rhizome-node/__plans__/beam-implementation.md
Lentil Hoffman d7c4fda93e
refactor(resolver): overhaul plugin system and dependency handling
Core Changes:
- Completely rewrote CustomResolver reducer with dependency-ordered processing
- Enhanced plugin initialization with proper dependency injection
- Improved delta processing and property value tracking
- Added robust error handling for duplicate property IDs

Resolver Improvements:
- Updated to use new accumulator structure
- Implemented execution order processing for plugins
- Enhanced debug logging and error reporting
- Simplified TimestampResolver by removing unused initializer

Configuration Updates:
- Added TypeScript path aliases for test helpers
- Improved module resolution paths

Key Benefits:
- More robust plugin dependency management
- More efficient state updates
- Enhanced type safety
- Better error messages and debugging
- More consistent plugin initialization

This refactoring focuses on improving the robustness of the resolver,
especially around plugin lifecycle management and dependency handling.
The changes ensure better separation of concerns and more predictable
behavior when dealing with complex plugin dependencies.
2025-06-25 06:10:34 -05:00

7.3 KiB

Rhizome on the BEAM: Implementation Guide

Note

: This document outlines a fresh implementation of Rhizome in Elixir, using the TypeScript implementation as a reference.

Table of Contents

Motivation

Moving Rhizome to Elixir and the BEAM virtual machine provides several key advantages:

  1. Distribution by Default

    • Built-in distribution primitives for node-to-node communication
    • Network partition tolerance out of the box
    • Location transparency for processes
  2. Fault Tolerance

    • Let it crash philosophy with supervision trees
    • Self-healing systems through process isolation
    • Hot code reloading for zero-downtime updates
  3. Concurrency Model

    • Lightweight processes for handling millions of concurrent connections
    • Efficient message passing between processes
    • Built-in backpressure handling
  4. Ecosystem Benefits

    • Mature tooling for distributed systems
    • Strong pattern matching and immutability
    • Excellent support for building resilient systems

Architecture Overview

Current TypeScript Architecture

graph TD
    subgraph "TypeScript Implementation"
        A[HTTP API<br/><small>Express</small>]
        B[WebSocket<br/><small>Socket.IO</small>]
        C[Core Engine]
        D[Delta Store]
        E[View Layer]
        F[Persistence<br/><small>LevelDB</small>]
        G[Peer Network<br/><small>Libp2p</small>]
        
        A --> C
        B --> C
        C --> D
        C --> E
        D --> F
        C --> G
    end

Proposed Elixir Architecture

graph TD
    subgraph "Elixir Implementation"
        A[HTTP/WebSocket<br/><small>Phoenix</small>]
        B[Core OTP App]
        C[Delta Store]
        D[View Layer]
        E[Process Supervision]
        F[Distribution<br/><small>EPMD/GenRPC</small>]
        G[Persistence<br/><small>Mnesia/ETS</small>]
        
        A <--> B
        B <--> C
        B <--> D
        B <--> E
        B <--> F
        C <--> G
    end

Implementation Roadmap

1. Core Engine

  • Delta Processing

    • Define core Delta types and operations
    • Implement DeltaBuilder
    • Design storage layer (Mnesia/ETS)
  • View System

    • Implement Lossy/Lossless views
    • Create resolver framework
    • Add caching layer

2. Distribution

  • Node Communication

    • Node discovery and membership
    • Delta synchronization protocol
    • Conflict resolution strategies
  • Plugin System

    • Plugin behavior and lifecycle
    • Dependency management
    • Hot code reloading

3. API & Tooling

  • HTTP/WebSocket API

    • RESTful endpoints
    • Real-time updates
    • Authentication/authorization
  • Developer Experience

    • TypeScript type generation
    • CLI tools
    • Monitoring and metrics

Key Components

1. Delta Processing

This implementation will follow similar patterns to the TypeScript version but leverage Elixir's strengths:

defmodule Rhizome.Delta do
  @type t :: %__MODULE__{
    id: String.t(),
    creator: String.t(),
    timestamp: integer(),
    operations: [operation()],
    transaction_id: String.t() | nil,
    negate: boolean()
  }
  
  defstruct [:id, :creator, :timestamp, :operations, :transaction_id, negate: false]
  
  def new(creator, host) do
    %__MODULE__{
      id: generate_id(),
      creator: creator,
      timestamp: System.system_time(:millisecond),
      operations: []
    }
  end
  
  def add_operation(delta, operation) do
    %{delta | operations: [operation | delta.operations]}
  end
end

