chore: proxy improvements (#3121)

* introduce global interceptors

* move proxy stuff to new folder

* implement resp framer

* properly handle request/response and push

* add global interceptor

packages/test-utils/lib/proxy/redis-proxy-spec.ts

@@ -0,0 +1,315 @@
+import { strict as assert } from 'node:assert';
+import { Buffer } from 'node:buffer';
+import { testUtils, GLOBAL } from '../test-utils';
+import { InterceptorDescription, RedisProxy } from './redis-proxy';
+import type { RedisClientType } from '@redis/client/lib/client/index.js';
+
+describe('RedisSocketProxy', function () {
+  testUtils.testWithClient('basic proxy functionality', async (client: RedisClientType<any, any, any, any, any>) => {
+    const socketOptions = client?.options?.socket;
+    //@ts-ignore
+    assert(socketOptions?.port, 'Test requires a TCP connection to Redis');
+
+    const proxyPort = 50000 + Math.floor(Math.random() * 10000);
+    const proxy = new RedisProxy({
+      listenHost: '127.0.0.1',
+      listenPort: proxyPort,
+      //@ts-ignore
+      targetPort: socketOptions.port,
+      //@ts-ignore
+      targetHost: socketOptions.host || '127.0.0.1',
+      enableLogging: true
+    });
+
+    const proxyEvents = {
+      connections: [] as any[],
+      dataTransfers: [] as any[]
+    };
+
+    proxy.on('connection', (connectionInfo) => {
+      proxyEvents.connections.push(connectionInfo);
+    });
+
+    proxy.on('data', (connectionId, direction, data) => {
+      proxyEvents.dataTransfers.push({ connectionId, direction, dataLength: data.length });
+    });
+
+    try {
+      await proxy.start();
+
+      const proxyClient = client.duplicate({
+        socket: {
+          port: proxyPort,
+          host: '127.0.0.1'
+        },
+      });
+
+      await proxyClient.connect();
+
+      const stats = proxy.getStats();
+      assert.equal(stats.activeConnections, 1, 'Should have one active connection');
+      assert.equal(proxyEvents.connections.length, 1, 'Should have recorded one connection event');
+
+      const pingResult = await proxyClient.ping();
+      assert.equal(pingResult, 'PONG', 'Client should be able to communicate with Redis through the proxy');
+
+      const clientToServerTransfers = proxyEvents.dataTransfers.filter(t => t.direction === 'client->server');
+      const serverToClientTransfers = proxyEvents.dataTransfers.filter(t => t.direction === 'server->client');
+
+      assert(clientToServerTransfers.length > 0, 'Should have client->server data transfers');
+      assert(serverToClientTransfers.length > 0, 'Should have server->client data transfers');
+
+      const testKey = `test:proxy:${Date.now()}`;
+      const testValue = 'proxy-test-value';
+
+      await proxyClient.set(testKey, testValue);
+      const retrievedValue = await proxyClient.get(testKey);
+      assert.equal(retrievedValue, testValue, 'Should be able to set and get values through proxy');
+
+      proxyClient.destroy();
+
+
+    } finally {
+      await proxy.stop();
+    }
+  }, GLOBAL.SERVERS.OPEN_RESP_3);
+
+  testUtils.testWithProxiedClient('custom message injection via proxy client',
+    async (proxiedClient: RedisClientType<any, any, any, any, any>, proxy: RedisProxy) => {
+      const customMessageTransfers: any[] = [];
+
+      proxy.on('data', (connectionId, direction, data) => {
+        if (direction === 'server->client') {
+          customMessageTransfers.push({ connectionId, dataLength: data.length, data });
+        }
+      });
+
+
+      const stats = proxy.getStats();
+      assert.equal(stats.activeConnections, 1, 'Should have one active connection');
+
+      // Send a resp3 push
+      const customMessage = Buffer.from('>4\r\n$6\r\nMOVING\r\n:1\r\n:2\r\n$6\r\nhost:3\r\n');
+
+      const sendResults = proxy.sendToAllClients(customMessage);
+      assert.equal(sendResults.length, 1, 'Should send to one client');
+      assert.equal(sendResults[0].success, true, 'Custom message send should succeed');
