Jester

JetStream tester using Golang. This is an open-source tool for testing a NATS JetStream cluster. Jester is a combination of three components, Agent Publisher, and Consumer. Agent is the brain behind Jester. What it does is to control publishers, consumers, and the NATS cluster. It monitors events that are being sent to cluster to give us a blackbox.

How it works?

Jester agent is the core component. Every other component sends its events to the agent via HTTP call over an endpoint named /cover. Agent uses an ETCD storage in order to keep track of these events. Finally, it exposes them as prometheus metrics over /metrics endpoint.

events

A list of the events that are being passed to Jester agent:

• New Subscriber
• Remove Subscriber
• New Publisher
• Remove Publisher
• Publish
• Consume
• Publish Failure
• Failed Connection
• Retry Per Connection
• Latency

Setup

If you want to test Jester, change the config files in config dir. The example config file is based on docker-compose.yml settings. Make sure to update the services names if you changed anything.

Start the example case:

docker-compose up -d

example.config

etcd:
  endpoints:
    - "etcd:2379"
  timeout: 5 # seconds
http:
  agent: "http://agent:8080" # address of the jester agenet
  port: 8080
nats:
  host: "nats://jetstream:4222"
  topic: "snappcloud.io.EVENTS"
  max_retry: 10 # times
metrics:
  enable: true
  subsystem: "jester"
  namespace: "default"
publisher_interval: 5 # seconds