improv: Support a composite primary key in DynamoDBPersistenceLayer (#740)

* ISSUE-694: add sort key to DynamoDBPersistenceLayer

* ISSUE-694: change default pk; revert test changes for now

* ISSUE-694: PR Updates - remove test-func default name

* ISSUE-694: Change key_attr_value based on PR feedback

Author: Tankanow

aws_lambda_powertools/utilities/idempotency/persistence/dynamodb.py

@@ -1,10 +1,12 @@
 import datetime
 import logging
+import os
 from typing import Any, Dict, Optional
 
 import boto3
 from botocore.config import Config
 
+from aws_lambda_powertools.shared import constants
 from aws_lambda_powertools.utilities.idempotency import BasePersistenceLayer
 from aws_lambda_powertools.utilities.idempotency.exceptions import (
     IdempotencyItemAlreadyExistsError,
@@ -20,6 +22,8 @@ def __init__(
         self,
         table_name: str,
         key_attr: str = "id",
+        static_pk_value: str = f"idempotency#{os.getenv(constants.LAMBDA_FUNCTION_NAME_ENV, '')}",
+        sort_key_attr: Optional[str] = None,
         expiry_attr: str = "expiration",
         status_attr: str = "status",
         data_attr: str = "data",
@@ -35,7 +39,12 @@ def __init__(
         table_name: str
             Name of the table to use for storing execution records
         key_attr: str, optional
-            DynamoDB attribute name for key, by default "id"
+            DynamoDB attribute name for partition key, by default "id"
+        static_pk_value: str, optional
+            DynamoDB attribute value for partition key, by default "idempotency#<function-name>".
+            This will be used if the sort_key_attr is set.
+        sort_key_attr: str, optional
+            DynamoDB attribute name for the sort key
         expiry_attr: str, optional
             DynamoDB attribute name for expiry timestamp, by default "expiration"
         status_attr: str, optional
@@ -64,10 +73,14 @@ def __init__(
 
         self._boto_config = boto_config or Config()
         self._boto3_session = boto3_session or boto3.session.Session()
+        if sort_key_attr == key_attr:
+            raise ValueError(f"key_attr [{key_attr}] and sort_key_attr [{sort_key_attr}] cannot be the same!")
 
         self._table = None
         self.table_name = table_name
         self.key_attr = key_attr
+        self.static_pk_value = static_pk_value
+        self.sort_key_attr = sort_key_attr
         self.expiry_attr = expiry_attr
         self.status_attr = status_attr
         self.data_attr = data_attr
@@ -93,6 +106,11 @@ def table(self, table):
         """
         self._table = table
 
+    def _get_key(self, idempotency_key: str) -> dict:
+        if self.sort_key_attr:
+            return {self.key_attr: self.static_pk_value, self.sort_key_attr: idempotency_key}
+        return {self.key_attr: idempotency_key}
+
     def _item_to_data_record(self, item: Dict[str, Any]) -> DataRecord:
         """
         Translate raw item records from DynamoDB to DataRecord
@@ -117,7 +135,7 @@ def _item_to_data_record(self, item: Dict[str, Any]) -> DataRecord:
         )
 
     def _get_record(self, idempotency_key) -> DataRecord:
-        response = self.table.get_item(Key={self.key_attr: idempotency_key}, ConsistentRead=True)
+        response = self.table.get_item(Key=self._get_key(idempotency_key), ConsistentRead=True)
 
         try:
             item = response["Item"]
@@ -127,7 +145,7 @@ def _get_record(self, idempotency_key) -> DataRecord:
 
     def _put_record(self, data_record: DataRecord) -> None:
         item = {
-            self.key_attr: data_record.idempotency_key,
+            **self._get_key(data_record.idempotency_key),
             self.expiry_attr: data_record.expiry_timestamp,
             self.status_attr: data_record.status,
         }
@@ -168,7 +186,7 @@ def _update_record(self, data_record: DataRecord):
             expression_attr_names["#validation_key"] = self.validation_key_attr
 
         kwargs = {
-            "Key": {self.key_attr: data_record.idempotency_key},
+            "Key": self._get_key(data_record.idempotency_key),
             "UpdateExpression": update_expression,
             "ExpressionAttributeValues": expression_attr_values,
             "ExpressionAttributeNames": expression_attr_names,
@@ -178,4 +196,4 @@ def _update_record(self, data_record: DataRecord):
 
     def _delete_record(self, data_record: DataRecord) -> None:
         logger.debug(f"Deleting record for idempotency key: {data_record.idempotency_key}")
-        self.table.delete_item(Key={self.key_attr: data_record.idempotency_key})
+        self.table.delete_item(Key=self._get_key(data_record.idempotency_key))

tests/functional/idempotency/test_idempotency.py

@@ -783,11 +783,11 @@ def test_jmespath_with_powertools_json(
     # GIVEN an event_key_jmespath with powertools_json custom function
     persistence_store.configure(idempotency_config)
     sub_attr_value = "cognito_user"
-    key_attr_value = "some_key"
-    expected_value = [sub_attr_value, key_attr_value]
+    static_pk_value = "some_key"
+    expected_value = [sub_attr_value, static_pk_value]
     api_gateway_proxy_event = {
         "requestContext": {"authorizer": {"claims": {"sub": sub_attr_value}}},
-        "body": serialize({"id": key_attr_value}),
+        "body": serialize({"id": static_pk_value}),
     }
 
     # WHEN calling _get_hashed_idempotency_key