Note: The primary documentation for Dito will be migrated to an mdBook format. Please be patient 🙂

Dito

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<img src="https://github.com/andrearaponi/dito/raw/0.7.5/dito.png" alt="Dito Logo">

Dito is an advanced, highly extensible reverse proxy server written in Go. It features a robust plugin-based architecture, custom certificate handling for backend connections, dynamic configuration reloading, and more. Plugins can manage their own dependencies and provide custom middleware functionality.

🚀 Features

• Layer 7 Reverse Proxy: Handles HTTP and HTTPS requests efficiently.
• WebSockets Support: Proxy WebSocket connections with ease.
• Dynamic Configuration Reloading (hot reload): Update configurations without restarting the server.
• Extensible Plugin System: Enhance Dito’s functionality with custom Go plugins that can:
  • Add authentication mechanisms
  • Implement caching strategies
  • Apply rate limiting
  • Transform requests/responses
  • Add custom logging
  • And much more!
• Plugin Security: Plugins are signed using Ed25519 keys, and Dito verifies these signatures at startup.
• Custom TLS Certificate Management: Support for mTLS and custom certificates for backend connections.
• Header Manipulation: Add or remove HTTP headers as needed.
• Advanced Logging: Asynchronous logging with customizable verbosity and performance optimizations.
• Custom Transport Configuration: Fine-tune HTTP transport settings per location or globally.
• Response Body Size Limits: Control maximum response body sizes globally and per location with proper error handling (413 status code).
• Response Buffering Control: Enable or disable response buffering per location for optimal performance.
• Prometheus Metrics: Monitor performance and behavior with detailed metrics.

📂 Project Structure

dito/
├── cmd/                   # Entry points (main application & plugin-signer)
├── app/                   # Core application logic
├── config/                # Configuration loader & hot-reload
├── handlers/              # Request routing & proxy handlers
├── middlewares/           # Built-in middlewares (plugins can add more)
├── plugin/                # Plugin loading, signing, and verification
├── plugins/               # Example and community plugins
├── transport/             # HTTP transport customization
├── websockets/            # WebSocket support
├── writer/                # Custom response writers
├── logging/               # Logging utilities
└── metrics/               # Prometheus metrics collection

⚙️ Installation

Ensure you have Go (>= 1.21) and make installed.

Quick Start (Recommended)

# Clone repo
git clone https://github.com/andrearaponi/dito.git && cd dito

# One-command setup & start
make quick-start

This will: 1. Build all binaries (Dito & plugin-signer) 2. Generate Ed25519 keys 3. Build & sign plugins 4. Update config with correct paths & hashes 5. Start the Dito server

Step-by-Step

# 1. Clone repo
git clone https://github.com/andrearaponi/dito.git && cd dito

# 2. Setup (build, keys, plugins, config)
make setup

# 3. Start server
make run

Makefile Commands

🛠️ Manual Installation (Advanced)

1. Build Dito: bash go build -o bin/dito ./cmd/dito/main.go (Note: Ensure the path to main.go is correct, e.g., ./cmd/dito/main.go if main.go is in cmd/dito/)

2. Build plugin-signer: bash cd cmd/plugin-signer && go build -o ../../bin/plugin-signer . && cd ../..

3. Generate keys: bash ./bin/plugin-signer generate-keys (This will create keys in the current directory, presumably bin/ if run from there, or the project root. Move them to bin/ if needed or specify paths)

4. Build plugins: bash find plugins -mindepth 1 -maxdepth 1 -type d -exec sh -c 'cd "$1" && go build -buildmode=plugin -o "$(basename "$1").so"' sh {} \;

5. Sign plugins: bash find plugins -name "*.so" -exec ./bin/plugin-signer sign {} \; (Ensure plugin-signer can find the private keys; you might need to specify -privateKey path/to/key)

6. Update config.yaml (ensure public_key_path & public_key_hash are correct).

7. Run Dito: bash ./bin/dito

⚙️ Usage

Start with default config:

make run

Or directly:

./bin/dito -f /path/to/custom-config.yaml -enable-profiler

Config File

• Template: cmd/config.yaml (or the correct path to your template)
• Runtime: bin/config.yaml (auto-updated by make setup or make quick-start)

Key fields:

port: '8081'
hot_reload: true
metrics:
  enabled: true
  path: "/metrics"
logging:
  enabled: true
  verbose: false
  level: "info"
plugins:
  directory: "./plugins" # Relative to where Dito is run, or absolute path
  public_key_path: "./ed25519_public.key" # Relative to where Dito is run, or absolute path
  public_key_hash: "<SHA256_HASH>" # The SHA256 hash of the public key
transport:
  http:
    idle_conn_timeout: 90s
    max_idle_conns: 1000
    max_idle_conns_per_host: 200
    max_conns_per_host: 0
    tls_handshake_timeout: 2s
    response_header_timeout: 2s
    expect_continue_timeout: 500ms
    disable_compression: false
    dial_timeout: 2s
    keep_alive: 30s
    force_http2: true
locations:
  - path: "^/test-ws$"
    target_url: "wss://echo.websocket.org"
    enable_websocket: true
    replace_path: true

  - path: "^/dito$"
    target_url: "https://httpbin.org/get"
    replace_path: true
    transport:
      http:
        disable_compression: true
    additional_headers:
      X-Custom: "true"
    excluded_headers:
      - Cookie
    middlewares:
      - hello-plugin # Plugin name as defined in its directory

📏 Response Limits Configuration

Dito provides flexible response body size limits that can be configured both globally and per location to prevent memory issues and control resource usage.

