> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/App-vNext/Polly/llms.txt
> Use this file to discover all available pages before exploring further.

# Polly.Extensions

> Dependency injection extensions for registering and managing resilience pipelines

The `Polly.Extensions` package provides integration with Microsoft.Extensions.DependencyInjection, enabling you to register and manage resilience pipelines through the service collection.

## Installation

```bash theme={null}
dotnet add package Polly.Extensions
```

## Core Extension Methods

### AddResiliencePipeline

Registers a resilience pipeline with the service collection.

```csharp theme={null}
public static IServiceCollection AddResiliencePipeline<TKey>(
    this IServiceCollection services,
    TKey key,
    Action<ResiliencePipelineBuilder> configure)
    where TKey : notnull
```

<ParamField path="services" type="IServiceCollection" required>
  The service collection to add the resilience pipeline to
</ParamField>

<ParamField path="key" type="TKey" required>
  The key used to identify the resilience pipeline
</ParamField>

<ParamField path="configure" type="Action<ResiliencePipelineBuilder>" required>
  An action that configures the resilience pipeline
</ParamField>

**Returns:** The updated `IServiceCollection` with the registered resilience pipeline.

**Example:**

```csharp theme={null}
services.AddResiliencePipeline("my-pipeline", builder =>
{
    builder.AddRetry(new RetryStrategyOptions
    {
        MaxRetryAttempts = 3,
        Delay = TimeSpan.FromSeconds(1)
    });
});
```

### AddResiliencePipeline (with context)

Registers a resilience pipeline with access to the service provider and pipeline context.

```csharp theme={null}
public static IServiceCollection AddResiliencePipeline<TKey>(
    this IServiceCollection services,
    TKey key,
    Action<ResiliencePipelineBuilder, AddResiliencePipelineContext<TKey>> configure)
    where TKey : notnull
```

<ParamField path="services" type="IServiceCollection" required>
  The service collection to add the resilience pipeline to
</ParamField>

<ParamField path="key" type="TKey" required>
  The key used to identify the resilience pipeline
</ParamField>

<ParamField path="configure" type="Action<ResiliencePipelineBuilder, AddResiliencePipelineContext<TKey>>" required>
  An action that configures the resilience pipeline with access to context
</ParamField>

**Example:**

```csharp theme={null}
services.AddResiliencePipeline("my-pipeline", (builder, context) =>
{
    var options = context.GetOptions<MyOptions>();
    builder.AddRetry(new RetryStrategyOptions
    {
        MaxRetryAttempts = options.MaxRetries
    });
    context.EnableReloads<MyOptions>();
});
```

### AddResiliencePipeline\<TResult>

Registers a resilience pipeline that handles a specific result type.

```csharp theme={null}
public static IServiceCollection AddResiliencePipeline<TKey, TResult>(
    this IServiceCollection services,
    TKey key,
    Action<ResiliencePipelineBuilder<TResult>> configure)
    where TKey : notnull
```

<ParamField path="services" type="IServiceCollection" required>
  The service collection to add the resilience pipeline to
</ParamField>

<ParamField path="key" type="TKey" required>
  The key used to identify the resilience pipeline
</ParamField>

<ParamField path="configure" type="Action<ResiliencePipelineBuilder<TResult>>" required>
  An action that configures the resilience pipeline for the specific result type
</ParamField>

**Example:**

```csharp theme={null}
services.AddResiliencePipeline<string, HttpResponseMessage>("http-pipeline", builder =>
{
    builder.AddRetry(new RetryStrategyOptions<HttpResponseMessage>
    {
        ShouldHandle = new PredicateBuilder<HttpResponseMessage>()
            .Handle<HttpRequestException>()
            .HandleResult(response => !response.IsSuccessStatusCode)
    });
});
```

### AddResiliencePipelines

Allows deferred addition of one or more resilience pipelines.

```csharp theme={null}
public static IServiceCollection AddResiliencePipelines<TKey>(
    this IServiceCollection services,
    Action<AddResiliencePipelinesContext<TKey>> configure)
    where TKey : notnull
```

<ParamField path="services" type="IServiceCollection" required>
  The service collection to add resilience pipelines to
</ParamField>

<ParamField path="configure" type="Action<AddResiliencePipelinesContext<TKey>>" required>
  An action that allows configuration of multiple resilience pipelines
</ParamField>

**Example:**

```csharp theme={null}
services.AddResiliencePipelines<string>(context =>
{
    context.AddResiliencePipeline("pipeline-1", (builder, ctx) =>
    {
        builder.AddRetry(new RetryStrategyOptions());
    });
    
    context.AddResiliencePipeline("pipeline-2", (builder, ctx) =>
    {
        builder.AddTimeout(TimeSpan.FromSeconds(30));
    });
});
```

### AddResiliencePipelineRegistry

Registers `ResiliencePipelineRegistry<TKey>` and `ResiliencePipelineProvider<TKey>` to the service collection.

```csharp theme={null}
public static IServiceCollection AddResiliencePipelineRegistry<TKey>(
    this IServiceCollection services)
    where TKey : notnull
```

<ParamField path="services" type="IServiceCollection" required>
  The service collection to add the registry to
</ParamField>

**Example:**

```csharp theme={null}
services.AddResiliencePipelineRegistry<string>();
```

## Context Classes

### AddResiliencePipelineContext\<TKey>

Represents the context for adding a resilience pipeline with the specified key.

