NSQ Realtime Distributed Messaging

NSQ is a real-time distributed messaging platform written in Go and created by well known service bit.ly.

It is simple and easy to use and has a good GUI of admin. NSQ is one of the best option if you want to implement Message Queue.

Concept of Message Queue

Message Queue is an implementation of the publisher/subscriber architectural pattern which is used for communication between different parts (applications, services, etc) of your system.

 

Message Queue process flow

 

In short, when an event happens by a message published (producer) to the Queue (shown as picture above).  Any services that interested in that services will subscribe (consumer) to get the message from the Queue.

NSQ Component

NSQ components consist of nsqd, nsqlookupd, nsqadmin.

nsqd is the daemon that receives, queues, and delivers messages to clients.

nsqlookupd is the daemon that manages topology information. Clients query nsqlookupd to discover nsqd producers for a specific topic and nsqd nodes broadcasts topic and channel information

nsqadmin is a Web UI to view aggregated cluster stats in realtime and perform various administrative tasks.

 

 nsqadmin GUI

 

Download

First of all, you need to download the binary here as following your operating system and in my case, I use Windows then I download binary for Windows.

Open extracted folder and there you can see different executables:

• nsqlookupd.exe
• nsqd.exe
• nsqadmin.exe
• .. and many others 

Step 1. Run nsqlookupd

Open extracted directory in shell/command terminal you prefer and run

C:\nsq-1.2.1.windows-amd64.go1.16.6\bin>nsqlookupd.exe

You should see the following output as below

nsqlookupd

 

 

This picture says that nsqlookupd is running and has two interfaces:
one is using TCP with port 4160 and another is using HTTP with port 4161

 

 Let's check the result

Check with browser http://localhost:4161/topics

 

Check with curl localhost:4161/topics

 

 

 This is the result you should get and its fine since there is no topics registered yet

 

 

Step 2. Run nsqd

Next step, run nsqd in terminal

 C:\nsq-1.2.1.windows-amd64.go1.16.6\bin>nsqd --lookupd-tcp-address=127.0.0.1:4160

 

 

 You should get result as shown as picture below

nsqd in terminal

 

 

Step 3. Publish a Message

Let us publish our first message in Queue. Open terminal to execute curl:

 

curl -H "Content-Type: application/json" -X POST http://localhost:4151/pub?topic=test -d "{\"Hello World 1\"}"

If the request is 200 OK, our new topic will be created automatically

 

  curl in terminal

 

 

Step 4. Run nsqadmin

 Let's check the message in admin UI. Open terminal to execute nsqadmin

 

 C:\nsq-1.2.1.windows-amd64.go1.16.6\bin>nsqadmin --lookupd-http-address=127.0.0.1:4161

 

 

Result in browser http://localhost:4171

 

 

 Click in topic to show detail

 

 

 

Step 5. Alternative to check with nsq_to_file

Open in terminal to execute nsq_to_file

C:\nsq-1.2.1.windows-amd64.go1.16.6\bin>nsq_to_file --topic=test --output-dir=/tmp --lookupd-http-address=127.0.0.1:4161

 

 nsq_to_file in terminal

 

 

 nsq_to_file will create new file test.LAPTOP-91JM58QI.2023-02-28_16.log in folder C:\tmp

 

 

 

File created by nsq_to_file

 

 

Try to send message as below

 

curl -H "Content-Type: application/json" -X POST http://localhost:4151/pub?topic=test -d "{\"Hello World 1\"}" 

 

curl -H "Content-Type: application/json" -X POST http://localhost:4151/pub?topic=test -d "{\"Hello World 2\"}" 

 

curl -H "Content-Type: application/json" -X POST http://localhost:4151/pub?topic=test -d "{\"Hello World 3\"}"

 

 

 

send Hello World

 

 

 If you open the file test.LAPTOP-91JM58QI.2023-02-28_16.log in notepad then you will get message

 

{"Hello World 1"}
{"Hello World 2"}
{"Hello World 3"}

 

 

 

I think that's all. If you read something interesting from this article, please like and comment below. Thank you all ... Happy coding!

 

 

 

 

 

Getting Started with KrakenD API Gateway on Docker

 If you want to develop an application in cloud environment and want to implement micro-services architecture pattern then sooner or later you will face with API Gateways. There are many API Gateway outside that we can use it and in terms of open source such as Kong, KrakenD, Tyk. In this session, I will use KrakenD API Gateway on Docker to implement API Gateway. As an example, I will use https://jsonplaceholder.typicode.com for accessing data through KrakenD as API Gateway.  

