class ActiveSupport::Cache::MemoryStore

A cache store implementation which stores everything into memory in the same process. If you're running multiple Ruby on Rails server processes (which is the case if you're using Phusion Passenger or puma clustered mode), then this means that Rails server process instances won't be able to share cache data with each other and this may not be the most appropriate cache in that scenario.

This cache has a bounded size specified by the :size options to the initializer (default is 32Mb). When the cache exceeds the allotted size, a cleanup will occur which tries to prune the cache down to three quarters of the maximum size by removing the least recently used entries.

MemoryStore is thread-safe.

Constants

PER_ENTRY_OVERHEAD

Public Class Methods

new(options = nil) click to toggle source
Calls superclass method ActiveSupport::Cache::Store.new
# File lib/active_support/cache/memory_store.rb, line 21
def initialize(options = nil)
  options ||= {}
  super(options)
  @data = {}
  @key_access = {}
  @max_size = options[:size] || 32.megabytes
  @max_prune_time = options[:max_prune_time] || 2
  @cache_size = 0
  @monitor = Monitor.new
  @pruning = false
end

Public Instance Methods

cleanup(options = nil) click to toggle source

Preemptively iterates through all stored keys and removes the ones which have expired.

# File lib/active_support/cache/memory_store.rb, line 43
def cleanup(options = nil)
  options = merged_options(options)
  instrument(:cleanup, size: @data.size) do
    keys = synchronize { @data.keys }
    keys.each do |key|
      entry = @data[key]
      delete_entry(key, options) if entry && entry.expired?
    end
  end
end
clear(options = nil) click to toggle source

Delete all data stored in a given cache store.

# File lib/active_support/cache/memory_store.rb, line 34
def clear(options = nil)
  synchronize do
    @data.clear
    @key_access.clear
    @cache_size = 0
  end
end
decrement(name, amount = 1, options = nil) click to toggle source

Decrement an integer value in the cache.

# File lib/active_support/cache/memory_store.rb, line 85
def decrement(name, amount = 1, options = nil)
  modify_value(name, -amount, options)
end
delete_matched(matcher, options = nil) click to toggle source

Deletes cache entries if the cache key matches a given pattern.

# File lib/active_support/cache/memory_store.rb, line 90
def delete_matched(matcher, options = nil)
  options = merged_options(options)
  instrument(:delete_matched, matcher.inspect) do
    matcher = key_matcher(matcher, options)
    keys = synchronize { @data.keys }
    keys.each do |key|
      delete_entry(key, options) if key.match(matcher)
    end
  end
end
increment(name, amount = 1, options = nil) click to toggle source

Increment an integer value in the cache.

# File lib/active_support/cache/memory_store.rb, line 80
def increment(name, amount = 1, options = nil)
  modify_value(name, amount, options)
end
prune(target_size, max_time = nil) click to toggle source

To ensure entries fit within the specified memory prune the cache by removing the least recently accessed entries.

# File lib/active_support/cache/memory_store.rb, line 56
def prune(target_size, max_time = nil)
  return if pruning?
  @pruning = true
  begin
    start_time = Time.now
    cleanup
    instrument(:prune, target_size, from: @cache_size) do
      keys = synchronize { @key_access.keys.sort { |a, b| @key_access[a].to_f <=> @key_access[b].to_f } }
      keys.each do |key|
        delete_entry(key, options)
        return if @cache_size <= target_size || (max_time && Time.now - start_time > max_time)
      end
    end
  ensure
    @pruning = false
  end
end
pruning?() click to toggle source

Returns true if the cache is currently being pruned.

# File lib/active_support/cache/memory_store.rb, line 75
def pruning?
  @pruning
end

Private Instance Methods

cached_size(key, entry) click to toggle source
# File lib/active_support/cache/memory_store.rb, line 115
def cached_size(key, entry)
  key.to_s.bytesize + entry.size + PER_ENTRY_OVERHEAD
end
delete_entry(key, options) click to toggle source
# File lib/active_support/cache/memory_store.rb, line 148
def delete_entry(key, options)
  synchronize do
    @key_access.delete(key)
    entry = @data.delete(key)
    @cache_size -= cached_size(key, entry) if entry
    !!entry
  end
end
modify_value(name, amount, options) click to toggle source
# File lib/active_support/cache/memory_store.rb, line 157
def modify_value(name, amount, options)
  synchronize do
    options = merged_options(options)
    if num = read(name, options)
      num = num.to_i + amount
      write(name, num, options)
      num
    end
  end
end
read_entry(key, options) click to toggle source
# File lib/active_support/cache/memory_store.rb, line 119
def read_entry(key, options)
  entry = @data[key]
  synchronize do
    if entry
      @key_access[key] = Time.now.to_f
    else
      @key_access.delete(key)
    end
  end
  entry
end
write_entry(key, entry, options) click to toggle source
# File lib/active_support/cache/memory_store.rb, line 131
def write_entry(key, entry, options)
  entry.dup_value!
  synchronize do
    old_entry = @data[key]
    return false if @data.key?(key) && options[:unless_exist]
    if old_entry
      @cache_size -= (old_entry.size - entry.size)
    else
      @cache_size += cached_size(key, entry)
    end
    @key_access[key] = Time.now.to_f
    @data[key] = entry
    prune(@max_size * 0.75, @max_prune_time) if @cache_size > @max_size
    true
  end
end