example: add callback examples

- add happy cases for create_callback examples

Author: Alex Wang

examples/examples-catalog.json

@@ -444,6 +444,61 @@
         "ExecutionTimeout": 300
       },
       "path": "./src/none_results/none_results.py"
+    },
+    {
+      "name": "Callback Success",
+      "description": "Creating a callback ID for external systems to use",
+      "handler": "callback_simple.handler",
+      "integration": true,
+      "durableConfig": {
+        "RetentionPeriodInDays": 7,
+        "ExecutionTimeout": 300
+      },
+      "path": "./src/callback/callback_simple.py"
+    },
+    {
+      "name": "Callback Success None",
+      "description": "Creating a callback ID for external systems to use",
+      "handler": "callback_simple.handler",
+      "integration": true,
+      "durableConfig": {
+        "RetentionPeriodInDays": 7,
+        "ExecutionTimeout": 300
+      },
+      "path": "./src/callback/callback_simple.py"
+    },
+    {
+      "name": "Create Callback Heartbeat",
+      "description": "Demonstrates callback failure scenarios where the error propagates and is handled by framework",
+      "handler": "callback_heartbeat.handler",
+      "integration": true,
+      "durableConfig": {
+        "RetentionPeriodInDays": 7,
+        "ExecutionTimeout": 300
+      },
+      "path": "./src/callback/callback_heartbeat.py"
+    },
+    {
+      "name": "Create Callback Mixed Operations",
+      "description": "Demonstrates createCallback mixed with steps, waits, and other operations",
+      "handler": "callback_mixed_ops.handler",
+      "integration": true,
+      "durableConfig": {
+        "RetentionPeriodInDays": 7,
+        "ExecutionTimeout": 300
+      },
+      "path": "./src/callback/callback_mixed_ops.py"
+    },
+    {
+      "name": "Create Callback Custom Serdes",
+      "description": "Demonstrates createCallback with custom serialization/deserialization for Date objects",
+      "handler": "callback_serdes.handler",
+      "integration": true,
+      "durableConfig": {
+        "RetentionPeriodInDays": 7,
+        "ExecutionTimeout": 300
+      },
+      "path": "./src/callback/callback_serdes.py"
     }
   ]
 }

examples/src/callback/callback_heartbeat.py

@@ -0,0 +1,22 @@
+from typing import TYPE_CHECKING, Any
+
+from aws_durable_execution_sdk_python.config import CallbackConfig, Duration
+from aws_durable_execution_sdk_python.context import DurableContext
+from aws_durable_execution_sdk_python.execution import durable_execution
+
+
+if TYPE_CHECKING:
+    from aws_durable_execution_sdk_python.types import Callback
+
+
+@durable_execution
+def handler(_event: Any, context: DurableContext) -> str:
+    callback_config = CallbackConfig(
+        timeout=Duration.from_seconds(60), heartbeat_timeout=Duration.from_seconds(10)
+    )
+
+    callback: Callback[str] = context.create_callback(
+        name="heartbeat_callback", config=callback_config
+    )
+
+    return callback.result()

examples/src/callback/callback_mixed_ops.py

@@ -0,0 +1,35 @@
+"""Demonstrates createCallback mixed with steps, waits, and other operations."""
+
+import time
+from typing import Any
+
+from aws_durable_execution_sdk_python.config import CallbackConfig, Duration
+from aws_durable_execution_sdk_python.context import DurableContext
+from aws_durable_execution_sdk_python.execution import durable_execution
+
+
+@durable_execution
+def handler(_event: Any, context: DurableContext) -> dict[str, Any]:
+    """Handler demonstrating createCallback mixed with other operations."""
+
+    step_result: dict[str, Any] = context.step(
+        lambda _: {"userId": 123, "name": "John Doe"},
+        name="fetch-data",
+    )
+
+    callback_config = CallbackConfig(timeout=Duration.from_minutes(1))
+    callback = context.create_callback(
+        name="process-user",
+        config=callback_config,
+    )
+
+    # Mix callback with step and wait operations
+    context.wait(Duration.from_seconds(1), name="initial-wait")
+
+    callback_result = callback.result()
+
+    return {
+        "stepResult": step_result,
+        "callbackResult": callback_result,
+        "completed": True,
+    }

examples/src/callback/callback_serdes.py

@@ -0,0 +1,76 @@
+"""Demonstrates createCallback with custom serialization/deserialization for Date objects."""
+
+import json
+from datetime import datetime, timezone
+from typing import Any, Optional
+
+from aws_durable_execution_sdk_python.config import CallbackConfig, Duration
+from aws_durable_execution_sdk_python.context import DurableContext
+from aws_durable_execution_sdk_python.execution import durable_execution
+from aws_durable_execution_sdk_python.serdes import SerDes, SerDesContext
+
+
+class CustomData:
+    """Data structure with datetime."""
+
+    def __init__(self, id: int, message: str, timestamp: datetime):
+        self.id = id
+        self.message = message
+        self.timestamp = timestamp
+
+    def to_dict(self) -> dict[str, Any]:
+        """Convert to dictionary."""
+        return {
+            "id": self.id,
+            "message": self.message,
+            "timestamp": self.timestamp.isoformat(),
+        }
+
+    @staticmethod
+    def from_dict(data: dict[str, Any]) -> "CustomData":
+        """Create from dictionary."""
+        return CustomData(
+            id=data["id"],
+            message=data["message"],
+            timestamp=datetime.fromisoformat(data["timestamp"].replace("Z", "+00:00")),
+        )
+
+
+class CustomDataSerDes(SerDes[CustomData]):
+    """Custom serializer for CustomData that handles datetime conversion."""
+
+    def serialize(self, value: Optional[CustomData], _: SerDesContext) -> Optional[str]:
+        """Serialize CustomData to JSON string."""
+        if value is None:
+            return None
+        return json.dumps(value.to_dict())
+
+    def deserialize(
+        self, payload: Optional[str], _: SerDesContext
+    ) -> Optional[CustomData]:
+        """Deserialize JSON string to CustomData."""
+        if payload is None:
+            return None
+        data = json.loads(payload)
+        return CustomData.from_dict(data)
+
+
+@durable_execution
+def handler(_event: Any, context: DurableContext) -> dict[str, Any]:
+    """Handler demonstrating createCallback with custom serdes."""
+    callback_config = CallbackConfig(
+        timeout=Duration.from_seconds(30),
+        serdes=CustomDataSerDes(),
+    )
+
+    callback = context.create_callback(
+        name="custom-serdes-callback",
+        config=callback_config,
+    )
+
+    result: CustomData = callback.result()
+
+    return {
+        "receivedData": result.to_dict(),
+        "isDateObject": isinstance(result.timestamp, datetime),
+    }

