NATS JetStream

Introduction

Core NATS delivers messages only to subscribers connected at the moment of publication. NATS JetStream adds a persistence layer on top, giving you at-least-once delivery.

Setting up JetStream

First, connect to NATS server, for this example we'll use localhost connection:

nats context add localhost --description "Localhost"

Then, create a log stream for FlowG:

nats stream add FLOWG --subjects "flowg" --storage file --retention limits --defaults

Setting up the FlowG pipeline

First, let's create a "JetStream Forwarder" named jetstream, with the following configuration:

Forwarder TypeJetStream

Servershttp://localhost:4222

Subjectflowg

BodytoJSON(log)

Message ID

Expected StreamFLOWG

Publish Timeout0

---

Auth modeNONE

---

TLS Insecure Skip Verify

Then, create a pipeline that forwards logs received via Syslog to the jetstream forwarder:

SourceSYSLOG

Forwarderjetstream

And that's it!

Testing

You can test the setup by sending a log to the pipeline using the logger command:

logger -n localhost -P 5514 -t myapp1 'hello world'

You can then find your logs using nats CLI interface, with command:

nats stream get FLOWG 1