#### Properties

```csharp theme={null}
public TKey PipelineKey { get; }
public IServiceProvider ServiceProvider { get; }
```

#### Methods

**EnableReloads\<TOptions>**

Enables dynamic reloading of the resilience pipeline whenever the specified options are changed.

```csharp theme={null}
public void EnableReloads<TOptions>(string? name = null)
```

<ParamField path="name" type="string?">
  The named options, if any. If null, global options are listened to
</ParamField>

**GetOptions\<TOptions>**

Gets the options identified by name.

```csharp theme={null}
public TOptions GetOptions<TOptions>(string? name = null)
```

<ParamField path="name" type="string?">
  The options name, if any. If null, global options are returned
</ParamField>

**OnPipelineDisposed**

Registers a callback that is called when the pipeline instance is disposed.

```csharp theme={null}
public void OnPipelineDisposed(Action callback)
```

<ParamField path="callback" type="Action" required>
  The callback delegate to invoke on disposal
</ParamField>

### AddResiliencePipelinesContext\<TKey>

Represents the context for configuring multiple resilience pipelines.

#### Properties

```csharp theme={null}
public IServiceProvider ServiceProvider { get; }
```

#### Methods

**AddResiliencePipeline**

Adds a resilience pipeline to the registry.

```csharp theme={null}
public void AddResiliencePipeline(
    TKey key,
    Action<ResiliencePipelineBuilder, AddResiliencePipelineContext<TKey>> configure)

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

## ResiliencePipelineProvider\<TKey>

Provides access to resilience pipelines that are registered by key.

### Methods

**GetPipeline**

Retrieves a resilience pipeline using the specified key.

```csharp theme={null}
public virtual ResiliencePipeline GetPipeline(TKey key)
```

<ParamField path="key" type="TKey" required>
  The key used to identify the resilience pipeline
</ParamField>

**Returns:** The resilience pipeline associated with the specified key.

**Throws:** `KeyNotFoundException` when no resilience pipeline is found for the specified key.

**GetPipeline\<TResult>**

Retrieves a generic resilience pipeline using the specified key.

```csharp theme={null}
public virtual ResiliencePipeline<TResult> GetPipeline<TResult>(TKey key)
```

<ParamField path="key" type="TKey" required>
  The key used to identify the resilience pipeline
</ParamField>

**Returns:** The generic resilience pipeline associated with the specified key.

**TryGetPipeline**

Tries to get a resilience pipeline using the specified key.

```csharp theme={null}
public abstract bool TryGetPipeline(TKey key, out ResiliencePipeline? pipeline)
public abstract bool TryGetPipeline<TResult>(TKey key, out ResiliencePipeline<TResult>? pipeline)
```

**Returns:** `true` if the pipeline was found, `false` otherwise.

## Telemetry Options

### TelemetryOptions

Configures the telemetry that is produced by resilience strategies.

```csharp theme={null}
public class TelemetryOptions
{
    public ICollection<TelemetryListener> TelemetryListeners { get; }
    public ILoggerFactory LoggerFactory { get; set; }
    public ICollection<MeteringEnricher> MeteringEnrichers { get; }
    public Func<ResilienceContext, object?, object?> ResultFormatter { get; set; }
    public Func<SeverityProviderArguments, ResilienceEventSeverity>? SeverityProvider { get; set; }
}
```

**Example:**

```csharp theme={null}
services.Configure<TelemetryOptions>(options =>
{
    options.LoggerFactory = loggerFactory;
    options.TelemetryListeners.Add(myCustomListener);
});
```

## Usage Example

Complete example of registering and using resilience pipelines:

```csharp theme={null}
// Register pipelines
services.AddResiliencePipeline("my-pipeline", (builder, context) =>
{
    var options = context.GetOptions<MyOptions>();
    
    builder
        .AddRetry(new RetryStrategyOptions
        {
            MaxRetryAttempts = options.MaxRetries,
            Delay = TimeSpan.FromSeconds(1)
        })
        .AddTimeout(TimeSpan.FromSeconds(30));
    
    // Enable dynamic reloading when options change
    context.EnableReloads<MyOptions>();
});

// Retrieve and use pipeline
public class MyService
{
    private readonly ResiliencePipeline _pipeline;
    
    public MyService(ResiliencePipelineProvider<string> pipelineProvider)
    {
        _pipeline = pipelineProvider.GetPipeline("my-pipeline");
    }
    
    public async Task<string> ExecuteAsync()
    {
        return await _pipeline.ExecuteAsync(async ct =>
        {
            // Your code here
            return "result";
        });
    }
}
```

## See Also

* [Polly Core Documentation](https://www.pollydocs.org/)
* [Dependency Injection in .NET](https://learn.microsoft.com/en-us/dotnet/core/extensions/dependency-injection)
* [Options Pattern in .NET](https://learn.microsoft.com/en-us/dotnet/core/extensions/options)