Request-Reply Walkthrough

NATS supports request-reply messaging. In this tutorial you explore how to exchange point-to-point messages using NATS.

Prerequisites

If you have not already done so, you need to install the nats CLI Tool and optionally, the nats-server on your machine.

Walkthrough

Start two terminal sessions. These will be used to run the NATS request and reply clients.

In one terminal, run the reply client listener

nats reply help.please 'OK, I CAN HELP!!!'

You should see the message: Listening on [help.please]

This means that the NATS receiver client is listening for request messages on the "help.please" subject. In NATS, the receiver is a subscriber.

In the other terminal, run the request client

nats request help.please 'I need help!'

The NATS requestor client makes a request by sending the message "I need help!" on the “help.please” subject.

The NATS receiver client receives the message, formulates the reply ("OK, I CAN HELP!!!"), and sends it to the inbox of the requester.