ThoughtMCP

/** * Health Checker * * Provides health check endpoints and component health monitoring. * * Requirements: 11.1, 11.2, 11.3, 11.4, 11.5 */ import type { HealthCheckResult, SystemHealthReport, SystemMetrics } from "./types.js"; /** * Health check function type */ export type HealthCheckFn = () => Promise<HealthCheckResult>; /** * Health Checker class * * Manages health checks for system components and generates health reports. */ export class HealthChecker { private checks: Map<string, HealthCheckFn> = new Map(); private lastResults: Map<string, HealthCheckResult> = new Map(); private startTime: Date; private version?: string; constructor(options?: { version?: string }) { this.startTime = new Date(); this.version = options?.version; } /** * Register a health check */ registerCheck(name: string, check: HealthCheckFn): void { this.checks.set(name, check); } /** * Unregister a health check */ unregisterCheck(name: string): void { this.checks.delete(name); this.lastResults.delete(name); } /** * Run a single health check */ async runCheck(name: string): Promise<HealthCheckResult> { const check = this.checks.get(name); if (!check) { return { component: name, status: "unhealthy", responseTimeMs: 0, error: `Health check '${name}' not found`, }; } const startTime = performance.now(); try { const result = await check(); result.responseTimeMs = performance.now() - startTime; result.lastSuccess = result.status === "healthy" ? new Date() : this.lastResults.get(name)?.lastSuccess; this.lastResults.set(name, result); return result; } catch (error) { const result: HealthCheckResult = { component: name, status: "unhealthy", responseTimeMs: performance.now() - startTime, error: error instanceof Error ? error.message : "Unknown error", lastSuccess: this.lastResults.get(name)?.lastSuccess, }; this.lastResults.set(name, result); return result; } } /** * Run all health checks */ async runAllChecks(): Promise<HealthCheckResult[]> { const results: HealthCheckResult[] = []; for (const name of this.checks.keys()) { const result = await this.runCheck(name); results.push(result); } return results; } /** * Get system metrics */ getSystemMetrics(): SystemMetrics { const memUsage = process.memoryUsage(); return { memoryUsed: memUsage.rss, memoryTotal: memUsage.rss + memUsage.external, memoryUsagePercent: 0, // Would need OS-level info for accurate percentage heapUsed: memUsage.heapUsed, heapTotal: memUsage.heapTotal, }; } /** * Generate a full health report */ async generateReport(): Promise<SystemHealthReport> { const components = await this.runAllChecks(); const metrics = this.getSystemMetrics(); const uptimeMs = Date.now() - this.startTime.getTime(); // Determine overall status let status: "healthy" | "unhealthy" | "degraded" = "healthy"; const unhealthyCount = components.filter((c) => c.status === "unhealthy").length; const degradedCount = components.filter((c) => c.status === "degraded").length; if (unhealthyCount > 0) { status = "unhealthy"; } else if (degradedCount > 0) { status = "degraded"; } return { status, timestamp: new Date(), components, metrics, uptimeMs, version: this.version, }; } /** * Get last result for a component */ getLastResult(name: string): HealthCheckResult | undefined { return this.lastResults.get(name); } /** * Get all last results */ getAllLastResults(): Map<string, HealthCheckResult> { return new Map(this.lastResults); } /** * Check if system is healthy */ async isHealthy(): Promise<boolean> { const report = await this.generateReport(); return report.status === "healthy"; } /** * Check if system is ready (healthy or degraded) */ async isReady(): Promise<boolean> { const report = await this.generateReport(); return report.status !== "unhealthy"; } /** * Get uptime in milliseconds */ getUptimeMs(): number { return Date.now() - this.startTime.getTime(); } /** * Get registered check names */ getCheckNames(): string[] { return Array.from(this.checks.keys()); } /** * Create a database health check */ static createDatabaseCheck( checkFn: () => Promise<boolean>, name: string = "database" ): HealthCheckFn { return async (): Promise<HealthCheckResult> => { try { const healthy = await checkFn(); return { component: name, status: healthy ? "healthy" : "unhealthy", responseTimeMs: 0, error: healthy ? undefined : "Database health check failed", }; } catch (error) { return { component: name, status: "unhealthy", responseTimeMs: 0, error: error instanceof Error ? error.message : "Unknown error", }; } }; } /** * Create a memory health check */ static createMemoryCheck(thresholdPercent: number = 90, name: string = "memory"): HealthCheckFn { return async (): Promise<HealthCheckResult> => { const memUsage = process.memoryUsage(); const usedPercent = (memUsage.heapUsed / memUsage.heapTotal) * 100; let status: "healthy" | "unhealthy" | "degraded" = "healthy"; if (usedPercent >= thresholdPercent) { status = "unhealthy"; } else if (usedPercent >= thresholdPercent * 0.8) { status = "degraded"; } return { component: name, status, responseTimeMs: 0, details: { heapUsed: memUsage.heapUsed, heapTotal: memUsage.heapTotal, usedPercent: Math.round(usedPercent * 100) / 100, threshold: thresholdPercent, }, }; }; } /** * Create a custom health check with timeout */ static createTimeoutCheck( checkFn: () => Promise<boolean>, timeoutMs: number, name: string ): HealthCheckFn { return async (): Promise<HealthCheckResult> => { try { const timeoutPromise = new Promise<never>((_, reject) => setTimeout(() => reject(new Error("Health check timeout")), timeoutMs) ); const healthy = await Promise.race([checkFn(), timeoutPromise]); return { component: name, status: healthy ? "healthy" : "unhealthy", responseTimeMs: 0, }; } catch (error) { return { component: name, status: "unhealthy", responseTimeMs: 0, error: error instanceof Error ? error.message : "Unknown error", }; } }; } } /** * Global health checker instance */ export const healthChecker = new HealthChecker();