Request: Subscription character separator

PubSub

This is a generic PubSub Factory exposing a listen and a emit method.

NOTE: Today, only Google Cloud PubSub has been added.

Installation

npm install --save @algoan/pubsub

Usage

Google Cloud PubSub

Run tests

To run tests or to try the PubSubFactory class, you need to have a google account and have installed gcloud sdk.

Then, to install the Google PubSub simulator, run:

gcloud components install pubsub-emulator
gcloud components install beta
gcloud components update

Start tests running:

npm test

It will launch a Google PubSub emulator thanks to the google-pubsub-emulator library.

Example

To create a PubSub instance using Google Cloud:

import { EmittedMessage, GCPubSub, PubSubFactory, Transport } from '@algoan/pubsub'

const pubsub: GCPubSub = PubSubFactory.create({
  transport: Transport.GOOGLE_PUBSUB,
  options: {
    projectId: 'test',
    // And all other Google PubSub properties
  }
});
const topicName: string = 'some_topic';

await pubsub.listen(topicName, {
  autoAck: true,
  onMessage: (data: EmittedMessage<{foo: string}>) => {
    console.log(data.parsedData); // { foo: 'bar', time: {Date.now}, _eventName: 'some_topic' }
    // do whatever you want. The message has already been acknowledged
  },
  onError: (error: Error) => {
    // Handle error as you wish
  }
});

await pubsub.emit(topicName, { foo: 'bar' });

Contribution

Thank you for your future contribution 😁 Please follow these instructions before opening a pull request!

API

`PubSubFactory.create({ transport, options })`

The only static method from the PubSubFactory class. It initiates a new PubSub instance depending on the transport. By default, it connects to Google Cloud PubSub.

transport: PubSub technology to use. Only GOOGLE_PUBSUB is available for now.
options: Options related to the transport.
- If transport === Transport.GOOGLE_PUBSUB, then have a look at the Google Cloud PubSub config client.
- debug: Display logs if it is set to true. It uses a pino logger and pino-pretty if NODE_ENV is not equal to production.
- pinoOptions: If debug is set to true, set the pino logger options. Default to level: debug and prettyPrint: true if NODE_ENV is not equal to production.
- topicsPrefix: Add a prefix to all created topics. Example: topicsPrefix: 'my-topic', all topics will begin with my-topic+{your topic name}.
- topicsSeparator: Customize separator between topicsPrefix and topic name. Example: topicsSeparator: '-', all topics will be {topic prefix}-{your topic name} (default to '+').
- subscriptionsPrefix: Add a prefix to all created subscriptions. Example: subscriptionsPrefix: 'my-sub', all subscriptions will begin with my-sub%{your topic name}.
- subscriptionsSeparator: Customize separator between subscriptionsPrefix and topic name. Example: subscriptionsSeparator: '-', all subscriptions will be {subscription prefix}-{your topic name} (default to '%').
- namespace: Add a namespace property to Message attributes when publishing on a topic.
- environment: Add a environment property to Message attributes when publishing on a topic.

`pubsub.listen(event, opts)`

Listen to a specific event.

NOTE: It only uses the Google Cloud subscription pull delivery for now.

event: Name of the event.
opts: Options related to the Listener method
- onMessage: Method called when receiving a message
- onError: Method called when an error occurs
- options: Option related to the chosen transport

If the chosen transport is Google Cloud PubSub, then options would be:

autoAck: Automatically ACK an event as soon as it is received (default to true)
subscriptionOptions: Options related to the created Subscription:
- name: Custom name for the subscription. Default: event (also equal to the topic name)
- get: Options applied to the getSubscription method (have a look at Subscription options)
- sub: Options applied to the subscription instance (see also setOptions method)
- create: Options applied to the createSubscription method (have a look at Create Subscription options)
topicOptions: Options applied to the created topic (have a look at Topic options)
topicName: Set the topic name. By default, it uses the default name with a prefix.

`pubsub.emit(event, payload, opts)`

Emit a specific event with a payload. It added attributes in the message if you have added a namespace or an environment when setting the PubSubFactory class. It also adds an _eventName and a time property in the emitted payload.

event: Name of the event to emit.
payload: Payload to send. It will be buffered by Google, and then parsed by the listen method.
opts: Options related to the Emit method
- metadata: Custom metadata added to the message
- options: Option related to the chosen transport

If the chosen transport is Google Cloud PubSub, then options would be:

topicOptions: Options applied to the created topic (have a look at Topic options)
publishOptions: Publish options set to the topic after its creation. Refer to Publish Options
messageOptions: Additional message options added to the message. Refer to Message Options

`pubsub.unsubscribe(event)`

Stop the server connection for a given subscription.

event: Name of of the event to stop listening for.

	public async listen<T>(
	event: string,
	opts: ListenOptions<T, GCListenOptions> = { options: { autoAck: true } },
	): Promise<void> {
	const topic: Topic = await this.getOrCreateTopic(event, opts.options?.topicOptions);
	const subscription: Subscription = await this.getOrCreateSubscription(
	event,
	topic,
	opts.options?.subscriptionOptions,
	);
	this.logger.debug(`Listened to topic ${topic.name} with subscription ${subscription.name}`);

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pubsub's Introduction

PubSub

Installation

Usage

Google Cloud PubSub

Run tests

Example

Contribution

API

PubSubFactory.create({ transport, options })

pubsub.listen(event, opts)

pubsub.emit(event, payload, opts)

pubsub.unsubscribe(event)

pubsub's People

Contributors

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pubsub's Issues

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`PubSubFactory.create({ transport, options })`

`pubsub.listen(event, opts)`

`pubsub.emit(event, payload, opts)`

`pubsub.unsubscribe(event)`

🚨 The automated release from the `master` branch failed. 🚨

`npm test`