diff options
Diffstat (limited to 'activesupport/lib/active_support/cache.rb')
| -rw-r--r-- | activesupport/lib/active_support/cache.rb | 83 |
1 files changed, 62 insertions, 21 deletions
diff --git a/activesupport/lib/active_support/cache.rb b/activesupport/lib/active_support/cache.rb index 4d8c2046e8..44f80dd379 100644 --- a/activesupport/lib/active_support/cache.rb +++ b/activesupport/lib/active_support/cache.rb @@ -88,10 +88,11 @@ module ActiveSupport private def retrieve_cache_key(key) case - when key.respond_to?(:cache_key) then key.cache_key - when key.is_a?(Array) then key.map { |element| retrieve_cache_key(element) }.to_param - when key.respond_to?(:to_a) then retrieve_cache_key(key.to_a) - else key.to_param + when key.respond_to?(:cache_key_with_version) then key.cache_key_with_version + when key.respond_to?(:cache_key) then key.cache_key + when key.is_a?(Array) then key.map { |element| retrieve_cache_key(element) }.to_param + when key.respond_to?(:to_a) then retrieve_cache_key(key.to_a) + else key.to_param end.to_s end @@ -219,6 +220,10 @@ module ActiveSupport # cache = ActiveSupport::Cache::MemoryStore.new(expires_in: 5.minutes) # cache.write(key, value, expires_in: 1.minute) # Set a lower value for one entry # + # Setting <tt>:version</tt> verifies the cache stored under <tt>name</tt> + # is of the same version. nil is returned on mismatches despite contents. + # This feature is used to support recyclable cache keys. + # # Setting <tt>:race_condition_ttl</tt> is very useful in situations where # a cache entry is used very frequently and is under heavy load. If a # cache expires and due to heavy load several different processes will try @@ -287,6 +292,7 @@ module ActiveSupport instrument(:read, name, options) do |payload| cached_entry = read_entry(key, options) unless options[:force] entry = handle_expired_entry(cached_entry, key, options) + entry = nil if entry && entry.mismatched?(normalize_version(name, options)) payload[:super_operation] = :fetch if payload payload[:hit] = !!entry if payload end @@ -303,21 +309,30 @@ module ActiveSupport end end - # Fetches data from the cache, using the given key. If there is data in + # Reads data from the cache, using the given key. If there is data in # the cache with the given key, then that data is returned. Otherwise, # +nil+ is returned. # + # Note, if data was written with the <tt>:expires_in<tt> or <tt>:version</tt> options, + # both of these conditions are applied before the data is returned. + # # Options are passed to the underlying cache implementation. def read(name, options = nil) options = merged_options(options) - key = normalize_key(name, options) + key = normalize_key(name, options) + version = normalize_version(name, options) + instrument(:read, name, options) do |payload| entry = read_entry(key, options) + if entry if entry.expired? delete_entry(key, options) payload[:hit] = false if payload nil + elsif entry.mismatched?(version) + payload[:hit] = false if payload + nil else payload[:hit] = true if payload entry.value @@ -341,11 +356,15 @@ module ActiveSupport results = {} names.each do |name| - key = normalize_key(name, options) - entry = read_entry(key, options) + key = normalize_key(name, options) + version = normalize_version(name, options) + entry = read_entry(key, options) + if entry if entry.expired? delete_entry(key, options) + elsif entry.mismatched?(version) + # Skip mismatched versions else results[name] = entry.value end @@ -396,7 +415,7 @@ module ActiveSupport options = merged_options(options) instrument(:write, name, options) do - entry = Entry.new(value, options) + entry = Entry.new(value, options.merge(version: normalize_version(name, options))) write_entry(normalize_key(name, options), entry, options) end end @@ -420,7 +439,7 @@ module ActiveSupport instrument(:exist?, name) do entry = read_entry(normalize_key(name, options), options) - (entry && !entry.expired?) || false + (entry && !entry.expired? && !entry.mismatched?(normalize_version(name, options))) || false end end @@ -517,6 +536,17 @@ module ActiveSupport end end + + # Prefixes a key with the namespace. Namespace and key will be delimited + # with a colon. + def normalize_key(key, options) + key = expanded_key(key) + namespace = options[:namespace] if options + prefix = namespace.is_a?(Proc) ? namespace.call : namespace + key = "#{prefix}:#{key}" if prefix + key + end + # Expands key to be a consistent string value. Invokes +cache_key+ if # object responds to +cache_key+. Otherwise, +to_param+ method will be # called. If the key is a Hash, then keys will be sorted alphabetically. @@ -537,14 +567,16 @@ module ActiveSupport key.to_param end - # Prefixes a key with the namespace. Namespace and key will be delimited - # with a colon. - def normalize_key(key, options) - key = expanded_key(key) - namespace = options[:namespace] if options - prefix = namespace.is_a?(Proc) ? namespace.call : namespace - key = "#{prefix}:#{key}" if prefix - key + def normalize_version(key, options = nil) + (options && options[:version].try(:to_param)) || expanded_version(key) + end + + def expanded_version(key) + case + when key.respond_to?(:cache_version) then key.cache_version.to_param + when key.is_a?(Array) then key.map { |element| expanded_version(element) }.compact.to_param + when key.respond_to?(:to_a) then expanded_version(key.to_a) + end end def instrument(operation, key, options = nil) @@ -555,6 +587,7 @@ module ActiveSupport ActiveSupport::Notifications.instrument("cache_#{operation}.active_support", payload) { yield(payload) } end + def log return unless logger && logger.debug? && !silence? logger.debug(yield) @@ -591,13 +624,16 @@ module ActiveSupport end end - # This class is used to represent cache entries. Cache entries have a value and an optional - # expiration time. The expiration time is used to support the :race_condition_ttl option - # on the cache. + # This class is used to represent cache entries. Cache entries have a value, an optional + # expiration time, and an optional version. The expiration time is used to support the :race_condition_ttl option + # on the cache. The version is used to support the :version option on the cache for rejecting + # mismatches. # # Since cache entries in most instances will be serialized, the internals of this class are highly optimized # using short instance variable names that are lazily defined. class Entry # :nodoc: + attr_reader :version + DEFAULT_COMPRESS_LIMIT = 16.kilobytes # Creates a new cache entry for the specified value. Options supported are @@ -610,6 +646,7 @@ module ActiveSupport @value = value end + @version = options[:version] @created_at = Time.now.to_f @expires_in = options[:expires_in] @expires_in = @expires_in.to_f if @expires_in @@ -619,6 +656,10 @@ module ActiveSupport compressed? ? uncompress(@value) : @value end + def mismatched?(version) + @version && version && @version != version + end + # Checks if the entry is expired. The +expires_in+ parameter can override # the value set when the entry was created. def expired? |