BREAKING CHANGE(core): Refactor to v3: introduce modular core/domain architecture, plugin system, observability and strict TypeScript configuration; remove legacy classes

This commit is contained in:
2025-11-29 18:32:00 +00:00
parent 53673e37cb
commit 7e89b6ebf5
68 changed files with 17020 additions and 720 deletions

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/**
* Circuit breaker states
*/
export enum CircuitState {
/** Circuit is closed, requests flow normally */
CLOSED = 'closed',
/** Circuit is open, requests are rejected immediately */
OPEN = 'open',
/** Circuit is half-open, testing if service recovered */
HALF_OPEN = 'half_open',
}
/**
* Circuit breaker configuration
*/
export interface CircuitBreakerConfig {
/** Number of failures before opening circuit */
failureThreshold: number;
/** Number of successes in half-open state before closing */
successThreshold: number;
/** Time in milliseconds circuit stays open before attempting half-open */
timeout: number;
/** Time window in milliseconds for counting failures */
rollingWindow: number;
/** Whether circuit breaker is enabled */
enabled: boolean;
}
/**
* Default circuit breaker configuration
*/
export const DEFAULT_CIRCUIT_BREAKER_CONFIG: CircuitBreakerConfig = {
failureThreshold: 5,
successThreshold: 2,
timeout: 60000, // 1 minute
rollingWindow: 10000, // 10 seconds
enabled: true,
};
/**
* Circuit breaker error thrown when circuit is open
*/
export class CircuitBreakerOpenError extends Error {
constructor(
public readonly circuitName: string,
public readonly nextAttemptTime: Date
) {
super(
`Circuit breaker "${circuitName}" is OPEN. Next attempt at ${nextAttemptTime.toISOString()}`
);
this.name = 'CircuitBreakerOpenError';
}
}
/**
* Failure record for tracking
*/
interface FailureRecord {
timestamp: number;
error: Error;
}
/**
* Circuit breaker for preventing cascading failures
*
* @example
* ```typescript
* const breaker = new CircuitBreaker('elasticsearch', {
* failureThreshold: 5,
* timeout: 60000,
* });
*
* try {
* const result = await breaker.execute(async () => {
* return await someElasticsearchOperation();
* });
* } catch (error) {
* if (error instanceof CircuitBreakerOpenError) {
* // Circuit is open, handle gracefully
* }
* }
* ```
*/
export class CircuitBreaker {
private config: CircuitBreakerConfig;
private state: CircuitState = CircuitState.CLOSED;
private failures: FailureRecord[] = [];
private successCount = 0;
private openedAt?: number;
private nextAttemptTime?: number;
constructor(
private name: string,
config: Partial<CircuitBreakerConfig> = {}
) {
this.config = { ...DEFAULT_CIRCUIT_BREAKER_CONFIG, ...config };
}
/**
* Execute an operation through the circuit breaker
*/
async execute<T>(operation: () => Promise<T>): Promise<T> {
if (!this.config.enabled) {
return operation();
}
// Check circuit state
this.updateState();
if (this.state === CircuitState.OPEN) {
const nextAttempt = this.nextAttemptTime
? new Date(this.nextAttemptTime)
: new Date(Date.now() + this.config.timeout);
throw new CircuitBreakerOpenError(this.name, nextAttempt);
}
try {
const result = await operation();
this.onSuccess();
return result;
} catch (error) {
this.onFailure(error as Error);
throw error;
}
}
/**
* Handle successful operation
*/
private onSuccess(): void {
this.removeOldFailures();
if (this.state === CircuitState.HALF_OPEN) {
this.successCount++;
if (this.successCount >= this.config.successThreshold) {
this.transitionTo(CircuitState.CLOSED);
}
}
}
/**
* Handle failed operation
*/
private onFailure(error: Error): void {
this.failures.push({
timestamp: Date.now(),
error,
});
this.removeOldFailures();
if (this.state === CircuitState.HALF_OPEN) {