2. View System

defmodule Rhizome.View.Lossy do
  @behaviour Rhizome.View.Behaviour
  
  @impl true
  def init(initial_state) do
    %{state: initial_state, cache: %{}}
  end
  
  @impl true
  def reduce(%{state: state} = view, delta) do
    new_state = apply_delta(state, delta)
    %{view | state: new_state}
  end
  
  @impl true
  def resolve(%{state: state}), do: state
  
  defp apply_delta(state, %Delta{operations: ops}) do
    Enum.reduce(ops, state, &apply_operation/2)
  end
end

3. Plugin System

defmodule Rhizome.Plugin do
  @callback init(args :: term) :: {:ok, state :: term} | {:error, reason :: term}
  @callback handle_delta(delta :: Delta.t(), state :: term) :: {:ok, new_state :: term} | {:error, term}
  @callback handle_call(request :: term, from :: {pid, reference}, state :: term) ::
    {:reply, reply, new_state} |
    {:reply, reply, new_state, timeout | :hibernate} |
    {:noreply, new_state} |
    {:noreply, new_state, timeout | :hibernate} |
    {:stop, reason, reply, new_state} |
    {:stop, reason, new_state} when reply: term, new_state: term, reason: term
  
  defmacro __using__(_opts) do
    quote do
      @behaviour Rhizome.Plugin
      use GenServer
      
      # Default implementations
      @impl true
      def init(_args), do: {:ok, %{}}
      
      @impl true
      def handle_call(_request, _from, state), do: {:reply, :ok, state}
      
      def start_link(args) do
        GenServer.start_link(__MODULE__, args, name: __MODULE__)
      end
    end
  end
end

Data Synchronization Model

1. Delta Propagation

sequenceDiagram
    participant C1 as Client 1
    participant N1 as Node 1
    participant N2 as Node 2
    participant N3 as Node 3
    
    C1->>N1: Submit Delta
    N1->>N1: Apply Delta Locally
    N1->>N2: Gossip Delta
    N1->>N3: Gossip Delta
    N2->>N2: Apply Delta
    N3->>N3: Apply Delta
    N2->>N1: Acknowledge
    N3->>N1: Acknowledge

2. Conflict Resolution

  1. Last Write Wins (Default)
  2. Custom Resolvers
  3. CRDT-based for special cases

Development Milestones

1. Core Delta Engine

  • Define delta types and operations
  • Implement DeltaBuilder
  • Basic storage with Mnesia/ETS
  • View system with Lossy/Lossless support

2. Distributed Foundation

  • Node discovery and membership
  • Delta synchronization protocol
  • Conflict resolution strategies
  • Plugin system

3. Production Features

  • HTTP/WebSocket API
  • Authentication & authorization
  • Monitoring and metrics
  • Developer tooling

Performance Characteristics

Key Advantages

  1. Concurrency

    • Handle 100K+ concurrent connections per node
    • Sub-millisecond delta processing
    • Linear scaling with cores
  2. Memory Usage

    • Shared binary heap for deltas
    • Efficient garbage collection
    • Process isolation for fault tolerance
  3. Network Efficiency

    • Delta compression
    • Batched updates
    • Smart backpressure handling

Getting Started

Prerequisites

  • Elixir 1.14+
  • Erlang/OTP 25+
  • Node.js (for assets)

Running Locally

# Clone the repository
git clone https://github.com/your-org/rhizome-beam.git
cd rhizome-beam

# Install dependencies
mix deps.get
cd assets && npm install && cd ..

# Start the application
iex -S mix phx.server

Contributing

  1. Fork the repository
  2. Create a feature branch
  3. Submit a pull request

License

[Your License Here]

Acknowledgments

  • The Elixir and Erlang communities
  • The original TypeScript implementation for inspiration
  • Research in distributed systems and CRDTs