Use Policy<IRestResponse>, AsyncPolicy<IRestResponse> in RetryConfiguration.mustache

[jeffshantz]

Summary

Use Policy<IRestResponse> and AsyncPolicy<IRestResponse> instead of RetryPolicy<IRestResponse> and AsyncRetryPolicy<IRestResponse> to allow for use of wrapped policies.

Background

In the .NET Core client generator, RetryConfiguration uses the type RetryPolicy<IRestResponse> and AsyncRetryPolicy<IRestResponse> for its properties RetryPolicy and AsyncRetryPolicy, respectively.

This is useful, as it allows one to define a retry policy:

      RetryConfiguration.RetryPolicy = 
        Policy
          .HandleResult<IRestResponse>(r => r.StatusCode == HttpStatusCode.Unauthorized)
          .Retry(retryCount: 3,
                 onRetry: ((result, retryNumber, context) =>
                            {
                              // Fetch new API token here
                              Console.WriteLine("Retrying...");
                            }));

The problem is that this does not allow us to exploit the full utility of Polly. For instance, after retrying 3 times, I might want to log a message or perform some action before giving up. In this case, it would be nice to use Policy.Wrap():

 var retryPolicy =
        Policy
          .HandleResult<IRestResponse>(r => r.StatusCode == HttpStatusCode.Unauthorized)
          .Retry(retryCount: 3,
                 onRetry: ((result, retryNumber, context) =>
                            {
                              // Fetch new API token here
                              Console.WriteLine("Retrying...");
                            }));

      var giveUpPolicy =
        Policy
          .HandleResult<IRestResponse>(r => true)
          .Fallback(fallbackValue: null, onFallback: result =>
          {
            Console.WriteLine("Giving up");
          });

      RetryConfiguration.RetryPolicy = giveUpPolicy.Wrap(retryPolicy);

Solution

This pull request simply changes the type of the RetryPolicy and AsyncRetryPolicy properties to their higher-level base classes in RetryConfiguration such that:

/// <summary>
/// Retry policy
/// </summary>
 public static RetryPolicy<IRestResponse> RetryPolicy { get; set; }

 /// <summary>
/// Async retry policy
/// </summary>
public static AsyncRetryPolicy<IRestResponse> AsyncRetryPolicy { get; set; }

becomes:

/// <summary>
/// Retry policy
/// </summary>
 public static Policy<IRestResponse> RetryPolicy { get; set; }

 /// <summary>
/// Async retry policy
/// </summary>
public static AsyncPolicy<IRestResponse> AsyncRetryPolicy { get; set; }

Then, one can still assign a RetryPolicy as usual, but one can now also use wrapped policies, as above. No other changes are required -- this worked out of the box when I made these type changes.

[wing328]

Updated samples via 998f5cc. Let's see if that fixes the CI failure.

[wing328]

cc @Ramanth (author of the PR adding the retry logic)

cc @mandrean (2017/08) @frankyjuang (2019/09) @shibayan (2020/02)

[jeffshantz]

Thanks, @wing328

[wing328]

If no further on this PR, I'll merge it tomorrow (Tue).