149 lines
4.0 KiB
TypeScript
149 lines
4.0 KiB
TypeScript
/*
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This file is part of GNU Taler
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(C) 2019 GNUnet e.V.
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GNU Taler is free software; you can redistribute it and/or modify it under the
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terms of the GNU General Public License as published by the Free Software
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Foundation; either version 3, or (at your option) any later version.
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TALER is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
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A PARTICULAR PURPOSE. See the GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along with
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GNU Taler; see the file COPYING. If not, see <http://www.gnu.org/licenses/>
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*/
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import { Logger } from "./logging.js";
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import { AbsoluteTime } from "./time.js";
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/**
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* Implementation of token bucket throttling.
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*/
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const logger = new Logger("RequestThrottler.ts");
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/**
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* Maximum request per second, per origin.
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*/
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const MAX_PER_SECOND = 100;
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/**
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* Maximum request per minute, per origin.
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*/
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const MAX_PER_MINUTE = 500;
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/**
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* Maximum request per hour, per origin.
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*/
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const MAX_PER_HOUR = 2000;
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/**
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* Throttling state for one origin.
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*/
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class OriginState {
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tokensSecond: number = MAX_PER_SECOND;
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tokensMinute: number = MAX_PER_MINUTE;
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tokensHour: number = MAX_PER_HOUR;
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private lastUpdate = AbsoluteTime.now();
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private refill(): void {
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const now = AbsoluteTime.now();
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if (AbsoluteTime.cmp(now, this.lastUpdate) < 0) {
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// Did the system time change?
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this.lastUpdate = now;
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return;
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}
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const d = AbsoluteTime.difference(now, this.lastUpdate);
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if (d.d_ms === "forever") {
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throw Error("assertion failed");
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}
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this.tokensSecond = Math.min(
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MAX_PER_SECOND,
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this.tokensSecond + d.d_ms / 1000,
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);
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this.tokensMinute = Math.min(
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MAX_PER_MINUTE,
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this.tokensMinute + d.d_ms / 1000 / 60,
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);
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this.tokensHour = Math.min(
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MAX_PER_HOUR,
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this.tokensHour + d.d_ms / 1000 / 60 / 60,
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);
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this.lastUpdate = now;
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}
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/**
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* Return true if the request for this origin should be throttled.
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* Otherwise, take a token out of the respective buckets.
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*/
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applyThrottle(): boolean {
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this.refill();
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if (this.tokensSecond < 1) {
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logger.warn("request throttled (per second limit exceeded)");
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return true;
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}
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if (this.tokensMinute < 1) {
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logger.warn("request throttled (per minute limit exceeded)");
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return true;
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}
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if (this.tokensHour < 1) {
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logger.warn("request throttled (per hour limit exceeded)");
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return true;
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}
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this.tokensSecond--;
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this.tokensMinute--;
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this.tokensHour--;
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return false;
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}
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}
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/**
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* Request throttler, used as a "last layer of defense" when some
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* other part of the re-try logic is broken and we're sending too
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* many requests to the same exchange/bank/merchant.
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*/
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export class RequestThrottler {
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private perOriginInfo: { [origin: string]: OriginState } = {};
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/**
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* Get the throttling state for an origin, or
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* initialize if no state is associated with the
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* origin yet.
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*/
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private getState(origin: string): OriginState {
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const s = this.perOriginInfo[origin];
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if (s) {
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return s;
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}
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const ns = (this.perOriginInfo[origin] = new OriginState());
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return ns;
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}
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/**
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* Apply throttling to a request.
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*
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* @returns whether the request should be throttled.
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*/
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applyThrottle(requestUrl: string): boolean {
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const origin = new URL(requestUrl).origin;
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return this.getState(origin).applyThrottle();
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}
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/**
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* Get the throttle statistics for a particular URL.
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*/
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getThrottleStats(requestUrl: string): Record<string, unknown> {
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const origin = new URL(requestUrl).origin;
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const state = this.getState(origin);
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return {
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tokensHour: state.tokensHour,
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tokensMinute: state.tokensMinute,
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tokensSecond: state.tokensSecond,
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maxTokensHour: MAX_PER_HOUR,
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maxTokensMinute: MAX_PER_MINUTE,
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maxTokensSecond: MAX_PER_SECOND,
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};
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}
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}
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