implement SkRateLimiterService with Leaky Bucket rate limiting

1 files changed, 703 insertions, 0 deletions

diff --git a/packages/backend/test/unit/server/api/SkRateLimiterServiceTests.ts b/packages/backend/test/unit/server/api/SkRateLimiterServiceTests.ts
new file mode 100644
index 0000000000..8554aa39ef
--- /dev/null
+++ b/packages/backend/test/unit/server/api/SkRateLimiterServiceTests.ts
@@ -0,0 +1,703 @@
+/*
+ * SPDX-FileCopyrightText: hazelnoot and other Sharkey contributors
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import { KEYWORD } from 'color-convert/conversions.js';
+import type Redis from 'ioredis';
+import { LegacyRateLimit, LimitCounter, RateLimit, SkRateLimiterService } from '@/server/api/SkRateLimiterService.js';
+import { LoggerService } from '@/core/LoggerService.js';
+
+/* eslint-disable @typescript-eslint/no-non-null-assertion */
+/* eslint-disable @typescript-eslint/no-unnecessary-condition */
+
+describe(SkRateLimiterService, () => {
+	let mockTimeService: { now: number, date: Date } = null!;
+	let mockRedisGet: ((key: string) => string | null) | undefined = undefined;
+	let mockRedisSet: ((args: unknown[]) => void) | undefined = undefined;
+	let mockEnvironment: Record<string, string | undefined> = null!;
+	let serviceUnderTest: () => SkRateLimiterService = null!;
+
+	let loggedMessages: { level: string, data: unknown[] }[] = [];
+
+	beforeEach(() => {
+		mockTimeService = {
+			now: 0,
+			get date() {
+				return new Date(mockTimeService.now);
+			},
+		};
+
+		mockRedisGet = undefined;
+		mockRedisSet = undefined;
+		const mockRedisClient = {
+			get(key: string) {
+				if (mockRedisGet) return Promise.resolve(mockRedisGet(key));
+				else return Promise.resolve(null);
+			},
+			set(...args: unknown[]): Promise<void> {
+				if (mockRedisSet) mockRedisSet(args);
+				return Promise.resolve();
+			},
+		} as unknown as Redis.Redis;
+
+		mockEnvironment = Object.create(process.env);
+		mockEnvironment.NODE_ENV = 'production';
+		const mockEnvService = {
+			env: mockEnvironment,
+		};
+
+		loggedMessages = [];
+		const mockLogService = {
+			getLogger() {
+				return {
+					createSubLogger(context: string, color?: KEYWORD) {
+						return mockLogService.getLogger(context, color);
+					},
+					error(...data: unknown[]) {
+						loggedMessages.push({ level: 'error', data });
+					},
+					warn(...data: unknown[]) {
+						loggedMessages.push({ level: 'warn', data });
+					},
+					succ(...data: unknown[]) {
+						loggedMessages.push({ level: 'succ', data });
+					},
+					debug(...data: unknown[]) {
+						loggedMessages.push({ level: 'debug', data });
+					},
+					info(...data: unknown[]) {
+						loggedMessages.push({ level: 'info', data });
+					},
+				};
+			},
+		} as unknown as LoggerService;
+
+		let service: SkRateLimiterService | undefined = undefined;
+		serviceUnderTest = () => {
+			return service ??= new SkRateLimiterService(mockTimeService, mockRedisClient, mockLogService, mockEnvService);
+		};
+	});
+
+	function expectNoUnhandledErrors() {
+		const unhandledErrors = loggedMessages.filter(m => m.level === 'error');
+		if (unhandledErrors.length > 0) {
+			throw new Error(`Test failed: got unhandled errors ${unhandledErrors.join('\n')}`);
+		}
+	}
+
+	describe('limit', () => {
+		const actor = 'actor';
+		const key = 'test';
+
+		let counter: LimitCounter | undefined = undefined;
+		let minCounter: LimitCounter | undefined = undefined;
+
+		beforeEach(() => {
+			counter = undefined;
