[Feature request]: Add ConfigureResiliencePipelineRegistry to IServiceCollection about polly

[martincostello]

This seems reasonable to me - what do you think @martintmk?

[martintmk]

I think the proposal addresses reasonable feature-gap. The only downside is ambiguity of ConfigureResiliencePipelineRegistry method that suggests (by the name) that ResiliencePipelineRegistryOptions<TKey> should be accepted. Instead, what it really does is to populate already configured registry with a new resilience pipelines.

How about this?

public static IServiceCollection AddResiliencePipelineRegistry<TKey>(
    this IServiceCollection services,
    Action<ResiliencePipelineRegistryOptions<TKey>> configure,
    Action<InitializeResiliencePipelineRegistryContext<TKey>> initialize)
    where TKey : notnull
{
}

public class InitializeResiliencePipelineRegistryContext<TKey>(ResiliencePipelineRegistry<TKey> registry, IServiceProvider serviceProvider)
    where TKey : notnull
{
    public ResiliencePipelineRegistry<TKey> Registry => registry;

    public IServiceProvider ServiceProvider => serviceProvider;
}

Here, we are just adding a new overload for AddResiliencePipelineRegistry that also allows initializing the registry (for advanced scenarios). It can be called as many times as needed and allows populating the registry.

services.AddResiliencePipelineRegistry<string>(_ => { }, context =>
{
    context.Registry.TryAddBuilder("my-pipeline-1", (builder, _) => builder.AddTimeout(TimeSpan.FromSeconds(1)));
    context.Registry.TryAddBuilder("my-pipeline-2", (builder, _) => builder.AddTimeout(TimeSpan.FromSeconds(1)));
    context.Registry.TryAddBuilder("my-pipeline-3", (builder, _) => builder.AddTimeout(TimeSpan.FromSeconds(1)));
});

services.AddResiliencePipelineRegistry<string>(_ => { }, context =>
{
    context.Registry.TryAddBuilder("my-pipeline-4", (builder, _) => builder.AddTimeout(TimeSpan.FromSeconds(1)));
    context.Registry.TryAddBuilder("my-pipeline-5", (builder, _) => builder.AddTimeout(TimeSpan.FromSeconds(1)));
    context.Registry.TryAddBuilder("my-pipeline-6", (builder, _) => builder.AddTimeout(TimeSpan.FromSeconds(1)));
});

(first callback configures the options, but we don't want to modify those, so I just provided empty lambda).

Wdyt, could this work for you?

[damienhoneyford]

I agree that the naming of ConfigureResiliencePipelineRegistry does leave some ambiguity, and given that the implementation (at least the intial one I hurried together) contains very similar code to the AddResiliencePipeline methods, it likely would be better named something akin to those. I did initially consider naming the method AddResiliencePipelines but felt like it was more in-keeping with other libraries to use 'Configure...'.

The big drawback for me in your proposed implementation, @martintmk, is that it works directly with the ResiliencePipelineRegistry class, which means it misses out on all the goodness available in the AddResiliencePipelineContext class -- possibly which could be introduced via a method on your proposed InitializeResiliencePipelineRegistryContext class though.

[martintmk]

I like the AddResiliencePipelines<TKey>, since it's something that it actually does. It's pretty unambiguous.

It can accept callback that has access to AddResiliencePipelinesContext<TKey> on which there are the following methods:

void AddResiliencePipeline(
   TKey key,
   Action<ResiliencePipelineBuilder, AddResiliencePipelineContext<TKey>> configure);

void AddResiliencePipeline<TResult>(
   TKey key,
   Action<ResiliencePipelineBuilder<TResult>, AddResiliencePipelineContext<TKey>> configure);

Should support your and more-advanced scenarios pretty well.