README.md

Kafka + Node

This is a simple example of how to use Kafka with Node.js created for the purpose of learning.

Architecture

stateDiagram-v2
    Producer --> Kafka: Messages

    state Kafka {
        [*] --> Topic_1: Message 1
        [*] --> Topic_2: Message 2

        Topic_1 --> Consumer_1: Message 1
        Topic_2 --> Consumer_2: Message 2

        state Group_1 {
            Consumer_1
            Consumer_2
        }

        Topic_1 --> Group_2: Message 1
        Topic_2 --> Group_2: Message 2

        state Group_2 {
            [*] --> Consumer_X: Message 1
            [*] --> Consumer_X: Message 2
        }
    }

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Requirements

• Docker
• Node.js

How to run

1. Clone this repository

2. Run docker-compose up -d to start Kafka and Zookeeper services

3. Run pnpm i to install the dependencies

   I have used pnpm to run the project, but you can use npm or yarn as well.

4. Once the docker containers are up and running, run node admin.js to create the topics

5. Now, run node consumer.js group-1 to start a consumer with the group name group-1. Let's call this consumer-1

6. Next, create another terminal with the same command to start consumer-2 with the same group name group-1

7. Next, create another terminal and run node consumer.js group-2 to start the consumer with the group name group-2. Let's call this consumer-x

8. Finally, run node producer.js to start the producer.

9. To transmit a message we need to provide it in the following format:

   [RIDER_NAME]<SPACE>[ZONE]<SPACE>[LATITUDE]<SPACE>[LONGITUDE]
   

   eg: `rider-1 north 12.123456 12.123456`
   

   P.s. Zone can be set to north or south, since we have 2 partitions & subsequently support 2 consumers.

10. Transmitting a message with zone north will be consumed by one of the group-1 consumers and consumer-x.

11. Similarly, transmitting a message with zone south will be consumed by the other group-1 consumer and consumer-x.

Demo

Admin Terminal

Producer Terminal

Consumer 1 (Group 1) Terminal

Consumer 2 (Group 1) Terminal

Consumer X (Group 2) Terminal