toil.lib.throttle

Module Contents

Classes

LocalThrottle	A thread-safe rate limiter that throttles each thread independently. Can be used as a
throttle	A context manager for ensuring that the execution of its body takes at least a given amount

class toil.lib.throttle.LocalThrottle(min_interval)

A thread-safe rate limiter that throttles each thread independently. Can be used as a function or method decorator or as a simple object, via its .throttle() method.

The use as a decorator is deprecated in favor of throttle().

Parameters:

min_interval (int)

throttle(wait=True)

If the wait parameter is True, this method returns True after suspending the current thread as necessary to ensure that no less than the configured minimum interval has passed since the last invocation of this method in the current thread returned True.

If the wait parameter is False, this method immediatly returns True (if at least the configured minimum interval has passed since the last time this method returned True in the current thread) or False otherwise.

Parameters:

wait (bool)

Return type:

bool

__call__(function)

class toil.lib.throttle.throttle(min_interval)

A context manager for ensuring that the execution of its body takes at least a given amount of time, sleeping if necessary. It is a simpler version of LocalThrottle if used as a decorator.

Ensures that body takes at least the given amount of time.

>>> start = time.time()
>>> with throttle(1):
...     pass
>>> 1 <= time.time() - start <= 1.1
True

Ditto when used as a decorator.

>>> @throttle(1)
... def f():
...     pass
>>> start = time.time()
>>> f()
>>> 1 <= time.time() - start <= 1.1
True

If the body takes longer by itself, don’t throttle.

>>> start = time.time()
>>> with throttle(1):
...     time.sleep(2)
>>> 2 <= time.time() - start <= 2.1
True

Ditto when used as a decorator.

>>> @throttle(1)
... def f():
...     time.sleep(2)
>>> start = time.time()
>>> f()
>>> 2 <= time.time() - start <= 2.1
True

If an exception occurs, don’t throttle.

>>> start = time.time()
>>> try:
...     with throttle(1):
...         raise ValueError('foo')
... except ValueError:
...     end = time.time()
...     raise
Traceback (most recent call last):
...
ValueError: foo
>>> 0 <= end - start <= 0.1
True

Ditto when used as a decorator.

>>> @throttle(1)
... def f():
...     raise ValueError('foo')
>>> start = time.time()
>>> try:
...     f()
... except ValueError:
...     end = time.time()
...     raise
Traceback (most recent call last):
...
ValueError: foo
>>> 0 <= end - start <= 0.1
True

Parameters:

min_interval (Union[int, float])

__enter__()

__exit__(exc_type, exc_val, exc_tb)

__call__(function)