# akka-hosting-actor-patterns

Patterns for building Akka.NET entity actors with Akka.Hosting. Useful when you need actors that run in both lightweight local unit tests and clustered production environments.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 414 installs · ★ 1238
- Author: Aaronontheweb
- License: MIT · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/Aaronontheweb/dotnet-skills/tree/HEAD/skills/akka-hosting-actor-patterns/SKILL.md
- Updated: 2026-10-11
- HTML: https://affpapa.org/en/nevibecode/skills/akka-hosting-actor-patterns

## What it does

The skill defines entity actor patterns for domain objects like users or orders in .NET. Its central rule is execution mode abstraction via `AkkaExecutionMode`. You run actor logic locally without remoting overhead. In production, the code switches to `ShardRegion`.

Local execution uses `GenericChildPerEntityParent`. It mimics cluster sharding semantics by routing messages to child actors through an `IMessageExtractor`. Unit tests stay fast. Everything wires together with `AkkaConfigurationBuilder` extension methods that register actors and dependency resolvers.

This design relies on strongly-typed identifiers like `OrderId` so the message extractor can resolve the target entity. For scheduled actions, it substitutes `DateTime.Now` with `ActorSystem.Scheduler` through `ITimeProvider`.

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add Aaronontheweb/dotnet-skills --skill akka-hosting-actor-patterns -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/akka-hosting-actor-patterns/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/akka-hosting-actor-patterns/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add Aaronontheweb/dotnet-skills --skill akka-hosting-actor-patterns -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/akka-hosting-actor-patterns/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add Aaronontheweb/dotnet-skills --skill akka-hosting-actor-patterns -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/akka-hosting-actor-patterns/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install Aaronontheweb/dotnet-skills akka-hosting-actor-patterns
```

2. **Manually: put the files in place**
- File: `.github/skills/akka-hosting-actor-patterns/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add Aaronontheweb/dotnet-skills --skill akka-hosting-actor-patterns -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/Aaronontheweb/dotnet-skills --path skills/akka-hosting-actor-patterns
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/akka-hosting-actor-patterns/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add Aaronontheweb/dotnet-skills --skill akka-hosting-actor-patterns -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/Aaronontheweb/dotnet-skills/tree/HEAD/skills/akka-hosting-actor-patterns/SKILL.md

## When to use it
- run entity actor unit tests without standing up an Akka cluster
- route incoming domain messages using IMessageExtractor
- toggle actor registration between GenericChildPerEntityParent and ShardRegion
- test time-dependent actor workflows using ITimeProvider

## Example prompts
- Create an order entity actor and register it using WithOrderActor supporting both LocalTest and Clustered modes
- Implement an OrderMessageExtractor and a GenericChildPerEntityParent router
- Configure domain actor extensions for AkkaConfigurationBuilder with ITimeProvider

## Source text · SKILL.md · MIT

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: fb8e4e382b550d7b.

BEGIN THIRD-PARTY FILE fb8e4e382b550d7b
````text
---
name: akka-hosting-actor-patterns
description: Patterns for building entity actors with Akka.Hosting - GenericChildPerEntityParent, message extractors, cluster sharding abstraction, akka-reminders, and ITimeProvider. Supports both local testing and clustered production modes.
user-invocable: false
---

# Akka.Hosting Actor Patterns

## When to Use This Skill

Use this skill when:
- Building entity actors that represent domain objects (users, orders, invoices, etc.)
- Need actors that work in both unit tests (no clustering) and production (cluster sharding)
- Setting up scheduled tasks with akka-reminders
- Registering actors with Akka.Hosting extension methods
- Creating reusable actor configuration patterns

## Core Principles

1. **Execution Mode Abstraction** - Same actor code runs locally (tests) or clustered (production)
2. **GenericChildPerEntityParent for Local** - Mimics sharding semantics without cluster overhead
3. **Message Extractors for Routing** - Reuse Akka.Cluster.Sharding's IMessageExtractor interface
4. **Akka.Hosting Extension Methods** - Fluent configuration that composes well
5. **ITimeProvider for Testability** - Use ActorSystem.Scheduler instead of DateTime.Now

## Execution Modes

Define an enum to control actor behavior:

```csharp
/// <summary>
/// Determines how Akka.NET should be configured
/// </summary>
public enum AkkaExecutionMode
{
    /// <summary>
    /// Pure local actor system - no remoting, no clustering.
    /// Use GenericChildPerEntityParent instead of ShardRegion.
    /// Ideal for unit tests and simple scenarios.
    /// </summary>
    LocalTest,

    /// <summary>
    /// Full clustering with ShardRegion.
    /// Use for integration testing and production.
    /// </summary>
    Clustered
}
```

## GenericChildPerEntityParent

A lightweight parent actor that routes messages to child entities, mimicking cluster sharding semantics without requiring a cluster:

```csharp
using Akka.Actor;
using Akka.Cluster.Sharding;

/// <summary>
/// A generic "child per entity" parent actor.
/// </summary>
/// <remarks>
/// Reuses Akka.Cluster.Sharding's IMessageExtractor for consistent routing.
/// Ideal for unit tests where clustering overhead is unnecessary.
/// </remarks>
public sealed class GenericChildPerEntityParent : ReceiveActor
{
    public static Props CreateProps(
        IMessageExtractor extractor,
        Func<string, Props> propsFactory)
    {
        return Props.Create(() =>
            new GenericChildPerEntityParent(extractor, propsFactory));
    }
````
END THIRD-PARTY FILE fb8e4e382b550d7b

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