113 lines
3.3 KiB
TypeScript
113 lines
3.3 KiB
TypeScript
/**
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* Circuit Breaker pour éviter de surcharger Komga quand il est défaillant
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* Évite l'effet avalanche en coupant les requêtes vers un service défaillant
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*/
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import type { CircuitBreakerConfig } from "@/types/preferences";
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import logger from "@/lib/logger";
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interface CircuitBreakerState {
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state: 'CLOSED' | 'OPEN' | 'HALF_OPEN';
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failureCount: number;
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lastFailureTime: number;
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nextAttemptTime: number;
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}
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class CircuitBreaker {
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private state: CircuitBreakerState = {
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state: 'CLOSED',
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failureCount: 0,
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lastFailureTime: 0,
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nextAttemptTime: 0,
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};
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private config = {
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failureThreshold: 5, // Nombre d'échecs avant ouverture
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recoveryTimeout: 30000, // 30s avant tentative de récupération
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resetTimeout: 60000, // Délai de reset après échec
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};
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private getConfigFromPreferences: (() => Promise<CircuitBreakerConfig>) | null = null;
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/**
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* Configure une fonction pour récupérer dynamiquement la config depuis les préférences
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*/
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setConfigGetter(getter: () => Promise<CircuitBreakerConfig>): void {
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this.getConfigFromPreferences = getter;
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}
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/**
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* Récupère la config actuelle, soit depuis les préférences, soit depuis les valeurs par défaut
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*/
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private async getCurrentConfig(): Promise<typeof this.config> {
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if (this.getConfigFromPreferences) {
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try {
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const prefConfig = await this.getConfigFromPreferences();
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return {
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failureThreshold: prefConfig.threshold ?? 5,
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recoveryTimeout: prefConfig.timeout ?? 30000,
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resetTimeout: prefConfig.resetTimeout ?? 60000,
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};
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} catch (error) {
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logger.error({ err: error }, 'Error getting circuit breaker config from preferences');
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return this.config;
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}
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}
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return this.config;
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}
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async execute<T>(operation: () => Promise<T>): Promise<T> {
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const config = await this.getCurrentConfig();
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if (this.state.state === 'OPEN') {
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if (Date.now() < this.state.nextAttemptTime) {
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throw new Error('Circuit breaker is OPEN - Komga service unavailable');
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}
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this.state.state = 'HALF_OPEN';
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}
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try {
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const result = await operation();
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this.onSuccess();
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return result;
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} catch (error) {
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await this.onFailure(config);
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throw error;
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}
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}
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private onSuccess(): void {
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if (this.state.state === 'HALF_OPEN') {
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this.state.failureCount = 0;
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this.state.state = 'CLOSED';
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logger.info('[CIRCUIT-BREAKER] ✅ Circuit closed - Komga recovered');
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}
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}
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private async onFailure(config: typeof this.config): Promise<void> {
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this.state.failureCount++;
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this.state.lastFailureTime = Date.now();
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if (this.state.failureCount >= config.failureThreshold) {
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this.state.state = 'OPEN';
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this.state.nextAttemptTime = Date.now() + config.resetTimeout;
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logger.warn(`[CIRCUIT-BREAKER] 🔴 Circuit OPEN - Komga failing (${this.state.failureCount} failures, reset in ${config.resetTimeout}ms)`);
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}
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}
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getState(): CircuitBreakerState {
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return { ...this.state };
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}
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reset(): void {
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this.state = {
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state: 'CLOSED',
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failureCount: 0,
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lastFailureTime: 0,
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nextAttemptTime: 0,
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};
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logger.info('[CIRCUIT-BREAKER] 🔄 Circuit reset');
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}
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}
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export const CircuitBreakerService = new CircuitBreaker();
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