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

context-cache

v0.0.6

Published

Efficiently caches data when the cache key is a context, which may take a very large number of values

Downloads

12

Readme

Context cache

Overview

Requests are often served differently depending on their "context". The context of a request is composed of multiple dimensions. Here are some examples of common dimensions:

  • environment { production, staging, regression, development, etc. }
  • lang { en-US, en-GB, fr-FR, fr-CA, etc. }
  • device { desktop, tablet, phone, etc. }
  • partner { foo, bar, baz, etc. }
  • experiment { A, B, C, etc. }

Oftentimes, meta-data necessary to handle a request has to be computed based on its context. That computing can be expensive, so the result is usually cached. Unfortunately, as you can see, the number of contexts can be extremely high since it is the combination of the values each dimension can take. This results in a very large cache containing a large number of objects. This in turns slows down garbage collection (GC). At Yahoo!, we've seen instances where GC ends up representing 70% of the average time needed to serve a request! Additionally, in some cases, only a small number of contexts may really be needed to serve a large percentage of traffic. For example, at Yahoo! Search, a node may cache meta-data for 1,000+ contexts, but we noticed that the 100 most requested contexts serve over 98% of our traffic.

This utility module solves this specific issue by caching data only for the most requested contexts. This will result in low latency for most of your traffic and low memory consumption, which is a requirement for efficient GC.

Usage

Install the context-cache npm package:

npm install context-cache

You can then create a ContextCache instance in your application code:

var ContextCache = require('./context-cache');
var cc = ContextCache.create();

You can pass configuration settings to create:

var cc = ContextCache.create({
    maxCacheSize: 200,
    cacheHitThreshold: 10,
    storeObjectsSerialized: true,
    hotcacheTTL: 300,
    isolationMode: true
});

You can then use that instance to store/retrieve in/from the cache:

var ctx = JSON.stringify(context);
cc.set(ctx, data);
var data = cc.get(ctx);

Finally, you can obtain information about the cache itself:

console.log(cc.getInfo());