Class: IsItWorking::DalliCheck

Inherits:
Object
  • Object
show all
Defined in:
lib/is_it_working/checks/dalli_check.rb

Instance Method Summary collapse

Constructor Details

#initialize(options = {}) ⇒ DalliCheck

Check if all the memcached servers in a cluster are responding. The memcache cluster to check is specified with the :cache options. The value can be either a Dalli::Client object (from the dalli gem) or an ActiveSupport::Cache::DalliStore (i.e. Rails.cache).

If making the IP addresses of the memcache servers known to the world could pose a security risk because they are not on a private network behind a firewall, you can provide the :alias option to change the host names that are reported.

Example

IsItWorking::Handler.new do |h|
  h.check :dalli, :cache => Rails.cache, :alias => "memcache server"
end

Raises:

  • (ArgumentError) 


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# File 'lib/is_it_working/checks/dalli_check.rb', line 19

def initialize(options={})
  memcache = options[:cache]
  raise ArgumentError.new(":cache not specified") unless memcache
  unless memcache.is_a?(Dalli::Client)
    if defined?(ActiveSupport::Cache::DalliStore) && memcache.is_a?(ActiveSupport::Cache::DalliStore)
      # Big hack to get the MemCache object from Rails.cache
      @memcache = memcache.instance_variable_get(:@data)
    else
      raise ArgumentError.new("#{memcache} is not a Dalli::Client")
    end
  else
    @memcache = memcache
  end
  @alias = options[:alias]
end

Instance Method Details

#call(status) ⇒ Object 



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# File 'lib/is_it_working/checks/dalli_check.rb', line 35

def call(status)
  servers = @memcache.send(:ring).servers
  servers.each_with_index do |server, i|
    public_host_name = @alias ? "#{@alias} #{i + 1}" : "#{server.hostname}:#{server.port}"

    if server.alive?
      status.ok("#{public_host_name} is available")
    else
      status.fail("#{public_host_name} is not available")
    end
  end
end