Memcached Cloud

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Memcached Cloud is a fully-managed service for running your Memcached in a reliable and fail-safe manner. Your dataset is constantly replicated, so if a node fails, an auto-switchover mechanism guarantees data is served without interruption. Memcached Cloud provides various data persistence options as well as remote backups for disaster recovery purposes. You can quickly and easily get your apps up and running with Memcached Cloud through its add-on for Cloud Foundry, just tell us how much memory you need and get started instantly with your first Memcached bucket.

A Memcached bucket is created in seconds and from that moment on, all operations are fully-automated. The service completely frees developers from dealing with nodes, clusters, server lists, scaling and failure recovery, while guaranteeing absolutely no data loss.

Managing Services

Creating A Memcached Cloud Service

Create a Memcached Cloud service with the following command:

$ cf create-service memcachedcloud PLAN_NAME INSTANCE_NAME

where PLAN_NAME is the desired plan’s name, and INSTANCE_NAME is a name meaningful to you.

Binding Your Memcached Cloud Service

Bind your Memcached Cloud service to your app, using the following command:

$ cf bind-service APP_NAME INSTANCE_NAME

Once your Memcached Cloud service is bound to your app, the service credentials will be stored in the VCAP_SERVICES environment variable in the following format:

{
  memcachedcloud: [
    {
      name: "memcachedcloud-42",
      label: "memcachedcloud",
      plan: "20mb",
      credentials: {
        servers: "pub-memcache-6379.us-east-1-1.1.ec2.redislabs.com:6379",
        username: "memcachedcloud-42",
        password: "your_memcached_password"
      }
    }
  ]
}

For more information, see Delivering Service Credentials to an Application and VCAP_SERVICES Environment Variable.

• Ruby
• Sinatra
• Unicorn
• Java
• Python
• Django
• PHP

Using Memcached with Ruby

Dalli is a high performance pure Ruby client for accessing memcached servers, which uses the binary protocol.

For usage with Rails 3.x, update the Gemfile:

gem 'dalli'

And then install the gem via Bundler:

bundle install

Parse your credentials as follows:

memcachedcloud_service = JSON.parse(ENV['VCAP_SERVICES'])["memcachedcloud"]
credentials = memcachedcloud_service.first["credentials"]

Lastly, in your config/environments/production.rb:

    config.cache_store = :dalli_store, credentials.servers, { :username => credentials.username, :password => credentials.password }

Configuring Memcached on Sinatra

Add this code snippet to your configure block:

configure do
    . . .
    require 'dalli'
    memcachedcloud_service = JSON.parse(ENV['VCAP_SERVICES'])["memcachedcloud"]
    credentials = memcachedcloud_service.first["credentials"]
    $cache = Dalli::Client.new(credentials.servers.split(','), :username => credentials.username, :password => credentials.password)
    . . .
end

Using Memcached on Unicorn

No special setup is required when using Memcached Cloud with a Unicorn server. For Sinatra apps on Unicorn see Configuring Memcached on Sinatra section.

Testing from Ruby

$cache.set("foo", "bar")
# => true
$cache.get("foo")
# => "bar"

Using Memcached with Java

spymemcached is a simple, asynchronous, single-threaded Memcached client written in Java. You can download the latest build from: https://code.google.com/p/spymemcached/downloads/list.

To use the maven repository, start by specifying the repository:

<repositories>
    <repository>
      <id>spy</id>
      <name>Spy Repository</name>
      <layout>default</layout>
      <url>http://files.couchbase.com/maven2/</url>
      <snapshots>
        <enabled>false</enabled>
      </snapshots>
    </repository>
</repositories>

And specify the actual artifact as follows:

<dependency>
  <groupId>spy</groupId>
  <artifactId>spymemcached</artifactId>
  <version>2.8.9</version>
  <scope>provided</scope>
</dependency>

