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 }

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 50

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] = ':'
    @namespace_length = client_options[:prefix_key].length + 1
  else
    @namespace_length = 0
  end
  client_options[:default_ttl] = options.delete(:expires_in).to_i if options[:expires_in]

  @options = options.reverse_merge(compress_threshold: DEFAULT_COMPRESS_THRESHOLD)
  @addresses = addresses
  @cache = Memcached.new(@addresses, client_options.reverse_merge(DEFAULT_CLIENT_OPTIONS))
  @cache.instance_eval { send(:extend, GetWithFlags) }
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 26

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 33

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 33

def silence
  @silence
end

Instance Method Details

#clear(options = nil) ⇒ Object 



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# File 'lib/active_support/cache/libmemcached_store.rb', line 171

def clear(options = nil)
  @cache.flush
end

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



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# File 'lib/active_support/cache/libmemcached_store.rb', line 143

def decrement(key, amount = 1, options = nil)
  key = expanded_key(key)
  instrument(:decrement, key, amount: amount) do
    @cache.decr(escape_and_normalize(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 110

def delete(key, options = nil)
  key = expanded_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 117

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

#fetch(key, options = nil) ⇒ Object 



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# File 'lib/active_support/cache/libmemcached_store.rb', line 69

def fetch(key, options = nil)
  if block_given?
    key = expanded_key(key)
    unless options && options[:force]
      entry = instrument(:read, key, options) do |payload|
        payload[:super_operation] = :fetch if payload
        read_entry(key, options)
      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
  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 131

def increment(key, amount = 1, options = nil)
  key = expanded_key(key)
  instrument(:increment, key, amount: amount) do
    @cache.incr(escape_and_normalize(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 43

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 94

def read(key, options = nil)
  key = expanded_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 155

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

  return {} if names.empty?

  mapping = Hash[names.map {|name| [escape_and_normalize(expanded_key(name)), name] }]
  raw_values, flags = @cache.get(mapping.keys, false, true)

  values = {}
  raw_values.each do |key, value|
    values[mapping[key]] = deserialize(value, options[:raw], flags[key])
  end
  values
end

#silence! ⇒ Object

Silence the logger.



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# File 'lib/active_support/cache/libmemcached_store.rb', line 37

def silence!
  @silence = true
  self
end

#stats ⇒ Object 



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# File 'lib/active_support/cache/libmemcached_store.rb', line 175

def stats
  @cache.stats
end

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



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# File 'lib/active_support/cache/libmemcached_store.rb', line 103

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