seneca-memcached

Node.js Seneca Memcached module

This module is a plugin for the Seneca framework. It provides a set of common caching actions (get, set, etc), backed by memcached. It also exposes all the memcached specific actions (append, prepend, etc).

By moving cache operations into Seneca, you can change your cache implementation or business rules at a later point. For example, you might decide to send certain kinds of keys to a different cache mechanism, such as redis.

Support

If you're using this module, feel free to contact me on twitter if you have any questions! :) @rjrodger

Current Version: 0.2.1

Tested on: node 0.10.6, 0.8.7, Seneca 0.5.9

Quick example

This code snippet sets a value and then retrieves it. You'll need to have memcached running for this to work:

$ memcached -vv

var seneca = require('seneca')()
seneca.use('memcached')
 
seneca.act({role:'cache', cmd:'set', key:'k1', val:'v1'}, function(err){
 
  seneca.act({role:'cache', cmd:'get', key:'k1'}, function(err,val){
    console.log('value = '+val)
  })
})

The full action argument pattern can be a bit tedious, so use a Seneca pin to make things more convenient:

var cache = seneca.pin({role:'cache',cmd:'*'})
 
cache.set({key:'k1', val:'v1'}, function(err){
 
  cache.get({key:'k1'}, function(err,val){
    console.log('value = '+val)
  })
})

Install

npm install seneca
npm install seneca-memcached

You'll also need memcached

Common Cache API

Seneca has a common caching API with the following actions:

• role:cache, cmd:set ; store a value - key and val arguments required
• role:cache, cmd:get ; retreive a value - key argument is required
• role:cache, cmd:add ; store a value, only if the key does not exist - key and val arguments required
• role:cache, cmd:delete ; delete a value - key argument is required, no error if key does not exist
• role:cache, cmd:incr ; increment a value - key and val (integer) arguments required
• role:cache, cmd:decr ; decrement a value - key and val (integer) arguments required

All caching plugins, including this one, implement this action API.

Extended API

The full memcached API is also available. Use the action pattern plugin:memcached, cmd:... where cmd is one of set, get, add, delete, incr, decr, replace, append, prepend, cas, gets, stats, flush.

To access the underlying memcached instance, use the action plugin:memcached, cmd:native.

The plugin also registers with the action role:seneca, cmd:close. This closes the memcached connection when you call the seneca.close method.

Options

You can use any of the options from the node-memcached module directly as options to this plugin:

seneca.use('memcached',{
  servers:[ '127.0.0.1:11211', '127.0.0.1:11212' ],
  expires: 60
})

Test

cd test
mocha cache.test.js --seneca.log.print