+			minCounter = undefined;
+
+			mockRedisGet = (key: string) => {
+				if (key === 'rl_actor_test' && counter) {
+					return JSON.stringify(counter);
+				}
+
+				if (key === 'rl_actor_test_min' && minCounter) {
+					return JSON.stringify(minCounter);
+				}
+
+				return null;
+			};
+
+			mockRedisSet = (args: unknown[]) => {
+				const [key, value] = args;
+
+				if (key === 'rl_actor_test') {
+					if (value == null) counter = undefined;
+					else if (typeof(value) === 'string') counter = JSON.parse(value);
+					else throw new Error('invalid redis call');
+				}
+
+				if (key === 'rl_actor_test_min') {
+					if (value == null) minCounter = undefined;
+					else if (typeof(value) === 'string') minCounter = JSON.parse(value);
+					else throw new Error('invalid redis call');
+				}
+			};
+		});
+
+		it('should bypass in non-production', async () => {
+			mockEnvironment.NODE_ENV = 'test';
+
+			const info = await serviceUnderTest().limit({ key: 'l', type: undefined, max: 0 }, 'actor');
+
+			expect(info.blocked).toBeFalsy();
+			expect(info.remaining).toBe(Number.MAX_SAFE_INTEGER);
+			expect(info.resetSec).toBe(0);
+			expect(info.resetMs).toBe(0);
+			expect(info.fullResetSec).toBe(0);
+			expect(info.fullResetMs).toBe(0);
+		});
+
+		describe('with bucket limit', () => {
+			let limit: RateLimit = null!;
+
+			beforeEach(() => {
+				limit = {
+					type: 'bucket',
+					key: 'test',
+					size: 1,
+				};
+			});
+
+			it('should allow when limit is not reached', async () => {
+				const info = await serviceUnderTest().limit(limit, actor);
+
+				expect(info.blocked).toBeFalsy();
+			});
+
+			it('should not error when allowed', async () => {
+				await serviceUnderTest().limit(limit, actor);
+
+				expectNoUnhandledErrors();
+			});
+
+			it('should return correct info when allowed', async () => {
+				limit.size = 2;
+				counter = { c: 1, t: 0 };
+
+				const info = await serviceUnderTest().limit(limit, actor);
+
+				expect(info.remaining).toBe(0);
+				expect(info.resetSec).toBe(1);
+				expect(info.resetMs).toBe(1000);
+				expect(info.fullResetSec).toBe(2);
+				expect(info.fullResetMs).toBe(2000);
+			});
+
+			it('should increment counter when called', async () => {
+				await serviceUnderTest().limit(limit, actor);
+
+				expect(counter).not.toBeUndefined();
+				expect(counter?.c).toBe(1);
+			});
+
+			it('should set timestamp when called', async () => {
+				mockTimeService.now = 1000;
+
+				await serviceUnderTest().limit(limit, actor);
+
+				expect(counter).not.toBeUndefined();
+				expect(counter?.t).toBe(1000);
+			});
+
+			it('should decrement counter when dripRate has passed', async () => {
+				counter = { c: 2, t: 0 };
+				mockTimeService.now = 2000;
+
+				await serviceUnderTest().limit(limit, actor);
+
+				expect(counter).not.toBeUndefined();
+				expect(counter?.c).toBe(1); // 2 (starting) - 2 (2x1 drip) + 1 (call) = 1
+			});
+
+			it('should decrement counter by dripSize', async () => {
+				counter = { c: 2, t: 0 };
+				limit.dripSize = 2;
+				mockTimeService.now = 1000;
+
+				await serviceUnderTest().limit(limit, actor);
+
+				expect(counter).not.toBeUndefined();
+				expect(counter?.c).toBe(1); // 2 (starting) - 2 (1x2 drip) + 1 (call) = 1
+			});
+
+			it('should maintain counter between calls over time', async () => {
+				limit.size = 5;
+
+				await serviceUnderTest().limit(limit, actor); // 0 + 1 = 1
+				mockTimeService.now += 1000; // 1 - 1 = 0
