python-sdk/open_feature/hooks/hook_support.py

134 lines
4.3 KiB
Python

import logging
import typing
from functools import reduce
from open_feature.evaluation_context.evaluation_context import EvaluationContext
from open_feature.flag_evaluation.flag_evaluation_details import FlagEvaluationDetails
from open_feature.flag_evaluation.flag_type import FlagType
from open_feature.hooks.hook import Hook
from open_feature.hooks.hook_context import HookContext
from open_feature.hooks.hook_type import HookType
def error_hooks(
flag_type: FlagType,
hook_context: HookContext,
exception: Exception,
hooks: typing.List[Hook],
hints: typing.Optional[typing.Mapping] = None,
):
kwargs = {"hook_context": hook_context, "exception": exception, "hints": hints}
_execute_hooks(
flag_type=flag_type, hooks=hooks, hook_method=HookType.ERROR, **kwargs
)
def after_all_hooks(
flag_type: FlagType,
hook_context: HookContext,
hooks: typing.List[Hook],
hints: typing.Optional[typing.Mapping] = None,
):
kwargs = {"hook_context": hook_context, "hints": hints}
_execute_hooks(
flag_type=flag_type, hooks=hooks, hook_method=HookType.FINALLY_AFTER, **kwargs
)
def after_hooks(
flag_type: FlagType,
hook_context: HookContext,
details: FlagEvaluationDetails,
hooks: typing.List[Hook],
hints: typing.Optional[typing.Mapping] = None,
):
kwargs = {"hook_context": hook_context, "details": details, "hints": hints}
_execute_hooks_unchecked(
flag_type=flag_type, hooks=hooks, hook_method=HookType.AFTER, **kwargs
)
def before_hooks(
flag_type: FlagType,
hook_context: HookContext,
hooks: typing.List[Hook],
hints: typing.Optional[typing.Mapping] = None,
) -> EvaluationContext:
kwargs = {"hook_context": hook_context, "hints": hints}
executed_hooks = _execute_hooks_unchecked(
flag_type=flag_type, hooks=hooks, hook_method=HookType.BEFORE, **kwargs
)
filtered_hooks = list(filter(lambda hook: hook is not None, executed_hooks))
if filtered_hooks:
return reduce(lambda a, b: a.merge(b), filtered_hooks)
return EvaluationContext()
def _execute_hooks(
flag_type: FlagType, hooks: typing.List[Hook], hook_method: HookType, **kwargs
) -> list:
"""
Run multiple hooks of any hook type. All of these hooks will be run through an
exception check.
:param flag_type: particular type of flag
:param hooks: a list of hooks
:param hook_method: the type of hook that is being run
:param kwargs: arguments that need to be provided to the hook method
:return: a list of results from the applied hook methods
"""
if hooks:
filtered_hooks = list(
filter(
lambda hook: hook.supports_flag_value_type(flag_type=flag_type), hooks
)
)
return [
_execute_hook_checked(hook, hook_method, **kwargs)
for hook in filtered_hooks
]
return []
def _execute_hooks_unchecked(
flag_type: FlagType, hooks, hook_method: HookType, **kwargs
) -> list:
"""
Execute a single hook without checking whether an exception is thrown. This is
used in the before and after hooks since any exception will be caught in the
client.
:param flag_type: particular type of flag
:param hooks: a list of hooks
:param hook_method: the type of hook that is being run
:param kwargs: arguments that need to be provided to the hook method
:return: a list of results from the applied hook methods
"""
if hooks:
filtered_hooks = list(
filter(
lambda hook: hook.supports_flag_value_type(flag_type=flag_type), hooks
)
)
return [getattr(hook, hook_method.value)(**kwargs) for hook in filtered_hooks]
return []
def _execute_hook_checked(hook: Hook, hook_method: HookType, **kwargs):
"""
Try and run a single hook and catch any exception thrown. This is used in the
after all and error hooks since any error thrown at this point needs to be caught.
:param hook: a list of hooks
:param hook_method: the type of hook that is being run
:param kwargs: arguments that need to be provided to the hook method
:return: the result of the hook method
"""
try:
return getattr(hook, hook_method.value)(**kwargs)
except Exception: # noqa
logging.error(f"Exception when running {hook_method.value} hooks")