Allow self.interrupt() inside on_start

[joefreeman]

I think it would make sense to allow interrupt()-ing from inside the on_start method.

This would allow a TaskSet for, say, updating 'widgets' where the on_start gets a list of widgets, then tasks within the TaskSet perform various updates to the widgets. However, in the case where there are no widgets yet, the TaskSet would be interrupt()-ed.

I was hoping to be able to do something like this:

class WidgetTasks(locust.TaskSet):

  def on_start(self):
    r = self.client.get("/widgets")
    self.widgets = r.json["widgets"]
    if not self.widgets:
      # there are no widgets to update, so jump out of this TaskSet
      self.interrupt()

  @locust.task
  def update_widget_name(self):
    widget = random.choice(self.widgets)
    self.client.put(
      "/widgets/{0}/name".format(widget["id"]),
      data="New Name")

  # etc...

class UserTasks(locust.TaskSet):

  tasks = {WidgetTasks: 1}

  @locust.task
  def create_widget(self):
    self.client.post("/widgets")

  # etc...

I hope this make sense?

I think it would just be a case of lifting this except block out into another try block that wrapped the call to on_start and the while loop? I'd submit a pull request myself, but I haven't been able to get the unit tests to run.

[heyman]

I agree. Pushed a fix!

What problem are you having with unit tests?

[joefreeman]

Awesome, thank you!

I initially wasn't sure how to run the tests, and then didn't spend enough time installing the dependencies. But python -m unittest discover seems to work now that I've installed python-msgpack and mock.

I do still occasionally get this failure though:

======================================================================
FAIL: test_moving_average_100 (locust.test.test_average.MovingAverageTest)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Users/joe/Projects/Public/locust/locust/test/test_average.py", line 58, in test_moving_average_100
    self._assertion(taskset, deviation, max_deviation, percentage)
  File "/Users/joe/Projects/Public/locust/locust/test/test_average.py", line 45, in _assertion
    self.assertTrue(deviation < max_deviation, msg="Deviation not within %s%% of wanted average" % percentage)
AssertionError: Deviation not within 5.0% of wanted average