[fix]: input payload too big to fit in initial execution state

src/aws_durable_execution_sdk_python/execution.py

@@ -69,32 +69,6 @@ def from_json_dict(input_dict: MutableMapping[str, Any]) -> InitialExecutionStat
             next_marker=input_dict.get("NextMarker", ""),
         )
 
-    def get_execution_operation(self) -> Operation | None:
-        if not self.operations:
-            # Due to payload size limitations we may have an empty operations list.
-            # This will only happen when loading the initial page of results and is
-            # expected behaviour. We don't fail, but instead return None
-            # as the execution operation does not exist
-            msg: str = "No durable operations found in initial execution state."
-            logger.debug(msg)
-            return None
-
-        candidate = self.operations[0]
-        if candidate.operation_type is not OperationType.EXECUTION:
-            msg = f"First operation in initial execution state is not an execution operation: {candidate.operation_type}"
-            raise DurableExecutionsError(msg)
-
-        return candidate
-
-    def get_input_payload(self) -> str | None:
-        # It is possible that backend will not provide an execution operation
-        # for the initial page of results.
-        if not (operations := self.get_execution_operation()):
-            return None
-        if not (execution_details := operations.execution_details):
-            return None
-        return execution_details.input_payload
-
     def to_dict(self) -> MutableMapping[str, Any]:
         return {
             "Operations": [op.to_dict() for op in self.operations],
@@ -275,23 +249,6 @@ def wrapper(event: Any, context: LambdaContext) -> MutableMapping[str, Any]:
                 else LambdaClient.initialize_client()
             )
 
-        raw_input_payload: str | None = (
-            invocation_input.initial_execution_state.get_input_payload()
-        )
-
-        # Python RIC LambdaMarshaller just uses standard json deserialization for event
-        # https://github.com/aws/aws-lambda-python-runtime-interface-client/blob/main/awslambdaric/lambda_runtime_marshaller.py#L46
-        input_event: MutableMapping[str, Any] = {}
-        if raw_input_payload and raw_input_payload.strip():
-            try:
-                input_event = json.loads(raw_input_payload)
-            except json.JSONDecodeError:
-                logger.exception(
-                    "Failed to parse input payload as JSON: payload: %r",
-                    raw_input_payload,
-                )
-                raise
-
         execution_state: ExecutionState = ExecutionState(
             durable_execution_arn=invocation_input.durable_execution_arn,
             initial_checkpoint_token=invocation_input.checkpoint_token,
@@ -309,6 +266,21 @@ def wrapper(event: Any, context: LambdaContext) -> MutableMapping[str, Any]:
             invocation_input.initial_execution_state.next_marker,
         )
 
+        raw_input_payload: str | None = execution_state.get_input_payload()
+
+        # Python RIC LambdaMarshaller just uses standard json deserialization for event
+        # https://github.com/aws/aws-lambda-python-runtime-interface-client/blob/main/awslambdaric/lambda_runtime_marshaller.py#L46
+        input_event: MutableMapping[str, Any] = {}
+        if raw_input_payload and raw_input_payload.strip():
+            try:
+                input_event = json.loads(raw_input_payload)
+            except json.JSONDecodeError:
+                logger.exception(
+                    "Failed to parse input payload as JSON: payload: %r",
+                    raw_input_payload,
+                )
+                raise
+
         durable_context: DurableContext = DurableContext.from_lambda_context(
             state=execution_state, lambda_context=context
         )

src/aws_durable_execution_sdk_python/state.py

@@ -290,6 +290,33 @@ def fetch_paginated_operations(
         with self._operations_lock:
             self.operations.update({op.operation_id: op for op in all_operations})
 
+    def get_input_payload(self) -> str | None:
+        # It is possible that backend will not provide an execution operation
+        # for the initial page of results.
+        if not (operations := self.get_execution_operation()):
+            return None
+        if not (execution_details := operations.execution_details):
+            return None
+        return execution_details.input_payload
+
+    def get_execution_operation(self) -> Operation | None:
+        # invocation id is id of execution operation
+        invocation_id = self.durable_execution_arn.split("/")[-1]
+        candidate = self.operations.get(invocation_id)
+        if not candidate:
+            # Due to payload size limitations we may have an empty operations list.
+            # This will only happen when loading the initial page of results and is
+            # expected behaviour. We don't fail, but instead return None
+            # as the execution operation does not exist
+            msg: str = "No durable operations found in execution state."
+            logger.debug(msg)
+            return None
+        if candidate.operation_type is not OperationType.EXECUTION:
+            msg = f"The execution operation in execution state does not have EXECUTION type: {candidate.operation_type}"
+            raise DurableExecutionsError(msg)
+
+        return candidate
+
     def track_replay(self, operation_id: str) -> None:
         """Check if operation exists with completed status; if not, transition to NEW status.
 

tests/execution_test.py

@@ -774,51 +774,6 @@ def test_handler(event: Any, context: DurableContext) -> dict:
         mock_lambda_client.initialize_client.assert_called_once()
 
