Introduce Polly.Extensions project

[martintmk]

The issue or feature being addressed

#1087

Details on the issue fix or feature implementation

Enables the configuration of ResilienceStrategy using the DI and additional extensibility. The API exposes only a single AddResilienceStrategy public extension for IServiceCollecion. Additional extensibility can be done using IOptions pattern.

var services = new ServiceCollection();

// define your strategy
services.AddResilienceStrategy(
  "my-key", 
   context => context.Builder.AddTimeout(TimeSpan.FromSeconds(10)));

// define your strategy using custom options
services.AddResilienceStrategy(
    "my-timeout",
    context =>
    {
        var myOptions = context.ServiceProvider.GetRequiredService<IOptions<MyTimeoutOptions>>().Value;
        context.Builder.AddTimeout(myOptions.Timeout);
    });

// configure global builder options that will be shared for all builders
services.Configure<ResilienceStrategyBuilderOptions>(options =>
{
    options.Properties.Set(new ResiliencePropertyKey<string>("my-key"), "shared-value");
});

// configure the default telemetry factory
services.TryAddSingleton<ResilienceTelemetryFactory, MyTelemetryFactory>();

// use your strategy
var serviceProvider = services.BuildServiceProvider();
var strategyProvider = serviceProvider.GetRequiredService<ResilienceStrategyProvider<string>>();

var resilienceStrategy = strategyProvider.Get("my-key");

// use your strategy

Additional Changes:

• using net462 target (net461 is out of support and some packages complained).

Confirm the following

• I started this PR by branching from the head of the default branch
• I have targeted the PR to merge into the default branch
• I have included unit tests for the issue/feature
• I have successfully run a local build

[codecov-commenter]

Codecov Report

Merging #1088 (1f95bd9) into main (2f84eab) will increase coverage by 0.06%.
The diff coverage is 100.00%.

📣 This organization is not using Codecov’s GitHub App Integration. We recommend you install it so Codecov can continue to function properly for your repositories. Learn more

@@            Coverage Diff             @@
##             main    #1088      +/-   ##
==========================================
+ Coverage   75.04%   75.10%   +0.06%     
==========================================
  Files         173      173              
  Lines        4243     4254      +11     
  Branches      790      791       +1     
==========================================
+ Hits         3184     3195      +11     
  Misses        854      854              
  Partials      205      205              

Flag	Coverage Δ
linux	75.10% <100.00%> (+0.06%)	⬆️
macos	75.10% <100.00%> (?)
windows	75.10% <100.00%> (+0.06%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...y.Core/Builder/ResilienceStrategyBuilderOptions.cs	100.00% <100.00%> (ø)

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

[juraj-blazek]

Polly.Hosting doesn't sound right => Polly.Extensions?
We could then follow the familiar pattern with Polly.Extensions.DependencyInjection

[martincostello]

Just my two outstanding comments from yesterday.

[martintmk]

Just my two outstanding comments from yesterday.

@martincostello Sorry, but I do not see any that I did not respond to. Are they lost somewhere? :)

[martincostello]

This one and the other it turns out wasn't submitted 😅

#1088 (comment)