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
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
Advertise cache versioning support.
# File lib/active_support/cache/memory_store.rb, line 34 def self.supports_cache_versioning? true 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 48 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 39 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 90 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 95 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 85 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 61 def prune(target_size, max_time = nil) return if pruning? @pruning = true begin start_time = Concurrent.monotonic_time 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 && Concurrent.monotonic_time - 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 80 def pruning? @pruning end
Private Instance Methods
# File lib/active_support/cache/memory_store.rb, line 119 def cached_size(key, entry) key.to_s.bytesize + entry.size + PER_ENTRY_OVERHEAD end
# File lib/active_support/cache/memory_store.rb, line 154 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 163 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 123 def read_entry(key, **options) entry = @data[key] synchronize do if entry entry = entry.dup entry.dup_value! @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 137 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