+				await serviceUnderTest().limit(limit, actor); // 0 + 1 = 1
+				await serviceUnderTest().limit(limit, actor); // 1 + 1 = 2
+				await serviceUnderTest().limit(limit, actor); // 2 + 1 = 3
+				mockTimeService.now += 1000; // 3 - 1 = 2
+				mockTimeService.now += 1000; // 2 - 1 = 1
+				await serviceUnderTest().limit(limit, actor); // 1 + 1 = 2
+
+				expect(counter?.c).toBe(2);
+				expect(counter?.t).toBe(3000);
+			});
+
+			it('should log error and continue when update fails', async () => {
+				mockRedisSet = () => {
+					throw new Error('test error');
+				};
+
+				await serviceUnderTest().limit(limit, actor);
+
+				const matchingError = loggedMessages
+					.find(m => m.level === 'error' && m.data
+						.some(d => typeof(d) === 'string' && d.includes('Failed to update limit')));
+				expect(matchingError).toBeTruthy();
+			});
+
+			it('should block when bucket is filled', async () => {
+				counter = { c: 1, t: 0 };
+
+				const info = await serviceUnderTest().limit(limit, actor);
+
+				expect(info.blocked).toBeTruthy();
+			});
+
+			it('should calculate correct info when blocked', async () => {
+				counter = { c: 1, t: 0 };
+
+				const info = await serviceUnderTest().limit(limit, actor);
+
+				expect(info.resetSec).toBe(1);
+				expect(info.resetMs).toBe(1000);
+				expect(info.fullResetSec).toBe(1);
+				expect(info.fullResetMs).toBe(1000);
+			});
+
+			it('should allow when bucket is filled but should drip', async () => {
+				counter = { c: 1, t: 0 };
+				mockTimeService.now = 1000;
+
+				const info = await serviceUnderTest().limit(limit, actor);
+
+				expect(info.blocked).toBeFalsy();
+			});
+
+			it('should scale limit by factor', async () => {
+				counter = { c: 1, t: 0 };
+
+				const i1 = await serviceUnderTest().limit(limit, actor, 2); // 1 + 1 = 2
+				const i2 = await serviceUnderTest().limit(limit, actor, 2); // 2 + 1 = 3
+
+				expect(i1.blocked).toBeFalsy();
+				expect(i2.blocked).toBeTruthy();
+			});
+
+			it('should set key expiration', async () => {
+				mockRedisSet = args => {
+					expect(args[2]).toBe('PX');
+					expect(args[3]).toBe(1000);
+				};
+
+				await serviceUnderTest().limit(limit, actor);
+			});
+
+			it('should not increment when already blocked', async () => {
+				counter = { c: 1, t: 0 };
+				mockTimeService.now += 100;
+
+				await serviceUnderTest().limit(limit, actor);
+
+				expect(counter?.c).toBe(1);
+				expect(counter?.t).toBe(0);
+			});
+		});
+
+		describe('with min interval', () => {
+			let limit: MutableLegacyRateLimit = null!;
+
+			beforeEach(() => {
+				limit = {
+					type: undefined,
+					key,
+					minInterval: 1000,
+				};
+			});
+
+			it('should allow when limit is not reached', async () => {
+				const info = await serviceUnderTest().limit(limit, actor);
+
+				expect(info.blocked).toBeFalsy();
+			});
+
+			it('should not error when allowed', async () => {
+				await serviceUnderTest().limit(limit, actor);
+
+				expectNoUnhandledErrors();
+			});
+
+			it('should calculate correct info when allowed', async () => {
+				const info = await serviceUnderTest().limit(limit, actor);
+
+				expect(info.remaining).toBe(0);
+				expect(info.resetSec).toBe(1);
+				expect(info.resetMs).toBe(1000);
+				expect(info.fullResetSec).toBe(1);
+				expect(info.fullResetMs).toBe(1000);
+			});
+
+			it('should increment counter when called', async () => {
+				await serviceUnderTest().limit(limit, actor);
+
+				expect(minCounter).not.toBeUndefined();
+				expect(minCounter?.c).toBe(1);
