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Explore NATS Queueing

NATS supports message queueing using queue groups. Subscribers register a queue group name. A single subscriber in the group is randomly selected to receive the message.



1. Start the NATS server.


2. Clone the repositories for each client examples

go get github.com/nats-io/go-nats
git clone https://github.com/nats-io/node-nats.git
git clone https://github.com/nats-io/ruby-nats.git

3. Run the Go client subscriber with queue group name.

cd $GOPATH/src/github.com/nats-io/go-nats/examples
go run nats-qsub.go foo my-queue

4. Install and run the Node client subscriber with queue group name.

npm install nats
cd node-nats/examples
node node-sub foo my-queue

5. Install and run the Ruby client subscriber with queue group name.

gem install nats
nats-queue foo my-queue &

6. Run another Go client subscriber without the queue group.

cd $GOPATH/src/github.com/nats-io/go-nats/examples
go run nats-sub.go foo

7. Publish a NATS message using the Go client.

cd $GOPATH/src/github.com/nats-io/go-nats/examples
go run nats-pub.go foo "Hello NATS!"

8. Verify message publication and receipt.

You should see that the publisher sends the message: Published [foo] : ‘Hello NATS!’

You should see that only one of the my-queue group subscribers receives the message. In addition, the Go client subscriber not in the my-queue group should also receive the message.

9. Publish another message.

go run nats-pub.go foo "Hello NATS Again!"

You should see that a different queue group subscriber receives the message this time, chosen at random among the 3 queue group members.