redis-command-cache

cache redis calls locally, and expire them at need

redis-command-cache

Sometimes we need to run at such an high pace that we cannot hit redis every time. We must cache values locally, and invalidate it at any change.

This module uses lru-cache.

var redis = require("redis");
var redisCache = require("redis-command-cache");
 
var size = 500; //Max size of local lru-cache, defaults to 500 
var ttl = 600; //Time-to-live on local and redis cache in seconds, local defaults to 10 
               //minutes, redis defaults to no ttl (always stays in redis cache) 
var cache = redisCache(db.createClient(), db.createClient(), size, ttl);
// var cache = redisCache(db.createClient(), db.createClient()); => local size 500, ttl on local 10 min, no ttl on redis 
 
cache.set("key", "aaa", function() {
  cache.get("key", function(errvalue) {
    // this value is cached until another set happens 
    // you might get stale data 
  });
});

The following commands have the same signature of node-redis, but they invalidate all the connected caches.

  • get()
  • set()
  • del()
  • sadd()
  • srem()
  • smembers()

redis-command-cache uses two redis connections one of which is used for a pubsub channel for key invalidations. It assumes that the number of writes on cached data is lower than the number of reads by some order of magnitude.

Copyright (c) 2014, Matteo Collina hello@matteocollina.com All rights reserved.

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