@betit/orion/lib/transport/nats.js

Pluggable microservice framework

"use strict";
const nats = require('nats');
const utils_1 = require('../utils');
const debug = utils_1.debugLog('orion:transport:nats');
/**
 * NATS transport.
 */
class NatsTransport {
    /**
     * Create new NATS transport.
     */
    constructor(options) {
        this.options = options;
        this.options = Object.assign({
            url: process.env.NATS || 'nats://localhost:4222',
            encoding: 'binary'
        }, options);
        this.client = nats.connect(this.options);
    }
    /**
     * Transport listen.
     */
    listen(callback) {
        this.client.flush(callback);
    }
    /**
     * Publish to a topic.
     */
    publish(topic, message) {
        this.client.publish(topic, message);
    }
    /**
     * Subscribe to a topic.
     */
    subscribe(topic, group, callback) {
        return this.client.subscribe(topic, { queue: group }, callback);
    }
    /**
    * Unsubscribe from a topic.
    */
    unsubscribe(sid, max) {
        this.client.unsubscribe(sid, max);
    }
    /**
     * Transport handle.
     */
    handle(route, group, callback) {
        debug('register handler:', route);
        this.client.subscribe(route, { queue: group }, (req, replyTo) => {
            debug('incoming request:', req, replyTo);
            callback(req, res => {
                debug('sending response:', replyTo, res);
                this.client.publish(replyTo, res);
            });
        });
    }
    /**
     * Client request.
     * Nats client implements this pattern out of the box.
     * Publish a request with an implicit inbox listener as the response.
     * This should be treated as a subscription.
     */
    request(route, payload, callback, timeout = 1000) {
        debug('sending request:', route);
        const sid = this.client.request(route, payload, { max: 1 }, response => {
            debug('got response:', response);
            callback(response);
        });
        this.client.timeout(sid, timeout, 1, () => {
            debug('request timeout:', route);
            callback(new Error(`Transport timeout: ${route}`));
        });
    }
    /**
     * Close connection.
     */
    close() {
        this.client.close();
    }
}
Object.defineProperty(exports, "__esModule", { value: true });
exports.default = NatsTransport;