Locust's default HTTP client uses python-requests. The reason for this is that requests is a very well-maintained python package, that provides a really nice API, that many python developers are familiar with. Therefore, in many cases, we recommend that you use the default :pyHttpLocust <locust.core.HttpLocust> which uses requests. However, if you're planning to run really large scale tests, Locust comes with an alternative HTTP client, :pyFastHttpLocust <locust.contrib.fasthttp.FastHttpLocust> which uses geventhttpclient instead of requests. This client is significantly faster, and we've seen 5x-6x performance increases for making HTTP-requests. This does not necessarily mean that the number of users one can simulate per CPU core will automatically increase 5x-6x, since it also depends on what else the load testing script does. However, if your locust scripts are spending most of their CPU time in making HTTP-requests, you are likely to see signifant performance gains.
Subclass FastHttpLocust instead of HttpLocust:
from locust import TaskSet, task, between
from locust.contrib.fasthttp import FastHttpLocust
class MyTaskSet(TaskSet):
@task
def index(self):
response = self.client.get("/")
class MyLocust(FastHttpLocust):
task_set = MyTaskSet
wait_time = between(1, 60)Note
FastHttpLocust uses a whole other HTTP client implementation, with a different API, compared to the default HttpLocust that uses python-requests. Therefore FastHttpLocust might not work as a drop-in replacement for HttpLocust, depending on how the HttpClient is used.
Note
SSL domain check is turned off in the FastHttpLocust's client implementation. So it will let through invalid SSL certificates without complaining.
locust.contrib.fasthttp.FastHttpSession
locust.contrib.fasthttp.FastResponse