Global Response Limits

Set default limits for all locations in the main configuration:

# Global response limits configuration
response_limits:
  max_response_body_size: 100000 # 100KB default limit for all locations

Per-Location Response Limits

Override global limits for specific locations with custom settings:

locations:
  - path: "^/api/small"
    target_url: "https://api.example.com"
    max_response_body_size: 1024 # 1KB limit for this specific endpoint
    disable_response_buffering: false # Enable response buffering (default)

  - path: "^/api/large"
    target_url: "https://api.example.com"
    max_response_body_size: 52428800 # 50MB limit for large responses
    disable_response_buffering: true # Disable buffering for streaming

Response Limit Features

• Automatic Error Handling: Returns proper 413 Request Entity Too Large status code when limits are exceeded
• JSON Error Responses: Provides structured error messages with limit details
• Early Detection: Checks Content-Length header before processing to fail fast
• Streaming Support: Works with both buffered and unbuffered responses
• Logging: Comprehensive warning logs when limits are exceeded
• Zero Downtime: Limits can be updated via hot reload without server restart

Error Response Format

When a response exceeds the configured limit, Dito returns a standardized JSON error:

{
  "error": {
    "code": 413,
    "message": "Response body size exceeds limit",
    "details": {
      "limit_bytes": 90,
      "path": "/api/endpoint"
    }
  }
}

Response Buffering Control

The disable_response_buffering option controls how responses are handled:

• false (default): Responses are buffered in memory before sending to client
• Better for small responses
• Allows Content-Length to be set accurately

• Enables proper error handling when limits are exceeded

• true: Responses are streamed directly to client

• Better for large responses or real-time data
• Lower memory usage
• Cannot recover if response exceeds limit mid-stream

🔌 Plugin System

Dito uses Go plugins (.so files). Each plugin must: 1. Be in its own subdirectory under plugins/. 2. Contain: * <plugin-name>.so * <plugin-name>.so.sig (signature file) * config.yaml (plugin-specific config, optional but common)

Signing & Verification

• Mandatory: Dito will not start without valid plugin signing.
• Uses Ed25519 digital signatures.

Steps (if done manually): 1. Generate key pair: bash ./bin/plugin-signer generate-keys -privateKey ed25519_private.key -publicKey ed25519_public.key (Save these keys securely, e.g., in bin/ or a dedicated directory)

1. Compute public key hash: bash shasum -a 256 ed25519_public.key | awk '{print $1}' (Ensure the path to ed25519_public.key is correct)

2. Update Dito's config.yaml with public_key_path (e.g., ./bin/ed25519_public.key) and the computed public_key_hash.

3. Sign plugin: bash ./bin/plugin-signer sign -plugin path/to/plugin.so -privateKey path/to/ed25519_private.key (This will create a .sig file next to the plugin's .so file)

🐛 Troubleshooting

• public key integrity validation failed: Regenerate hash and update config. Ensure the hash exactly matches the specified public key file.
• failed to read public key: Check public key file path in config.yaml & file permissions.
• plugin signature verification failed: Re-sign with correct private key. Ensure public key in config.yaml matches the private key used for signing.

Custom Transport Configuration

This allows for fine-grained control over how Dito connects to backend services, including:

• Timeouts and Connection Limits: Configure timeouts and maximum connections to handle backend service behavior.
• TLS Settings: Manage TLS handshake timeouts and enforce HTTP/2 if needed.
• Custom Certificates: Specify client certificates for mTLS connections to backends.

WebSocket Support

Dito supports WebSocket proxying, allowing you to seamlessly forward WebSocket connections to your backend servers. This can be configured per location, enabling WebSocket support on specific routes.

Configuration

To enable WebSocket support, add enable_websocket: true to the location configuration. Here’s an example:

# List of location configurations for proxying requests.
locations:
  - path: "^/test-ws$" # Regex pattern to match the request path.
    target_url: "wss://echo.websocket.org" # The target URL to which the request will be proxied.
    enable_websocket: true # Enable WebSocket support for this location.
    replace_path: true # Replace the matched path with the target URL.

Upcoming Enhancements

Future versions of Dito will include more advanced WebSocket features, such as:

• Enhanced TLS Support: Configurable TLS settings for secure WebSocket connections, allowing for encrypted communication and improved security.
• Comprehensive Error Handling: Improved resilience and error management for WebSocket connections to ensure stability during unexpected interruptions.
• Detailed Metrics: Real-time metrics for WebSocket traffic, enabling better performance monitoring and insight into connection stability and throughput.

These features aim to provide full control, security, and reliability for WebSocket connections in Dito, enhancing the overall communication experience.

TLS/SSL

Dito supports mTLS (mutual TLS) for secure connections to backends. You can specify:

• cert_file: The