// Any failure in half-open state opens the circuit immediately
this.transitionTo(CircuitState.OPEN);
} else if (this.state === CircuitState.CLOSED) {
// Check if we've exceeded failure threshold
if (this.failures.length >= this.config.failureThreshold) {
this.transitionTo(CircuitState.OPEN);
}
}
}
/**
* Update circuit state based on time
*/
private updateState(): void {
if (this.state === CircuitState.OPEN && this.nextAttemptTime) {
if (Date.now() >= this.nextAttemptTime) {
this.transitionTo(CircuitState.HALF_OPEN);
}
}
}
/**
* Transition to a new state
*/
private transitionTo(newState: CircuitState): void {
const previousState = this.state;
this.state = newState;
switch (newState) {
case CircuitState.OPEN:
this.openedAt = Date.now();
this.nextAttemptTime = Date.now() + this.config.timeout;
this.successCount = 0;
break;
case CircuitState.HALF_OPEN:
this.successCount = 0;
break;
case CircuitState.CLOSED:
this.failures = [];
this.successCount = 0;
this.openedAt = undefined;
this.nextAttemptTime = undefined;
break;
}
if (previousState !== newState) {
this.onStateChange(previousState, newState);
}
}
/**
* Remove failures outside the rolling window
*/
private removeOldFailures(): void {
const cutoff = Date.now() - this.config.rollingWindow;
this.failures = this.failures.filter((f) => f.timestamp >= cutoff);
}
/**
* Callback when state changes (can be overridden)
*/
protected onStateChange(from: CircuitState, to: CircuitState): void {
// Override in subclass or use getState() to monitor
console.log(`Circuit breaker "${this.name}" transitioned from ${from} to ${to}`);
}
/**
* Get current circuit state
*/
getState(): CircuitState {
this.updateState();
return this.state;
}
/**
* Get circuit statistics
*/
getStats(): {
state: CircuitState;
failureCount: number;
successCount: number;
openedAt?: Date;
nextAttemptTime?: Date;
} {
this.removeOldFailures();
this.updateState();
return {
state: this.state,
failureCount: this.failures.length,
successCount: this.successCount,
...(this.openedAt && { openedAt: new Date(this.openedAt) }),
...(this.nextAttemptTime && { nextAttemptTime: new Date(this.nextAttemptTime) }),
};
}
/**
* Manually open the circuit
*/
open(): void {
this.transitionTo(CircuitState.OPEN);
}
/**
* Manually close the circuit
*/
close(): void {
this.transitionTo(CircuitState.CLOSED);
}
/**
* Reset the circuit breaker
*/
reset(): void {
this.failures = [];
this.successCount = 0;
this.openedAt = undefined;
this.nextAttemptTime = undefined;
this.state = CircuitState.CLOSED;
}
/**
* Check if circuit is open
*/
isOpen(): boolean {
this.updateState();
return this.state === CircuitState.OPEN;
}
/**
* Check if circuit is closed
*/
isClosed(): boolean {
this.updateState();
return this.state === CircuitState.CLOSED;
}
/**
* Check if circuit is half-open
*/
isHalfOpen(): boolean {
this.updateState();
return this.state === CircuitState.HALF_OPEN;
}
}

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import { Client as ElasticClient } from '@elastic/elasticsearch';
import { ElasticsearchConfig } from '../config/types.js';
import { HealthChecker, HealthCheckResult, HealthStatus } from './health-check.js';
import { CircuitBreaker } from './circuit-breaker.js';
import { Logger, defaultLogger } from '../observability/logger.js';
import { MetricsCollector, defaultMetricsCollector } from '../observability/metrics.js';
import { ConnectionError, ClusterUnavailableError } from '../errors/elasticsearch-error.js';
/**
* Connection manager configuration
*/
export interface ConnectionManagerConfig extends ElasticsearchConfig {
/** Enable health checks */
enableHealthCheck?: boolean;
/** Enable circuit breaker */
enableCircuitBreaker?: boolean;
/** Logger instance */