+			});
+
+			it('should set timestamp when called', async () => {
+				mockTimeService.now = 1000;
+
+				await serviceUnderTest().limit(limit, actor);
+
+				expect(minCounter).not.toBeUndefined();
+				expect(minCounter?.t).toBe(1000);
+			});
+
+			it('should decrement counter when minInterval has passed', async () => {
+				minCounter = { c: 1, t: 0 };
+				mockTimeService.now = 1000;
+
+				await serviceUnderTest().limit(limit, actor);
+
+				expect(minCounter).not.toBeUndefined();
+				expect(minCounter?.c).toBe(1); // 1 (starting) - 1 (interval) + 1 (call) = 1
+			});
+
+			it('should reset counter entirely', async () => {
+				minCounter = { c: 2, t: 0 };
+				mockTimeService.now = 1000;
+
+				await serviceUnderTest().limit(limit, actor);
+
+				expect(minCounter).not.toBeUndefined();
+				expect(minCounter?.c).toBe(1); // 2 (starting) - 2 (interval) + 1 (call) = 1
+			});
+
+			it('should maintain counter between calls over time', async () => {
+				await serviceUnderTest().limit(limit, actor); // 0 + 1 = 1
+				mockTimeService.now += 1000; // 1 - 1 = 0
+				await serviceUnderTest().limit(limit, actor); // 0 + 1 = 1
+				await serviceUnderTest().limit(limit, actor); // blocked
+				await serviceUnderTest().limit(limit, actor); // blocked
+				mockTimeService.now += 1000; // 1 - 1 = 0
+				mockTimeService.now += 1000; // 0 - 1 = 0
+				await serviceUnderTest().limit(limit, actor); // 0 + 1 = 1
+
+				expect(minCounter?.c).toBe(1);
+				expect(minCounter?.t).toBe(3000);
+			});
+
+			it('should log error and continue when update fails', async () => {
+				mockRedisSet = () => {
+					throw new Error('test error');
+				};
+
+				await serviceUnderTest().limit(limit, actor);
+
+				const matchingError = loggedMessages
+					.find(m => m.level === 'error' && m.data
+						.some(d => typeof(d) === 'string' && d.includes('Failed to update limit')));
+				expect(matchingError).toBeTruthy();
+			});
+
+			it('should block when interval exceeded', async () => {
+				minCounter = { c: 1, t: 0 };
+
+				const info = await serviceUnderTest().limit(limit, actor);
+
+				expect(info.blocked).toBeTruthy();
+			});
+
+			it('should calculate correct info when blocked', async () => {
+				minCounter = { c: 1, t: 0 };
+
+				const info = await serviceUnderTest().limit(limit, actor);
+
+				expect(info.resetSec).toBe(1);
+				expect(info.resetMs).toBe(1000);
+				expect(info.fullResetSec).toBe(1);
+				expect(info.fullResetMs).toBe(1000);
+			});
+
+			it('should allow when bucket is filled but interval has passed', async () => {
+				minCounter = { c: 1, t: 0 };
+				mockTimeService.now = 1000;
+
+				const info = await serviceUnderTest().limit(limit, actor);
+
+				expect(info.blocked).toBeFalsy();
+			});
+
+			it('should scale limit by factor', async () => {
+				minCounter = { c: 1, t: 0 };
+
+				const i1 = await serviceUnderTest().limit(limit, actor, 2); // 1 + 1 = 2
+				const i2 = await serviceUnderTest().limit(limit, actor, 2); // 2 + 1 = 3
+
+				expect(i1.blocked).toBeFalsy();
+				expect(i2.blocked).toBeTruthy();
+			});
+
+			it('should set key expiration', async () => {
+				mockRedisSet = args => {
+					expect(args[2]).toBe('PX');
+					expect(args[3]).toBe(1000);
+				};
+
+				await serviceUnderTest().limit(limit, actor);
+			});
+
+			it('should not increment when already blocked', async () => {
+				minCounter = { c: 1, t: 0 };
+				mockTimeService.now += 100;
+
+				await serviceUnderTest().limit(limit, actor);
