RetryDemoFunctionApp

Overview

A .NET 8 Azure Functions app (isolated mode) demonstrating resilient retrying when calling an API that might return a 429 http status code with a retry-after header. In the case of a 429 response, the interval specified in the retry-after header is used to determine when to retry the operation. Other transient failures are retried using a Durable Function retry policy object.

This is a demo app that can be used for learning purposes. It can also be used as a starting point for building more complex Durable Function applications that require robust retry mechanisms.

Features

• Durable Functions orchestration with retry support, including handling of 429 responses
• Configurable retry options (max attempts, backoff)
• Activity demonstrating transient failures and retry behavior
• Local emulator function for testing

Project Structure

• Program.cs: Functions host startup and configuration
• Functions/HttpFunctions.cs: HTTP triggers to start orchestrations
• Orchestrations/RetryOrchestrator.cs: Durable orchestrators handling retrying and coordinating activities
• Activities/RetryActivity.cs: Activity showcasing transient and 429 http code error handling
• Emulator/EmulatorFunction.cs: Emulator helper for local testing

Requirements

• .NET 8 SDK
• Azure Functions Core Tools
• Azurite (optional) for local storage emulation`

Notes

• Intended for demonstration and learning of durable retries with http 429 and other transient failures.