fan-out-fan-in

Fan-out/Fan-in with Durable Functions (Python)

Python | Durable Functions

Description

This sample demonstrates the fan-out/fan-in pattern using Azure Durable Functions with Python. It processes a batch of work items in parallel and aggregates the results — a fundamental pattern for parallel data processing.

The orchestration:

1. Generates a list of work items
2. Fans out by scheduling parallel activity executions for each item
3. Waits for all activities to complete
4. Aggregates and returns the combined results

Prerequisites

1. Python 3.9+
2. Docker
3. Azure Functions Core Tools v4

Quick Run

1. Start the emulator:

   docker run -d -p 8080:8080 -p 8082:8082 mcr.microsoft.com/dts/dts-emulator:latest

2. Set up and run:

   python -m venv venv
   source venv/bin/activate
   pip install -r requirements.txt
   func start

3. Trigger the orchestration:

   curl -X POST http://localhost:7071/api/StartFanOutFanIn

4. View in dashboard: http://localhost:8082

Learn More

• Fan-out/Fan-in Pattern
• Durable Functions Python Guide