+
+				expect(minCounter?.c).toBe(1);
+				expect(minCounter?.t).toBe(0);
+			});
+		});
+
+		describe('with legacy limit', () => {
+			let limit: MutableLegacyRateLimit = null!;
+
+			beforeEach(() => {
+				limit = {
+					type: undefined,
+					key,
+					max: 1,
+					duration: 1000,
+				};
+			});
+
+			it('should allow when limit is not reached', async () => {
+				const info = await serviceUnderTest().limit(limit, actor);
+
+				expect(info.blocked).toBeFalsy();
+			});
+
+			it('should not error when allowed', async () => {
+				await serviceUnderTest().limit(limit, actor);
+
+				expectNoUnhandledErrors();
+			});
+
+			it('should infer dripRate from duration', async () => {
+				limit.max = 10;
+				limit.duration = 10000;
+				counter = { c: 10, t: 0 };
+
+				const i1 = await serviceUnderTest().limit(limit, actor);
+				mockTimeService.now += 1000;
+				const i2 = await serviceUnderTest().limit(limit, actor);
+				mockTimeService.now += 2000;
+				const i3 = await serviceUnderTest().limit(limit, actor);
+				const i4 = await serviceUnderTest().limit(limit, actor);
+				const i5 = await serviceUnderTest().limit(limit, actor);
+				mockTimeService.now += 2000;
+				const i6 = await serviceUnderTest().limit(limit, actor);
+
+				expect(i1.blocked).toBeTruthy();
+				expect(i2.blocked).toBeFalsy();
+				expect(i3.blocked).toBeFalsy();
+				expect(i4.blocked).toBeFalsy();
+				expect(i5.blocked).toBeTruthy();
+				expect(i6.blocked).toBeFalsy();
+			});
+
+			it('should calculate correct info when allowed', async () => {
+				limit.max = 10;
+				limit.duration = 10000;
+				counter = { c: 10, t: 0 };
+				mockTimeService.now += 2000;
+
+				const info = await serviceUnderTest().limit(limit, actor);
+
+				expect(info.remaining).toBe(1);
+				expect(info.resetSec).toBe(0);
+				expect(info.resetMs).toBe(0);
+				expect(info.fullResetSec).toBe(9);
+				expect(info.fullResetMs).toBe(9000);
+			});
+
+			it('should calculate correct info when blocked', async () => {
+				limit.max = 10;
+				limit.duration = 10000;
+				counter = { c: 10, t: 0 };
+
+				const info = await serviceUnderTest().limit(limit, actor);
+
+				expect(info.remaining).toBe(0);
+				expect(info.resetSec).toBe(1);
+				expect(info.resetMs).toBe(1000);
+				expect(info.fullResetSec).toBe(10);
+				expect(info.fullResetMs).toBe(10000);
+			});
+
+			it('should allow when bucket is filled but interval has passed', async () => {
+				counter = { c: 10, t: 0 };
+				mockTimeService.now = 1000;
+
+				const info = await serviceUnderTest().limit(limit, actor);
+
+				expect(info.blocked).toBeTruthy();
+			});
+
+			it('should scale limit by factor', async () => {
+				counter = { c: 10, t: 0 };
+
+				const info = await serviceUnderTest().limit(limit, actor, 2); // 10 + 1 = 11
+
+				expect(info.blocked).toBeTruthy();
+			});
+
+			it('should set key expiration', async () => {
+				mockRedisSet = args => {
+					expect(args[2]).toBe('PX');
+					expect(args[3]).toBe(1000);
+				};
+
+				await serviceUnderTest().limit(limit, actor);
+			});
+
+			it('should not increment when already blocked', async () => {
+				counter = { c: 1, t: 0 };
+				mockTimeService.now += 100;
+
+				await serviceUnderTest().limit(limit, actor);
+
+				expect(counter?.c).toBe(1);
+				expect(counter?.t).toBe(0);
+			});
+		});
+
+		describe('with legacy limit and min interval', () => {
+			let limit: MutableLegacyRateLimit = null!;
+
+			beforeEach(() => {
+				limit = {
+					type: undefined,
