koop-cache-apache-ignite

This is a "cache" plugin for the Koop Web Server. It adheres to Koop's plugin specification. Registering this plugin with Koop will cause it to replace its in-memory cache with a cache backed by Apache Ignite.

An important fact about Koop cache plugins - registering a cache does not necessarily mean data from provider plugins will be cached. The provider must set a ttl (in seconds) on its data payload for it to be cached by any cache-plugin. This gives the provider developer ultimate control over data caching.

Why use the Apache-Ignite plugin?

Koop's default cache uses a simple key/value store to cache data in-memory. This means you are using a chunk of your deployment machine's memory for the cache. The size of cache entries isn't limited by the in-memory cache-plugin (though the number of entries is limited), which makes it hard to plan for how much memory you need. In contrast, using a backing store like Apache Ignite is a much more scalable solution as you can provision the Ignite instance independently and it's memory consumption has no impact on the web-server.

Using a plugin like the Apache-Ignite cache also benefits deployments that leverage horizontal scaling of the web-server. Imagine you are using the default in-memory cache and that you are deploying multiple Koop server instances with traffic routed to each by a load balancer. In this architecture, each Koop server has its own cache. Caching is therefore inefficient; a cache entry on server (A) is not accessible to server (B). Rather, each server instance has to build up its own cache. Alternatively, if you use the Apache-Ignite plugin with an independently deployed Apache-Ignite backing store, each Koop server instance will share a single cache; entries cached by server (A) can be retrieved by server (B).

Usage

As a Koop cache plugin

With registration options:

const Koop = require('koop')
const koop = new Koop()
const { Cache } = require('@koopjs/cache-apache-ignite')
koop.register(Cache, {
  connStr: '127.0.0.1:10800', // connection string for the Ignite deployment,
  cacheName: 'koop-ignite-cache' // a name to use for the cache; will be created if not found
})

With options set in "node-config" module:

Create a configuration json file (see node-config for details).

{
  "apacheIgnite": {
    "connStr": "127.0.0.1:10800",
    "cacheName": "koop-ignite-cache"
  }
}

Then register the cache plugin without options.

const Koop = require('koop')
const koop = new Koop()
const { Cache } = require('@koopjs/cache-apache-ignite')
koop.register(Cache)