+
+
+      const customMessageFound = customMessageTransfers.find(transfer =>
+        transfer.dataLength === customMessage.length
+      );
+      assert(customMessageFound, 'Should have recorded the custom message transfer');
+
+      assert.equal(customMessageFound.dataLength, customMessage.length,
+        'Custom message length should match');
+
+      const pingResult = await proxiedClient.ping();
+      assert.equal(pingResult, 'PONG', 'Client should be able to communicate with Redis through the proxy');
+
+    }, GLOBAL.SERVERS.OPEN_RESP_3);
+
+  describe("Middleware", () => {
+    testUtils.testWithProxiedClient(
+      "Modify request/response via middleware",
+      async (
+        proxiedClient: RedisClientType<any, any, any, any, any>,
+        proxy: RedisProxy,
+      ) => {
+
+        // Intercept PING commands and modify the response
+        const pingInterceptor: InterceptorDescription = {
+          name: `ping`,
+          fn: async (data, next) => {
+            if (data.includes('PING')) {
+              return Buffer.from("+PINGINTERCEPTED\r\n");
+            }
+            return next(data);
+          }
+        };
+
+        // Only intercept GET responses and double numeric values
+        // Does not modify other commands or non-numeric GET responses
+        const doubleNumberGetInterceptor: InterceptorDescription = {
+          name: `double-number-get`,
+          fn: async (data, next) => {
+            const response = await next(data);
+
+            // Not a GET command, return original response
+            if (!data.includes("GET")) return response;
+
+            const value = (response.toString().split("\r\n"))[1];
+            const number = Number(value);
+            // Not a number, return original response
+            if(isNaN(number)) return response;
+
+            const doubled = String(number * 2);
+            return Buffer.from(`$${doubled.length}\r\n${doubled}\r\n`);
+          }
+        };
+
+        proxy.setGlobalInterceptors([ pingInterceptor, doubleNumberGetInterceptor ])
+
+        const pingResponse = await proxiedClient.ping();
+        assert.equal(pingResponse, 'PINGINTERCEPTED', 'Response should be modified by middleware');
+
+        await proxiedClient.set('foo', 1);
+        const getResponse1 = await proxiedClient.get('foo');
+        assert.equal(getResponse1, '2', 'GET response should be doubled for numbers by middleware');
+
+        await proxiedClient.set('bar', 'Hi');
+        const getResponse2 = await proxiedClient.get('bar');
+        assert.equal(getResponse2, 'Hi', 'GET response should not be modified for strings by middleware');
+
+        await proxiedClient.hSet('baz', 'foo', 'dictvalue');
+        const hgetResponse = await proxiedClient.hGet('baz', 'foo');
+        assert.equal(hgetResponse, 'dictvalue', 'HGET response should not be modified by middleware');
+
+      },
+      GLOBAL.SERVERS.OPEN_RESP_3,
+    );
+
+    testUtils.testWithProxiedClient(
+      "Stats reflect middleware activity",
+      async (
+        proxiedClient: RedisClientType<any, any, any, any, any>,
+        proxy: RedisProxy,
+      ) => {
+        const PING = `ping`;
+        const SKIPPED = `skipped`;
+        proxy.setGlobalInterceptors([
+          {
+            name: PING,
+            matchLimit: 3,
+            fn: async (data, next, state) => {
+              state.invokeCount++;
+              if(state.matchCount === state.matchLimit) return next(data);
+              if (data.includes("PING")) {
+                state.matchCount++;
+                return Buffer.from("+PINGINTERCEPTED\r\n");
+              }
+              return next(data);
+            },
+          },
+          {
+            name: SKIPPED,
+            fn: async (data, next, state) => {
+              state.invokeCount++;
+              state.matchCount++;
+              // This interceptor does not match anything
