myst-cli/dist/utils/fetchWithRetry.js

Command line tools for MyST

/**
 * Recursively fetch a URL with retry and exponential backoff.
 */
export async function fetchWithRetry(session, 
/** The URL to fetch. */
url, 
/** Options to pass to fetch (e.g., headers, method). */
options, 
/** How many times total to attempt the fetch. */
maxRetries = 3, 
/** The current attempt number. */
attempt = 1, 
/** The current backoff duration in milliseconds. */
backoff = 250) {
    try {
        const resp = await session.fetch(url, options);
        if (resp.ok) {
            // If it's a 2xx response, we consider it a success and return it
            return resp;
        }
        else {
            // For non-2xx, we treat it as a failure that triggers a retry
            session.log.warn(`Fetch of ${url} failed with HTTP status ${resp.status} for URL: ${url} (Attempt #${attempt})`);
        }
    }
    catch (error) {
        // This covers network failures and other errors that cause fetch to reject
        session.log.warn(`Fetch of ${url} threw an error (Attempt #${attempt})`, error);
    }
    // If we haven't reached the max retries, wait and recurse
    if (attempt < maxRetries) {
        session.log.debug(`Waiting ${backoff}ms before retry #${attempt + 1}...`);
        await new Promise((resolve) => setTimeout(resolve, backoff));
        return fetchWithRetry(session, url, options, maxRetries, attempt + 1, backoff * 2);
    }
    // If we made it here, all retries have been exhausted
    throw new Error(`Failed to fetch ${url} after ${maxRetries} attempts.`);
}