Restsharp polly retry policy based on status

Question

I am trying to manipulate polly retry policy based on response status code. If status code is 500, I need to retry after 3 minutes else I need to retry after 2, 4 seconds. I have something like this right now,

.OrResult<RestResponse>(
    (response) => {
        return !response.IsSuccessful || response.StatusCode != System.Net.HttpStatusCode.Conflict;
    })
.WaitAndRetryAsync(new[] { TimeSpan.FromSeconds(2), TimeSpan.FromSeconds(5), TimeSpan.FromSeconds(15) })

I can possibly add TimeSpan.FromSeconds(180) but I only want to do it if the response status code is 500.

Is there a way to do that?

Peter Csala · Answer 1 · 2022-06-26T19:01:25.780

The WaitAndRetryAsync has several overloads. In your case you have used one which accepts an IEnumerable<TimeSpan> which defines the retry count and the delays between each attempt.

There are overloads which allows you to define the sleepDurations dynamically. In those cases you have to provide a sleepDurationProvider.

In the bellow example I've used this overload:

 public static AsyncRetryPolicy<TResult> WaitAndRetryAsync<TResult>(
       this PolicyBuilder<TResult> policyBuilder, 
       int retryCount,
       Func<int, DelegateResult<TResult>, Context, TimeSpan> sleepDurationProvider, 
       Func<DelegateResult<TResult>, TimeSpan, int, Context, Task> onRetryAsync)

int retryCount: At most how many retry attempts should be issued
Func<int, DelegateResult<TResult>, Context, TimeSpan> sleepDurationProvider: A user-defined function which receives the number of retry attempt, the result of the attempt, a context and anticipates a TimeSpan in return
Func<DelegateResult<TResult>, TimeSpan, int, Context, Task> onRetryAsync: A user-defined function which is called if the policy should be triggered but before the sleep

With this you can achieve the desired behaviour:

.WaitAndRetryAsync(retryCount: 3, 
    sleepDurationProvider: (int retryCount, DelegateResult<RestResponse> response, Context ctx) =>
{
    if (response.Result.StatusCode == HttpStatusCode.InternalServerError)
        return TimeSpan.FromMinutes(3);
    return retryCount switch
    {
        1 => TimeSpan.FromSeconds(2),
        2 => TimeSpan.FromSeconds(5),
        3 => TimeSpan.FromSeconds(15),
        _ => TimeSpan.FromSeconds(1) //It won't be used due to the retryCount
    };
}, onRetryAsync: (_, __, ___, ____) => Task.CompletedTask);

If the response's status code is 500 then return with a 3 minutes sleep duration
- For every other cases decide the sleep duration based on the number of attempt
The onRetryAsync delegate needs to be defined otherwise the compiler will not find this overload

Restsharp polly retry policy based on status

1 Answers1