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fd8c36707f
The `expires_in` option is easy to misremember or mistype as `expire_in` or `expired_in`, with potentially harmful results. If a developer wants to cache a value for only 2 seconds but mistakenly types `expire_in: 2.seconds`, that value will instead be cached for the default time, likely 6 hours, meaning that users of the site will see the same data for much longer than they should, and the only recovery (short of waiting for the 6 hours to elapse) is to manually expire all relevant keys. This commit allows cache stores to recognize these common typos as aliases by normalizing them before consuming the options. In general, we should be careful about adding too many aliases for options to the cache stores, since each option key used by the base Cache::Store class is one fewer key that each cache implementation can customize for itself. This case was approved because of the similarity of the aliases to the root key and the potential damage caused by mistaking them. Fixes #39850.
891 lines
33 KiB
Ruby
891 lines
33 KiB
Ruby
# frozen_string_literal: true
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require "zlib"
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require "active_support/core_ext/array/extract_options"
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require "active_support/core_ext/array/wrap"
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require "active_support/core_ext/enumerable"
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require "active_support/core_ext/module/attribute_accessors"
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require "active_support/core_ext/numeric/bytes"
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require "active_support/core_ext/numeric/time"
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require "active_support/core_ext/object/to_param"
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require "active_support/core_ext/object/try"
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require "active_support/core_ext/string/inflections"
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module ActiveSupport
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# See ActiveSupport::Cache::Store for documentation.
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module Cache
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autoload :FileStore, "active_support/cache/file_store"
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autoload :MemoryStore, "active_support/cache/memory_store"
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autoload :MemCacheStore, "active_support/cache/mem_cache_store"
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autoload :NullStore, "active_support/cache/null_store"
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autoload :RedisCacheStore, "active_support/cache/redis_cache_store"
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# These options mean something to all cache implementations. Individual cache
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# implementations may support additional options.
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UNIVERSAL_OPTIONS = [:namespace, :compress, :compress_threshold, :expires_in, :expire_in, :expired_in, :race_condition_ttl, :coder, :skip_nil]
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# Mapping of canonical option names to aliases that a store will recognize.
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OPTION_ALIASES = {
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expires_in: [:expire_in, :expired_in]
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}.freeze
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module Strategy
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autoload :LocalCache, "active_support/cache/strategy/local_cache"
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end
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class << self
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# Creates a new Store object according to the given options.
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#
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# If no arguments are passed to this method, then a new
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# ActiveSupport::Cache::MemoryStore object will be returned.
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#
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# If you pass a Symbol as the first argument, then a corresponding cache
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# store class under the ActiveSupport::Cache namespace will be created.
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# For example:
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#
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# ActiveSupport::Cache.lookup_store(:memory_store)
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# # => returns a new ActiveSupport::Cache::MemoryStore object
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#
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# ActiveSupport::Cache.lookup_store(:mem_cache_store)
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# # => returns a new ActiveSupport::Cache::MemCacheStore object
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#
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# Any additional arguments will be passed to the corresponding cache store
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# class's constructor:
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#
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# ActiveSupport::Cache.lookup_store(:file_store, '/tmp/cache')
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# # => same as: ActiveSupport::Cache::FileStore.new('/tmp/cache')
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#
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# If the first argument is not a Symbol, then it will simply be returned:
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#
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# ActiveSupport::Cache.lookup_store(MyOwnCacheStore.new)
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# # => returns MyOwnCacheStore.new
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def lookup_store(store = nil, *parameters)
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case store
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when Symbol
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options = parameters.extract_options!
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retrieve_store_class(store).new(*parameters, **options)
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when Array
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lookup_store(*store)
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when nil
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ActiveSupport::Cache::MemoryStore.new
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else
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store
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end
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end
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# Expands out the +key+ argument into a key that can be used for the
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# cache store. Optionally accepts a namespace, and all keys will be
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# scoped within that namespace.
