Class: ActiveSupport::Cache::DalliStore

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

Defined Under Namespace

Modules: LocalCacheEntryUnwrapAndRaw

Constant Summary collapse

ESCAPE_KEY_CHARS = 
/[\x00-\x20%\x7F-\xFF]/

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(*addresses) ⇒ DalliStore

Creates a new DalliStore object, with the given memcached server addresses. Each address is either a host name, or a host-with-port string in the form of “host_name:port”. For example:

ActiveSupport::Cache::DalliStore.new("localhost", "server-downstairs.localnetwork:8229")

If no addresses are specified, then DalliStore will connect to localhost port 11211 (the default memcached port).

Connection Pool support

If you are using multithreaded Rails, the Rails.cache singleton can become a source of contention. You can use a connection pool of Dalli clients with Rails.cache by passing :pool_size and/or :pool_timeout:

config.cache_store = :dalli_store, ‘localhost:11211’, :pool_size => 10

Both pool options default to 5. You must include the ‘connection_pool` gem if you wish to use pool support.



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# File 'lib/active_support/cache/dalli_store.rb', line 47

def initialize(*addresses)
  addresses = addresses.flatten
  options = addresses.extract_options!
  @options = options.dup

  pool_options = {}
  pool_options[:size] = options[:pool_size] if options[:pool_size]
  pool_options[:timeout] = options[:pool_timeout] if options[:pool_timeout]

  @options[:compress] ||= @options[:compression]

  addresses.compact!
  servers = if addresses.empty?
              nil # use the default from Dalli::Client
            else
              addresses
            end
  if pool_options.empty?
    @data = Dalli::Client.new(servers, @options)
  else
    @data = ::ConnectionPool.new(pool_options) { Dalli::Client.new(servers, @options.merge(:threadsafe => false)) }
  end

  extend Strategy::LocalCache
  extend LocalCacheEntryUnwrapAndRaw
end

Instance Attribute Details

#options ⇒ Object (readonly)

Returns the value of attribute options.



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# File 'lib/active_support/cache/dalli_store.rb', line 8

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/dalli_store.rb', line 8

def silence
  @silence
end

Instance Method Details

#cleanup(options = nil) ⇒ Object

Clear any local cache



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# File 'lib/active_support/cache/dalli_store.rb', line 274

def cleanup(options=nil)
end

#clear(options = nil) ⇒ Object

Clear the entire cache on all memcached servers. This method should be used with care when using a shared cache.



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# File 'lib/active_support/cache/dalli_store.rb', line 263

def clear(options=nil)
  instrument(:clear, 'flushing all keys') do
    with { |c| c.flush_all }
  end
rescue Dalli::DalliError => e
  logger.error("DalliError: #{e.message}") if logger
  raise if raise_errors?
  nil
end

#dalli ⇒ Object

Access the underlying Dalli::Client or ConnectionPool instance for access to get_multi, etc.



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# File 'lib/active_support/cache/dalli_store.rb', line 77

def dalli
  @data
end

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

Decrement a cached value. This method uses the memcached decr atomic operator and can only be used on values written with the :raw option. Calling it on a value not stored with :raw will fail. :initial defaults to zero, as if the counter was initially zero. memcached counters cannot hold negative values.



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# File 'lib/active_support/cache/dalli_store.rb', line 247

def decrement(name, amount = 1, options=nil)
  options ||= {}
  name = namespaced_key(name, options)
  initial = options.has_key?(:initial) ? options[:initial] : 0
  expires_in = options[:expires_in]
  instrument(:decrement, name, :amount => amount) do
    with { |c| c.decr(name, amount, expires_in, initial) }
  end
rescue Dalli::DalliError => e
  logger.error("DalliError: #{e.message}") if logger
  raise if raise_errors?
  nil
end

#delete(name, options = nil) ⇒ Object 



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# File 'lib/active_support/cache/dalli_store.rb', line 157

def delete(name, options=nil)
  options ||= {}
  name = namespaced_key(name, options)

  instrument(:delete, name, options) do |payload|
    delete_entry(name, options)
  end
end

#exist?(name, options = nil) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_support/cache/dalli_store.rb', line 149

def exist?(name, options=nil)
  options ||= {}
  name = namespaced_key(name, options)

  log(:exist, name, options)
  !read_entry(name, options).nil?
end

#fetch(name, options = nil) ⇒ Object

Fetch the value associated with the key. If a value is found, then it is returned.

If a value is not found and no block is given, then nil is returned.

If a value is not found (or if the found value is nil and :cache_nils is false) and a block is given, the block will be invoked and its return value written to the cache and returned.



