HttpClient retry policy with Polly

How to implement a retry policy with Polly in HttpClient

Required packages

In order to implement a retry policy with Polly in HttpClient, you need to install the Polly package from NuGet.

Retry policy

The following code snippet shows how to implement a retry policy using Polly's built-in Decorrelated Jitter Backoff V2. The method takes 2 parameters: the median first retry delay (TimeSpan.FromMilliseconds(100)) and the retry count (5).

var exponentialBackoffRetryPolicy =
    HttpPolicyExtensions.HandleTransientHttpError()
        .WaitAndRetryAsync(
            Backoff.DecorrelatedJitterBackoffV2(TimeSpan.FromMilliseconds(100), 5),
            onRetryAsync: (result, _) =>
            {
                // You can log the retry here
                return Task.CompletedTask;
            });

Applying the retry policy

The retry policy can be applied to a class SomeApiClient into which HttpClient instance is injected during the registration. It will apply to all calls made by the HttpClient instance.

services.AddHttpClient<ISomeApiClient, SomeApiClient>()
    .AddPolicyHandler(exponentialBackoffRetryPolicy);