refactor: move circuit breaker to a separate class

Author: gitcommitshow

CircuitBreaker.js

@@ -0,0 +1,132 @@
+/**
+ * Circuit Breaker implementation with configurable failure thresholds and cooldown periods
+ */
+class CircuitBreaker {
+    static #instances = new Map(); // bucketId -> instance
+    
+    constructor({
+        failureThreshold = 5,
+        cooldownPeriod = 30000,
+        name = 'default'
+    }) {
+        this.failureThreshold = failureThreshold;
+        this.cooldownPeriod = cooldownPeriod;
+        this.name = name;
+        
+        // State
+        this.failCount = 0;
+        this.isOpen = false;
+        this.openedAt = null;
+        this.lastFailureTime = null;
+    }
+    
+    /**
+     * Get or create a circuit breaker instance for the given bucketId
+     * @param {string} bucketId - The service identifier
+     * @param {Object} config - Circuit breaker configuration
+     * @returns {CircuitBreaker} - The circuit breaker instance
+     */
+    static getInstance(bucketId, config) {
+        if (!this.#instances.has(bucketId)) {
+            this.#instances.set(bucketId, new CircuitBreaker({
+                ...config,
+                name: `CircuitBreaker-${bucketId}`
+            }));
+        }
+        return this.#instances.get(bucketId);
+    }
+    
+    /**
+     * Clear a circuit breaker instance for the given bucketId
+     * @param {string} bucketId - The service identifier
+     */
+    static clear(bucketId) {
+        this.#instances.delete(bucketId);
+    }
+
+    /**
+     * Check if the circuit breaker is open, reset if cooldown period has expired
+     * @returns {boolean} - True if circuit is open, false if closed
+     */
+    isCircuitOpen() {
+        if (!this.isOpen) return false;
+        
+        // Check if cooldown period has expired
+        if (Date.now() - this.openedAt > this.cooldownPeriod) {
+            this._reset();
+            return false;
+        }
+        
+        return true;
+    }
+
+    /**
+     * Record a successful operation
+     */
+    recordSuccess() {
+        this._reset();
+    }
+
+    /**
+     * Record a failed operation
+     */
+    recordFailure() {
+        this.failCount++;
+        this.lastFailureTime = Date.now();
+        
+        if (this.failCount >= this.failureThreshold) {
+            this._open();
+        }
+    }
+
+    /**
+     * Get current circuit breaker status
+     * @returns {Object} - Status information
+     */
+    getStatus() {
+        return {
+            isOpen: this.isCircuitOpen(),
+            failCount: this.failCount,
+            failureThreshold: this.failureThreshold,
+            cooldownRemaining: this.isOpen ? 
+                Math.max(0, this.cooldownPeriod - (Date.now() - this.openedAt)) : 0,
+            lastFailureTime: this.lastFailureTime,
+            name: this.name
+        };
+    }
+
+    /**
+     * Manually open the circuit breaker
+     */
+    forceOpen() {
+        this._open();
+    }
+
+    /**
+     * Manually close the circuit breaker
+     */
+    forceClose() {
+        this._reset();
+    }
+
+    /**
+     * Reset circuit breaker to closed state
+     * @private
+     */
+    _reset() {
+        this.isOpen = false;
+        this.failCount = 0;
+        this.openedAt = null;
+    }
+
+    /**
+     * Open the circuit breaker
+     * @private
+     */
+    _open() {
+        this.isOpen = true;
+        this.openedAt = Date.now();
+    }
+}
+
+export default CircuitBreaker;