KeyboardInterrupt does not gracefully exit custom load shape

[ghost]

Describe the bug

KeyboardInterrupt does not gracefully exit custom load shape.

Expected behavior

A report should be generated after Ctrl-C, like with a normal test case.

Actual behavior

The program crashes:

[2021-10-21 10:07:23,218] user-vm/INFO/locust.runners: Shape worker starting
[2021-10-21 10:07:23,218] user-vm/INFO/locust.runners: Shape test updating to 10 users at 10.00 spawn rate
[2021-10-21 10:07:23,218] user-vm/INFO/locust.runners: Ramping to 10 users at a rate of 10.00 per second
[2021-10-21 10:07:23,219] user-vm/INFO/locust.runners: All users spawned: {"WebsiteUser": 10} (10 total users)
^CKeyboardInterrupt
2021-10-21T08:07:24Z
Traceback (most recent call last):
  File "/home/user/.local/bin/locust", line 8, in <module>
    sys.exit(main())
  File "/home/user/.local/lib/python3.7/site-packages/locust/main.py", line 383, in main
    start_automatic_run()
  File "/home/user/.local/lib/python3.7/site-packages/locust/main.py", line 370, in start_automatic_run
    environment.runner.shape_greenlet.join()
  File "src/gevent/greenlet.py", line 831, in gevent._gevent_cgreenlet.Greenlet.join
  File "src/gevent/greenlet.py", line 857, in gevent._gevent_cgreenlet.Greenlet.join
  File "src/gevent/greenlet.py", line 846, in gevent._gevent_cgreenlet.Greenlet.join
  File "src/gevent/_greenlet_primitives.py", line 61, in gevent._gevent_c_greenlet_primitives.SwitchOutGreenletWithLoop.switch
  File "src/gevent/_greenlet_primitives.py", line 61, in gevent._gevent_c_greenlet_primitives.SwitchOutGreenletWithLoop.switch
  File "src/gevent/_greenlet_primitives.py", line 65, in gevent._gevent_c_greenlet_primitives.SwitchOutGreenletWithLoop.switch
  File "src/gevent/_gevent_c_greenlet_primitives.pxd", line 35, in gevent._gevent_c_greenlet_primitives._greenlet_switch
KeyboardInterrupt

Steps to reproduce

Use this example from this very repo, launched as locust --headless -f step_load.py --host https://localhost:

Environment

• OS: Linux
• Python version: 3.7.3
• Locust version: 2.4.1
• Locust command line that you ran:locust --headless -f step_load.py --host https://localhost
• Locust file contents (anonymized if necessary): https://github.com/locustio/locust/blob/master/examples/custom_shape/step_load.py

[cyberw]

@max-rocket-internet Do you have a minute to look at this?

[github-actions]

This issue is stale because it has been open 30 days with no activity. Remove stale label or comment or this will be closed in 10 days.

[github-actions]

This issue was closed because it has been stalled for 10 days with no activity. This does not necessarily mean that the issue is bad, but it most likely means that nobody is willing to take the time to fix it. If you have found Locust useful, then consider contributing a fix yourself!

[JevonCowell]

I believe this issue still persists (using 2.14.2). From the error trace we see that it fails in
environment.runner.shape_greenlet.join()

It's dirty, but we could catch it like this to let it end gracefully:

# start the test
            if environment.shape_class:
                if options.run_time:
                    sys.stderr.write("It makes no sense to combine --run-time and LoadShapes. Bailing out.\n")
                    sys.exit(1)
                try:
                    logger.info("Modified Locust Main is running")
                    environment.runner.start_shape()
                    environment.runner.shape_greenlet.join()
                except KeyboardInterrupt:
                    logging.info("Exiting due to CTRL+C interruption")
                finally:
                    stop_and_optionally_quit()

Thoughts? Locust's inability to gracefully exit means @events.test_stop.add_listener doesn't work.

[cyberw]

LGTM, PR very welcome. PR with unit test even more so :)

I'd skip the "modified locust main is running" logging though (unclear what that even means)

[JevonCowell]

#2375

[JevonCowell]

Sorry to reopen this issue, I was wondering what the release cadence of locust was or something I have to do on my end to get the next version released with these changes

[cyberw]

There’s no particular cadence and the current master version has a feature that I might not want to release after all :) but I can probably squeeze it in this weekend. But you can always use the latest PR merge using pip install --pre locust