Durable Task SDK for Python

This repository contains Python SDKs for building durable orchestrations with Azure Durable Task Scheduler and Azure Durable Functions:

• durabletask is the core orchestration SDK.
• durabletask.azuremanaged is the Azure Durable Task Scheduler provider.
• azure-functions-durable is a preview Azure Durable Functions provider built on durabletask.

Python Requirements

The core SDK and Azure Managed provider require Python 3.11 or later. The Azure Functions Durable provider requires Python 3.13 or later.

References

• Supported Patterns
• Available Features
• Getting Started
• Development Guide
• Azure Functions Durable 2.x
• Contributing Guide

Optional Features

Task Hub Query Filters

Set OrchestrationQuery.task_hub_names to filter orchestration queries by one or more task hubs. The filter is available through synchronous and asynchronous core and Azure Managed clients; filtering support depends on the backend.

from durabletask.client import OrchestrationQuery

query = OrchestrationQuery(task_hub_names=["orders", "billing"])

Set Serialization

The default JsonDataConverter serializes sets and frozensets as JSON arrays ordered by their canonical JSON representation, not numeric order. For example, {2, 10} serializes as [10, 2]. To reconstruct annotated sets and frozensets instead of receiving lists, configure the same converter on clients and workers:

from durabletask.serialization import JsonDataConverter

converter = JsonDataConverter(enable_generic_sets=True)

Pass it using the data_converter parameter on core or Azure Managed clients and workers. enable_set_coercion=True is an alias for the same option. Azure Functions uses its own shared codec rather than this converter.

Warning

Set reconstruction is disabled by default to preserve the order and duplicates of recorded JSON arrays. Enabling it for existing orchestrations can change replay behavior. Iteration over reconstructed sets is not replay-safe; sort values explicitly before using their order to schedule durable work.

Entity IDs

EntityInstanceId values are immutable, hashable, and usable as dictionary keys or set elements. Construct a new ID to change an entity name or key; attribute assignment and deletion raise AttributeError.

Large Payload Externalization

Install the azure-blob-payloads extra to automatically offload oversized orchestration payloads to Azure Blob Storage:

pip install durabletask[azure-blob-payloads]

See the feature documentation and the example for usage details.

Failure Details Properties

Configure an ExceptionPropertiesProvider to attach portable diagnostic properties to activity, entity, and orchestration failures:

from durabletask import ExceptionPropertiesProvider
from durabletask.worker import TaskHubGrpcWorker


class FailureProperties(ExceptionPropertiesProvider):
    def get_exception_properties(self, exception: Exception):
        return {"error_code": getattr(exception, "error_code", None)}


worker = TaskHubGrpcWorker(exception_properties_provider=FailureProperties())

Properties support None, booleans, numbers, strings, nested mappings, and lists. They are available from TaskFailedError.details, orchestration state, and history as FailureDetails.properties.

Note

Python intentionally treats .NET's dt: and dto: property strings as ordinary strings, matching the Java SDK. Consequently, datetime values do not retain their type across Python/.NET failure-details property round trips; this is a .NET SDK parity gap.

Trademarks

This project may contain trademarks or logos for projects, products, or services. Authorized use of Microsoft trademarks or logos is subject to and must follow Microsoft's Trademark & Brand Guidelines. Use of Microsoft trademarks or logos in modified versions of this project must not cause confusion or imply Microsoft sponsorship. Any use of third-party trademarks or logos are subject to those third-party's policies.