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Design Principles

VMProber is built on several key design principles that guide architectural decisions.

1. Reliability First

WAL System

  • All probe results written to Write-Ahead Log before processing
  • Ensures no data loss on crashes or restarts
  • Supports compression and rotation for efficiency

Retry Logic

  • Exponential backoff for failed operations
  • Configurable retry attempts and delays
  • Circuit breaker pattern to prevent cascading failures

Graceful Shutdown

  • Proper cleanup of resources
  • Finishes in-flight operations
  • Prioritized shutdown order

2. Performance

Efficient Scheduling

  • Jitter to distribute load
  • Rate limiting per host and globally
  • Worker pool with bounded concurrency

Batch Processing

  • Batch metrics export for efficiency
  • Buffer management for optimal throughput
  • Connection pooling for HTTP clients

Resource Management

  • Memory-efficient data structures
  • Proper goroutine lifecycle management
  • CPU usage monitoring and limits

3. Observability

Comprehensive Metrics

  • Prometheus-compatible metrics
  • Detailed probe statistics
  • System resource metrics

Structured Logging

  • JSON format for machine parsing
  • Contextual information in logs
  • Configurable log levels

Health Checks

  • Health endpoint for liveness
  • Readiness endpoint for startup
  • Component-level health status

4. Extensibility

Pluggable Architecture

  • Interface-based design
  • Easy to add new probe types
  • Configurable components

Hot Reload

  • Configuration reload without restart
  • Dynamic target discovery
  • Runtime configuration updates

Modular Design

  • Clear separation of concerns
  • Minimal dependencies between modules
  • Well-defined interfaces

5. Production Readiness

Security

  • TLS support for HTTP server
  • Authentication for push endpoints
  • Input validation and sanitization

Scalability

  • Horizontal scaling support
  • Efficient resource usage
  • Performance under load

Maintainability

  • Clear code structure
  • Comprehensive documentation
  • Testing at all levels

Implementation Patterns

Interface-Based Design

All major components use interfaces for flexibility and testability.

Context Propagation

Context used throughout for cancellation and timeouts.

Error Handling

Consistent error handling with wrapping and context.

Configuration Management

Centralized configuration with validation and hot reload.

Next Steps