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Primary interface for idempotent Lambda functions utility
"""
from __future__ import annotations
import functools
import logging
import os
import warnings
from inspect import isclass
from typing import TYPE_CHECKING, Any, Callable, cast
from aws_lambda_powertools.middleware_factory import lambda_handler_decorator
from aws_lambda_powertools.shared import constants
from aws_lambda_powertools.shared.functions import strtobool
from aws_lambda_powertools.shared.types import AnyCallableT
from aws_lambda_powertools.utilities.idempotency.base import IdempotencyHandler
from aws_lambda_powertools.utilities.idempotency.config import IdempotencyConfig
from aws_lambda_powertools.utilities.idempotency.serialization.base import (
BaseIdempotencyModelSerializer,
BaseIdempotencySerializer,
)
if TYPE_CHECKING:
from aws_lambda_powertools.utilities.idempotency.persistence.base import (
BasePersistenceLayer,
)
from aws_lambda_powertools.utilities.typing import LambdaContext
from aws_lambda_powertools.warnings import PowertoolsUserWarning
logger = logging.getLogger(__name__)
@lambda_handler_decorator
def idempotent(
handler: Callable[[Any, LambdaContext], Any],
event: dict[str, Any],
context: LambdaContext,
persistence_store: BasePersistenceLayer,
config: IdempotencyConfig | None = None,
**kwargs,
) -> Any:
"""
Decorator to handle idempotency
Parameters
----------
handler: Callable
Lambda's handler
event: dict
Lambda's Event
context: dict
Lambda's Context
persistence_store: BasePersistenceLayer
Instance of BasePersistenceLayer to store data
config: IdempotencyConfig
Configuration
Examples
--------
**Processes Lambda's event in an idempotent manner**
>>> from aws_lambda_powertools.utilities.idempotency import (
>>> idempotent, DynamoDBPersistenceLayer, IdempotencyConfig
>>> )
>>>
>>> idem_config=IdempotencyConfig(event_key_jmespath="body")
>>> persistence_layer = DynamoDBPersistenceLayer(table_name="idempotency_store")
>>>
>>> @idempotent(config=idem_config, persistence_store=persistence_layer)
>>> def handler(event, context):
>>> return {"StatusCode": 200}
"""
# Skip idempotency controls when POWERTOOLS_IDEMPOTENCY_DISABLED has a truthy value
# Raises a warning if not running in development mode
if strtobool(os.getenv(constants.IDEMPOTENCY_DISABLED_ENV, "false")):
warnings.warn(
message="Disabling idempotency is intended for development environments only "
"and should not be used in production.",
category=PowertoolsUserWarning,
stacklevel=2,
)
return handler(event, context, **kwargs)
config = config or IdempotencyConfig()
config.register_lambda_context(context)
args = event, context
idempotency_handler = IdempotencyHandler(
function=handler,
function_payload=event,
config=config,
persistence_store=persistence_store,
function_args=args,
function_kwargs=kwargs,
)
return idempotency_handler.handle()
def idempotent_function(
function: AnyCallableT | None = None,
*,
data_keyword_argument: str,
persistence_store: BasePersistenceLayer,
config: IdempotencyConfig | None = None,
output_serializer: BaseIdempotencySerializer | type[BaseIdempotencyModelSerializer] | None = None,
**kwargs: Any,
) -> Any:
"""
Decorator to handle idempotency of any function
Parameters
----------
function: Callable
Function to be decorated
data_keyword_argument: str
Keyword parameter name in function's signature that we should hash as idempotency key, e.g. "order"
persistence_store: BasePersistenceLayer
Instance of BasePersistenceLayer to store data
config: IdempotencyConfig
Configuration
output_serializer: BaseIdempotencySerializer | type[BaseIdempotencyModelSerializer] | None
Serializer to transform the data to and from a dictionary.
If not supplied, no serialization is done via the NoOpSerializer.
In case a serializer of type inheriting BaseIdempotencyModelSerializer is given,
the serializer is derived from the function return type.
Examples
--------
**Processes an order in an idempotent manner**
from aws_lambda_powertools.utilities.idempotency import (
idempotent_function, DynamoDBPersistenceLayer, IdempotencyConfig
)
idem_config=IdempotencyConfig(event_key_jmespath="order_id")
persistence_layer = DynamoDBPersistenceLayer(table_name="idempotency_store")
@idempotent_function(data_keyword_argument="order", config=idem_config, persistence_store=persistence_layer)
def process_order(customer_id: str, order: dict, **kwargs):
return {"StatusCode": 200}
"""
if not function:
return cast(
AnyCallableT,
functools.partial(
idempotent_function,
data_keyword_argument=data_keyword_argument,
persistence_store=persistence_store,
config=config,
output_serializer=output_serializer,
**kwargs,
),
)
if isclass(output_serializer) and issubclass(output_serializer, BaseIdempotencyModelSerializer):
# instantiate an instance of the serializer class
output_serializer = output_serializer.instantiate(function.__annotations__.get("return", None))
config = config or IdempotencyConfig()
@functools.wraps(function)
def decorate(*args, **kwargs):
# Skip idempotency controls when POWERTOOLS_IDEMPOTENCY_DISABLED has a truthy value
# Raises a warning if not running in development mode
if strtobool(os.getenv(constants.IDEMPOTENCY_DISABLED_ENV, "false")):
warnings.warn(
message="Disabling idempotency is intended for development environments only "
"and should not be used in production.",
category=PowertoolsUserWarning,
stacklevel=2,
)
return function(*args, **kwargs)
if data_keyword_argument not in kwargs:
raise RuntimeError(
f"Unable to extract '{data_keyword_argument}' from keyword arguments."
f" Ensure this exists in your function's signature as well as the caller used it as a keyword argument",
)
payload = kwargs.get(data_keyword_argument)
idempotency_handler = IdempotencyHandler(
function=function,
function_payload=payload,
config=config,
persistence_store=persistence_store,
output_serializer=output_serializer,
function_args=args,
function_kwargs=kwargs,
)
return idempotency_handler.handle()
return cast(AnyCallableT, decorate)
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