Configuring Policies

Apizr comes with a Policy attribute to apply some policies on apis, handled by Polly.

You’ll find also policy attributes dedicated to CRUD apis like CreatePolicy, ReadPolicy and so on…

Polly will help you to manage some retry scenarios but can do more. Please refer to its official documentation if you’d like to know more about it.

Registering

Here is how to define a policy, adding it to a policy registry.

var registry = new PolicyRegistry
{
    {
        "TransientHttpError", HttpPolicyExtensions.HandleTransientHttpError().WaitAndRetryAsync(new[]
        {
            TimeSpan.FromSeconds(1),
            TimeSpan.FromSeconds(5),
            TimeSpan.FromSeconds(10)
        }, LoggedPolicies.OnLoggedRetry).WithPolicyKey("TransientHttpError")
    }
};

TransiantHttpError policy is actually provided by Polly itself, so we jsut call its HttpPolicyExtensions.HandleTransientHttpError() method.

We're also giving here an OnLoggedRetry method provided by Apizr, so we coud get some logging outputs when Polly comes in the party in case of handled failures.

PolicyRegistry is where you register all your named policies to be used by Polly thanks to attribute decoration, TransiantHttpError is just an example.

Now we have to register our policy registry:

• Static
• Extended

You'll be able to register your policy registry with this option:

// direct configuration
options => options.WithPolicyRegistry(registry)

// OR factory configuration
options => options.WithPolicyRegistry(() => registry)

Defining

Now we can use it thanks to attribute decoration:

[assembly:Policy("TransientHttpError")]
namespace Apizr.Sample
{
    [WebApi("https://reqres.in/api")]
    public interface IReqResService
    {
        [Get("/users")]
        Task<UserList> GetUsersAsync();
    }
}

Here we are using it at assembly level, telling Apizr to apply TransiantHttpError policy to all apis.

You can mix levels and mix policies as all will be wrapped.

Using

Apizr will automatically tell Polly to handle request of any decorated api method.