Add URL prefix for Locust test

Question

I've developed a self-service tool in AWS that allows the user to spin up a Locust instance with Fargate containers as workers. This requires that every test have a name, e.g. "my-test-1", and that every test be accessed via a unique URL. Previously, that URL was (e.g.) https://locust-test-my-test-1.mycompany.tld/. I want to change it to (e.g.) https://locust-test-runner.mycompany.tld/my-test-1. I can get the ELB to route traffic to the right place, but I get a 404 from the running instance of Locust. How do I add a URL prefix to Locust such that (e.g.) /my-test-1 is prepended to all Locust paths?

Answer 1

I ended up using DispatcherMiddleware from werkzeug like so:

web_ui = env.create_web_ui(
  port=LOCUST_HTTP_PORT,
  stats_csv_writer=stats_csv_writer,
  delayed_start=True
)
if TEST_PATH: # defined in process.env
  path = TEST_PATH
  if path[0] != '/':
    path = '/' + path
  config = copy.deepcopy(web_ui.app.config)
  logger.debug(f"Set prefix to {path}")
  # h/t: https://dlukes.github.io/flask-wsgi-url-prefix.html
  web_ui.app = DispatcherMiddleware(Response('Not Found', status=404), {path: web_ui.app})
  web_ui.app.config = config # Necessary to keep the Locust web UI working