Merge pull request #1166 from modelcontextprotocol/force-bump-redis-and-memory

Add missing capabilities and improve connection handling for server-redis

Author: olaservo

src/redis/README.md

@@ -2,6 +2,31 @@
 
 A Model Context Protocol server that provides access to Redis databases. This server enables LLMs to interact with Redis key-value stores through a set of standardized tools.
 
+## Prerequisites
+
+1. Redis server must be installed and running
+   - [Download Redis](https://redis.io/download)
+   - For Windows users: Use [Windows Subsystem for Linux (WSL)](https://redis.io/docs/getting-started/installation/install-redis-on-windows/) or [Memurai](https://www.memurai.com/) (Redis-compatible Windows server)
+   - Default port: 6379
+
+## Common Issues & Solutions
+
+### Connection Errors
+
+**ECONNREFUSED**
+  - **Cause**: Redis server is not running or unreachable
+  - **Solution**: 
+    - Verify Redis is running: `redis-cli ping` should return "PONG"
+    - Check Redis service status: `systemctl status redis` (Linux) or `brew services list` (macOS)
+    - Ensure correct port (default 6379) is not blocked by firewall
+    - Verify Redis URL format: `redis://hostname:port`
+
+### Server Behavior
+
+- The server implements exponential backoff with a maximum of 5 retries
+- Initial retry delay: 1 second, maximum delay: 30 seconds
+- Server will exit after max retries to prevent infinite reconnection loops
+
 ## Components
 
 ### Tools
@@ -77,4 +102,4 @@ docker build -t mcp/redis -f src/redis/Dockerfile .
 
 ## License
 
-This MCP server is licensed under the MIT License. This means you are free to use, modify, and distribute the software, subject to the terms and conditions of the MIT License. For more details, please see the LICENSE file in the project repository.
+This MCP server is licensed under the MIT License. This means you are free to use, modify, and distribute the software, subject to the terms and conditions of the MIT License. For more details, please see the LICENSE file in the project repository.

src/redis/src/index.ts

@@ -7,10 +7,26 @@ import {
 import { z } from "zod";
 import { createClient } from 'redis';
 
-// Get Redis URL from command line args or use default
+// Configuration
 const REDIS_URL = process.argv[2] || "redis://localhost:6379";
+const MAX_RETRIES = 5;
+const MIN_RETRY_DELAY = 1000; // 1 second
+const MAX_RETRY_DELAY = 30000; // 30 seconds
+
+// Create Redis client with retry strategy
 const redisClient = createClient({
-    url: REDIS_URL
+    url: REDIS_URL,
+    socket: {
+        reconnectStrategy: (retries) => {
+            if (retries >= MAX_RETRIES) {
+                console.error(`Maximum retries (${MAX_RETRIES}) reached. Giving up.`);
+                return new Error('Max retries reached');
+            }
+            const delay = Math.min(Math.pow(2, retries) * MIN_RETRY_DELAY, MAX_RETRY_DELAY);
+            console.error(`Reconnection attempt ${retries + 1}/${MAX_RETRIES} in ${delay}ms`);
+            return delay;
+        }
+    }
 });
 
 // Define Zod schemas for validation
@@ -36,7 +52,12 @@ const ListArgumentsSchema = z.object({
 const server = new Server(
     {
         name: "redis",
-        version: "1.0.0"
+        version: "0.0.1"
+    },
+    {
+        capabilities: {
+            tools: {}
+        }
     }
 );
 
@@ -215,22 +236,51 @@ server.setRequestHandler(CallToolRequestSchema, async (request) => {
 // Start the server
 async function main() {
     try {
+        // Set up Redis event handlers
+        redisClient.on('error', (err: Error) => {
+            console.error('Redis Client Error:', err);
+        });
+
+        redisClient.on('connect', () => {
+            console.error(`Connected to Redis at ${REDIS_URL}`);
+        });
+
+        redisClient.on('reconnecting', () => {
+            console.error('Attempting to reconnect to Redis...');
+        });
+
+        redisClient.on('end', () => {
+            console.error('Redis connection closed');
+        });
+
         // Connect to Redis
-        redisClient.on('error', (err: Error) => console.error('Redis Client Error', err));
         await redisClient.connect();
-        console.error(`Connected to Redis successfully at ${REDIS_URL}`);
 
+        // Set up MCP server
         const transport = new StdioServerTransport();
         await server.connect(transport);
         console.error("Redis MCP Server running on stdio");
     } catch (error) {
         console.error("Error during startup:", error);
+        await cleanup();
+    }
+}
+
+// Cleanup function
+async function cleanup() {
+    try {
         await redisClient.quit();
-        process.exit(1);
+    } catch (error) {
+        console.error("Error during cleanup:", error);
     }
+    process.exit(1);
 }
 
+// Handle process termination
+process.on('SIGINT', cleanup);
+process.on('SIGTERM', cleanup);
+
 main().catch((error) => {
     console.error("Fatal error in main():", error);
-    redisClient.quit().finally(() => process.exit(1));
-});
+    cleanup();
+});