logger?: Logger;
/** Metrics collector */
metricsCollector?: MetricsCollector;
}
/**
* Connection manager for Elasticsearch client
*
* Provides:
* - Singleton client instance
* - Connection pooling
* - Health monitoring
* - Circuit breaker pattern
* - Automatic reconnection
*
* @example
* ```typescript
* const manager = ElasticsearchConnectionManager.getInstance({
* nodes: ['http://localhost:9200'],
* auth: { type: 'basic', username: 'elastic', password: 'changeme' }
* });
*
* const client = manager.getClient();
* await client.search({ index: 'my-index', query: { match_all: {} } });
* ```
*/
export class ElasticsearchConnectionManager {
private static instance: ElasticsearchConnectionManager | null = null;
private client: ElasticClient;
private healthChecker: HealthChecker;
private circuitBreaker: CircuitBreaker;
private logger: Logger;
private metrics: MetricsCollector;
private config: ConnectionManagerConfig;
private isInitialized = false;
private connectionCount = 0;
private constructor(config: ConnectionManagerConfig) {
this.config = config;
this.logger = config.logger || defaultLogger.child('connection-manager');
this.metrics = config.metricsCollector || defaultMetricsCollector;
// Initialize Elasticsearch client
this.client = this.createClient(config);
// Initialize health checker
this.healthChecker = new HealthChecker(this.client, {
interval: config.pool?.maxIdleTime || 30000,
timeout: config.request?.timeout || 5000,
checkClusterHealth: true,
});
// Initialize circuit breaker
this.circuitBreaker = new CircuitBreaker('elasticsearch', {
enabled: config.enableCircuitBreaker !== false,
failureThreshold: 5,
timeout: 60000,
});
this.logger.info('Elasticsearch connection manager created', {
nodes: config.nodes,
poolEnabled: !!config.pool,
healthCheckEnabled: config.enableHealthCheck !== false,
circuitBreakerEnabled: config.enableCircuitBreaker !== false,
});
}
/**
* Get singleton instance
*/
static getInstance(config?: ConnectionManagerConfig): ElasticsearchConnectionManager {
if (!ElasticsearchConnectionManager.instance) {
if (!config) {
throw new Error('Configuration required for first initialization');
}
ElasticsearchConnectionManager.instance = new ElasticsearchConnectionManager(config);
}
return ElasticsearchConnectionManager.instance;
}
/**
* Reset singleton instance (useful for testing)
*/
static resetInstance(): void {
if (ElasticsearchConnectionManager.instance) {
ElasticsearchConnectionManager.instance.destroy();
ElasticsearchConnectionManager.instance = null;
}
}
/**
* Create Elasticsearch client with configuration
*/
private createClient(config: ConnectionManagerConfig): ElasticClient {
const nodes = Array.isArray(config.nodes) ? config.nodes : [config.nodes];
const clientConfig: any = {
nodes,
};
// Authentication
if (config.auth) {
switch (config.auth.type) {
case 'basic':
clientConfig.auth = {
username: config.auth.username,
password: config.auth.password,
};
break;
case 'apiKey':
clientConfig.auth = {
apiKey: config.auth.apiKey,
};
break;
case 'bearer':
clientConfig.auth = {
bearer: config.auth.token,
};
break;
case 'cloud':
clientConfig.cloud = {
id: config.auth.id,
};
if (config.auth.apiKey) {
clientConfig.auth = { apiKey: config.auth.apiKey };
} else if (config.auth.username && config.auth.password) {
clientConfig.auth = {
username: config.auth.username,
password: config.auth.password,
};
}
break;
}
}
// TLS configuration
if (config.tls) {
clientConfig.tls = config.tls;
}
// Request configuration
if (config.request) {
clientConfig.requestTimeout = config.request.timeout;
clientConfig.maxRetries = config.request.maxRetries;
clientConfig.compression = config.request.compression;
}
// Discovery/sniffing configuration
