Implemented a new throttling module to remove redundance in the project.

This commit is contained in:
pablo 2020-12-26 18:54:04 +01:00
parent f207dd5dda
commit 2a9483981e
2 changed files with 298 additions and 0 deletions

192
core/throttling_utils.py Normal file
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from typing import List, Callable
import datetime
class BaseThrottlingRule:
"""
Interface for all throttling rules.
"""
def __call__(self, **kwargs) -> bool:
"""
Upon calling the rule itself, the underlying check gets executed.
:param kwargs: arguments for check
:return: True if the check is OK, False otherwise
"""
return self._check_rule(**kwargs)
def _check_rule(self, **kwargs) -> bool:
"""
Interface for internal method to check the rule.
:param kwargs: arguments for check
:return: True if the check is OK, False otherwise
"""
raise NotImplementedError
class WorkingHoursThrottlingRule(BaseThrottlingRule):
"""
Rule for checking if current time is within the defined working hours.
"""
def __init__(self, working_hours: dict) -> None:
"""
Set the working hours as a dict with "start" and "end" keys, which
contain time objects.
:param working_hours: the definition of the working hours range
:return: None
"""
self._working_hours = working_hours
def _check_rule(self) -> bool:
"""
Call underyling check method.
:return: True if the check is OK, False otherwise
"""
return self._inside_working_hours()
def _inside_working_hours(self) -> bool:
"""
Checks if the current time is between the defined window of working
hours.
:return: True if within range, False otherwise
"""
return (
self._working_hours["start"]
<= datetime.datetime.now().time()
<= self._working_hours["end"]
)
class CooldownThrottlingRule(BaseThrottlingRule):
"""
Rule for checking if a certain time period has passed since the last
execution.
:attribute required_arguments: the list with arguments expected to be ready
for unpacking when checking the rule.
"""
required_arguments = ["last_attempt_timestamp"]
def __init__(self, cooldown_time_generator: Callable) -> None:
"""
Set the passed cooldown timer generator.
:param cooldown_time_generator: a callable object that returns some
number of seconds. Can be random or static.
"""
self._cooldown_time_generator = cooldown_time_generator
self._current_cooldown_time = self._cooldown_time_generator()
def _check_rule(self, **kwargs) -> bool:
"""
Unpack argument and call underyling check method.
:return: True if the check is OK, False otherwise
"""
last_attempt_timestamp = kwargs["last_attempt_timestamp"]
return self._check_if_cooldowned(last_attempt_timestamp)
def _check_if_cooldowned(self, last_attempt_timestamp: datetime) -> bool:
"""
Checks if the cooldown time has passed. If so, set a new one.
:param last_attempt_timestamp: timestamp for the last time whatever
must be throttled happened.
:return: True if the cooldown time has passed, False otherwise
"""
cooldown_release_timestamp = last_attempt_timestamp + datetime.timedelta(
seconds=self._current_cooldown_time
)
if datetime.datetime.now() > cooldown_release_timestamp:
self._current_cooldown_time = self._cooldown_time_generator()
return True
return False
class DynamicThrottlingRule(BaseThrottlingRule):
"""
A basic interface to dynamically set any function, optionally with
arguments, as a throttling rule.
"""
def __init__(self, any_callable: Callable) -> None:
"""
Sets the callable that will act as a check. Only condition is that the
callable should return a boolean value.
:param any_callable: the check callable object
"""
self._some_rule = any_callable
def _check_rule(self, **kwargs) -> bool:
"""
Calls the dynamically set callable while passing any given arguments.
:param kwargs: arguments for check
:return: True if the check is OK, False otherwise
"""
return self._some_rule(**kwargs)
class ThrottleManager:
"""
Holds and runs all throttling rules on demand.
"""
def __init__(self) -> None:
"""
Initialize internal attributes.
"""
self._rules_to_check = []
self._rules_and_required_arguments = dict()
def allow_next_task(self, **kwargs) -> bool:
"""
Checks all the internal rules and returns whether all of them passed
successfully or not.
:param kwargs: any arguments needed by the rules
:return: True if all rules passed positively, False otherwise
"""
check_results = self._check_all_rules(**kwargs)
if not all(check_results):
return False
return True
def add_rule(
self, rule: BaseThrottlingRule, required_argument_names: List[str] = None
) -> "ThrottleManager":
"""
Includes a new rule to the manager together with the argument names
that the rule call expects.
:param rule: the rule instance
:param required_argument_names: the required argument names to execute
the check for that rule
:return: the ThrottleManager instance
"""
required_argument_names = required_argument_names or []
self._rules_to_check.append(rule)
self._rules_and_required_arguments[rule.__class__] = required_argument_names
return self
def _check_all_rules(self, **kwargs) -> List[bool]:
"""
Executes all checks with the right arguments for each of them and
collects results.
:param kwargs: all passed arguments
:return: the result of each individual check
"""
checks = []
for rule in self._rules_to_check:
arguments_for_rule = {
argument_name: kwargs[argument_name]
for argument_name in self._rules_and_required_arguments[rule.__class__]
}
checks.append(rule(**arguments_for_rule))
continue
return checks

