@betit/orion/lib/service/index.js

Pluggable microservice framework

"use strict";
const codec_1 = require('../codec');
const transport_1 = require('../transport');
const reply_1 = require('./reply');
const utils_1 = require('../utils');
const debug = utils_1.debugLog('orion:service');
/**
 * Provides an interface to create your service and register request handlers.
 */
class Service {
    /**
     * Create new service.
     */
    constructor(name, options = {}) {
        this.name = name;
        this.options = options;
        this.id = utils_1.generateId();
        this.codec = this.options.codec || new codec_1.DefaultBinaryCodec();
        this.transport = this.options.transport || new transport_1.DefaultTransport();
    }
    /**
     * Publish to a topic.
     * @param {any} topic
     * @param {Object} message
     */
    emit(topic, message) {
        debug('emit:', topic);
        this.transport.publish(topic, this.codec.encode(message));
    }
    /**
     * Subscribe to a topic.
     * @param {string} topic
     * @param {Function} callback
     */
    on(topic, callback, disableGroup = false) {
        const subject = `${this.name}:${topic}`;
        debug('on:', subject);
        return this.transport.subscribe(subject, disableGroup ? null : this.name, message => {
            callback(this.codec.decode(message));
        });
    }
    /**
     * Register request handler method.
     * @param {string} method
     * @param {Function} callback
     * @param {string} [prefix]
     */
    handle(path, callback, prefix) {
        const route = `${prefix || this.name}.${path}`;
        debug('register handler:', route);
        this.transport.handle(route, this.name, (data, send) => {
            const req = this.codec.decode(data);
            debug('incoming request:', req);
            const reply = new reply_1.default(data => {
                debug('sending response:', data.err, data.res);
                const response = this.codec.encode(data);
                send(response);
            });
            callback(req, reply.fn());
        });
    }
    /**
     * Start listenning on the underlying transport connection.
     * @param {Function} callback
     */
    listen(callback) {
        debug('listen');
        this.transport.listen(callback);
    }
    /**
     * Close underlying transport connection.
     */
    close() {
        debug('close');
        this.transport.close();
    }
    /**
     * Service name and id.
     */
    toString() {
        return `${this.name}-${this.id}`;
    }
}
Object.defineProperty(exports, "__esModule", { value: true });
exports.default = Service;