/**
* Utility functions for the YouTube Info MCP server
*/
interface RetryOptions {
maxRetries?: number;
baseDelay?: number;
maxDelay?: number;
factor?: number;
}
/**
* Implements exponential backoff retry logic
* @param fn The function to retry
* @param options Retry configuration options
* @returns The result of the function
*/
export async function withRetry<T>(
fn: () => Promise<T>,
options: RetryOptions = {}
): Promise<T> {
const {
maxRetries = 3,
baseDelay = 1000,
maxDelay = 10000,
factor = 2
} = options;
let lastError: Error | undefined;
for (let attempt = 0; attempt <= maxRetries; attempt++) {
try {
return await fn();
} catch (error) {
lastError = error instanceof Error ? error : new Error(String(error));
// Don't retry on the last attempt
if (attempt === maxRetries) {
break;
}
// Calculate delay with exponential backoff
const delay = Math.min(
baseDelay * Math.pow(factor, attempt),
maxDelay
);
// Add jitter to avoid thundering herd
const jitter = Math.random() * 0.3 * delay;
const totalDelay = delay + jitter;
await sleep(totalDelay);
}
}
throw lastError || new Error('Retry failed');
}
/**
* Sleep for specified milliseconds
* @param ms Milliseconds to sleep
*/
export function sleep(ms: number): Promise<void> {
return new Promise(resolve => setTimeout(resolve, ms));
}
/**
* Check if an error is retryable
* @param error The error to check
* @returns True if the error is retryable
*/
export function isRetryableError(error: unknown): boolean {
if (!(error instanceof Error)) {
return false;
}
// Network errors are retryable
if (error.message.includes('ECONNRESET') ||
error.message.includes('ETIMEDOUT') ||
error.message.includes('ENOTFOUND')) {
return true;
}
// Some HTTP status codes are retryable
if ('status' in error && typeof error.status === 'number') {
const status = error.status;
// Retry on 5xx errors and some 4xx errors
return status >= 500 || status === 429 || status === 408;
}
return false;
}