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#
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# If the +key+ argument provided is an array, or responds to +to_a+, then
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# each of elements in the array will be turned into parameters/keys and
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# concatenated into a single key. For example:
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#
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# ActiveSupport::Cache.expand_cache_key([:foo, :bar]) # => "foo/bar"
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# ActiveSupport::Cache.expand_cache_key([:foo, :bar], "namespace") # => "namespace/foo/bar"
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#
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# The +key+ argument can also respond to +cache_key+ or +to_param+.
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def expand_cache_key(key, namespace = nil)
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expanded_cache_key = namespace ? +"#{namespace}/" : +""
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if prefix = ENV["RAILS_CACHE_ID"] || ENV["RAILS_APP_VERSION"]
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expanded_cache_key << "#{prefix}/"
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end
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expanded_cache_key << retrieve_cache_key(key)
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expanded_cache_key
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end
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private
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def retrieve_cache_key(key)
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case
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when key.respond_to?(:cache_key_with_version) then key.cache_key_with_version
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when key.respond_to?(:cache_key) then key.cache_key
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when key.is_a?(Array) then key.map { |element| retrieve_cache_key(element) }.to_param
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when key.respond_to?(:to_a) then retrieve_cache_key(key.to_a)
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else key.to_param
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end.to_s
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end
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# Obtains the specified cache store class, given the name of the +store+.
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# Raises an error when the store class cannot be found.
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def retrieve_store_class(store)
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# require_relative cannot be used here because the class might be
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# provided by another gem, like redis-activesupport for example.
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require "active_support/cache/#{store}"
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rescue LoadError => e
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raise "Could not find cache store adapter for #{store} (#{e})"
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else
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ActiveSupport::Cache.const_get(store.to_s.camelize)
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end
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end
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# An abstract cache store class. There are multiple cache store
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# implementations, each having its own additional features. See the classes
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# under the ActiveSupport::Cache module, e.g.
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# ActiveSupport::Cache::MemCacheStore. MemCacheStore is currently the most
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# popular cache store for large production websites.
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#
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# Some implementations may not support all methods beyond the basic cache
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# methods of +fetch+, +write+, +read+, +exist?+, and +delete+.
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#
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# ActiveSupport::Cache::Store can store any serializable Ruby object.
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#
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# cache = ActiveSupport::Cache::MemoryStore.new
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#
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# cache.read('city') # => nil
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# cache.write('city', "Duckburgh")
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# cache.read('city') # => "Duckburgh"
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#
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# Keys are always translated into Strings and are case sensitive. When an
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# object is specified as a key and has a +cache_key+ method defined, this
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# method will be called to define the key. Otherwise, the +to_param+
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# method will be called. Hashes and Arrays can also be used as keys. The
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# elements will be delimited by slashes, and the elements within a Hash
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# will be sorted by key so they are consistent.
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#
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# cache.read('city') == cache.read(:city) # => true
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#
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# Nil values can be cached.
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#
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# If your cache is on a shared infrastructure, you can define a namespace
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# for your cache entries. If a namespace is defined, it will be prefixed on
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# to every key. The namespace can be either a static value or a Proc. If it
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# is a Proc, it will be invoked when each key is evaluated so that you can
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# use application logic to invalidate keys.
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#
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# cache.namespace = -> { @last_mod_time } # Set the namespace to a variable
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# @last_mod_time = Time.now # Invalidate the entire cache by changing namespace
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#
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# Cached data larger than 1kB are compressed by default. To turn off
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# compression, pass <tt>compress: false</tt> to the initializer or to
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# individual +fetch+ or +write+ method calls. The 1kB compression
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# threshold is configurable with the <tt>:compress_threshold</tt> option,
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# specified in bytes.
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class Store
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DEFAULT_CODER = Marshal
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cattr_accessor :logger, instance_writer: true
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attr_reader :silence, :options
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alias :silence? :silence
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class << self
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private
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def retrieve_pool_options(options)
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{}.tap do |pool_options|
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pool_options[:size] = options.delete(:pool_size) if options[:pool_size]
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pool_options[:timeout] = options.delete(:pool_timeout) if options[:pool_timeout]
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end
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end
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def ensure_connection_pool_added!
