Class: ActiveSupport::Cache::LibmemcachedStore

Inherits:
Object
  • Object
show all
Defined in:
lib/active_support/cache/libmemcached_store.rb

Overview

Store using memcached gem as client

Global options can be passed to be applied to each method by default. Supported options are

  • :compress : if set to true, data will be compress before stored

  • :compress_threshold : specify the threshold at which to compress

value, default is 4K

  • :namespace : prepend each key with this value for simple namespacing

  • :expires_in : default TTL in seconds for each. Default value is 0, i.e. forever

Specific value can be passed per key with write and fetch command.

Options can also be passed direclty to the memcache client, via the :client option. For example, if you want to use pipelining, you can use :client => { :no_block => true }

Direct Known Subclasses

LibmemcachedLocalStore

Defined Under Namespace

Classes: FetchWithRaceConditionTTLEntry

Constant Summary collapse

DEFAULT_CLIENT_OPTIONS = 
{ distribution: :consistent_ketama, binary_protocol: true, default_ttl: 0 }
ESCAPE_KEY_CHARS = 
/[\x00-\x20%\x7F-\xFF]/n
DEFAULT_COMPRESS_THRESHOLD = 
4096
FLAG_COMPRESSED = 
0x2

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(*addresses) ⇒ LibmemcachedStore

Returns a new instance of LibmemcachedStore.



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# File 'lib/active_support/cache/libmemcached_store.rb', line 67

def initialize(*addresses)
  addresses.flatten!
  options = addresses.extract_options!
  client_options = options.delete(:client) || {}
  if options[:namespace]
    client_options[:prefix_key] = options.delete(:namespace)
    client_options[:prefix_delimiter] = ':'
  end
  @namespace_length = "#{client_options[:prefix_key]}#{client_options[:prefix_delimiter]}".force_encoding("BINARY").size

  client_options[:default_ttl] = options.delete(:expires_in).to_i if options[:expires_in]

  @options = {compress_threshold: DEFAULT_COMPRESS_THRESHOLD}.merge(options)
  @addresses = addresses
  @cache = ::LibmemcachedStore::MemcachedWithFlags.new(@addresses, DEFAULT_CLIENT_OPTIONS.merge(client_options))
end

Instance Attribute Details

#addresses ⇒ Object (readonly)

Returns the value of attribute addresses.



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# File 'lib/active_support/cache/libmemcached_store.rb', line 43

def addresses
  @addresses
end

#options ⇒ Object (readonly)

Returns the value of attribute options.



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# File 'lib/active_support/cache/libmemcached_store.rb', line 50

def options
  @options
end

#silence ⇒ Object (readonly) Also known as: silence?

Returns the value of attribute silence.



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# File 'lib/active_support/cache/libmemcached_store.rb', line 50

def silence
  @silence
end

Instance Method Details

#clear(options = nil) ⇒ Object 



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# File 'lib/active_support/cache/libmemcached_store.rb', line 200

def clear(options = nil)
  instrument(:clear, "*") do
    @cache.flush
  end
end

#decrement(key, amount = 1, options = nil) ⇒ Object 



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# File 'lib/active_support/cache/libmemcached_store.rb', line 166

def decrement(key, amount = 1, options = nil)
  key = normalize_key(key)
  instrument(:decrement, key, amount: amount) do
    @cache.decr(key, amount)
  end
rescue Memcached::NotFound
  nil
rescue Memcached::Error => e
  log_error(e)
  nil
end

#delete(key, options = nil) ⇒ Object 



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# File 'lib/active_support/cache/libmemcached_store.rb', line 133

def delete(key, options = nil)
  key = normalize_key(key)
  instrument(:delete, key) do |payload|
    delete_entry(key, options)
  end
end

#exist?(key, options = nil) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_support/cache/libmemcached_store.rb', line 140

def exist?(key, options = nil)
  key = normalize_key(key)
  instrument(:exist?, key) do |payload|
    if @cache.respond_to?(:exist)
      @cache.exist(key)
      true
    else
      read_entry(key, options) != nil
    end
  end
rescue Memcached::NotFound
  false
end

#fetch(key, options = nil, &block) ⇒ Object 



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# File 'lib/active_support/cache/libmemcached_store.rb', line 84

def fetch(key, options = nil, &block)
  if block_given?
    if options && options[:race_condition_ttl] && options[:expires_in]
      fetch_with_race_condition_ttl(key, options, &block)
    else
      key = normalize_key(key)
      unless options && options[:force]
        entry = instrument(:read, key, options) do |payload|
          read_entry(key, options).tap do |result|
            if payload
              payload[:super_operation] = :fetch
              payload[:hit] = !!result
            end
          end
        end
      end

      if entry.nil?
        result = instrument(:generate, key, options) do |payload|
          yield
        end
        write_entry(key, result, options)
        result
      else
        instrument(:fetch_hit, key, options) { |payload| }
        entry
      end
    end
  else
    read(key, options)
  end
end

#increment(key, amount = 1, options = nil) ⇒ Object 



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# File 'lib/active_support/cache/libmemcached_store.rb', line 154

def increment(key, amount = 1, options = nil)
  key = normalize_key(key)
  instrument(:increment, key, amount: amount) do
    @cache.incr(key, amount)
  end
rescue Memcached::NotFound
  nil
rescue Memcached::Error => e
  log_error(e)
  nil
end

#mute ⇒ Object

Silence the logger within a block.



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# File 'lib/active_support/cache/libmemcached_store.rb', line 60

def mute
  previous_silence, @silence = defined?(@silence) && @silence, true
  yield
ensure
  @silence = previous_silence
end

#read(key, options = nil) ⇒ Object 



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# File 'lib/active_support/cache/libmemcached_store.rb', line 117

def read(key, options = nil)
  key = normalize_key(key)
  instrument(:read, key, options) do |payload|
    entry = read_entry(key, options)
    payload[:hit] = !!entry if payload
    entry
  end
end

#read_multi(*names) ⇒ Object 



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# File 'lib/active_support/cache/libmemcached_store.rb', line 178

def read_multi(*names)
  names.flatten!
  options = names.extract_options!

  return {} if names.empty?

  mapping = Hash[names.map {|name| [normalize_key(name), name] }]
  keys = mapping.keys
  raw_values, flags = instrument(:read_multi, keys, options) do
    @cache.get(keys, false, true)
  end

  values = {}
  raw_values.each do |key, value|
    values[mapping[key]] = convert_race_condition_entry(deserialize(value, options[:raw], flags[key]))
  end
  values
rescue Memcached::Error => e
  log_error(e)
  {}
end

#silence! ⇒ Object

Silence the logger.



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# File 'lib/active_support/cache/libmemcached_store.rb', line 54

def silence!
  @silence = true
  self
end

#stats ⇒ Object 



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# File 'lib/active_support/cache/libmemcached_store.rb', line 206

def stats
  @cache.stats
end

#write(key, value, options = nil) ⇒ Object 



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# File 'lib/active_support/cache/libmemcached_store.rb', line 126

def write(key, value, options = nil)
  key = normalize_key(key)
  instrument(:write, key, options) do |payload|
    write_entry(key, value, options)
  end
end