doomi-helper/utilities/rabbitReceiveUtility.js

Doomisoft NodeJs Common Utilities

const path = require('path');
const fs = require('fs');
const _ = require('lodash');
const amqp = require('amqp-connection-manager');


class MessageQueueReceiveHelper {
    constructor(connectionConfig) {
        this.consummerQueues = [];

        if (connectionConfig) {
            this.connectionConfig = connectionConfig;
        } else {
            let config = process.env.CONFIGFILE || 'configuration.json';

            let configfile = path.join(process.cwd(), config);

            // eslint-disable-next-line no-sync
            if (fs.existsSync(configfile)) {
                this.config = require(configfile);
                this.connectionConfig = this.config.messageQueue || {};
            }
        }

        // Create a connetion manager
        const { hostname, port, username, password = '', vhost } = this.connectionConfig;
        this.connection = amqp.connect({
            hostname,
            port,
            username,
            password,
            vhost,
        });
        this.connection.on('connect', function () {
            console.log('Rabbitmq Receiver Connected!');
        });
        this.connection.on('disconnect', function (err) {
            console.log('Rabbitmq Receiver Disconnected.', err.message);
        });
    }

    /**
     * 拿到一个队列实例单例
     * @returns 
     */
    static getSingletonInstance(connectionOption) {
        if (!MessageQueueReceiveHelper.ProducerInstance) {
            MessageQueueReceiveHelper.ProducerInstance = new MessageQueueReceiveHelper(connectionOption);
        }

        return MessageQueueReceiveHelper.ProducerInstance;
    }

    static createInstanceByName(instanceName, connectionOption) {
        if (!MessageQueueReceiveHelper[instanceName]) {
            MessageQueueReceiveHelper[instanceName] = new MessageQueueReceiveHelper(connectionOption);
        }

        return MessageQueueReceiveHelper[instanceName];
    }

    registerConsummer({ queue, fn: onMessage, fetch = 1 }) {

        if (MessageQueueReceiveHelper.channels[queue]) {
            return;
        }
        // Set up a channel listening for messages in the queue.
        MessageQueueReceiveHelper.channels[queue] = this.connection.createChannel({
            setup: function (channel) {
                // `channel` here is a regular amqplib `ConfirmChannel`.
                return Promise.all([
                    channel.assertQueue(queue, { durable: true }),
                    channel.prefetch(fetch),
                    channel.consume(queue, async msg => {
                        try {
                            const content = msg.content.toString();
                            const msgContent = JSON.parse(content);
                            await onMessage(msgContent);
                        } catch (error) {
                            console.log('error:', error);
                        }
                        MessageQueueReceiveHelper.channels[queue].ack(msg);
                    })
                ]);
            }
        });

        MessageQueueReceiveHelper.channels[queue].waitForConnect()
            .then(function () {
                console.log(`queue:${queue} Listening for messages`);
            });
    }
}
MessageQueueReceiveHelper.channels = {};
exports = module.exports = MessageQueueReceiveHelper;