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require "connection_pool"
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rescue LoadError => e
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$stderr.puts "You don't have connection_pool installed in your application. Please add it to your Gemfile and run bundle install"
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raise e
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end
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end
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# Creates a new cache. The options will be passed to any write method calls
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# except for <tt>:namespace</tt> which can be used to set the global
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# namespace for the cache.
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def initialize(options = nil)
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@options = options ? normalize_options(options) : {}
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@coder = @options.delete(:coder) { self.class::DEFAULT_CODER } || NullCoder
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end
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# Silences the logger.
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def silence!
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@silence = true
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self
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end
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# Silences the logger within a block.
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def mute
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previous_silence, @silence = defined?(@silence) && @silence, true
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yield
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ensure
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@silence = previous_silence
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end
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# Fetches data from the cache, using the given key. If there is data in
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# the cache with the given key, then that data is returned.
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#
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# If there is no such data in the cache (a cache miss), then +nil+ will be
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# returned. However, if a block has been passed, that block will be passed
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# the key and executed in the event of a cache miss. The return value of the
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# block will be written to the cache under the given cache key, and that
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# return value will be returned.
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#
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# cache.write('today', 'Monday')
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# cache.fetch('today') # => "Monday"
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#
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# cache.fetch('city') # => nil
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# cache.fetch('city') do
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# 'Duckburgh'
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# end
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# cache.fetch('city') # => "Duckburgh"
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#
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# You may also specify additional options via the +options+ argument.
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# Setting <tt>force: true</tt> forces a cache "miss," meaning we treat
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# the cache value as missing even if it's present. Passing a block is
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# required when +force+ is true so this always results in a cache write.
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#
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# cache.write('today', 'Monday')
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# cache.fetch('today', force: true) { 'Tuesday' } # => 'Tuesday'
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# cache.fetch('today', force: true) # => ArgumentError
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#
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# The +:force+ option is useful when you're calling some other method to
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# ask whether you should force a cache write. Otherwise, it's clearer to
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# just call <tt>Cache#write</tt>.
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#
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# Setting <tt>skip_nil: true</tt> will not cache nil result:
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#
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# cache.fetch('foo') { nil }
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# cache.fetch('bar', skip_nil: true) { nil }
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# cache.exist?('foo') # => true
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# cache.exist?('bar') # => false
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#
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#
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# Setting <tt>compress: false</tt> disables compression of the cache entry.
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#
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# Setting <tt>:expires_in</tt> will set an expiration time on the cache.
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# All caches support auto-expiring content after a specified number of
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# seconds. This value can be specified as an option to the constructor
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# (in which case all entries will be affected), or it can be supplied to
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# the +fetch+ or +write+ method to affect just one entry.
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# <tt>:expire_in</tt> and <tt>:expired_in</tt> are aliases for
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# <tt>:expires_in</tt>.
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#
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# cache = ActiveSupport::Cache::MemoryStore.new(expires_in: 5.minutes)
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# cache.write(key, value, expires_in: 1.minute) # Set a lower value for one entry
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#
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# Setting <tt>:version</tt> verifies the cache stored under <tt>name</tt>
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# is of the same version. nil is returned on mismatches despite contents.
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# This feature is used to support recyclable cache keys.
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#
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# Setting <tt>:race_condition_ttl</tt> is very useful in situations where
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# a cache entry is used very frequently and is under heavy load. If a
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# cache expires and due to heavy load several different processes will try
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# to read data natively and then they all will try to write to cache. To
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# avoid that case the first process to find an expired cache entry will
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# bump the cache expiration time by the value set in <tt>:race_condition_ttl</tt>.
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# Yes, this process is extending the time for a stale value by another few
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# seconds. Because of extended life of the previous cache, other processes
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# will continue to use slightly stale data for a just a bit longer. In the
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# meantime that first process will go ahead and will write into cache the
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# new value. After that all the processes will start getting the new value.
