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
# 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
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
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 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
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 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
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
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
# 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
# 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
# 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
# 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
# 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