+					key,
+					max: 5,
+					duration: 5000,
+					minInterval: 1000,
+				};
+			});
+
+			it('should allow when limit is not reached', async () => {
+				const info = await serviceUnderTest().limit(limit, actor);
+
+				expect(info.blocked).toBeFalsy();
+			});
+
+			it('should not error when allowed', async () => {
+				await serviceUnderTest().limit(limit, actor);
+
+				expectNoUnhandledErrors();
+			});
+
+			it('should block when limit exceeded', async () => {
+				counter = { c: 5, t: 0 };
+
+				const info = await serviceUnderTest().limit(limit, actor);
+
+				expect(info.blocked).toBeTruthy();
+			});
+
+			it('should block when minInterval exceeded', async () => {
+				minCounter = { c: 1, t: 0 };
+
+				const info = await serviceUnderTest().limit(limit, actor);
+
+				expect(info.blocked).toBeTruthy();
+			});
+
+			it('should calculate correct info when allowed', async () => {
+				counter = { c: 1, t: 0 };
+
+				const info = await serviceUnderTest().limit(limit, actor);
+
+				expect(info.remaining).toBe(0);
+				expect(info.resetSec).toBe(1);
+				expect(info.resetMs).toBe(1000);
+				expect(info.fullResetSec).toBe(2);
+				expect(info.fullResetMs).toBe(2000);
+			});
+
+			it('should calculate correct info when blocked by limit', async () => {
+				counter = { c: 5, t: 0 };
+
+				const info = await serviceUnderTest().limit(limit, actor);
+
+				expect(info.remaining).toBe(0);
+				expect(info.resetSec).toBe(1);
+				expect(info.resetMs).toBe(1000);
+				expect(info.fullResetSec).toBe(5);
+				expect(info.fullResetMs).toBe(5000);
+			});
+
+			it('should calculate correct info when blocked by minInterval', async () => {
+				minCounter = { c: 1, t: 0 };
+
+				const info = await serviceUnderTest().limit(limit, actor);
+
+				expect(info.remaining).toBe(0);
+				expect(info.resetSec).toBe(1);
+				expect(info.resetMs).toBe(1000);
+				expect(info.fullResetSec).toBe(1);
+				expect(info.fullResetMs).toBe(1000);
+			});
+
+			it('should allow when counter is filled but interval has passed', async () => {
+				counter = { c: 5, t: 0 };
+				mockTimeService.now = 1000;
+
+				const info = await serviceUnderTest().limit(limit, actor);
+
+				expect(info.blocked).toBeFalsy();
+			});
+
+			it('should allow when minCounter is filled but interval has passed', async () => {
+				minCounter = { c: 1, t: 0 };
+				mockTimeService.now = 1000;
+
+				const info = await serviceUnderTest().limit(limit, actor);
+
+				expect(info.blocked).toBeFalsy();
+			});
+
+			it('should scale limit by factor', async () => {
+				minCounter = { c: 5, t: 0 };
+
+				const info = await serviceUnderTest().limit(limit, actor, 2);
+
+				expect(info.blocked).toBeTruthy();
+			});
+
+			it('should set key expiration', async () => {
+				mockRedisSet = args => {
+					expect(args[2]).toBe('PX');
+					expect(args[3]).toBe(1000);
+				};
+
+				await serviceUnderTest().limit(limit, actor);
+			});
+
+			it('should not increment when already blocked', async () => {
+				counter = { c: 5, t: 0 };
+				minCounter = { c: 1, t: 0 };
+				mockTimeService.now += 100;
+
+				await serviceUnderTest().limit(limit, actor);
+
+				expect(counter?.c).toBe(5);
+				expect(counter?.t).toBe(0);
+				expect(minCounter?.c).toBe(1);
+				expect(minCounter?.t).toBe(0);
+			});
+		});
+	});
+});
+
+// The same thing, but mutable
+interface MutableLegacyRateLimit extends LegacyRateLimit {
+	key: string;
+	duration?: number;
+	max?: number;
+	minInterval?: number;
+}