Mountain/IPC/Common/

ServiceInfo.rs

//! # Service Discovery and Information
//!
//! Provides service discovery and information tracking for Mountain services.
//! Used to monitor and manage registered services.

use std::{
	collections::HashMap,
	time::{Duration, Instant},
};

use serde::{Deserialize, Serialize};

/// State of a service
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
pub enum ServiceState {
	/// Service is running normally
	Running,
	/// Service is degraded but operational
	Degraded,
	/// Service is stopped
	Stopped,
	/// Service has encountered an error
	Error,
	/// Service is starting up
	Starting,
	/// Service is shutting down
	ShuttingDown,
}

impl ServiceState {
	/// Check if service is operational
	pub fn is_operational(&self) -> bool {
		matches!(self, ServiceState::Running | ServiceState::Degraded | ServiceState::Starting)
	}
}

/// Information about a single service
#[derive(Debug, Clone, Serialize)]
pub struct ServiceInfo {
	/// Service name
	pub name:String,
	/// Service version
	pub version:String,
	/// Current state
	pub state:ServiceState,
	/// When the service entered its current state (skipped for serialization as
	/// Instant is not serializable)
	#[serde(skip)]
	pub state_since:Instant,
	/// Service uptime
	pub uptime:Duration,
	/// Last heartbeat timestamp (skipped for serialization as Instant is not
	/// serializable)
	#[serde(skip)]
	pub last_heartbeat:Option<Instant>,
	/// Services this service depends on
	pub dependencies:Vec<String>,
	/// Performance metrics for this service
	pub performance:ServicePerformance,
	/// Optional network endpoint
	pub endpoint:Option<ServiceEndpoint>,
}

/// Performance metrics for a service
#[derive(Debug, Clone, Serialize)]
pub struct ServicePerformance {
	/// Request count
	pub request_count:u64,
	/// Error count
	pub error_count:u64,
	/// Average response time in milliseconds
	pub average_response_time_ms:f64,
	/// Last updated timestamp (skipped for serialization as Instant is not
	/// serializable)
	#[serde(skip)]
	pub last_updated:Instant,
}

impl ServicePerformance {
	/// Create new service performance metrics
	pub fn new() -> Self {
		Self {
			request_count:0,
			error_count:0,
			average_response_time_ms:0.0,
			last_updated:Instant::now(),
		}
	}

	/// Record a request
	pub fn record_request(&mut self, response_time_ms:f64) {
		self.request_count += 1;

		// Update average response time
		if self.average_response_time_ms == 0.0 {
			self.average_response_time_ms = response_time_ms;
		} else {
			self.average_response_time_ms = (self.average_response_time_ms * (self.request_count - 1) as f64
				+ response_time_ms)
				/ self.request_count as f64;
		}

		self.last_updated = Instant::now();
	}

	/// Record an error
	pub fn record_error(&mut self) {
		self.error_count += 1;
		self.last_updated = Instant::now();
	}

	/// Calculate error rate (0.0 to 1.0)
	pub fn error_rate(&self) -> f64 {
		if self.request_count == 0 {
			return 0.0;
		}
		self.error_count as f64 / self.request_count as f64
	}
}

impl Default for ServicePerformance {
	fn default() -> Self { Self::new() }
}

/// Network endpoint for a service
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ServiceEndpoint {
	/// Protocol (e.g., "ipc", "tcp", "udp")
	pub protocol:String,
	/// Host address
	pub address:String,
	/// Port number
	pub port:u16,
	/// Path (for Unix domain sockets)
	pub path:Option<String>,
}

impl ServiceEndpoint {
	/// Create a new service endpoint
	pub fn new(protocol:impl Into<String>, address:impl Into<String>, port:u16) -> Self {
		Self { protocol:protocol.into(), address:address.into(), port, path:None }
	}

	/// Create a Unix domain socket endpoint
	pub fn new_unix(path:impl Into<String>) -> Self {
		Self {
			protocol:"unix".to_string(),
			address:String::new(),
			port:0,
			path:Some(path.into()),
		}
	}
}

impl ServiceInfo {
	/// Create a new service info
	pub fn new(name:impl Into<String>, version:impl Into<String>) -> Self {
		Self {
			name:name.into(),
			version:version.into(),
			state:ServiceState::Starting,
			state_since:Instant::now(),
			uptime:Duration::ZERO,
			last_heartbeat:None,
			dependencies:Vec::new(),
			performance:ServicePerformance::new(),
			endpoint:None,
		}
	}

	/// Update service state
	pub fn update_state(&mut self, new_state:ServiceState) {
		self.state = new_state;
		self.state_since = Instant::now();
	}

	/// Record heartbeat
	pub fn record_heartbeat(&mut self) {
		self.last_heartbeat = Some(Instant::now());

		// Update uptime if service is running
		if self.state == ServiceState::Running {
			self.uptime = self.state_since.elapsed();
		}
	}

	/// Check if service is healthy
	pub fn is_healthy(&self) -> bool {
		if !self.state.is_operational() {
			return false;
		}

		// Check if heartbeat is recent (within 30 seconds)
		if let Some(heartbeat) = self.last_heartbeat {
			if heartbeat.elapsed() > Duration::from_secs(30) {
				return false;
			}
		}

		// Check error rate (should be below 10%)
		if self.performance.error_rate() > 0.1 {
			return false;
		}

		true
	}

	/// Add a dependency
	pub fn add_dependency(&mut self, dependency:impl Into<String>) { self.dependencies.push(dependency.into()); }
}

/// Registry of all discovered services
#[derive(Debug, Clone)]
pub struct ServiceRegistry {
	/// Map of service name to service info
	pub services:HashMap<String, ServiceInfo>,
	/// Last discovery timestamp (not serializable)
	pub last_discovery:Instant,
	/// Configurable discovery interval
	pub discovery_interval:Duration,
}

impl ServiceRegistry {
	/// Create a new service registry
	pub fn new(discovery_interval:Duration) -> Self {
		Self { services:HashMap::new(), last_discovery:Instant::now(), discovery_interval }
	}

	/// Register a service
	pub fn register(&mut self, service:ServiceInfo) {
		self.services.insert(service.name.clone(), service);
		self.last_discovery = Instant::now();
	}

	/// Unregister a service
	pub fn unregister(&mut self, name:&str) -> Option<ServiceInfo> {
		self.services.remove(name).map(|service| {
			self.last_discovery = Instant::now();
			service
		})
	}

	/// Get service info by name
	pub fn get(&self, name:&str) -> Option<&ServiceInfo> { self.services.get(name) }

	/// Get mutable service info by name
	pub fn get_mut(&mut self, name:&str) -> Option<&mut ServiceInfo> { self.services.get_mut(name) }

	/// Check if it's time for discovery
	pub fn should_discover(&self) -> bool { self.last_discovery.elapsed() >= self.discovery_interval }

	/// Get all healthy services
	pub fn healthy_services(&self) -> Vec<&ServiceInfo> {
		self.services.values().filter(|service| service.is_healthy()).collect()
	}

	/// Get all unhealthy services
	pub fn unhealthy_services(&self) -> Vec<&ServiceInfo> {
		self.services.values().filter(|service| !service.is_healthy()).collect()
	}

	/// Mark discovery time
	pub fn mark_discovery(&mut self) { self.last_discovery = Instant::now(); }
}

impl Default for ServiceRegistry {
	fn default() -> Self { Self::new(Duration::from_secs(60)) }
}