Provide a way to specify locust counts and hatch rate per locust class

[hyperair]

Description of issue / feature request

Currently, when running locust with multiple Locust classes, there isn't a way to specify how many instances of each locust class we want to hatch from the web interface, whether by UI widget or by API call. As a result, if we want to run tests with multiple combinations of FooLocust and BarLocust counts, we need to mess with the weightage of each locust class in the codebase of each locust slave.

Expected behavior

Ideally, there would be a way to specify the exact counts of each locust type during runtime without requiring code changes, e.g.

{
    "FooLocust": {"locust_count": 123, "hatch_rate": 12},
    "BarLocust": {"locust_count": 234, "hatch_rate": 34}
}

[thomas-phillips-nz]

You could use environment variables to change the weighting of each class as a work-around for now, rather than changing the codebase.

[cgoldberg]

send a pull request

[hyperair]

@cgoldberg Yeah, working on it.

@thomas-phillips-nz That's what I'm doing now, but the slaves need to be restarted with different environment variables set, which makes it a bit clunky.

[hyperair]

@cgoldberg PR submitted: ^

[hyperair]

Oops, it's all red, hang on.

[hyperair]

Yay, it's all green now

[cyberw]

Hi! Is this something you still need? See my comment on the PR...

[hyperair]

Hey @cyberw, thanks for getting back to me. I don't think I'll need it in the near future, but I'll keep my branch around in case I do. I still do think that the feature is desirable though.

[cyberw]

Closing this for now. Again, sorry for the slow respone on your PR :)