+              return next(data);
+            },
+          },
+        ]);
+
+        await proxiedClient.ping();
+        await proxiedClient.ping();
+        await proxiedClient.ping();
+
+        let stats = proxy.getStats();
+        let pingInterceptor = stats.globalInterceptors.find(
+          (i) => i.name === PING,
+        );
+        assert.ok(pingInterceptor, "PING interceptor stats should be present");
+        assert.equal(pingInterceptor.invokeCount, 3);
+        assert.equal(pingInterceptor.matchCount, 3);
+
+        let skipInterceptor = stats.globalInterceptors.find(
+          (i) => i.name === SKIPPED,
+        );
+        assert.ok(skipInterceptor, "SKIPPED interceptor stats should be present");
+        assert.equal(skipInterceptor.invokeCount, 0);
+        assert.equal(skipInterceptor.matchCount, 0);
+
+        await proxiedClient.set("foo", "bar");
+        await proxiedClient.get("foo");
+
+        stats = proxy.getStats();
+        pingInterceptor = stats.globalInterceptors.find(
+          (i) => i.name === PING,
+        );
+        assert.ok(pingInterceptor, "PING interceptor stats should be present");
+        assert.equal(pingInterceptor.invokeCount, 5);
+        assert.equal(pingInterceptor.matchCount, 3);
+
+        await proxiedClient.ping();
+
+        stats = proxy.getStats();
+        pingInterceptor = stats.globalInterceptors.find(
+          (i) => i.name === PING,
+        );
+        assert.ok(pingInterceptor, "PING interceptor stats should be present");
+        assert.equal(pingInterceptor.invokeCount, 6);
+        assert.equal(pingInterceptor.matchCount, 3, 'Should not match more than limit');
+
+        skipInterceptor = stats.globalInterceptors.find(
+          (i) => i.name === SKIPPED,
+        );
+        assert.ok(skipInterceptor, "PING interceptor stats should be present");
+        assert.equal(skipInterceptor.invokeCount, 3);
+        assert.equal(skipInterceptor.matchCount, 3);
+      },
+      GLOBAL.SERVERS.OPEN_RESP_3,
+    );
+
+    testUtils.testWithProxiedClient(
+      "Middleware is given exactly one RESP message at a time",
+      async (
+        proxiedClient: RedisClientType<any, any, any, any, any>,
+        proxy: RedisProxy,
+      ) => {
+        proxy.setGlobalInterceptors([
+          {
+            name: `ping`,
+            fn: async (data, next, state) => {
+              state.invokeCount++;
+              if (data.equals(Buffer.from("*1\r\n$4\r\nPING\r\n"))) {
+                state.matchCount++;
+              }
+              return next(data);
+            },
+          },
+        ]);
+
+        await Promise.all([proxiedClient.ping(), proxiedClient.ping()]);
+
+        const stats = proxy.getStats();
+        const pingInterceptor = stats.globalInterceptors.find(
+          (i) => i.name === `ping`,
+        );
+        assert.ok(pingInterceptor, "PING interceptor stats should be present");
+        assert.equal(pingInterceptor.invokeCount, 2);
+        assert.equal(pingInterceptor.matchCount, 2);
+      },
+      GLOBAL.SERVERS.OPEN_RESP_3,
+    );
+
+    testUtils.testWithProxiedClient(
+      "Proxy passes through push messages",
+      async (
+        proxiedClient: RedisClientType<any, any, any, any, any>,
+        proxy: RedisProxy,
+      ) => {
+        let resolve: (value: string) => void;
+        const promise = new Promise((rs) => { resolve = rs; });
+        await proxiedClient.subscribe("test-push-channel", (message) => {
+          resolve(message);
+        });
+
+        await proxiedClient.publish("test-push-channel", "hello");
+        const result = await promise;
+        assert.equal(result, "hello", "Should receive push message through proxy");
+      },
+      {
+        ...GLOBAL.SERVERS.OPEN_RESP_3,
+        clientOptions: {
+          maintNotifications: 'disabled',
+          disableClientInfo: true,
+          RESP: 3
+        }
+      },
+    );
+  });
+
+
+});