Implement a retry policy in .NET 6 Applications with Polly

In this article, I will showcase how to manage failures in .NET 6 applications using Polly. In today's fast-paced digital era, systems are expected to be available 24/7 to meet the demands of valued users. Ensuring the reliability and resilience of software applications has become a critical priority in the modern technological landscape.

Fault Tolerance in .NET 6 Applications using Polly

In today’s dynamic digital world, creating resilient applications is essential. Applications need to effectively manage failures like transient faults, timeouts, or resource unavailability while maintaining reliable performance and a seamless user experience. Polly, a powerful .NET library, streamlines the implementation of fault-tolerance strategies in .NET 6 applications. This article delves into Polly’s features and illustrates how to integrate it into your projects.

What Is Polly?

Polly is a powerful and flexible .NET library designed to help developers implement fault-tolerance and resilience strategies in their applications. It provides a rich set of features that allow you to define policies to handle various types of transient faults, such as network interruptions, timeouts, and resource unavailability. These policies enable applications to recover gracefully from unexpected errors, ensuring stability, reliability, and an enhanced user experience.

You can integrate Polly into your projects.

• Automatically retry failed operations caused by transient issues.
• Use circuit breakers to prevent cascading failures within the system.
• Set time limits for operations to minimize unnecessary delays.
• Implement fallback mechanisms to handle failures when primary operations are unsuccessful.
• Manage resource consumption with bulkhead isolation to ensure overall system stability.

In this article, I will explain Retry Policies and walk you through a step-by-step implementation of Polly in a .NET 6 application.

Integrating Polly into .NET 6 Applications

Follow these steps to add fault tolerance with Polly in your .NET 6 application.

Create a console application using .Net 6.

Install Polly

Add the Polly NuGet package to your project.

After successfully installing the required package, the next step is to implement a retry policy. This policy is designed to attempt the operation up to three times if an error occurs during its execution. The retry mechanism ensures that transient issues, such as network glitches or temporary unavailability of resources, are handled gracefully by retrying the operation before failing completely.

How to Implement Retry Policies?

using Polly;
var retryPolicy = Policy
    .Handle<Exception>()
    .Retry(3, (exception, retryCount) =>
    {
        Console.WriteLine($"Retry {retryCount} due to: {exception.Message}");
    });
retryPolicy.Execute(() =>
{
    // Code, method, or logic that might fail
    // In this example, I have created a method designed to throw an exception.
    PerformYourOperation();
});
void PerformYourOperation()
{
    throw new Exception("Simulated failure");
}

The output for the retry policy configuration with 3 attempts.

How does the above code work?

• First Attempt: The policy executes PerformYourOperation(). Since it always throws an exception, the first attempt fails.
• Retries: The retry policy catches the exception and retries up to 3 times. After each failure, it logs a message to the console indicating the retry count and the reason for the failure.
• Final Outcome: If all 3 attempts fail, the exception is propagated, and the retry process stops. Without additional fallback mechanisms, the application will fail.

Summary

In this article, we explored how the Retry Policy in Polly for .NET enables the automatic handling of transient failures by retrying an operation multiple times before it ultimately fails. This pattern ensures that applications can recover from temporary issues without negatively affecting overall system performance.

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