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

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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/               # Plugin implementations
├── transport/             # HTTP transport configuration
├── websocket/             # WebSocket proxy support
├── writer/                # Response writers and buffering
├── metrics/               # Prometheus metrics
├── logging/               # Structured logging
├── deployments/           # Deployment configurations
│   ├── kubernetes/        # Basic Kubernetes deployments
│   ├── openshift/         # OpenShift production deployments
│   └── docker/            # Docker Compose for development
├── configs/               # Configuration files and templates
│   └── templates/         # Configuration templates
├── scripts/               # Deployment and utility scripts
└── bin/                   # Built binaries and runtime files
├── 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 (>= 1.27.1) and make installed. Plugins must be built with exactly the same Go toolchain as the Dito binary.

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:

   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:

   cd cmd/plugin-signer && go build -o ../../bin/plugin-signer . && cd ../..
   

3. Generate keys:

   ./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:

   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:

   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:

   ./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:

   ./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)

2. Compute public key hash:

   shasum -a 256 ed25519_public.key | awk '{print $1}'
   

   (Ensure the path to ed25519_public.key is correct)

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

4. Sign plugin:

   ./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 client certificate.
• key_file: The client private key.
• ca_file: The certificate authority (CA) for verifying the backend.

Metrics

Dito supports monitoring through Prometheus by exposing various metrics related to the proxy's performance and behavior. The metrics are accessible at the configured path (default is /metrics).

Available Metrics

Dito provides both custom metrics and standard metrics from the Go runtime and Prometheus libraries:

Custom Metrics

• http_requests_total: Total number of HTTP requests processed, partitioned by method, path, and status code.
• http_request_duration_seconds: Duration of HTTP requests in seconds, with predefined buckets.
• active_connections: Number of active connections currently being handled by the proxy.
• data_transferred_bytes_total: Total amount of data transferred in bytes, partitioned by direction (inbound or outbound).

Standard Metrics

• Go runtime metrics: Metrics such as memory usage, garbage collection statistics, and the number of goroutines, which are automatically exposed by the Go Prometheus client library. Examples include:
  • go_goroutines: Number of goroutines currently running.
  • go_memstats_alloc_bytes: Number of bytes allocated in the heap.
  • go_gc_duration_seconds: Duration of garbage collection cycles.
• Prometheus HTTP handler metrics: Metrics related to the Prometheus HTTP handler itself, such as:
  • promhttp_metric_handler_requests_total: Total number of HTTP requests handled by the metrics endpoint.
  • promhttp_metric_handler_requests_in_flight: Current number of scrapes being served.

Configuration Example

To enable metrics, make sure the following section is present in the config.yaml file:

metrics:
   enabled: true # Enable or disable metrics.
   path: "/metrics" # The path on which the metrics will be exposed.

🔁 Continuous Integration

Every pull request to main, every push to main and a weekly scheduled run (Mondays, 06:00 UTC) run the CI workflow (.github/workflows/ci.yml). Each job runs exactly one make target, so every check can be reproduced locally:

make ci runs all of them except image, in the same order, and stops at the first failure. make ci-selftest runs the mutation harness: for every gate it injects the defect the gate must catch (a compile error, a data race, an untidy go.mod, a tampered plugin signature, a coverage drop, ...) and verifies that the gate fails.

Local requirements

• Go with automatic toolchain switching: the Makefile sets GOTOOLCHAIN=auto and uses the version declared in go.mod, even if the installed Go is older.
• A C compiler (CGO) for the race detector and the plugins, plus curl and jq.
• make test-hermetic: on macOS it uses the built-in sandbox-exec; on Linux it needs sudo, unshare, setpriv and ip (util-linux, iproute2).
• make image: Docker or Podman.

Policies

• Tool versions live only in tools.mk. Tools run with go run, so they never enter go.mod, whose versions are shared with the plugins.
• Coverage floors may only go up: raise them in scripts/ci/coverage-floors.txt when you add tests, and remove a line only when its package is deleted.
• Lint blocks only new issues, so the existing debt does not block unrelated changes; make lint-all shows everything.

Required checks (Controlli obbligatori)

Enable branch protection on main (Settings → Branches) and mark these checks as required: tools, build, vet, modules, test, hermetic, lint, vuln, coverage, smoke, image, workflows. Validate Walden runs only when .walden/ changes, so it must not be required.

Dependency updates

Renovate keeps Go modules, GitHub Actions (pinned by commit SHA), Docker base images (pinned by digest) and the tools in tools.mk up to date. Install the Renovate GitHub App on the repository; its configuration is renovate.json: non-major updates are grouped in one weekly pull request, and go mod tidy also runs in the plugin module.

🧪 End-to-end scenarios

The e2e/ package checks the proxy as a client sees it: every scenario starts real backends on loopback, a proxy with a real configuration, and observes status, headers, bodies (compared by hash), framing, streaming, WebSocket traffic and the proxy logs. The catalog covers every feature of this README; each scenario carries its reproduction ID (R-xx) or probe (P-xx) when it has one.

make e2e                           # the whole suite, with the race detector, in random order
make e2e SCENARIO=^TestLimits_     # one area
make e2e SCENARIO=_R05_            # one scenario, by its ID

The suite also runs inside make test-race, make test-hermetic and make coverage, so every pull request runs it. It ends with a summary such as e2e summary: 48 passed, 0 failed, 27 known bugs (F-01: 6, ...).