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# The key is to keep <tt>:race_condition_ttl</tt> small.
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#
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# If the process regenerating the entry errors out, the entry will be
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# regenerated after the specified number of seconds. Also note that the
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# life of stale cache is extended only if it expired recently. Otherwise
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# a new value is generated and <tt>:race_condition_ttl</tt> does not play
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# any role.
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#
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# # Set all values to expire after one minute.
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# cache = ActiveSupport::Cache::MemoryStore.new(expires_in: 1.minute)
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#
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# cache.write('foo', 'original value')
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# val_1 = nil
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# val_2 = nil
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# sleep 60
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#
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# Thread.new do
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# val_1 = cache.fetch('foo', race_condition_ttl: 10.seconds) do
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# sleep 1
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# 'new value 1'
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# end
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# end
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#
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# Thread.new do
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# val_2 = cache.fetch('foo', race_condition_ttl: 10.seconds) do
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# 'new value 2'
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# end
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# end
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#
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# cache.fetch('foo') # => "original value"
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# sleep 10 # First thread extended the life of cache by another 10 seconds
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# cache.fetch('foo') # => "new value 1"
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# val_1 # => "new value 1"
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# val_2 # => "original value"
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#
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# Other options will be handled by the specific cache store implementation.
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# Internally, #fetch calls #read_entry, and calls #write_entry on a cache
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# miss. +options+ will be passed to the #read and #write calls.
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#
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# For example, MemCacheStore's #write method supports the +:raw+
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# option, which tells the memcached server to store all values as strings.
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# We can use this option with #fetch too:
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#
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# cache = ActiveSupport::Cache::MemCacheStore.new
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# cache.fetch("foo", force: true, raw: true) do
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# :bar
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# end
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# cache.fetch('foo') # => "bar"
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def fetch(name, options = nil, &block)
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if block_given?
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options = merged_options(options)
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key = normalize_key(name, options)
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entry = nil
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instrument(:read, name, options) do |payload|
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cached_entry = read_entry(key, **options, event: payload) unless options[:force]
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entry = handle_expired_entry(cached_entry, key, options)
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entry = nil if entry && entry.mismatched?(normalize_version(name, options))
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payload[:super_operation] = :fetch if payload
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payload[:hit] = !!entry if payload
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end
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if entry
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get_entry_value(entry, name, options)
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else
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save_block_result_to_cache(name, options, &block)
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end
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elsif options && options[:force]
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raise ArgumentError, "Missing block: Calling `Cache#fetch` with `force: true` requires a block."
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else
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read(name, options)
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end
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end
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# Reads data from the cache, using the given key. If there is data in
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# the cache with the given key, then that data is returned. Otherwise,
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# +nil+ is returned.
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#
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# Note, if data was written with the <tt>:expires_in</tt> or
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# <tt>:version</tt> options, both of these conditions are applied before
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# the data is returned.
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#
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# Options are passed to the underlying cache implementation.
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def read(name, options = nil)
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options = merged_options(options)
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key = normalize_key(name, options)
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version = normalize_version(name, options)
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instrument(:read, name, options) do |payload|
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entry = read_entry(key, **options, event: payload)
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if entry
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if entry.expired?
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delete_entry(key, **options)
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payload[:hit] = false if payload
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nil
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elsif entry.mismatched?(version)
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payload[:hit] = false if payload
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nil
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else
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payload[:hit] = true if payload
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entry.value
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end
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else
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payload[:hit] = false if payload
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nil
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end
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end
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end
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# Reads multiple values at once from the cache. Options can be passed
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# in the last argument.
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#
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# Some cache implementation may optimize this method.
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#
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# Returns a hash mapping the names provided to the values found.
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def read_multi(*names)
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options = names.extract_options!
