Features

Navigator provides a comprehensive set of features for multi-tenant web applications, from basic process management to advanced regional routing.

What's New in v0.13.0

• Dynamic Version Reporting: --version flag shows build information
• Automatic Trailing Slash Handling: Normalize URLs with redirects
• Enhanced Proxy Handlers: Fixed regex capture group substitution
• WebSocket Improvements: Fixed subprotocol negotiation for Action Cable
• Path Stripping Fix: Correct strip_path behavior with target paths

Core Features

Process Management

• On-demand startup - Web applications start when first requested
• Dynamic port allocation - Automatically finds available ports
• Graceful shutdown - Clean termination with proper cleanup
• Auto-restart - Crashed processes automatically restart
• Resource limits - Configurable pool sizes and timeouts

Learn more about Process Management

Memory Limits

• Per-tenant limits - Enforce memory limits using Linux cgroups
• Cgroups v1/v2 support - Automatic detection and support for both versions
• OOM protection - Isolate memory-hungry tenants from others
• Auto-restart on OOM - Tenants restart automatically after kernel kills
• Memory statistics - Automatic logging of peak usage and utilization
• User/group isolation - Run tenant processes as non-root users

Learn more about Memory Limits

Static File Serving

• Direct filesystem serving - Bypass application for static content
• Configurable caching - Set cache headers for different content types
• Try files behavior - Flexible file resolution with fallbacks
• MIME type detection - Automatic content type headers
• Performance optimization - 10-40x faster than application serving

Learn more about Static Files

Authentication

• Multiple hash formats - APR1, bcrypt, SHA support
• Pattern-based exclusions - Flexible public path configuration
• Per-application auth - Different authentication per app
• htpasswd files - Standard htpasswd format support

Learn more about Authentication

Hot Configuration Reload

• Zero-downtime updates - Reload config without restart
• Signal-based - SIGHUP or command-line trigger
• Atomic changes - All changes applied together
• Process preservation - Existing Rails processes continue running

Learn more about Hot Reload

WebSocket Support

• Action Cable integration - Built-in Rails Action Cable support
• Standalone servers - Manage WebSocket servers as separate processes
• Connection upgrades - Automatic WebSocket protocol upgrades
• Long-lived connections - Efficient handling of persistent connections

Learn more about WebSocket Support

Lifecycle Hooks

• Server hooks - Execute commands at Navigator lifecycle events (start, ready, idle, resume)
• Tenant hooks - Execute commands when tenants start or stop
• Variable substitution - Use tenant variables in hook commands
• Flexible integration - Integrate with external services, monitoring, backups

Learn more about Lifecycle Hooks

Advanced Features

Fly-Replay Routing

• Multi-target routing - Route to regions, apps, or specific machines
• Smart fallback - Automatic reverse proxy for large requests
• Pattern matching - Flexible URL pattern configuration
• Method filtering - Apply rules to specific HTTP methods

Learn more about Fly-Replay

Machine Suspension

• Auto-suspend - Fly.io machines suspend after idle timeout
• Request tracking - Monitor active requests for idle detection
• Automatic wake - Machines wake on incoming requests
• Zero-downtime - Seamless suspend/resume cycles

Learn more about Machine Suspension

Sticky Sessions

• Cookie-based affinity - Route users to the same machine
• Cross-region support - Works across all Fly.io regions
• Automatic failover - Graceful handling of unavailable machines
• Path-specific sessions - Configure sticky sessions for specific paths

Learn more about Sticky Sessions

Try Files Behavior

• Flexible resolution - Try multiple file paths and extensions
• Multiple suffixes - Try different file extensions
• Index file support - Automatic index.html resolution
• Application fallback - Proxy to application when no file found

Learn more about Try Files

Structured Logging

• slog integration - Modern Go logging with structured output
• Configurable levels - Debug, info, warn, error levels
• Request tracking - Detailed request flow logging
• Performance metrics - Response times and process information

Learn more about Logging

Performance Features

Smart Resource Management

• Dynamic allocation - Processes start/stop based on demand
• Connection pooling - Efficient connection reuse
• Memory optimization - Minimal memory footprint
• CPU efficiency - Low CPU overhead

Caching Strategies

• Static file caching - Long-lived cache headers
• Process caching - Keep Rails processes warm
• Configuration caching - Cached config parsing

Load Balancing

• Round-robin - Distribute requests across processes
• Health checking - Avoid sending requests to crashed processes
• Graceful degradation - Handle process failures elegantly

Security Features

Access Control

• HTTP Basic Auth - Industry standard authentication
• Pattern-based exclusions - Flexible public path configuration
• Per-application security - Different security policies per app

Process Isolation

• Separate processes - Rails apps run in separate processes
• Memory isolation - Per-tenant memory limits with cgroups (Linux)
• User/group isolation - Run tenants as non-root users (Unix)
• Working directories - Each app has its own working directory
• Environment isolation - Separate environment variables

Configuration Security

• Environment variables - Secrets from environment, not config files
• File permissions - Secure configuration file handling
• No hardcoded secrets - Template-based secret management

Monitoring and Observability

Request Tracking

• Structured logging - JSON-formatted logs with request context
• Response time tracking - Monitor application performance
• Error tracking - Detailed error information

Process Monitoring

• Process lifecycle - Track process starts, stops, crashes
• Resource usage - Monitor memory and CPU usage
• Health status - Process health checking

System Integration

• systemd compatibility - Works well with systemd
• Log aggregation - Compatible with log management systems
• Metrics export - Structured data for monitoring systems

Platform-Specific Features

Cross-Platform Support (v0.11.0+)

• Linux: AMD64, ARM64 - Full feature support with SIGTSTP/SIGTERM
• macOS: Intel (AMD64), Apple Silicon (ARM64) - Native macOS signal handling
• Windows: AMD64, ARM64 - Graceful shutdown with os.Exit
• Platform-specific optimizations - Uses native OS primitives where appropriate

Learn more about Architecture

Fly.io Integration

• Machine suspension - Auto-suspend idle machines
• Fly-Replay routing - Intelligent request routing
• Regional deployment - Deploy close to users
• Internal networking - Secure inter-service communication

General Cloud Support

• Health check endpoints - Standard health checking
• Graceful shutdown - Proper signal handling
• Environment configuration - 12-factor app compliance
• Container friendly - Works well in containers

Feature Roadmap

Short Term (Next Release)

• Metrics endpoint - Prometheus-compatible metrics
• SSL termination - Optional HTTPS support
• Rate limiting - Built-in rate limiting

Medium Term

• Auto-scaling - Dynamic process scaling
• Circuit breakers - Failure isolation
• Distributed tracing - OpenTelemetry integration

Long Term

• Multi-server support - Clustering capabilities
• Advanced routing - Content-based routing
• Plugin system - Extensible architecture

Getting Started with Features

1. Start Simple - Begin with basic process management
2. Add Static Files - Optimize performance with direct serving
3. Configure Authentication - Secure your applications
4. Enable Hot Reload - Streamline configuration updates
5. Explore Advanced Features - Try Fly-Replay and machine suspension

See Also

• Configuration Guide
• Examples
• Deployment Guide