            getHandlerForLegacyBehavior(
+              rpcOptions.errorBehavior ||
+                this.config.defaultSubscribeErrorBehavior
+            );
+
+          await errorHandler(channel, msg, e);
         }
       }
     });
@@ -401,37 +411,4 @@ export class AmqpConnection {
 
     return handler(message, msg);
   }
-
-  private async handleError(
-    channel: amqplib.Channel,
-    msgOptions: MessageHandlerOptions,
-    errorBehavior: MessageHandlerErrorBehavior,
-    msg: amqplib.Message,
-    error: any
-  ) {
-    if (msg == null) {
-      return;
-    } else {
-      try {
-        if (msgOptions.errorCallbacks) {
-          for (const callback of msgOptions.errorCallbacks) {
-            await callback(channel, msg, error);
-          }
-        }
-      } finally {
-        switch (errorBehavior) {
-          case MessageHandlerErrorBehavior.ACK: {
-            channel.ack(msg);
-            break;
-          }
-          case MessageHandlerErrorBehavior.REQUEUE: {
-            channel.nack(msg, false, true);
-            break;
-          }
-          default:
-            channel.nack(msg, false, false);
-        }
-      }
-    }
-  }
 }
diff --git a/packages/rabbitmq/src/amqp/errorBehaviors.ts b/packages/rabbitmq/src/amqp/errorBehaviors.ts
@@ -0,0 +1,55 @@
+import * as amqplib from 'amqplib';
+
+export enum MessageHandlerErrorBehavior {
+  ACK,
+  NACK,
+  REQUEUE,
+}
+
+export type MessageErrorHandler = (
+  channel: amqplib.Channel,
+  msg: amqplib.ConsumeMessage,
+  error: any
+) => Promise<void> | void;
+
+/**
+ * An error handler that will ack the message which caused an error during processing
+ */
+export const ackErrorHandler: MessageErrorHandler = (channel, msg, error) => {
+  channel.ack(msg);
+};
+
+/**
+ * An error handler that will nack and requeue a message which created an error during processing
+ */
+export const requeueErrorHandler: MessageErrorHandler = (
+  channel,
+  msg,
+  error
+) => {
+  channel.nack(msg, false, true);
+};
+
+/**
+ * An error handler that will nack a message which created an error during processing
+ */
+export const defaultNackErrorHandler: MessageErrorHandler = (
+  channel,
+  msg,
+  error
+) => {
+  channel.nack(msg, false, false);
+};
+
+export const getHandlerForLegacyBehavior = (
+  behavior: MessageHandlerErrorBehavior
+) => {
+  switch (behavior) {
+    case MessageHandlerErrorBehavior.ACK:
+      return ackErrorHandler;
+    case MessageHandlerErrorBehavior.REQUEUE:
+      return requeueErrorHandler;
+    default:
+      return defaultNackErrorHandler;
+  }
+};
diff --git a/packages/rabbitmq/src/index.ts b/packages/rabbitmq/src/index.ts
@@ -1,4 +1,5 @@
 export * from './amqp/connection';
+export * from './amqp/errorBehaviors';
 export * from './amqp/handlerResponses';
 export * from './rabbitmq.constants';
 export * from './rabbitmq.decorators';