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options = merged_options(options)
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instrument :read_multi, names, options do |payload|
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read_multi_entries(names, **options, event: payload).tap do |results|
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payload[:hits] = results.keys
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end
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end
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end
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# Cache Storage API to write multiple values at once.
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def write_multi(hash, options = nil)
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options = merged_options(options)
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instrument :write_multi, hash, options do |payload|
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entries = hash.each_with_object({}) do |(name, value), memo|
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memo[normalize_key(name, options)] = Entry.new(value, **options.merge(version: normalize_version(name, options)))
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end
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write_multi_entries entries, **options
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end
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end
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# Fetches data from the cache, using the given keys. If there is data in
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# the cache with the given keys, then that data is returned. Otherwise,
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# the supplied block is called for each key for which there was no data,
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# and the result will be written to the cache and returned.
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# Therefore, you need to pass a block that returns the data to be written
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# to the cache. If you do not want to write the cache when the cache is
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# not found, use #read_multi.
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#
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# Returns a hash with the data for each of the names. For example:
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#
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# cache.write("bim", "bam")
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# cache.fetch_multi("bim", "unknown_key") do |key|
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# "Fallback value for key: #{key}"
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# end
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# # => { "bim" => "bam",
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# # "unknown_key" => "Fallback value for key: unknown_key" }
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#
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# Options are passed to the underlying cache implementation. For example:
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#
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# cache.fetch_multi("fizz", expires_in: 5.seconds) do |key|
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# "buzz"
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# end
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# # => {"fizz"=>"buzz"}
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# cache.read("fizz")
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# # => "buzz"
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# sleep(6)
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# cache.read("fizz")
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# # => nil
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def fetch_multi(*names)
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raise ArgumentError, "Missing block: `Cache#fetch_multi` requires a block." unless block_given?
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options = names.extract_options!
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options = merged_options(options)
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instrument :read_multi, names, options do |payload|
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reads = read_multi_entries(names, **options)
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writes = {}
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ordered = names.index_with do |name|
|
|
reads.fetch(name) { writes[name] = yield(name) }
|
|
end
|
|
|
|
payload[:hits] = reads.keys
|
|
payload[:super_operation] = :fetch_multi
|
|
|
|
write_multi(writes, options)
|
|
|
|
ordered
|
|
end
|
|
end
|
|
|
|
# Writes the value to the cache, with the key.
|
|
#
|
|
# Options are passed to the underlying cache implementation.
|
|
def write(name, value, options = nil)
|
|
options = merged_options(options)
|
|
|
|
instrument(:write, name, options) do
|
|
entry = Entry.new(value, **options.merge(version: normalize_version(name, options)))
|
|
write_entry(normalize_key(name, options), entry, **options)
|
|
end
|
|
end
|
|
|
|
# Deletes an entry in the cache. Returns +true+ if an entry is deleted.
|
|
#
|
|
# Options are passed to the underlying cache implementation.
|
|
def delete(name, options = nil)
|
|
options = merged_options(options)
|
|
|
|
instrument(:delete, name) do
|
|
delete_entry(normalize_key(name, options), **options)
|
|
end
|
|
end
|
|
|
|
# Deletes multiple entries in the cache.
|
|
#
|
|
# Options are passed to the underlying cache implementation.
|
|
def delete_multi(names, options = nil)
|
|
options = merged_options(options)
|
|
names.map! { |key| normalize_key(key, options) }
|
|
|
|
instrument :delete_multi, names do
|
|
delete_multi_entries(names, **options)
|
|
end
|
|
end
|
|
|
|
# Returns +true+ if the cache contains an entry for the given key.
|
|
#
|
|
# Options are passed to the underlying cache implementation.
|
|
def exist?(name, options = nil)
|
|
options = merged_options(options)
|
|
|
|
instrument(:exist?, name) do |payload|
|
|
entry = read_entry(normalize_key(name, options), **options, event: payload)
|
|
(entry && !entry.expired? && !entry.mismatched?(normalize_version(name, options))) || false
