Get Number of Connections in Node Redis (Detailed Guide w/ Code Examples)

Use Case(s)

For monitoring and diagnostics, it is often necessary to know the number of client connections to your Redis server. This might be especially useful when debugging issues related to connection limits or evaluating the load on a Redis instance.

Code Examples

The client.server_info object contains various information about the connected Redis server, including the number of connections. Here's an example:

const redis = require('redis');
const client = redis.createClient();

client.on('connect', function() {
  console.log('Connected!');
});

client.info(function (err, response) {
  if(err) throw err;

  let serverInfo = client.server_info;
  console.log('Number of connections:', serverInfo.connected_clients);
});

In this snippet, we create a Redis client, connect to the server, and retrieve server information using the info method. The number of connections can be accessed via server_info.connected_clients.

Best Practices

Ensure that exceptions are handled appropriately when working with Redis connections. If an error occurs while trying to get server information, it should be caught so that it doesn't crash the application.

Common Mistakes

One common mistake is not checking for connection errors before attempting to get the number of connections. If the client isn't correctly connected to the server, this could lead to unhandled exceptions.

FAQs

Q: Is there a limit to the number of connections to a Redis server?

A: Yes, each Redis server has a maximum number of client connections, which defaults to 10000. However, this limit can be changed in the Redis configuration file.

Q: How do I close a connection to a Redis server?

A: You can close a connection using the quit method on the client object: client.quit(). It's also good practice to close connections when they're no longer needed to free up resources.