Azure Functions Durable (Python)

azure-functions-durable is the Python SDK provider for Durable Azure Functions, built on top of the durabletask SDK.

Requirements

• Python 3.13+
• The decorator-based Azure Functions programming model (DFApp / Blueprint)

Installation

pip install azure-functions-durable

Overview

Author orchestrations, activities, and entities as Azure Functions and let the Durable Task runtime handle scheduling, checkpointing, and replay. Both durabletask-native two-argument functions (def orchestrator(ctx, input)) and v1-style single-argument functions (def orchestrator(context)) are supported, along with class-based entities and a compatibility layer over the v1 API.

Key capabilities include durable orchestrations and sub-orchestrations, durable timers, external events, durable entities, retries, versioning, durable HTTP calls (context.call_http(...)), recurring scheduled tasks, and history export.

Unit testing entities

Use execute_entity() to run one entity operation in-process without a Functions host or Durable Task backend. It supports v1-style entity functions, durabletask-native entity functions, and DurableEntity subclasses:

from azure.durable_functions.testing import execute_entity
from durabletask.entities import DurableEntity


class Counter(DurableEntity):
    def add(self, amount: int) -> int:
        value = self.get_state(int, 0) + amount
        self.set_state(value)
        return value


outcome = execute_entity(Counter, "add", input=2, state=3)

assert outcome.get_result() == 5
assert outcome.get_state() == 5
assert outcome.actions == ()

For an entity_trigger-decorated function, pass the exposed entity function:

import azure.durable_functions as df
from azure.durable_functions.testing import execute_entity


app = df.DFApp()


@app.entity_trigger(context_name="context")
def counter(context: df.DurableEntityContext) -> None:
    value = context.get_state(initializer=lambda: 0)
    value += context.get_input()
    context.set_state(value)
    context.set_result(value)


entity_function = counter.build().get_user_function().entity_function
outcome = execute_entity(entity_function, "add", input=2, state=3)

assert outcome.get_result() == 5
assert outcome.get_state() == 5

The returned EntityTestResult provides get_result() and get_state() methods plus typed signal or orchestration-start actions scheduled by the operation. Pass expected_type when reconstructing a custom payload:

assert outcome.get_state(expected_type=CounterState) == CounterState(value=5)

Links

• 2.x samples
• Migration guide from 1.x
• Changelog
• Durable Functions documentation
• durabletask on PyPI
• Azure Functions Durable 1.x source
• Azure Functions Python library
• Azure Functions Python worker
• Repository

License

Licensed under the MIT License.