|
|
end
|
|
end
|
|
|
|
# Deletes all entries with keys matching the pattern.
|
|
#
|
|
# Options are passed to the underlying cache implementation.
|
|
#
|
|
# Some implementations may not support this method.
|
|
def delete_matched(matcher, options = nil)
|
|
raise NotImplementedError.new("#{self.class.name} does not support delete_matched")
|
|
end
|
|
|
|
# Increments an integer value in the cache.
|
|
#
|
|
# Options are passed to the underlying cache implementation.
|
|
#
|
|
# Some implementations may not support this method.
|
|
def increment(name, amount = 1, options = nil)
|
|
raise NotImplementedError.new("#{self.class.name} does not support increment")
|
|
end
|
|
|
|
# Decrements an integer value in the cache.
|
|
#
|
|
# Options are passed to the underlying cache implementation.
|
|
#
|
|
# Some implementations may not support this method.
|
|
def decrement(name, amount = 1, options = nil)
|
|
raise NotImplementedError.new("#{self.class.name} does not support decrement")
|
|
end
|
|
|
|
# Cleanups the cache by removing expired entries.
|
|
#
|
|
# Options are passed to the underlying cache implementation.
|
|
#
|
|
# Some implementations may not support this method.
|
|
def cleanup(options = nil)
|
|
raise NotImplementedError.new("#{self.class.name} does not support cleanup")
|
|
end
|
|
|
|
# Clears the entire cache. Be careful with this method since it could
|
|
# affect other processes if shared cache is being used.
|
|
#
|
|
# The options hash is passed to the underlying cache implementation.
|
|
#
|
|
# Some implementations may not support this method.
|
|
def clear(options = nil)
|
|
raise NotImplementedError.new("#{self.class.name} does not support clear")
|
|
end
|
|
|
|
private
|
|
# Adds the namespace defined in the options to a pattern designed to
|
|
# match keys. Implementations that support delete_matched should call
|
|
# this method to translate a pattern that matches names into one that
|
|
# matches namespaced keys.
|
|
def key_matcher(pattern, options) # :doc:
|
|
prefix = options[:namespace].is_a?(Proc) ? options[:namespace].call : options[:namespace]
|
|
if prefix
|
|
source = pattern.source
|
|
if source.start_with?("^")
|
|
source = source[1, source.length]
|
|
else
|
|
source = ".*#{source[0, source.length]}"
|
|
end
|
|
Regexp.new("^#{Regexp.escape(prefix)}:#{source}", pattern.options)
|
|
else
|
|
pattern
|
|
end
|
|
end
|
|
|
|
# Reads an entry from the cache implementation. Subclasses must implement
|
|
# this method.
|
|
def read_entry(key, **options)
|
|
raise NotImplementedError.new
|
|
end
|
|
|
|
# Writes an entry to the cache implementation. Subclasses must implement
|
|
# this method.
|
|
def write_entry(key, entry, **options)
|
|
raise NotImplementedError.new
|
|
end
|
|
|
|
def serialize_entry(entry)
|
|
@coder.dump(entry)
|
|
end
|
|
|
|
def deserialize_entry(payload)
|
|
payload.nil? ? nil : @coder.load(payload)
|
|
end
|
|
|
|
# Reads multiple entries from the cache implementation. Subclasses MAY
|
|
# implement this method.
|
|
def read_multi_entries(names, **options)
|
|
names.each_with_object({}) do |name, results|
|
|
key = normalize_key(name, options)
|
|
entry = read_entry(key, **options)
|
|
|
|
next unless entry
|
|
|
|
version = normalize_version(name, options)
|
|
|
|
if entry.expired?
