Redis ratelimits

test/rate-limit.test.js

@@ -1,5 +1,5 @@
-import { describe, expect, it } from 'vitest';
-import { createRateLimiter } from '../src/rate-limit.js';
+import { describe, expect, it, vi } from 'vitest';
+import { createRateLimiter, createRedisRateLimiter } from '../src/rate-limit.js';
 
 describe('rate limiter', () => {
   it('enforces request and spend windows', () => {
@@ -23,4 +23,26 @@ describe('rate limiter', () => {
     expect(limiter.check('a').allowed).toBe(false);
     expect(limiter.check('b').allowed).toBe(true);
   });
+
+  it('uses Redis scripts and namespaces keys by client IP', async () => {
+    const client = { eval: vi.fn().mockResolvedValueOnce([1]).mockResolvedValueOnce(1) };
+    const limiter = createRedisRateLimiter({ client, now: () => 10_000, keyPrefix: 'test:limits' });
+
+    await expect(limiter.check('2001:db8::1')).resolves.toEqual({ allowed: true });
+    await limiter.recordCost('2001:db8::1', 1.25);
+
+    expect(client.eval).toHaveBeenCalledTimes(2);
+    expect(client.eval.mock.calls[0][1].keys).toEqual([
+      'test:limits:{2001%3Adb8%3A%3A1}:requests',
+      'test:limits:{2001%3Adb8%3A%3A1}:spend',
+      'test:limits:{2001%3Adb8%3A%3A1}:sequence',
+    ]);
+    expect(client.eval.mock.calls[1][1].arguments).toEqual(['10000', '-17990000', '1.25', '18000000']);
+  });
+
+  it('converts Redis denials into rate-limit responses', async () => {
+    const client = { eval: vi.fn().mockResolvedValue([0, 'spend', 1_001]) };
+    const limiter = createRedisRateLimiter({ client, now: () => 10_000 });
+    await expect(limiter.check('ip')).resolves.toEqual({ allowed: false, reason: 'spend', retryAfter: 2 });
+  });
 });