Understanding the Asynchronous Request-Reply Pattern in Modern Development
Asynchronous Request-Reply pattern - Azure Architecture Center 🔗
The Asynchronous Request-Reply pattern is a strategy for modern application development that decouples backend processing from frontend requests. This is particularly useful when backend tasks are long-running and cannot provide immediate responses to client applications. Instead of waiting for a task to finish, the client receives an HTTP 202 (Accepted) response, which indicates that the request has been received. The client can then poll a status endpoint to check the progress of the operation. This approach allows for better scalability and responsiveness, although it introduces complexity, especially in how clients handle notifications. Various implementation methods are discussed, including the use of Azure Functions and considerations for error handling and client behavior.
- Asynchronous processing helps manage long-running tasks without blocking the client.
- Clients receive a location reference to check the status of their requests.
- HTTP response codes (202, 200, 400, etc.) play a crucial role in communication between the client and server.
- Extra complexity arises in managing client notifications and response semantics across different services.
What is the purpose of the Asynchronous Request-Reply pattern?
This pattern allows for separating backend processing from frontend requests, enabling clients to continue functioning without waiting for long-running tasks to complete.
How does a client know the status of a long-running operation?
The client receives an HTTP 202 response with a location reference to a status endpoint, which it can poll to check the operation's progress.
What are some scenarios where this pattern is beneficial?
It is particularly useful when client-side code cannot easily handle callbacks or when working with legacy systems that do not support modern asynchronous techniques.