if (config.discovery) {
clientConfig.sniffOnStart = config.discovery.sniffOnStart;
clientConfig.sniffInterval = config.discovery.interval;
clientConfig.sniffOnConnectionFault = config.discovery.sniffOnConnectionFault;
}
// Proxy
if (config.proxy) {
clientConfig.proxy = config.proxy;
}
// Custom agent
if (config.agent) {
clientConfig.agent = config.agent;
}
return new ElasticClient(clientConfig);
}
/**
* Initialize connection manager
*/
async initialize(): Promise<void> {
if (this.isInitialized) {
return;
}
try {
this.logger.info('Initializing connection manager...');
// Test connection
await this.client.ping();
this.logger.info('Successfully connected to Elasticsearch');
// Start health checks if enabled
if (this.config.enableHealthCheck !== false) {
this.healthChecker.startPeriodicChecks((result) => {
this.onHealthChange(result);
});
this.logger.info('Health checks started');
}
this.isInitialized = true;
this.metrics.activeConnections.set(1);
this.logger.info('Connection manager initialized successfully');
} catch (error) {
this.logger.error('Failed to initialize connection manager', error as Error);
throw new ConnectionError(
'Failed to connect to Elasticsearch cluster',
{
operation: 'initialize',
},
error as Error
);
}
}
/**
* Get Elasticsearch client
*/
getClient(): ElasticClient {
if (!this.isInitialized) {
throw new Error('Connection manager not initialized. Call initialize() first.');
}
// Check circuit breaker
if (this.circuitBreaker.isOpen()) {
const stats = this.circuitBreaker.getStats();
throw new ClusterUnavailableError(
`Elasticsearch cluster unavailable. Circuit breaker open until ${stats.nextAttemptTime?.toISOString()}`,
{
circuitState: stats.state,
}
);
}
this.connectionCount++;
return this.client;
}
/**
* Execute operation through circuit breaker
*/
async execute<T>(operation: () => Promise<T>): Promise<T> {
return this.circuitBreaker.execute(operation);
}
/**
* Health check callback
*/
private onHealthChange(result: HealthCheckResult): void {
this.logger.info('Cluster health changed', {
status: result.status,
clusterHealth: result.clusterHealth,
activeNodes: result.activeNodes,
responseTimeMs: result.responseTimeMs,
});
// Open circuit breaker if unhealthy
if (result.status === HealthStatus.UNHEALTHY) {
this.logger.warn('Cluster unhealthy, opening circuit breaker');
this.circuitBreaker.open();
} else if (result.status === HealthStatus.HEALTHY && this.circuitBreaker.isOpen()) {
this.logger.info('Cluster recovered, closing circuit breaker');
this.circuitBreaker.close();
}
// Update metrics
this.metrics.activeConnections.set(result.available ? 1 : 0);
}
/**
* Perform health check
*/
async healthCheck(): Promise<HealthCheckResult> {
return this.healthChecker.check();
}
/**
* Get current health status
*/
getHealthStatus(): HealthStatus {
return this.healthChecker.getStatus();
}
/**
* Check if cluster is healthy
*/
isHealthy(): boolean {
return this.healthChecker.isHealthy();
}
/**
* Check if cluster is available
*/
isAvailable(): boolean {
return this.healthChecker.isAvailable();
}
/**
* Get circuit breaker state
*/
getCircuitState(): string {
return this.circuitBreaker.getState();
}
/**
* Get connection statistics
*/
getStats(): {
initialized: boolean;
connectionCount: number;
healthStatus: HealthStatus;
circuitState: string;
lastHealthCheck?: HealthCheckResult;
} {
return {
initialized: this.isInitialized,
connectionCount: this.connectionCount,
healthStatus: this.healthChecker.getStatus(),
circuitState: this.circuitBreaker.getState(),
lastHealthCheck: this.healthChecker.getLastCheckResult(),
};
}
/**
* Cleanup and close connections
*/
async destroy(): Promise<void> {