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# File 'lib/active_support/cache/dalli_store.rb', line 93

def fetch(name, options=nil)
  options ||= {}
  options[:cache_nils] = true if @options[:cache_nils]
  namespaced_name = namespaced_key(name, options)
  not_found = options[:cache_nils] ? Dalli::Server::NOT_FOUND : nil
  if block_given?
    entry = not_found
    unless options[:force]
      entry = instrument(:read, namespaced_name, options) do |payload|
        read_entry(namespaced_name, options).tap do |result|
          if payload
            payload[:super_operation] = :fetch
            payload[:hit] = result != not_found
          end
        end
      end
    end

    if entry == not_found
      result = instrument(:generate, namespaced_name, options) do |payload|
        yield
      end
      write(name, result, options)
      result
    else
      instrument(:fetch_hit, namespaced_name, options) { |payload| }
      entry
    end
  else
    read(name, options)
  end
end

#fetch_multi(*names) ⇒ Object

Fetches data from the cache, using the given keys. If there is data in the cache with the given keys, then that data is returned. Otherwise, the supplied block is called for each key for which there was no data, and the result will be written to the cache and returned.



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# File 'lib/active_support/cache/dalli_store.rb', line 198

def fetch_multi(*names)
  options = names.extract_options!
  mapping = names.inject({}) { |memo, name| memo[namespaced_key(name, options)] = name; memo }

  instrument(:fetch_multi, mapping.keys) do
    with do |connection|
      results = connection.get_multi(mapping.keys)

      connection.multi do
        mapping.inject({}) do |memo, (expanded, name)|
          memo[name] = results[expanded]
          if memo[name].nil?
            value = yield(name)
            memo[name] = value
            options = options.merge(:connection => connection)
            write_entry(expanded, value, options)
          end

          memo
        end
      end
    end
  end
end

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

Increment a cached value. This method uses the memcached incr atomic operator and can only be used on values written with the :raw option. Calling it on a value not stored with :raw will fail. :initial defaults to the amount passed in, as if the counter was initially zero. memcached counters cannot hold negative values.



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# File 'lib/active_support/cache/dalli_store.rb', line 228

def increment(name, amount = 1, options=nil)
  options ||= {}
  name = namespaced_key(name, options)
  initial = options.has_key?(:initial) ? options[:initial] : amount
  expires_in = options[:expires_in]
  instrument(:increment, name, :amount => amount) do
    with { |c| c.incr(name, amount, expires_in, initial) }
  end
rescue Dalli::DalliError => e
  logger.error("DalliError: #{e.message}") if logger
  raise if raise_errors?
  nil
end

#logger ⇒ Object 



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# File 'lib/active_support/cache/dalli_store.rb', line 286

def logger
  Dalli.logger
end

#logger=(new_logger) ⇒ Object 



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# File 'lib/active_support/cache/dalli_store.rb', line 290

def logger=(new_logger)
  Dalli.logger = new_logger
end

#mute ⇒ Object

Silence the logger within a block.



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# File 'lib/active_support/cache/dalli_store.rb', line 18

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

#read(name, options = nil) ⇒ Object 



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

def read(name, options=nil)
  options ||= {}
  name = namespaced_key(name, options)

  instrument(:read, name, options) do |payload|
    entry = read_entry(name, options)
    payload[:hit] = !entry.nil? if payload
    entry
  end
end

#read_multi(*names) ⇒ Object

Reads multiple keys from the cache using a single call to the servers for all keys. Keys must be Strings.



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# File 'lib/active_support/cache/dalli_store.rb', line 168

def read_multi(*names)
  options  = names.extract_options!
  mapping = names.inject({}) { |memo, name| memo[namespaced_key(name, options)] = name; memo }
  instrument(:read_multi, mapping.keys) do
    results = {}
    if local_cache
      mapping.each_key do |key|
        if value = local_cache.read_entry(key, options)
          results[key] = value
        end
      end
    end

    data = with { |c| c.get_multi(mapping.keys - results.keys) }
    results.merge!(data)
    results.inject({}) do |memo, (inner, _)|
      entry = results[inner]
      # NB Backwards data compatibility, to be removed at some point
      value = (entry.is_a?(ActiveSupport::Cache::Entry) ? entry.value : entry)
      memo[mapping[inner]] = value
      local_cache.write_entry(inner, value, options) if local_cache
      memo
    end
  end
end

#reset ⇒ Object 



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# File 'lib/active_support/cache/dalli_store.rb', line 282

def reset
  with { |c| c.reset }
end

#silence! ⇒ Object

Silence the logger.



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# File 'lib/active_support/cache/dalli_store.rb', line 12

def silence!
  @silence = true
  self
end

#stats ⇒ Object

Get the statistics from the memcached servers.



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# File 'lib/active_support/cache/dalli_store.rb', line 278

def stats
  with { |c| c.stats }
end

#with(&block) ⇒ Object 



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# File 'lib/active_support/cache/dalli_store.rb', line 81

def with(&block)
  @data.with(&block)
end

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



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# File 'lib/active_support/cache/dalli_store.rb', line 137

def write(name, value, options=nil)
  options ||= {}
  name = namespaced_key(name, options)

  instrument(:write, name, options) do |payload|
    with do |connection|
      options = options.merge(:connection => connection)
      write_entry(name, value, options)
    end
  end
end