This article, is nothing more, than a silly way of how to push random rabbitMq messages in a controlled (lol) way in an exchange. Really Useful to simulate a load test.
From this point I am going to refer to RabbitMq, as just rabbit 🐇 and I am going to use a large number of emoji....just because.
Step 1 import all the necessary libraries 📚, which are basically the following two-ish.
- amqplib - rabbit library and client
- fs - aka filesystem
import * as amqp from 'amqplib';
import * as fs from 'fs';
Step 2 declare all our configurable values;
const DATA_LENGTH = 100;
const EXCHANGE = "MyExchange";
const ROUTING_KEY = "MyRoutingKey";
const MESSAGE_TYPE = "MyMessageType";
const RABBIT_USERNAME = "MyUsername";
const RABBIT_PASSWORD = "MyPassword";
const RABBIT_HOSTNAME = "localhost";
const RABBIT_PORT = "5672";
const RABBIT_VIRTUAL_HOST= "/";
const DELAY_BETWEEN_MESSAGES= "80";
Step 3 define a model with some initial values (any other way, is way more complicated for such simple example)
class UserModel {
userId: number = 1;
fistName: string = "";
lastName: string = "";
}
Step 4 write a function that gives random values to our model
function generateRandomValue(value: any): any {
if (typeof (value) == "string") {
return Math.random().toString(36).substring(7);
}
if (typeof (value) == "number") {
return Math.random();
}
}
Step 5 (optional) log to a file 🗄️, if you really care about any errors. Logging to console would also work fine, except, sometimes on load tests, you could send million of messages, which could make logging to console a bit of a fuss, 🥁 soooooo I would say we need one.
function log2file(obj: any) {
fs.appendFile(`./log.txt`, `${JSON.stringify(obj)}
`, (err) => {
if (err) {
console.log("undefined error");
}
});
}
Step 6 send Random object(🥕) to rabbit
function send2Rabbit(channel: any) {
// GENERATE RANDOM MESSAGE
const user: any = new UserModel();
for (var prop in user) {
if (Object.prototype.hasOwnProperty.call(user, prop)) {
user[prop] = generateRandomValue((user[prop]) as unknown as any);
}
}
const content = new Buffer(JSON.stringify(user));
if (channel) {
try {
channel.publish(EXCHANGE, ROUTING_KEY, content, {
type: MESSAGE_TYPE
});
} catch (error) {
log2file(error);
}
}
}
Step 7 push the power on 🔌 and see the world 🌍 crumble 💥 before your eyes 👀
// IIFE
(async () => {
try {
const rabbitConnection = await amqp.connect({
protocol: 'amqp',
hostname: RABBIT_HOSTNAME,
port: RABBIT_PORT,
username: RABBIT_USERNAME,
password: RABBIT_PASSWORD,
vhost: RABBIT_VIRTUAL_HOST,
});
const rabbitChannel = await rabbitConnection.createChannel();
for (let index = 0; index < DATA_LENGTH; index++) {
send2Rabbit(rabbitChannel)
await threadSleep(DELAY_BETWEEN_MESSAGES);
}
} catch (error) {
log2file(error);
}
})();
Step 8 bonus (sleep function 💤)
function threadSleep(ms: any) {
return new Promise((resolve) => setTimeout(resolve, ms));
}
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