docs: Small errors in docs

[jscanlannyc]

Hi,

Thank you all so much for all your hard work on this project. I recently used this for a demonstration and was amazed by its power an elegance, and would like to give back however I can.

I encountered two small issues in the docs which that I would like to address. I will gladly issue a pull request for the bugs and changes mentioned in this issue. I felt it was courtesy to raise this issue first before issuing the pull request to ensure it would be acknowledged and accepted.

Describe the bug

https://docs.locust.io/en/stable/extending-locust.html#run-a-background-greenlet

There are two python errors in the code provided on this page, which is generated by https://github.com/locustio/locust/blob/master/docs/extending-locust.rst:

Bug 1

The first example is as follows:

from locust import events

@events.request.add_listener
def my_request_handler(request_type, name, response_time, response_length, response,
                       context, exception, start_time, url, **kwargs):
    if exception:
        print(f"Request to {name} failed with exception {exception}")
    else:
        print(f"Successfully made a request to: {name})
        print(f"The response was {response.text}")

The "Successfully made a request to" f-string is invalid. Running this sample code will raise an error at runtime.

Bug 2

In Running a background greenlet in

from locust import events
from locust.runners import STATE_STOPPING, STATE_STOPPED, STATE_CLEANUP, MasterRunner, LocalRunner

def checker(environment):
    while not environment.runner.state in [STATE_STOPPING, STATE_STOPPED, STATE_CLEANUP]:
        time.sleep(1)
        if environment.runner.stats.total.fail_ratio > 0.2:
            print(f"fail ratio was {environment.runner.stats.total.fail_ratio}, quitting")
            environment.runner.quit()
            return


@events.init.add_listener
def on_locust_init(environment, **_kwargs):
    # dont run this on workers, we only care about the aggregated numbers
    if isinstance(environment.runner, MasterRunner) or isinstance(environment.runner, LocalRunner):
        gevent.spawn(checker, environment)

This sample code will fail in on_locust_init as it does not import gevent before using it. Running this code will raise an error at runtime.

Expected behavior

The code should be copy-and-pasteable from the docs without much modification to work. In both instances these are whole self-contained tasks and not classes.

Actual behavior

The code fails when copy-pasting into a new locust task file.

Steps to reproduce

1. After installing locust, copy and paste the code into a locustfile.py and run locust.

Suggested Fixes

Bug 1

Change invalid f-string to:

print(f"Successfully made a request to: {name}")

Bug 2

Import gevent, which gets installed as a dependency of locust.

import gevent
from locust import events
from locust.runners import STATE_STOPPING, STATE_STOPPED, STATE_CLEANUP, MasterRunner, LocalRunner

I again will gladly volunteer to make this change and issue a pull request.

Environment

• OS: Mac OS Big Sur 11.6.8
• Python version: 3.10.8
• Locust version: 2.13.0
• Locust command line that you ran: locust
• Locust file contents (anonymized if necessary):

[cyberw]

Looking forward to the PR! Thanks!

[jscanlannyc]

PR: #2254

[jscanlannyc]

Hi,

Closing out this issue. Thanks for taking my contribution.

[cyberw]

👍👍