Retry Policies

When creating modules, you can set a retry policy per module using the Configure() method. The retry policy uses Polly, so if you've used Polly before you should be familiar with how to use it.

Using ModuleConfiguration

Simple Retry Count

The easiest way to add retries is with WithRetryCount():

public class MyModule : Module<CommandResult>
{
    protected override ModuleConfiguration Configure() => ModuleConfiguration.Create()
        .WithRetryCount(3)  // Retry up to 3 times with exponential backoff
        .Build();

    protected override async Task<CommandResult?> ExecuteAsync(IModuleContext context, CancellationToken cancellationToken)
    {
        // Do something that might fail transiently
    }
}

Custom Polly Policy

For more control, you can provide a custom Polly policy:

public class MyModule : Module<CommandResult>
{
    protected override ModuleConfiguration Configure() => ModuleConfiguration.Create()
        .WithRetryPolicy(
            Policy.Handle<HttpRequestException>()
                .WaitAndRetryAsync(5, i => TimeSpan.FromSeconds(i * i)))
        .Build();

    protected override async Task<CommandResult?> ExecuteAsync(IModuleContext context, CancellationToken cancellationToken)
    {
        // Do something
    }
}

Context-Aware Retry Policy

If you need access to the pipeline context when building your policy:

public class MyModule : Module<CommandResult>
{
    protected override ModuleConfiguration Configure() => ModuleConfiguration.Create()
        .WithRetryPolicy(ctx =>
        {
            var retryCount = ctx.Environment.IsCI ? 5 : 2;
            return Policy.Handle<Exception>()
                .WaitAndRetryAsync(retryCount, i => TimeSpan.FromSeconds(i));
        })
        .Build();
}

Combining with Other Behaviors

Retry policies can be combined with other module behaviors:

public class ResilientModule : Module<CommandResult>
{
    protected override ModuleConfiguration Configure() => ModuleConfiguration.Create()
        .WithRetryCount(3)
        .WithTimeout(TimeSpan.FromMinutes(10))
        .WithIgnoreFailures()  // Don't fail the pipeline even after all retries
        .Build();
}

Default Retry Policy

Retry policies are off by default. You can set a default retry count on the PipelineOptions:

var builder = Pipeline.CreateBuilder(args);

builder.Services
    .AddModule<Module1>()
    .AddModule<Module2>()
    .AddModule<Module3>();

builder.Options.DefaultRetryCount = 3;

await builder.Build().RunAsync();

This applies to all modules that don't override their retry policy. Modules can override this default by configuring their own retry policy in Configure().