Writing a scenario

A scenario is a Go test in e2e/, in the file of its area, named Test<Area>_<ID>_<Description>:

func TestRouting_ReplacePathTrue(t *testing.T) {
	Run(t, func(s *S) {
		api := s.Backend("api", text("ok"))
		p := s.Proxy(`
  - path: "^/old/path$"
    target_url: "{{backend "api"}}/new/path"
    replace_path: true`)
		s.Get(p.URL + "/old/path")
		assert.Equal(s, "/new/path", onlyRequest(s, api).Path)
	})
}

• Proxy: s.Proxy(locations, opts...) runs the handler chain of the binary in-process; s.Binary(...) runs the compiled proxy, for configuration files, hot reload (WithHotReload, s.Reload), signals and signed plugins (WithSignedPlugin). Options: WithMetrics, WithLogging, WithConfig, WithTransport, WithPlugins.
• Configuration: {{backend "name"}}, {{ws "name"}}, {{ca "name"}}, {{clientCert}} and {{clientKey}} are replaced with the addresses and TLS files of the scenario.
• Backends: s.Backend(name, handler) records every request (Requests()); WithTLS and WithClientAuth serve HTTPS and mutual TLS; deterministicBody(n, framing) serves bodies of any size with a known hash; s.RawBackend sends raw bytes.
• Client: s.Get, s.Head, s.Do, s.Stream (line by line, with timing), s.DialWebSocket, s.DoPartialUpload; logs with s.WaitLog and s.NoLog.
• Assertions: pass s to testify (assert.Equal(s, ...), require.NoError(s, ...)). Use s.Fatalf only for harness errors (a backend that does not start, a timeout).

Known bugs

A behavior still broken by an open finding stays in the catalog, marked with the finding:

func TestRouting_R05_ReplacePathFalse(t *testing.T) {
	KnownBug("F-04").Run(t, func(s *S) { /* assertions on the correct behavior */ })
}

• While its assertions fail, the scenario is reported as skipped with KNOWN BUG F-04 and the suite passes.
• When they all pass, the scenario fails with scenario passes: remove KnownBug("F-04"): the change that fixes a finding also removes its markers.
• Harness errors fail the scenario even when it is marked.
• A marked scenario must reproduce its bug every time: if the broken code is racy, repeat the exchange (see TestLimits_P04_OverLimitAfterStart).
• Scenarios that would demonstrate an open security finding are added together with its fix.

Reporting Issues

If you encounter any issues while using Dito, please follow these steps to open an issue on the GitHub repository:

1. Go Version: Specify the version of Go you are using.

   • You can find your Go version by running go version in your terminal.

2. Error Details: Provide a detailed description of the error or issue you encountered. Include:

   • The exact error message.
   • The steps you took to produce the error.
   • Any relevant logs or console outputs.

3. Configuration File: Include the config.yaml file you are using.

   • This will help us understand the context in which the issue occurred and allow us to replicate the problem.

👏 Contributing

1. Fork the repo.
2. Create your feature branch (git checkout -b feature/AmazingFeature).
3. Commit your changes (git commit -m 'Add some AmazingFeature').
4. Push to the branch (git push origin feature/AmazingFeature).
5. Open a Pull Request.

🐳 Containerization & OpenShift Deployment

Dito is fully containerized and optimized for OpenShift Container Platform (OCP) with enterprise-grade security and deployment practices.

Quick Deployment

For a complete OpenShift deployment with automatic key management and configuration:

# Make the deployment script executable
chmod +x scripts/deploy-ocp.sh

# Deploy with defaults (namespace: dito, version: v2.0.0-production)
./scripts/deploy-ocp.sh

# Deploy to custom namespace with specific version
./scripts/deploy-ocp.sh -n my-dito -v latest

# Force key regeneration
./scripts/deploy-ocp.sh -f

# Only update configuration (no deployment)
./scripts/deploy-ocp.sh -c

# Only deploy (skip config/key generation)
./scripts/deploy-ocp.sh -d

Manual Deployment Steps

1. Build and Push Container Image

# Build for OpenShift with automatic registry login and push
./docker-build.sh

# Or with custom settings
VERSION=v2.1.0 NAMESPACE=my-dito ./docker-build.sh

2. Generate Production Keys

# Generate persistent production keys (only if they don't exist)
make generate-prod-keys

3. Create OpenShift Resources

# Create namespace
oc new-project dito

# Create Secret for keys
oc create secret generic dito-keys \
    --from-file=ed25519_public.key=bin/ed25519_public_prod.key \
    --from-file=ed25519_private.key=bin/ed25519_private_prod.key

# Create ConfigMap for application config
# First, create Kubernetes-specific config from template
HASH=$(shasum -a 256 bin/ed25519_public_prod.key | awk '{print $1}')
sed "s/PLACEHOLDER_HASH_TO_BE_REPLACED/$HASH/" configs/templates/application.yaml > configs/config-prod-k8s.yaml

oc create configmap dito-config \
    --from-file=config.yaml=configs/config-prod-k8s.yaml

4. Deploy Application

# Deploy the application
oc apply -f deployments/openshift/production-deployment.yaml

Deployment Models

Security Features

Container Security

• Non-root execution: Runs as user ID 1001
• Read-only root filesystem: Prevents runtime modifications
• Dropped capabilities: Minimal privilege model
• Security contexts: OpenShift security context constraints

Key Management

• External key generation: Keys never stored in container images
• Runtime plugin signing: Plugins signed during pod initialization
• Secure secret mounting: Keys mounted as Kubernetes Secrets
• Proper file permissions: Keys accessible only to application user

Configuration Management

Dito supports multiple configuration approaches:

1. Template-based: Use configs/templates/application.yaml with hash substitution
2. Environment-specific: Separate configs for dev/prod/staging in configs/
3. ConfigMap injection: Runtime configuration via Kubernetes ConfigMaps
4. Hot-reload: Dynamic configuration updates without restarts

See configs/README.md for detailed configuration management.

📄 License

This project is licensed under the Apache License 2.0. See the LICENSE file for details.

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