@fedify/fedify/esm/federation/retry.js

An ActivityPub server framework

/**
 * The context passed to a {@link RetryPolicy} callback.
 * @since 0.12.0
 */
import * as dntShim from "../_dnt.shims.js";
/**
 * Creates an exponential backoff retry policy.  The delay between retries
 * starts at the `initialDelay` and is multiplied by the `factor` for each
 * subsequent retry, up to the `maxDelay`.  The policy will give up after
 * `maxAttempts` attempts.  The actual delay is randomized to avoid
 * synchronization (jitter).
 * @param options The options for the policy.
 * @returns The retry policy.
 * @since 0.12.0
 */
export function createExponentialBackoffPolicy(options = {}) {
    const initialDelay = dntShim.Temporal.Duration.from(options.initialDelay ?? { seconds: 1 });
    const maxDelay = dntShim.Temporal.Duration.from(options.maxDelay ?? { hours: 12 });
    const maxAttempts = options.maxAttempts ?? 10;
    const factor = options.factor ?? 2;
    const jitter = options.jitter ?? true;
    return ({ attempts }) => {
        if (attempts >= maxAttempts)
            return null;
        let milliseconds = initialDelay.total("millisecond");
        milliseconds *= factor ** attempts;
        if (jitter) {
            milliseconds *= 1 + Math.random();
            milliseconds = Math.round(milliseconds);
        }
        const delay = dntShim.Temporal.Duration.from({ milliseconds });
        return dntShim.Temporal.Duration.compare(delay, maxDelay) > 0 ? maxDelay : delay;
    };
}