amqptools/lib/Task.js

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
const ChannelManager_1 = require("./ChannelManager");
const uuid = require("node-uuid");
const util = require("util");
const EXCHANGE_PREFIX = "nimbus:jobs:";
const EXCHANGE_OPTIONS = { durable: true, autoDelete: false };
const JOB_QUEUE_PREFIX = "nimbus:jobs:queue:";
const JOB_QUEUE_OPTIONS = { durable: true, autoDelete: false };
const debug = util.debuglog("amqptools");
class Task {
    constructor(type, params) {
        this.onReconnect = () => {
            if (this.taskCallback) {
                debug("Trying to re establish consuming on task queue %s", this.queueName);
                this.consume();
            }
        };
        this.uuid = uuid.v4();
        this.type = type;
        this.params = params;
        ChannelManager_1.channelManager.on("reconnect", this.onReconnect);
    }
    get exchangeName() {
        return EXCHANGE_PREFIX + Task.taskManager.service;
    }
    get queueName() {
        return JOB_QUEUE_PREFIX + this.type;
    }
    start(cb) {
        if (!this.params)
            return;
        ChannelManager_1.channelManager.getChannel()
            .then(() => this.assertExchange())
            .then(() => this.assertQueue())
            .then(() => this.bindQueue())
            .then((channel) => {
            let params = JSON.parse(JSON.stringify(this.params));
            params['uuid'] = this.uuid;
            var eventData = new Buffer(JSON.stringify(params));
            channel.publish(this.exchangeName, this.type, eventData);
            if (cb)
                cb();
        });
        return this;
    }
    assertExchange() {
        return ChannelManager_1.channelManager.getChannel().then((channel) => {
            return new Promise((resolve, reject) => {
                channel.assertExchange(this.exchangeName, 'direct', EXCHANGE_OPTIONS, (err) => {
                    if (err)
                        return reject(err);
                    resolve(channel);
                });
            });
        });
    }
    assertQueue() {
        return ChannelManager_1.channelManager.getChannel().then((channel) => {
            return new Promise((resolve, reject) => {
                channel.assertQueue(this.queueName, JOB_QUEUE_OPTIONS, (err) => {
                    if (err)
                        return reject(err);
                    resolve(channel);
                });
            });
        });
    }
    bindQueue() {
        return ChannelManager_1.channelManager.getChannel().then((channel) => {
            channel.bindQueue(this.queueName, this.exchangeName, this.type);
            return channel;
        });
    }
    purgeQueue() {
        return ChannelManager_1.channelManager.getChannel().then((channel) => {
            return new Promise((resolve, reject) => {
                channel.checkQueue(this.queueName, (err, ok) => {
                    if (err)
                        return resolve(null);
                    if (ok) {
                        return channel.purgeQueue(this.queueName, (err, reply) => {
                            if (err)
                                return reject(err);
                            resolve(reply);
                        });
                    }
                    resolve(null);
                });
            });
        });
    }
    consume() {
        return ChannelManager_1.channelManager.getChannel()
            .then(() => this.assertQueue())
            .then((channel) => {
            channel.prefetch(this.opts.prefetchCount);
            debug("Attaching task listener for %s, prefetch=%d", this.type, this.opts.prefetchCount);
            channel.consume(this.queueName, (msg) => {
                var taskData = JSON.parse(msg.content.toString());
                this.taskCallback(taskData, err => {
                    if (err && err.nack) {
                        channel.nack(msg, false, false);
                    }
                    else {
                        channel.ack(msg);
                    }
                });
            }, { noAck: false });
        });
    }
    processTask(opts, taskCallback) {
        if (this.taskCallback) {
            throw new Error("Task callback already set");
        }
        if (typeof opts === "function") {
            taskCallback = opts;
            opts = {};
        }
        this.taskCallback = taskCallback;
        opts = opts || {};
        opts.prefetchCount = opts.prefetchCount || 1;
        this.opts = opts;
        return this.consume();
    }
}
exports.Task = Task;
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