npm package discovery and stats viewer.

Discover Tips

  • General search

    [free text search, go nuts!]

  • Package details

    pkg:[package-name]

  • User packages

    @[username]

Sponsor

Optimize Toolset

I’ve always been into building performant and accessible sites, but lately I’ve been taking it extremely seriously. So much so that I’ve been building a tool to help me optimize and monitor the sites that I build to make sure that I’m making an attempt to offer the best experience to those who visit them. If you’re into performant, accessible and SEO friendly sites, you might like it too! You can check it out at Optimize Toolset.

About

Hi, 👋, I’m Ryan Hefner  and I built this site for me, and you! The goal of this site was to provide an easy way for me to check the stats on my npm packages, both for prioritizing issues and updates, and to give me a little kick in the pants to keep up on stuff.

As I was building it, I realized that I was actually using the tool to build the tool, and figured I might as well put this out there and hopefully others will find it to be a fast and useful way to search and browse npm packages as I have.

If you’re interested in other things I’m working on, follow me on Twitter or check out the open source projects I’ve been publishing on GitHub.

I am also working on a Twitter bot for this site to tweet the most popular, newest, random packages from npm. Please follow that account now and it will start sending out packages soon–ish.

Open Software & Tools

This site wouldn’t be possible without the immense generosity and tireless efforts from the people who make contributions to the world and share their work via open source initiatives. Thank you 🙏

© 2024 – Pkg Stats / Ryan Hefner

@shuhei/pollen

v0.0.5

Published

DNS polling for HTTP Keep-Alive of Node.js HTTP clients

Downloads

598

Readme

pollen

DNS polling for HTTP Keep-Alive of Node.js HTTP clients

CircleCI codecov npm version

Why?

  • Support server-side traffic switch using weighted DNS routing
  • Eliminate latency of making new connections (DNS query, TCP & TLS handshakes)
  • Stay resilient to DNS query failures

To achieve good performance, we want to keep Keep-Alive connections as much as possible. On the over hand, DNS-based traffic switch doesn't allow us to keep connections forever because existing persistent connections can become stale when DNS records change.

Solution

This package polls DNS records and keep Keep-Alive connections using agentkeepalive as long as DNS records stay same. When DNS records change, it creates new connections with already retrieved IP addresses without making new DNS queries.

Even when DNS records change, existing connections are not immediately terminated. We can keep them for the next DNS record change (for example, DNS records can go back and forth with weighted DNS routing) with freeSocketTimeout option of agentkeepalive.

Install

npm install -S @shuhei/pollen
# or
yarn add @shuhei/pollen

Example

const https = require('https');
const { DnsPolling, HttpsAgent } = require('@shuhei/pollen');

const dnsPolling = new DnsPolling({
  interval: 30 * 1000 // 30 seconds by default
});
// Just a thin wrapper of https://github.com/node-modules/agentkeepalive
// It accepts all the options of `agentkeepalive`.
const agent = new HttpsAgent();

const hostname = 'shuheikagawa.com';
const req = https.request({
  hostname,
  path: '/',
  // Make sure to call `getLookup()` for each request!
  lookup: dnsPolling.getLookup(hostname),
  agent,
});

Limitations

  • Only IPv4 is supported.
  • /etc/hosts, etc are not supported because this package internally uses dns.resolve4(). See Node.js documentation for more details.