If you’re looking to monitor the state of your web application during a deployment it can be useful to run a bunch of requests to see the impact during deployment. We can use a load testing tool, like Artillery, to accomplish this.

Using Artillery

Artillery can be configured via test scripts, but it can also use command line arguments for simple scenarios. You’ll need Node.js installed to run Artillery. From the command line you can test the endpoint for 10 requests per second (rate) for 10 minutes (duration in seconds):

npx artillery quick --rate=10 --duration=600 https://example.org/health

Artillery provides an update every 10 seconds, and provides a summary at the end like this:

Summary report @ 15:28:18(-0500) 2020-12-16
  Scenarios launched:  6000
  Scenarios completed: 6000
  Requests completed:  6000
  Mean response/sec: 9.99
  Response time (msec):
    min: 77.2
    max: 909.3
    median: 98
    p95: 158.5
    p99: 279.7
  Scenario counts:
    0: 6000 (100%)
    200: 6000

If any non-success status codes were returned, like 500, they’d show up here. This means users could be impacted during the deployment.

Global install

If you’re frequently running Artillery you may want to globally install it via npm install -g artillery, rather than use npx each time. After it’s globally installed you can omit npx from the above command.