|
|
delete_entry(key, **options)
|
|
elsif !entry.mismatched?(version)
|
|
results[name] = entry.value
|
|
end
|
|
end
|
|
end
|
|
|
|
# Writes multiple entries to the cache implementation. Subclasses MAY
|
|
# implement this method.
|
|
def write_multi_entries(hash, **options)
|
|
hash.each do |key, entry|
|
|
write_entry key, entry, **options
|
|
end
|
|
end
|
|
|
|
# Deletes an entry from the cache implementation. Subclasses must
|
|
# implement this method.
|
|
def delete_entry(key, **options)
|
|
raise NotImplementedError.new
|
|
end
|
|
|
|
# Deletes multiples entries in the cache implementation. Subclasses MAY
|
|
# implement this method.
|
|
def delete_multi_entries(entries, **options)
|
|
entries.count { |key| delete_entry(key, **options) }
|
|
end
|
|
|
|
# Merges the default options with ones specific to a method call.
|
|
def merged_options(call_options)
|
|
if call_options
|
|
call_options = normalize_options(call_options)
|
|
if options.empty?
|
|
call_options
|
|
else
|
|
options.merge(call_options)
|
|
end
|
|
else
|
|
options
|
|
end
|
|
end
|
|
|
|
# Normalize aliased options to their canonical form
|
|
def normalize_options(options)
|
|
options = options.dup
|
|
OPTION_ALIASES.each do |canonical_name, aliases|
|
|
alias_key = aliases.detect { |key| options.key?(key) }
|
|
options[canonical_name] ||= options[alias_key] if alias_key
|
|
options.except!(*aliases)
|
|
end
|
|
options
|
|
end
|
|
|
|
# Expands and namespaces the cache key. May be overridden by
|
|
# cache stores to do additional normalization.
|
|
def normalize_key(key, options = nil)
|
|
namespace_key expanded_key(key), options
|
|
end
|
|
|
|
# Prefix the key with a namespace string:
|
|
#
|
|
# namespace_key 'foo', namespace: 'cache'
|
|
# # => 'cache:foo'
|
|
#
|
|
# With a namespace block:
|
|
#
|
|
# namespace_key 'foo', namespace: -> { 'cache' }
|
|
# # => 'cache:foo'
|
|
def namespace_key(key, options = nil)
|
|
options = merged_options(options)
|
|
namespace = options[:namespace]
|
|
|
|
if namespace.respond_to?(:call)
|
|
namespace = namespace.call
|
|
end
|
|
|
|
if key && key.encoding != Encoding::UTF_8
|
|
key = key.dup.force_encoding(Encoding::UTF_8)
|
|
end
|
|
|
|
if namespace
|
|
"#{namespace}:#{key}"
|
|
else
|
|
key
|
|
end
|
|
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.
|
|
def expanded_key(key)
|
|
return key.cache_key.to_s if key.respond_to?(:cache_key)
|
|
|
|
case key
|
|
when Array
|
|
if key.size > 1
|
|
key.collect { |element| expanded_key(element) }
|
|
else
|
|
expanded_key(key.first)
|
|
end
|
|
when Hash
|
|
key.collect { |k, v| "#{k}=#{v}" }.sort!
|
|
else
|
|
key
|
|
end.to_param
|
|
end
|
|
|
|
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) }.tap(&:compact!).to_param
|
|
when key.respond_to?(:to_a) then expanded_version(key.to_a)
|
|
end
|
|
end
|
|
|
|
def instrument(operation, key, options = nil)
|
|
if logger && logger.debug? && !silence?
|
|
logger.debug "Cache #{operation}: #{normalize_key(key, options)}#{options.blank? ? "" : " (#{options.inspect})"}"
|
|
end
|
|
|
|
payload = { key: key, store: self.class.name }
|
|
payload.merge!(options) if options.is_a?(Hash)
|
|
ActiveSupport::Notifications.instrument("cache_#{operation}.active_support", payload) { yield(payload) }
|
|
end
|
|
|
|
def handle_expired_entry(entry, key, options)
|
|
if entry && entry.expired?
