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Datablock Storage: rate limiting (#58479)
* Implement rate limiting for datablock storage at the block level. * Fixes #55481 --------- Co-authored-by: Cassi Brenci <cassi.brenci@code.org>
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,35 @@ | ||
| // rateLimit() throws an error if called more than RATE_LIMIT times per RATE_LIMIT_INTERVAL_MS | ||
| // we use this in Applab commands.js to rate limit access to Datablock Storage from student code | ||
| let rateLimitAccessLog = []; | ||
| export const RATE_LIMIT = 600; | ||
| export const RATE_LIMIT_INTERVAL_MS = 60000; | ||
| export function rateLimit(now = Date.now()) { | ||
| const timeSinceEarliestLog = () => now - rateLimitAccessLog[0]; | ||
|
|
||
| // Drop log entries older than RATE_LIMIT_INTERVAL_MS | ||
| while ( | ||
| rateLimitAccessLog.length > 0 && | ||
| timeSinceEarliestLog() >= RATE_LIMIT_INTERVAL_MS | ||
| ) { | ||
| rateLimitAccessLog.shift(); | ||
| } | ||
|
|
||
| // If we're over the rate limit, throw an error | ||
| if (rateLimitAccessLog.length >= RATE_LIMIT) { | ||
| const waitTime = Math.ceil( | ||
| (RATE_LIMIT_INTERVAL_MS - timeSinceEarliestLog()) / 1000 | ||
| ); | ||
| throw new Error( | ||
| `Data access rate limit exceeded; Please wait ${waitTime} seconds before retrying. ` + | ||
| 'The app is reading/writing data too many times per second. ' + | ||
| "If you were trying to write data, it wasn't written." | ||
| ); | ||
| } else { | ||
| // Log the current access | ||
| rateLimitAccessLog.push(now); | ||
| } | ||
| } | ||
|
|
||
| export function resetRateLimit() { | ||
| rateLimitAccessLog = []; | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,57 @@ | ||
| import {expect} from '../../util/reconfiguredChai'; | ||
| import { | ||
| rateLimit, | ||
| resetRateLimit, | ||
| RATE_LIMIT, | ||
| RATE_LIMIT_INTERVAL_MS, | ||
| } from '../../../src/storage/rateLimit'; | ||
|
|
||
| describe('DatablockStorage', () => { | ||
| beforeEach(() => { | ||
| resetRateLimit(); | ||
| }); | ||
| afterEach(() => { | ||
| resetRateLimit(); | ||
| }); | ||
|
|
||
| describe('rate limiting', () => { | ||
| it('succeeds if calling less times than the rate limit', done => { | ||
| const now = Date.now(); | ||
|
|
||
| for (let i = 0; i < RATE_LIMIT; i++) { | ||
| const time = now + i; | ||
| rateLimit(time); | ||
| } | ||
|
|
||
| done(); | ||
| }); | ||
| it('fails if called one more time than the rate limit', done => { | ||
| const now = Date.now(); | ||
|
|
||
| for (let i = 0; i < RATE_LIMIT; i++) { | ||
| const time = now + i; | ||
| rateLimit(time); | ||
| } | ||
|
|
||
| // This should be over the rate limit | ||
| expect(() => rateLimit(now + RATE_LIMIT)).to.throw(Error); | ||
|
|
||
| done(); | ||
| }); | ||
| it('it succeeds if called more than the rate limit, but after waiting rate limit interval', done => { | ||
| let now = Date.now(); | ||
|
|
||
| for (let i = 0; i < RATE_LIMIT; i++) { | ||
| const time = now + i; | ||
| rateLimit(time); | ||
| } | ||
|
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||
| now += RATE_LIMIT_INTERVAL_MS; | ||
| for (let i = 0; i < RATE_LIMIT; i++) { | ||
| const time = now + i; | ||
| rateLimit(time); | ||
| } | ||
| done(); | ||
| }); | ||
| }); | ||
| }); |