this.logger.info('Destroying connection manager...');
// Stop health checks
this.healthChecker.destroy();
// Close Elasticsearch client
try {
await this.client.close();
this.logger.info('Elasticsearch client closed');
} catch (error) {
this.logger.error('Error closing Elasticsearch client', error as Error);
}
this.isInitialized = false;
this.metrics.activeConnections.set(0);
this.logger.info('Connection manager destroyed');
}
}

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import type { Client as ElasticClient } from '@elastic/elasticsearch';
/**
* Health status
*/
export enum HealthStatus {
HEALTHY = 'healthy',
DEGRADED = 'degraded',
UNHEALTHY = 'unhealthy',
UNKNOWN = 'unknown',
}
/**
* Cluster health status from Elasticsearch
*/
export enum ClusterHealth {
GREEN = 'green',
YELLOW = 'yellow',
RED = 'red',
}
/**
* Health check result
*/
export interface HealthCheckResult {
/** Overall health status */
status: HealthStatus;
/** Cluster health from Elasticsearch */
clusterHealth?: ClusterHealth;
/** Whether the cluster is available */
available: boolean;
/** Response time in milliseconds */
responseTimeMs?: number;
/** Number of active nodes */
activeNodes?: number;
/** Error if health check failed */
error?: Error;
/** Timestamp of health check */
timestamp: Date;
/** Additional details */
details?: Record<string, unknown>;
}
/**
* Health check configuration
*/
export interface HealthCheckConfig {
/** Interval between health checks in milliseconds */
interval: number;
/** Timeout for health check requests */
timeout: number;
/** Number of consecutive failures before marking unhealthy */
unhealthyThreshold: number;
/** Number of consecutive successes before marking healthy */
healthyThreshold: number;
/** Whether to check cluster health */
checkClusterHealth: boolean;
}
/**
* Default health check configuration
*/
export const DEFAULT_HEALTH_CHECK_CONFIG: HealthCheckConfig = {
interval: 30000, // 30 seconds
timeout: 5000, // 5 seconds
unhealthyThreshold: 3,
healthyThreshold: 2,
checkClusterHealth: true,
};
/**
* Health checker for Elasticsearch cluster
*/
export class HealthChecker {
private config: HealthCheckConfig;
private consecutiveFailures = 0;
private consecutiveSuccesses = 0;
private currentStatus: HealthStatus = HealthStatus.UNKNOWN;
private lastCheckResult?: HealthCheckResult;
private checkInterval?: NodeJS.Timeout;
private isChecking = false;
constructor(
private client: ElasticClient,
config: Partial<HealthCheckConfig> = {}
) {
this.config = { ...DEFAULT_HEALTH_CHECK_CONFIG, ...config };
}
/**
* Perform a single health check
*/
async check(): Promise<HealthCheckResult> {
const startTime = Date.now();
try {
// Ping the cluster
const pingResponse = await Promise.race([
this.client.ping(),
this.timeout(this.config.timeout),
]);
const responseTime = Date.now() - startTime;
const available = pingResponse === true || (pingResponse as any).statusCode === 200;
if (!available) {
throw new Error('Cluster ping failed');
}
// Check cluster health if enabled
let clusterHealth: ClusterHealth | undefined;
let activeNodes: number | undefined;
if (this.config.checkClusterHealth) {
try {
const healthResponse = await this.client.cluster.health({
timeout: `${this.config.timeout}ms`,
});
clusterHealth = healthResponse.status as ClusterHealth;
activeNodes = healthResponse.number_of_nodes;
} catch (error) {
// Cluster health check failed, but ping succeeded
// Mark as degraded
this.consecutiveSuccesses = 0;
this.consecutiveFailures++;
const result: HealthCheckResult = {
status: HealthStatus.DEGRADED,
available: true,
responseTimeMs: responseTime,
error: error as Error,
timestamp: new Date(),
};
this.lastCheckResult = result;
return result;
}
}
// Success!