Configure the connection to your Memcached Cloud service using the VCAP_SERVICES environment variable and the following code snippet:

try {
    String vcap_services = System.getenv("VCAP_SERVICES");
    if (vcap_services != null && vcap_services.length() > 0) {
        // parsing memcachedcloud credentials
        JsonRootNode root = new JdomParser().parse(vcap_services);
        JsonNode "memcachedcloudNode = root.getNode("memcachedcloud");
        JsonNode credentials = "memcachedcloudNode.getNode(0).getNode("credentials");

        // building the memcached client
        AuthDescriptor ad = new AuthDescriptor(new String[] { "PLAIN" },
                new PlainCallbackHandler(credentials.getStringValue("username"), credentials.getStringValue("password")));

        MemcachedClient mc = new MemcachedClient(
                  new ConnectionFactoryBuilder()
                      .setProtocol(ConnectionFactoryBuilder.Protocol.BINARY)
                      .setAuthDescriptor(ad).build(),
                  AddrUtil.getAddresses(credentials.getStringValue("servers")));

    }
} catch (InvalidSyntaxException ex) {
    // vcap_services could not be parsed.
} catch (IOException ex) {
    // the memcached client could not be initialized.
}

Testing from Java

mc.set("foo", 0, "bar");
Object value = mc.get("foo");

Using Memcached with Python

bmemcached is a pure, thread safe, python module to access Memcached via its binary protocol.

Use pip to install it:

pip install python-binary-memcached

Configure the connection to your Memcached Cloud service using VCAP_SERVICES environment variable and the following code snippet:

import os
import urlparse
import bmemcached
import json

memcachedcloud_service = json.loads(os.environ['VCAP_SERVICES'])['memcachedcloud'][0]
credentials = memcached_service['credentials']
mc = bmemcached.Client(credentials['servers'].split(','), credentials['username'], credentials['password'])

Testing from Python

mc.set('foo', 'bar')
print client.get('foo')

Using Memcached with Django

Memcached can be used as a django cache backend, with django-bmemcached.

To do so, install django-bmemcached:

pip install django-bmemcached

Next, configure your CACHES in the settings.py file:

import os
import urlparse
import json

memcachedcloud_service = json.loads(os.environ['VCAP_SERVICES'])['memcachedcloud'][0]
credentials = memcachedcloud_service['credentials']
CACHES = {
    'default': {
    'BACKEND': 'django_bmemcached.memcached.BMemcached',
    'LOCATION': credentials['servers'].split(','),
    'OPTIONS': {
                'username' credentials['username'],
                'password': credentials['password']

    }
  }
}

Testing from Django

from django.core.cache import cache
cache.set("foo", "bar")
print cache.get("foo")

Using Memcached with PHP

PHPMemcacheSASL is a simple PHP class with SASL support.

Include the class in your project, and configure a connection to your Memcached Cloud service using VCAP_SERVICES environment variable with the following code snippet:

<?php
include('MemcacheSASL.php');

$vcap_services = getenv("VCAP_SERVICES");
$"memcachedcloud_service = json_decode($vcap_services, true)["memcachedcloud"][0]
$credentials = $"memcachedcloud_service["credentials"]

$mc = new MemcacheSASL;
list($host, $port) = explode(':', $credentials['servers']);
$mc->addServer($host, $port);
$mc->setSaslAuthData($credentials['username], $credentials['password']);

Testing from PHP

$mc->add("foo", "bar");
echo $mc->get("foo");

Dashboard

Our dashboard presents all performance and usage metrics of your Memcached Cloud service on a single screen, as shown below:

To access your Memcached Cloud dashboard, click the ‘Manage’ button next to the Memcached Cloud service in Apps Manager. You can find your dashboard under the MY DATABASES menu.

Support

Any Memcached Cloud support issues or product feedbacks are welcome via email at support@redislabs.com. Please make sure you are familiar with the CloudFoundry method of contacting service providers for support.

Additional resources

• Developers Resources
• Memcached Wiki