1 | import { channelManager } from './ChannelManager'
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2 | import { TaskManager } from "./TaskManager"
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3 | import { Channel } from "amqplib/callback_api"
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4 |
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5 | import uuid = require("node-uuid")
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6 | import util = require("util")
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7 |
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8 | const EXCHANGE_PREFIX = "nimbus:jobs:";
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9 | const EXCHANGE_OPTIONS = {durable: true, autoDelete: false};
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10 |
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11 | const JOB_QUEUE_PREFIX = "nimbus:jobs:queue:";
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12 | const JOB_QUEUE_OPTIONS = {durable: true, autoDelete: false};
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13 |
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14 | const debug = util.debuglog("amqptools");
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15 |
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16 | export interface TaskParams {
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17 | title: string,
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18 | data: any
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19 | }
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20 |
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21 | export class Task {
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22 | uuid:string;
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23 | type:string;
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24 | params:TaskParams;
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25 | taskCallback: any;
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26 | opts: any;
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27 | static taskManager:TaskManager;
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28 |
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29 | constructor(type:string, params?:TaskParams) {
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30 | this.uuid = uuid.v4();
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31 | this.type = type;
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32 | this.params = params;
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33 |
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34 | channelManager.on("reconnect", this.onReconnect);
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35 | }
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36 |
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37 | onReconnect = () => {
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38 | if(this.taskCallback) {
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39 | debug("Trying to re establish consuming on task queue %s", this.queueName);
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40 | this.consume();
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41 | }
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42 | }
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43 |
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44 | get exchangeName() {
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45 | return EXCHANGE_PREFIX + Task.taskManager.service;
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46 | }
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47 |
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48 | get queueName() {
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49 | return JOB_QUEUE_PREFIX + this.type;
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50 | }
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51 |
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52 | start(cb?) {
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53 | if (!this.params) return;
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54 |
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55 | channelManager.getChannel()
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56 | .then(() => this.assertExchange())
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57 | .then(() => this.assertQueue())
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58 | .then(() => this.bindQueue())
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59 | .then((channel) => {
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60 | let params = JSON.parse(JSON.stringify(this.params));
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61 | params['uuid'] = this.uuid;
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62 | var eventData = new Buffer(JSON.stringify(params));
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63 |
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64 | channel.publish(this.exchangeName, this.type, eventData);
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65 | if (cb) cb();
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66 | });
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67 |
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68 | return this;
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69 | }
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70 |
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71 | private assertExchange() {
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72 | return channelManager.getChannel().then((channel) => {
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73 | return new Promise((resolve, reject) => {
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74 | channel.assertExchange(this.exchangeName, 'direct', EXCHANGE_OPTIONS, (err) => {
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75 | if (err) return reject(err);
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76 | resolve(channel);
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77 | })
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78 | });
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79 | })
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80 | }
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81 |
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82 | private assertQueue() {
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83 | return channelManager.getChannel().then((channel) => {
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84 | return new Promise<Channel>((resolve, reject) => {
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85 | channel.assertQueue(this.queueName, JOB_QUEUE_OPTIONS, (err) => {
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86 | if (err) return reject(err);
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87 | resolve(channel);
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88 | })
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89 | })
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90 | })
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91 | }
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92 |
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93 | private bindQueue() {
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94 | return channelManager.getChannel().then((channel) => {
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95 | channel.bindQueue(this.queueName, this.exchangeName, this.type);
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96 | return channel;
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97 | });
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98 | }
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99 |
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100 | purgeQueue() {
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101 | return channelManager.getChannel().then((channel) => {
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102 | return new Promise((resolve, reject) => {
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103 | channel.checkQueue(this.queueName, (err, ok) => {
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104 | if (err) return resolve(null);
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105 | if (ok) {
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106 | return channel.purgeQueue(this.queueName, (err, reply) => {
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107 | if (err) return reject(err);
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108 | resolve(reply)
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109 | })
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110 | }
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111 | resolve(null);
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112 | })
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113 | });
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114 | });
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115 | }
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116 |
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117 | consume() {
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118 | return channelManager.getChannel()
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119 | .then(() => this.assertQueue())
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120 | .then((channel) => {
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121 | channel.prefetch(this.opts.prefetchCount);
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122 | debug("Attaching task listener for %s, prefetch=%d", this.type, this.opts.prefetchCount);
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123 | channel.consume(this.queueName, (msg) => {
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124 | var taskData = JSON.parse(msg.content.toString());
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125 | this.taskCallback(taskData, err => {
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126 | if (err && err.nack) {
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127 |
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128 | channel.nack(msg, false, false)
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129 | } else {
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130 | channel.ack(msg)
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131 | }
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132 | })
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133 | }, {noAck: false});
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134 | });
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135 | }
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136 |
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137 | processTask(opts, taskCallback) {
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138 | if(this.taskCallback) {
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139 | throw new Error("Task callback already set");
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140 | }
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141 | if(typeof opts === "function") {
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142 | taskCallback = opts;
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143 | opts = {};
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144 | }
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145 | this.taskCallback = taskCallback;
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146 | opts = opts || {};
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147 | opts.prefetchCount = opts.prefetchCount || 1;
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148 | this.opts = opts;
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149 | return this.consume();
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150 | }
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151 | }
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152 |
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\ | No newline at end of file |