 
-def test_initial_execution_state_get_execution_operation_no_operations():
-    """Test get_execution_operation logs debug and returns None when no operations exist."""
-    state = InitialExecutionState(operations=[], next_marker="")
-
-    with patch("aws_durable_execution_sdk_python.execution.logger") as mock_logger:
-        result = state.get_execution_operation()
-
-        assert result is None
-        mock_logger.debug.assert_called_once_with(
-            "No durable operations found in initial execution state."
-        )
-
-
-def test_initial_execution_state_get_execution_operation_wrong_type():
-    """Test get_execution_operation raises error when first operation is not EXECUTION."""
-    operation = Operation(
-        operation_id="step1",
-        operation_type=OperationType.STEP,
-        status=OperationStatus.STARTED,
-    )
-
-    state = InitialExecutionState(operations=[operation], next_marker="")
-
-    with pytest.raises(
-        Exception,
-        match="First operation in initial execution state is not an execution operation",
-    ):
-        state.get_execution_operation()
-
-
-def test_initial_execution_state_get_input_payload_none():
-    """Test get_input_payload returns None when execution_details is None."""
-    operation = Operation(
-        operation_id="exec1",
-        operation_type=OperationType.EXECUTION,
-        status=OperationStatus.STARTED,
-        execution_details=None,
-    )
-
-    state = InitialExecutionState(operations=[operation], next_marker="")
-
-    result = state.get_input_payload()
-    assert result is None
-
-
 def test_durable_handler_empty_input_payload():
     """Test durable_handler handles empty input payload correctly."""
     mock_client = Mock(spec=DurableServiceClient)
@@ -916,7 +871,7 @@ def test_handler(event: Any, context: DurableContext) -> dict:
     initial_state = InitialExecutionState(operations=[operation], next_marker="")
 
     invocation_input = DurableExecutionInvocationInputWithClient(
-        durable_execution_arn="arn:test:execution",
+        durable_execution_arn="arn:test:execution/exec1",
         checkpoint_token="token123",  # noqa: S106
         initial_execution_state=initial_state,
         service_client=mock_client,

tests/state_test.py

@@ -9,7 +9,7 @@
 import time
 import unittest.mock
 from concurrent.futures import ThreadPoolExecutor
-from unittest.mock import Mock, call
+from unittest.mock import Mock, call, patch
 
 import pytest
 
@@ -3562,3 +3562,90 @@ def test_collect_checkpoint_batch_first_empty_counts_toward_limit():
     )  # Only the leading empty; trailing deferred to next batch
     # op_2 and trailing empties remain in the queue
     assert state._checkpoint_queue.qsize() == 51
+
+
+def test_execution_state_get_execution_operation_no_operations():
+    """Test get_execution_operation logs debug and returns None when no operations exist."""
+    mock_lambda_client = Mock(spec=LambdaClient)
+    config = CheckpointBatcherConfig(
+        max_batch_size_bytes=10 * 1024 * 1024,
+        max_batch_time_seconds=10.0,
+        max_batch_operations=2,
+    )
+    state = ExecutionState(
+        durable_execution_arn="test_arn",
+        initial_checkpoint_token="token123",  # noqa: S106
+        operations={},
+        service_client=mock_lambda_client,
+        batcher_config=config,
+    )
+
+    with patch("aws_durable_execution_sdk_python.state.logger") as mock_logger:
+        result = state.get_execution_operation()
+
+        assert result is None
+        mock_logger.debug.assert_called_once_with(
+            "No durable operations found in execution state."
+        )
+
+
+def test_initial_execution_state_get_execution_operation_wrong_type():
+    """Test get_execution_operation raises error when first operation is not EXECUTION."""
+    operation = Operation(
+        operation_id="step1",
+        operation_type=OperationType.STEP,
+        status=OperationStatus.STARTED,
+    )
+
+    mock_lambda_client = Mock(spec=LambdaClient)
+    config = CheckpointBatcherConfig(
+        max_batch_size_bytes=10 * 1024 * 1024,
+        max_batch_time_seconds=10.0,
+        max_batch_operations=2,
+    )
+    state = ExecutionState(
+        durable_execution_arn="test_arn/step1",
+        initial_checkpoint_token="token123",  # noqa: S106
+        operations={"step1": operation},
+        service_client=mock_lambda_client,
+        batcher_config=config,
+    )
+
+    with pytest.raises(
+        Exception,
+        match="The execution operation in execution state does not have EXECUTION type: OperationType.STEP",
+    ):
+        state.get_execution_operation()
+
+
+def test_initial_execution_state_get_input_payload_none():
+    """Test get_input_payload returns None when execution_details is None."""
+    operation = Operation(
+        operation_id="exec1",
+        operation_type=OperationType.EXECUTION,
+        status=OperationStatus.STARTED,
+        execution_details=None,
+    )
+
+    operation = Operation(
+        operation_id="step1",
+        operation_type=OperationType.STEP,
+        status=OperationStatus.STARTED,
+    )
+
+    mock_lambda_client = Mock(spec=LambdaClient)
+    config = CheckpointBatcherConfig(
+        max_batch_size_bytes=10 * 1024 * 1024,
+        max_batch_time_seconds=10.0,
+        max_batch_operations=2,
+    )
+    state = ExecutionState(
+        durable_execution_arn="test_arn/exec1",
+        initial_checkpoint_token="token123",  # noqa: S106
+        operations={"step1": operation},
+        service_client=mock_lambda_client,
+        batcher_config=config,
+    )
+
+    result = state.get_input_payload()
+    assert result is None