Add @only decorator to TaskSets

Is your feature request related to a problem? Please describe.

Whenever I want to add a new task to one of the TaskSets, I have to manually set all @task decorators’ weights to 0 (or comment them) in order to be able to debug the new task; otherwise I have to wait until the locust randomly pick the new task.

Describe the solution you’d like

Create a @only decorator. This decorator would be attachable to methods in TaskSet classes and would cause that method to be always be called instead of the other tasks. This should be effectively equivalent to setting all existing @task decorators’ weights of that class to 0.

e.g.

@task(4)
def my_task(self):
    ...
@task(6)
def my_other_task(self):
    ...
@only
@task(3)
def task_being_tested(self):
    ...

should behave the same as

@task(0)
def my_task(self):
    ...
@task(0)
def my_other_task(self):
    ...
@task(1)
def task_being_tested(self):
    ...

This is inspired by test frameworks that let you run a single test in a suite so that you can debug it.

Describe alternatives you’ve considered

Manually setting all other @task weights to 0, or commenting them.

Additional context

N/A

[abhijitmamarde]

This is great idea, infact I would suggest to go one step ahead and instead of adding a decorator, to mark to run only that specific task, use markers concept of pytest framework (doc link).

so for the tasks defined as below:

@mark("admin")
@task(3)
def my_task(self):
    ...
@task(2)
def my_other_task(self):
    ...
@task(1)
def task_being_tested(self):
    ...

and say executed like:

$ locust -f locustfile.py -m admin

then only my_task should be executed.

Let me know what you all think about this suggestion.

[Trouv]

Thought I’d let y’all know that I’ve started implementing this in my fork, will make a PR sometime soon assuming the maintainers are interested in this feature