Google PubSub

Google Pub/Sub Channel Integration

The Google Pub/Sub extension for @nestjstools/messaging enables cloud-native, event-driven communication across distributed systems. It’s ideal for scalable, serverless-friendly applications that rely on Google Cloud infrastructure.

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📦 Installation

Install the core messaging package and the Google Pub/Sub extension:

npm install @nestjstools/messaging @nestjstools/messaging-google-pubsub-extension

or

yarn add @nestjstools/messaging @nestjstools/messaging-google-pubsub-extension

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⚙️ Example Configuration

import { MessagingModule } from '@nestjstools/messaging';
import { PubSubChannelConfig, MessagingGooglePubSubExtensionModule } from '@nestjstools/messaging-google-pubsub-extension';
import { InMemoryChannelConfig } from '@nestjstools/messaging/channels';
import { SendMessageHandler } from './handlers/send-message.handler';

@Module({
  imports: [
    MessagingGooglePubSubExtensionModule,
    MessagingModule.forRoot({
      messageHandlers: [SendMessageHandler],
      buses: [
        {
          name: 'default.bus',
          channels: ['in-memory', 'pubsub-events'],
        },
      ],
      channels: [
        new InMemoryChannelConfig({
          name: 'in-memory',
          avoidErrorsForNotExistedHandlers: true,
        }),
        new PubSubChannelConfig({
          name: 'pubsub-events',
          projectId: 'your-gcp-project-id',
          topic: 'your-topic-name',
          subscription: 'your-subscription-name',
          middlewares: [],
          autoCreate: true,
          enableSubscriber: true,
          avoidErrorsForNotExistedHandlers: true,
        }),
      ],
      debug: true,
    }),
  ],
})
export class AppModule {}

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🛠️ PubSubChannelConfig Properties

Property	Description	Default Value
name	The channel name (e.g., 'pubsub-events').	—
projectId	Google Cloud project ID.	—
topic	The Pub/Sub topic to publish messages to.	—
subscription	Subscription name to consume messages from.	—
middlewares	Array of middlewares applied to incoming/outgoing messages.	[]
autoCreate	Automatically create topic/subscription if they do not exist.	true
enableSubscriber	Enables the background subscriber to listen to incoming Pub/Sub messages.	true
avoidErrorsForNotExistedHandlers	Silently skips messages without a matching handler.	false

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🌐 Key Features

• Cloud-Native Messaging: Leverages Google Pub/Sub for reliable, asynchronous communication across microservices.

• Auto Resource Provisioning: Automatically creates missing topics and subscriptions when autoCreate is enabled.

• Efficient Scaling: Suitable for horizontally scaled environments (e.g., Kubernetes, Cloud Run).

• Graceful Error Handling: Skip errors when no handler exists by enabling avoidErrorsForNotExistedHandlers.

• Subscriber Control: Toggle subscriber activation with enableSubscriber.