this.consecutiveFailures = 0;
this.consecutiveSuccesses++;
// Determine status based on cluster health
let status: HealthStatus;
if (clusterHealth === ClusterHealth.GREEN) {
status = HealthStatus.HEALTHY;
} else if (clusterHealth === ClusterHealth.YELLOW) {
status = HealthStatus.DEGRADED;
} else if (clusterHealth === ClusterHealth.RED) {
status = HealthStatus.UNHEALTHY;
} else {
// No cluster health, but ping succeeded
status =
this.consecutiveSuccesses >= this.config.healthyThreshold
? HealthStatus.HEALTHY
: HealthStatus.DEGRADED;
}
this.currentStatus = status;
const result: HealthCheckResult = {
status,
clusterHealth,
available: true,
responseTimeMs: responseTime,
activeNodes,
timestamp: new Date(),
};
this.lastCheckResult = result;
return result;
} catch (error) {
this.consecutiveSuccesses = 0;
this.consecutiveFailures++;
const status =
this.consecutiveFailures >= this.config.unhealthyThreshold
? HealthStatus.UNHEALTHY
: HealthStatus.DEGRADED;
this.currentStatus = status;
const result: HealthCheckResult = {
status,
available: false,
error: error as Error,
timestamp: new Date(),
};
this.lastCheckResult = result;
return result;
}
}
/**
* Start periodic health checks
*/
startPeriodicChecks(onHealthChange?: (result: HealthCheckResult) => void): void {
if (this.checkInterval) {
return; // Already running
}
const performCheck = async () => {
if (this.isChecking) return;
this.isChecking = true;
try {
const previousStatus = this.currentStatus;
const result = await this.check();
if (onHealthChange && result.status !== previousStatus) {
onHealthChange(result);
}
} catch (error) {
// Error already handled in check()
} finally {
this.isChecking = false;
}
};
// Perform initial check
performCheck();
// Schedule periodic checks
this.checkInterval = setInterval(performCheck, this.config.interval);
}
/**
* Stop periodic health checks
*/
stopPeriodicChecks(): void {
if (this.checkInterval) {
clearInterval(this.checkInterval);
this.checkInterval = undefined;
}
}
/**
* Get current health status
*/
getStatus(): HealthStatus {
return this.currentStatus;
}
/**
* Get last health check result
*/
getLastCheckResult(): HealthCheckResult | undefined {
return this.lastCheckResult;
}
/**
* Check if cluster is healthy
*/
isHealthy(): boolean {
return this.currentStatus === HealthStatus.HEALTHY;
}
/**
* Check if cluster is available
*/
isAvailable(): boolean {
return this.lastCheckResult?.available ?? false;
}
/**
* Reset health check state
*/
reset(): void {
this.consecutiveFailures = 0;
this.consecutiveSuccesses = 0;
this.currentStatus = HealthStatus.UNKNOWN;
this.lastCheckResult = undefined;
}
/**
* Helper to create a timeout promise
*/
private timeout(ms: number): Promise<never> {
return new Promise((_, reject) => {
setTimeout(() => reject(new Error(`Health check timeout after ${ms}ms`)), ms);
});
}
/**
* Cleanup resources
*/
destroy(): void {
this.stopPeriodicChecks();
}
}

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/**
* Connection management for Elasticsearch client
*
* This module provides:
* - Connection pooling and lifecycle management
* - Health monitoring with periodic checks
* - Circuit breaker pattern for fault tolerance
* - Automatic reconnection
*
* @packageDocumentation
*/
export * from './health-check.js';
export * from './circuit-breaker.js';
export * from './connection-manager.js';