|
|
race_ttl = options[:race_condition_ttl].to_i
|
|
if (race_ttl > 0) && (Time.now.to_f - entry.expires_at <= race_ttl)
|
|
# When an entry has a positive :race_condition_ttl defined, put the stale entry back into the cache
|
|
# for a brief period while the entry is being recalculated.
|
|
entry.expires_at = Time.now + race_ttl
|
|
write_entry(key, entry, expires_in: race_ttl * 2)
|
|
else
|
|
delete_entry(key, **options)
|
|
end
|
|
entry = nil
|
|
end
|
|
entry
|
|
end
|
|
|
|
def get_entry_value(entry, name, options)
|
|
instrument(:fetch_hit, name, options) { }
|
|
entry.value
|
|
end
|
|
|
|
def save_block_result_to_cache(name, options)
|
|
result = instrument(:generate, name, options) do
|
|
yield(name)
|
|
end
|
|
|
|
write(name, result, options) unless result.nil? && options[:skip_nil]
|
|
result
|
|
end
|
|
end
|
|
|
|
module NullCoder # :nodoc:
|
|
class << self
|
|
def load(payload)
|
|
payload
|
|
end
|
|
|
|
def dump(entry)
|
|
entry
|
|
end
|
|
end
|
|
end
|
|
|
|
# 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 = 1.kilobyte
|
|
|
|
# Creates a new cache entry for the specified value. Options supported are
|
|
# +:compress+, +:compress_threshold+, +:version+ and +:expires_in+.
|
|
def initialize(value, compress: true, compress_threshold: DEFAULT_COMPRESS_LIMIT, version: nil, expires_in: nil, **)
|
|
@value = value
|
|
@version = version
|
|
@created_at = Time.now.to_f
|
|
@expires_in = expires_in && expires_in.to_f
|
|
|
|
compress!(compress_threshold) if compress
|
|
end
|
|
|
|
def value
|
|
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?
|
|
@expires_in && @created_at + @expires_in <= Time.now.to_f
|
|
end
|
|
|
|
def expires_at
|
|
@expires_in ? @created_at + @expires_in : nil
|
|
end
|
|
|
|
def expires_at=(value)
|
|
if value
|
|
@expires_in = value.to_f - @created_at
|
|
else
|
|
@expires_in = nil
|
|
end
|
|
end
|
|
|
|
# Returns the size of the cached value. This could be less than
|
|
# <tt>value.bytesize</tt> if the data is compressed.
|
|
def bytesize
|
|
case value
|
|
when NilClass
|
|
0
|
|
when String
|
|
@value.bytesize
|
|
else
|
|
@s ||= Marshal.dump(@value).bytesize
|
|
end
|
|
end
|
|
|
|
# Duplicates the value in a class. This is used by cache implementations that don't natively
|
|
# serialize entries to protect against accidental cache modifications.
|
|
def dup_value!
|
|
if @value && !compressed? && !(@value.is_a?(Numeric) || @value == true || @value == false)
|
|
if @value.is_a?(String)
|
|
@value = @value.dup
|
|
else
|
|
@value = Marshal.load(Marshal.dump(@value))
|
|
end
|
|
end
|
|
end
|
|
|
|
private
|
|
def compress!(compress_threshold)
|
|
case @value
|
|
when nil, true, false, Numeric
|
|
uncompressed_size = 0
|
|
when String
|
|
uncompressed_size = @value.bytesize
|
|
else
|
|
serialized = Marshal.dump(@value)
|
|
uncompressed_size = serialized.bytesize
|
|
end
|
|
|
|
if uncompressed_size >= compress_threshold
|
|
serialized ||= Marshal.dump(@value)
|
|
compressed = Zlib::Deflate.deflate(serialized)
|
|
|
|
if compressed.bytesize < uncompressed_size
|
|
@value = compressed
|
|
@compressed = true
|
|
end
|
|
end
|
|
end
|
|
|
|
def compressed?
|
|
defined?(@compressed)
|
|
end
|
|
|
|
def uncompress(value)
|
|
Marshal.load(Zlib::Inflate.inflate(value))
|
|
end
|
|
end
|
|
end
|
|
end
|