Node.js process crushes if a user has no permissions to run the 'monitor' command

[artyom-podymov]

1. If create a user that has no permissions to run the monitor command

$ redis-cli 
localhost:6379> ACL SETUSER alice on nopass ~* &* +@all -monitor
OK

2. Connect to Redis and call monitor function

const Redis = require("ioredis");

var redis = new Redis({host: 'localhost', port: 6379, username: 'alice'});

redis.on("connect", () => {
  console.log('Connected to DB \n');
  redis.monitor((err, monitor) => {
    console.log('Error', err)
    if (!err) {
      monitor.on('monitor', (...args) => console.log(JSON.stringify(args)))
    }
  });
});

3. As a result in the callback function we don't see any error and Node.js process just crushes (the same behavior for async function implementation)

Connected to DB 

Error null                                                                                    
node_modules\redis-parser\lib\parser.js:179    
    return new ReplyError(string)                                                             
           ^                                                                                  
                                                                                              
ReplyError: NOPERM this user has no permissions to run the 'monitor' command or its subcommand
    at parseError (node_modules\redis-parser\lib\parser.js:179:12)
    at parseType (node_modules\redis-parser\lib\parser.js:302:14) {
  command: { name: 'monitor', args: [] }
}

Is it possible to handle such cases and properly throw errors without stopping the Node.js process?

[udochify]

Attach an event handler to the node.js process like this

process.on("uncaughtException", (error) => {
     console.error("Uncaught Exception Description: ", error);
     // process.exit(1); // uncomment this line if you want your application to close gracefully.
});

Just include it anywhere in the global scope of your file (i.e. not inside any function or class).
If you leave the last line commented, your node.js process won't crash. But it is really not advisable for production.

[artyom-podymov]

Attach an event handler to the node.js process like this

process.on("uncaughtException", (error) => {
     console.error("Uncaught Exception Description: ", error);
     // process.exit(1); // uncomment this line if you want your application to close gracefully.
});

Just include it anywhere in the global scope of your file (i.e. not inside any function or class). If you leave the last line commented, your node.js process won't crash. But it is really not advisable for production.

@udochify Thanks. But this approach looks like a workaround and I think such cases should be handled on the ioredis side.

[udochify]

ok. Have you tried putting the part where you call monitor in a try catch block, like this?

const Redis = require("ioredis"); 

var redis = new Redis({host: 'localhost', port: 6379, username: 'alice'}); 

redis.on("connect", () => { 
    console.log('Connected to DB \n'); 
    try {
        redis.monitor((err, monitor) => { 
            console.log('Error', err) // You only logged error here (and if the call to monitor completes). What if the call to monitor never starts as in your case
            if (!err) { 
                monitor.on('monitor', (...args) => console.log(JSON.stringify(args))) 
            } 
        });
    } catch (error) { // you caught and handled the error here
        console.error("Redis Client Monitor Exception ", error);
    }
});

Usually, catching errors (and not just logging them to the console) handles them and allows execution to continue.

Same thing goes when you use async-await syntax

async function foo () {
    await redis.monitor(...).catch((error) => console.error(error));
}

[artyom-podymov]

@udochify Yes, I tried) it doesn't help, the error does not fall into the catch block

[artyom-podymov]

@udochify By the way, did you manage to reproduce this issue? Or maybe it's just me having this problem?

[github-actions]

🎉 This issue has been resolved in version 5.0.3 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

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