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tests/throttling_test.py Normal file
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import datetime
from core.throttling_utils import (
ThrottleManager,
CooldownThrottlingRule,
WorkingHoursThrottlingRule,
DynamicThrottlingRule,
)
def test_working_hours_throttling_rule_checks():
working_hours_rule = WorkingHoursThrottlingRule(
working_hours={
"start": datetime.datetime.now().time(),
"end": (datetime.datetime.now() + datetime.timedelta(hours=1)).time(),
}
)
assert working_hours_rule() == True
def test_working_hours_throttling_rule_does_not_check():
working_hours_rule = WorkingHoursThrottlingRule(
working_hours={
"start": (datetime.datetime.now() + datetime.timedelta(hours=1)).time(),
"end": (datetime.datetime.now() + datetime.timedelta(hours=2)).time(),
}
)
assert working_hours_rule() == False
def test_cooldown_throttling_rule_checks():
time_generator = lambda: 60
cooldown_rule = CooldownThrottlingRule(cooldown_time_generator=time_generator)
assert (
cooldown_rule(
last_attempt_timestamp=datetime.datetime.now()
+ datetime.timedelta(seconds=-120)
)
== True
)
def test_cooldown_throttling_rule_does_not_check():
time_generator = lambda: 60
cooldown_rule = CooldownThrottlingRule(cooldown_time_generator=time_generator)
assert cooldown_rule(last_attempt_timestamp=datetime.datetime.now()) == False
def test_dynamic_rule_checks():
mock_check = lambda: True
rule = DynamicThrottlingRule(any_callable=mock_check)
assert rule() == True
def test_dynamic_rule_does_not_check():
mock_check = lambda: False
rule = DynamicThrottlingRule(any_callable=mock_check)
assert rule() == False
def test_dynamic_rule_arguments_pass_properly():
def pass_a_bool(some_bool):
return some_bool
rule = DynamicThrottlingRule(pass_a_bool)
assert (rule(some_bool=True) == True) and (rule(some_bool=False) == False)
def test_throttle_manager_checks_rules():
throttle_manager = ThrottleManager()
def pass_a_bool(some_bool):
return some_bool
some_rules = [
WorkingHoursThrottlingRule(
working_hours={
"start": datetime.datetime.now().time(),
"end": (datetime.datetime.now() + datetime.timedelta(hours=1)).time(),
}
),
CooldownThrottlingRule(cooldown_time_generator=lambda: 0),
DynamicThrottlingRule(any_callable=pass_a_bool),
]
some_arguments = [[], ["last_attempt_timestamp"], ["some_bool"]]
some_rules_and_arguments = zip(some_rules, some_arguments)
for rule, arguments in some_rules_and_arguments:
throttle_manager.add_rule(rule, required_argument_names=arguments)
assert throttle_manager.allow_next_task(
last_attempt_timestamp=datetime.datetime.now(), some_bool=True
)