Task: a cooperative thread

The tasks module provides one of the most important pieces of evergreen, the Task class along with some utility functions. The Task class encapsulates a unit of cooperative work and it has an API which is very similar to the Thread class in the standard library.

evergreen.tasks.sleep(seconds)

Suspend the current task until the given amount of time has elapsed.

evergreen.tasks.spawn(func, *args, **kwargs)

Create a Task object to run func(*args, **kwargs) and start it. Returns the Task object.

evergreen.tasks.task()

Decorator to run the decorated function in a Task.

class evergreen.tasks.Task(target=None, args=(), kwargs={})

Runs the given target function with the specified arguments as a cooperative task.

classmethod current()

Returns the current running task instance.

start()

Schedules the task to be run.

run()

Main method the task will execute. Subclasses may want to override this method instead of passing arguments to __init__.

join(timeout=None)

Wait until the task finishes for the given amount of time. Returns a boolean flag indicating if the task finished the work or not.

kill(typ=TaskExit[, value[, tb]])

Raises the given exception (TaskExit by default) in the task. If the task wasn’t run yet it will be raised the moment it runs. If the task was already running, it will be raised when it yields control.

Calling this function doesn’t unschedule the current task.

exception evergreen.tasks.TaskExit

Exception used to kill a single task. It does not propagate.