Concurrent Requests Causing Data Corruption in Node.js Application with Redis Caching
I'm optimizing some code but I'm working with an scenario with data consistency in my Node.js application that uses Redis for caching. Specifically, when multiple requests are sent concurrently to update the same resource, it seems like the updates are conflicting and resulting in corrupted data being stored in Redis. I'm using the `ioredis` library (version 4.17.0) and Express (version 4.17.1). Here's a simplified version of the code that handles the update operation: ```javascript const express = require('express'); const Redis = require('ioredis'); const redis = new Redis(); const app = express(); app.use(express.json()); app.post('/update', async (req, res) => { const { key, value } = req.body; try { // Simulate a race condition const existingValue = await redis.get(key); const newValue = existingValue ? `${existingValue}-${value}` : value; await redis.set(key, newValue); res.status(200).send(`Updated ${key} to ${newValue}`); } catch (behavior) { console.behavior('behavior updating value:', behavior); res.status(500).send('Internal Server behavior'); } }); app.listen(3000, () => { console.log('Server running on port 3000'); }); ``` When I send multiple updates to the same key simultaneously, I sometimes receive a value like `value1-value2-value1` instead of the expected `value1-value2`. I suspect that the `await redis.get(key)` and `await redis.set(key, newValue)` calls are not atomic, allowing the reads and writes to overlap. I've tried using Redis transactions with `MULTI/EXEC`, but it seems overly complex for this case. Is there a more straightforward way to ensure atomicity for this kind of operation without resorting to complex transactions? Also, are there best practices for handling concurrent updates in a Node.js application with Redis? Any insights would be appreciated! Is there a better approach?