agent.maxSockets Method in Node.js

Introduction to agent.maxSockets

In Node.js, the agent.maxSockets property of the http module determines the maximum number of concurrent sockets the agent can have open per origin. This setting is crucial for managing the number of simultaneous connections to a particular host, helping to optimize resource usage and control load.

Default Behavior

By default, agent.maxSockets is set to Infinity, allowing an unlimited number of concurrent sockets per origin. While this may be suitable for applications with low traffic, it can lead to resource exhaustion under high load. Adjusting this value helps in controlling the number of active connections and can prevent potential bottlenecks.

Setting agent.maxSockets

To configure the maximum number of sockets, you can set the maxSockets property when creating a new agent:

const http = require('http');

const agent = new http.Agent({ maxSockets: 5 });

This configuration limits the agent to a maximum of 5 concurrent sockets per origin.

Using agent.maxSockets in HTTP Requests

When making HTTP requests, you can specify the custom agent with the configured maxSockets:

const options = {
  hostname: 'example.com',
  port: 80,
  path: '/',
  method: 'GET',
  agent: agent
};

const req = http.request(options, (res) => {
  console.log(`STATUS: ${res.statusCode}`);
});

req.end();

This setup ensures that the number of concurrent connections to 'example.com' does not exceed the specified limit.

Best Practices

- Monitor your application's connection patterns to determine an optimal maxSockets value.
- Avoid setting maxSockets too low, as it may lead to increased latency due to queued requests.
- Consider the overall system resources and the expected load when configuring this property.

Conclusion

The agent.maxSockets property is a powerful tool for managing concurrent connections in Node.js applications. By fine-tuning this setting, developers can achieve a balance between performance and resource utilization, ensuring efficient and reliable network communication.