Retry Policies

When creating modules, you can configure retries per module using the Configure() method. The standard API supports exponential backoff, jitter, and exception filtering without exposing the underlying resilience library.

Using ModuleConfiguration

Simple Retries

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

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

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

The default base delay is 100 milliseconds. Each retry uses equal jitter between half and all of its exponential-backoff ceiling. You can set a different base delay and limit retries to selected exceptions:

protected override ModuleConfiguration Configure() => ModuleConfiguration.Create()
    .WithRetry(
        count: 5,
        baseDelay: TimeSpan.FromSeconds(1),
        shouldRetry: exception => exception is HttpRequestException)
    .Build();

Advanced Polly Policy

For policy features outside the standard API, use the explicit .Advanced surface:

public class MyModule : Module<CommandResult>
{
    protected override ModuleConfiguration Configure() => ModuleConfiguration.Create()
        .Advanced
        .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()
        .Advanced
        .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()
        .WithRetry(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
    .AddModule<Module1>()
    .AddModule<Module2>()
    .AddModule<Module3>();

builder.ConfigurePipelineOptions(options => options with
{
    DefaultRetryCount = 3,
});

await builder.ExecutePipelineAsync();

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().