retry.ts•3.39 kB
/**
* Retry utility with exponential backoff for E2E tests
*/
export interface RetryOptions {
maxAttempts?: number;
initialDelayMs?: number;
maxDelayMs?: number;
backoffMultiplier?: number;
onRetry?: (attempt: number, error: Error, delayMs: number) => void;
}
/**
* Retry a function with exponential backoff
* @param fn Function to retry
* @param options Retry options
* @returns Result of successful function execution
* @throws Last error if all attempts fail
*/
export async function retryWithBackoff<T>(
fn: () => Promise<T>,
options: RetryOptions = {}
): Promise<T> {
const {
maxAttempts = 3,
initialDelayMs = 1000,
maxDelayMs = 10000,
backoffMultiplier = 2,
onRetry
} = options;
let lastError: Error | undefined;
let delayMs = initialDelayMs;
for (let attempt = 1; attempt <= maxAttempts; attempt++) {
try {
return await fn();
} catch (error) {
lastError = error as Error;
if (attempt === maxAttempts) {
throw lastError;
}
// Calculate next delay with exponential backoff and jitter
// Add 20% jitter to help prevent thundering herd in CI
const jitterFactor = 0.8 + Math.random() * 0.4; // 80% to 120% of delay
const currentDelay = Math.min(Math.floor(delayMs * jitterFactor), maxDelayMs);
if (onRetry) {
onRetry(attempt, lastError, currentDelay);
}
// Wait before next attempt
await new Promise(resolve => setTimeout(resolve, currentDelay));
// Increase delay for next attempt
delayMs = Math.min(delayMs * backoffMultiplier, maxDelayMs);
}
}
throw lastError;
}
/**
* Check if an error is retryable
* @param error The error to check
* @returns True if the error is retryable
*/
export function isRetryableError(error: any): boolean {
// Network errors
if (error.code === 'ECONNRESET' ||
error.code === 'ETIMEDOUT' ||
error.code === 'ENOTFOUND') {
return true;
}
// HTTP status codes that are retryable
if (error.status) {
const status = error.status;
// 429 Too Many Requests, 502 Bad Gateway, 503 Service Unavailable, 504 Gateway Timeout
if (status === 429 || status === 502 || status === 503 || status === 504) {
return true;
}
// GitHub specific: 409 Conflict can happen in parallel CI runs when SHA changes
if (status === 409 && error.message?.includes('is at')) {
return true;
}
// GitHub specific: 422 can sometimes be transient
if (status === 422 && error.message?.includes('is at')) {
return true;
}
}
// GitHub API specific errors
if (error.message) {
const msg = error.message.toLowerCase();
if (msg.includes('rate limit') ||
msg.includes('timeout') ||
msg.includes('econnreset') ||
msg.includes('socket hang up')) {
return true;
}
}
return false;
}
/**
* Retry only if the error is retryable
* @param fn Function to retry
* @param options Retry options
* @returns Result of successful function execution
* @throws Error if non-retryable or all attempts fail
*/
export async function retryIfRetryable<T>(
fn: () => Promise<T>,
options: RetryOptions = {}
): Promise<T> {
try {
return await fn();
} catch (error) {
if (!isRetryableError(error)) {
throw error;
}
return retryWithBackoff(fn, options);
}
}