For KrakenD documentation, you can read it from here

For JSONPlaceholder guide, you can read it from here

 

Configuration KrakenD Gateway

To configure KrakenD json gateway can be done by using KrakenD designer. You can design and download the file configuration easily by online.

KrakenD API Gateway designer

Here is some endpoint that I have made it through KrakenD API gateway designer

 Endpoint in KrakenD designer

 

 

Route Mapping

 I download it the file and rename it with krakend.json shown as below

{

  "$schema": "https://www.krakend.io/schema/v3.json",

  "name": "KrakenD-API Gateway",

  "version": 3,

  "timeout": "3000ms",

  "cache_ttl": "300s",

  "port": 8080,

  "endpoints": [

    {

      "endpoint": "/v1/api/posts",

      "output_encoding": "no-op",

      "backend": [

        {

          "host": [

              "https://jsonplaceholder.typicode.com"

          ],

          "url_pattern": "/posts",

          "is_collection": "true",

          "encoding": "no-op"

        }

      ]

    },

    {

      "endpoint": "/v1/api/posts/{userId}",

      "output_encoding": "no-op",

      "backend": [

        {

          "host": [

              "https://jsonplaceholder.typicode.com"

          ],

          "url_pattern": "/posts/{userId}",

          "encoding": "no-op"

        }

      ]

    }

  ],

  "extra_config": {

    "github_com/devopsfaith/krakend-cors": {

      "allow_methods": [

        "GET",

        "HEAD",

        "POST",

        "PUT",

        "DELETE",

        "CONNECT",

        "OPTIONS",

        "TRACE",

        "PATCH"

      ]

    }

  },

  "output_encoding": "no-op"

}

Installing Docker

Installing docker on Windows is easy, you just downloaded the binary and install it by following the instruction. I have installed Docker Desktop on my windows and it is including docker compose. 

My Docker version shown as below:

C:\>docker --version
Docker version 20.10.22, build 3a2c30b

C:\>docker-compose version
Docker Compose version v2.15.1

 

Dockerfile as below

FROM devopsfaith/krakend:2.0.5

COPY krakend.json /etc/krakend/krakend.json

Implementing

Create a new folder with name krakend then copy Dockerfile and krakend.json into that folder. 

From folder krakend, run this command:

 

docker build . -t api-gateway-v1

Result docker build

 

Make sure your port setting is the same as krakend.json

 docker run -it -p "8080:8080" api-gateway-v1

Result docker run

Docker desktop will create the container and images as shown as below

 

 

 

Testing

To check KrakenD is running well, it can be done by inputting 

http://localhost:8080/__health 

to your browser, shown as below

 

KrakenD is running well

To check the endpoint KrakenD, it can be done in browser by inputting 

http://localhost:8080/v1/api/posts

 

 To check another endpoint by inputting 

http://localhost:8080/v1/api/posts/1

 

 

Summary

I think KrakenD has bright future. All features that you need in API Gateway is covered by KrakenD. If you have any problem in implementing KrakenD, they have very good community to support you. I hope this article will help you in implementing KrakenD. Thank you

 

 

Programming a Guess Game in Rust

 

Setting Up a New Project

Create new project with cargo

    cargo new --bin guessing-game
    cd guessing-game

 

Processing The Code

 Setting dependencies in Cargo.toml

[package]

name = "guessing-game"

version = "0.1.0"

edition = "2021"

[dependencies]

rand = "0.8.5"

 

 Replace the code in src/main.rs

use std::io;

use rand::Rng;

fn main() {

    println!("Guess the number!");

    //Generating random number from 1 to 100

    let secret_number = rand::thread_rng().gen_range(1..=100);

    println!("Please input your guess.");

    let mut guess = String::new();

    //Receiving input

    io::stdin()

        .read_line(&mut guess)

        .expect("Failed to read line");

    //Converting String to Int

    let input: u32 = guess

        .trim()

        .parse()

        .expect("Wanted a number");    

   

    if secret_number == input {

        println!("You are the Best");

    } else {

        println!("You are wrong");

    }

    println!("You guessed: {guess}");

 }

 

 

Testing The Code

 Run the code in terminal with command

    cd guessing-game

    cargo run
 

 Here is the Result 

 PS C:\guessing-game> cargo run
    Finished dev [unoptimized + debuginfo] target(s) in 0.02s
     Running `target\debug\guess.exe`
    Guess the number!
    Please input your guess.
    15
    You are wrong
    You guessed: 15

 Code can be downloaded here