cache-chain

An abstract multilayer cache system.

Purpose

The main purpose of the system is to build a multipurpose key/value caching or caching/storage system.

Installation

npm install cache-chain

Examples

Very basic example (More here):

In this example, a simple chain of Memory->Redis is setup.

var redis = require('redis');
var cc = require('cache-chain');
var ccr = require('cache-chain-redis');
var ccm = require('cache-chain-memory');

var chain = cc.chain({
    stale: 10000,			// Setting default chain timeouts
    ttl: 10000 * 2
});

var redisClient = redis.createClient();
var layerRedis = cc.layer(ccr(redisClient));
var layerMemory = cc.layer(ccm());
layerMemory.append(layerRedis);
chain.append(layerMemory);

var key = "key";
var value = "value";

chain.set(key, value, {ttl: 10, stale: 5}, function(err, reply) {
    if (err) {
        console.error('Error occured');
        console.error(err);
    } else {
        chain.get(key, {ttl: 10, stale: 5}, function(err, reply) {
            if(value === reply) {
                console.log('OK');
            } else {
                console.log('Something happened');
            }
            redisClient.end();
        });
    }
})

Please go here for more examples

Key/Value caching system

The main characteristic of a key/value chained caching system is that the last item in the chain is an authoritative backend that always contains the data. The client makes a request for a key, which is then verified in each cacheing layer until it reaches the bottom layer. The bottom layer resolves the key, and returns the output to upper layer while they update they own storage with correct values.

Consult the following diagram: Usecase 1