examples/src/callback/callback.py renamed to examples/src/callback/callback_simple.py

@@ -1,9 +1,8 @@
 from typing import TYPE_CHECKING, Any
 
-from aws_durable_execution_sdk_python.config import CallbackConfig
+from aws_durable_execution_sdk_python.config import CallbackConfig, Duration
 from aws_durable_execution_sdk_python.context import DurableContext
 from aws_durable_execution_sdk_python.execution import durable_execution
-from aws_durable_execution_sdk_python.config import Duration
 
 
 if TYPE_CHECKING:
@@ -20,6 +19,4 @@ def handler(_event: Any, context: DurableContext) -> str:
         name="example_callback", config=callback_config
     )
 
-    # In a real scenario, you would pass callback.callback_id to an external system
-    # For this example, we'll just return the callback_id to show it was created
-    return f"Callback created with ID: {callback.callback_id}"
+    return callback.result()

examples/template.yaml

@@ -557,3 +557,58 @@ Resources:
       DurableConfig:
         RetentionPeriodInDays: 7
         ExecutionTimeout: 300
+  CallbackSimple:
+    Type: AWS::Serverless::Function
+    Properties:
+      CodeUri: build/
+      Handler: callback_simple.handler
+      Description: Creating a callback ID for external systems to use
+      Role:
+        Fn::GetAtt:
+        - DurableFunctionRole
+        - Arn
+      DurableConfig:
+        RetentionPeriodInDays: 7
+        ExecutionTimeout: 300
+  CallbackHeartbeat:
+    Type: AWS::Serverless::Function
+    Properties:
+      CodeUri: build/
+      Handler: callback_heartbeat.handler
+      Description: Demonstrates callback failure scenarios where the error propagates
+        and is handled by framework
+      Role:
+        Fn::GetAtt:
+        - DurableFunctionRole
+        - Arn
+      DurableConfig:
+        RetentionPeriodInDays: 7
+        ExecutionTimeout: 300
+  CallbackMixedOps:
+    Type: AWS::Serverless::Function
+    Properties:
+      CodeUri: build/
+      Handler: callback_mixed_ops.handler
+      Description: Demonstrates createCallback mixed with steps, waits, and other
+        operations
+      Role:
+        Fn::GetAtt:
+        - DurableFunctionRole
+        - Arn
+      DurableConfig:
+        RetentionPeriodInDays: 7
+        ExecutionTimeout: 300
+  CallbackSerdes:
+    Type: AWS::Serverless::Function
+    Properties:
+      CodeUri: build/
+      Handler: callback_serdes.handler
+      Description: Demonstrates createCallback with custom serialization/deserialization
+        for Date objects
+      Role:
+        Fn::GetAtt:
+        - DurableFunctionRole
+        - Arn
+      DurableConfig:
+        RetentionPeriodInDays: 7
+        ExecutionTimeout: 300

examples/test/callback/test_callback.py

@@ -0,0 +1,51 @@
+"""Tests for create_callback_heartbeat."""
+
+import pytest
+from aws_durable_execution_sdk_python.execution import InvocationStatus
+import time
+import json
+from src.callback import callback_heartbeat
+from test.conftest import deserialize_operation_payload
+
+
+@pytest.mark.example
+@pytest.mark.durable_execution(
+    handler=callback_heartbeat.handler,
+    lambda_function_name="Create Callback Heartbeat",
+)
+def test_handle_callback_operations_with_failure_uncaught(durable_runner):
+    """Test handling callback operations with failure."""
+    test_payload = {"shouldCatchError": False}
+
+    heartbeat_interval = 5
+    total_duration = 20
+    num_heartbeats = total_duration // heartbeat_interval
+
+    with durable_runner:
+        execution_arn = durable_runner.run_async(input=test_payload, timeout=30)
+
+        callback_id = durable_runner.wait_for_callback(execution_arn=execution_arn)
+
+        for i in range(num_heartbeats):
+            print(
+                f"Sending heartbeat {i + 1}/{num_heartbeats} at {(i + 1) * heartbeat_interval}s"
+            )
+            durable_runner.send_callback_heartbeat(callback_id=callback_id)
+            time.sleep(heartbeat_interval)
+
+        callback_result = json.dumps(
+            {
+                "status": "completed",
+                "data": "success after heartbeats",
+            }
+        )
+        durable_runner.send_callback_success(
+            callback_id=callback_id, result=callback_result.encode()
+        )
+
+        result = durable_runner.wait_for_result(execution_arn=execution_arn)
+    assert result.status is InvocationStatus.SUCCEEDED
+
+    # Assert the callback result is returned
+    result_data = deserialize_operation_payload(result.result)
+    assert result_data == callback_result