@ceramicnetwork/core/lib/pubsub/pubsub-ratelimit.js

Typescript implementation of the Ceramic protocol

import PQueue from 'p-queue';
import { empty, from, Observable } from 'rxjs';
import { MsgType } from './pubsub-message.js';
import { whenSubscriptionDone } from '../__tests__/when-subscription-done.util.js';
const DEFAULT_WARNINGS_INTERVAL = 30 * 60 * 1000;
export class PubsubRateLimit extends Observable {
    constructor(pubsub, logger, queriesPerSecond, rateLimitWarningsIntervalMs = DEFAULT_WARNINGS_INTERVAL) {
        super((subscriber) => {
            pubsub.subscribe(subscriber);
        });
        this.pubsub = pubsub;
        this.logger = logger;
        this.queriesPerSecond = queriesPerSecond;
        this.rateLimitWarningsIntervalMs = rateLimitWarningsIntervalMs;
        this.queue = new PQueue({ interval: 1000, intervalCap: queriesPerSecond });
        let lastWarning = 0;
        this.queue.on('add', () => {
            if (this.queue.size > 0 && Date.now() - lastWarning >= this.rateLimitWarningsIntervalMs) {
                this.logger.warn(`More than ${this.queriesPerSecond} query messages published in less than a second. Query messages will be rate limited`);
                lastWarning = Date.now();
            }
        });
        this.maxQueuedQueries = queriesPerSecond * 10;
        this.logger.debug(`Configuring pubsub to rate limit query messages to ${queriesPerSecond} per second`);
    }
    next(message) {
        if (message.typ === MsgType.QUERY) {
            if (this.queue.size >= this.maxQueuedQueries) {
                this.logger.err(`Cannot publish query message to pubsub because we have exceeded the maximum allowed rate. Cannot have more than ${this.maxQueuedQueries} queued queries.`);
                return empty().subscribe();
            }
            return from(this.queue.add(() => whenSubscriptionDone(this.pubsub.next(message)))).subscribe();
        }
        else {
            return this.pubsub.next(message);
        }
    }
}
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