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-rw-r--r--activesupport/lib/active_support/cache/mem_cache_store.rb212
1 files changed, 212 insertions, 0 deletions
diff --git a/activesupport/lib/active_support/cache/mem_cache_store.rb b/activesupport/lib/active_support/cache/mem_cache_store.rb
new file mode 100644
index 0000000000..174c784deb
--- /dev/null
+++ b/activesupport/lib/active_support/cache/mem_cache_store.rb
@@ -0,0 +1,212 @@
+# frozen_string_literal: true
+
+begin
+ require "dalli"
+rescue LoadError => e
+ $stderr.puts "You don't have dalli installed in your application. Please add it to your Gemfile and run bundle install"
+ raise e
+end
+
+require "active_support/core_ext/marshal"
+require "active_support/core_ext/array/extract_options"
+
+module ActiveSupport
+ module Cache
+ # A cache store implementation which stores data in Memcached:
+ # https://memcached.org
+ #
+ # This is currently the most popular cache store for production websites.
+ #
+ # Special features:
+ # - Clustering and load balancing. One can specify multiple memcached servers,
+ # and MemCacheStore will load balance between all available servers. If a
+ # server goes down, then MemCacheStore will ignore it until it comes back up.
+ #
+ # MemCacheStore implements the Strategy::LocalCache strategy which implements
+ # an in-memory cache inside of a block.
+ class MemCacheStore < Store
+ # Provide support for raw values in the local cache strategy.
+ module LocalCacheWithRaw # :nodoc:
+ private
+ def read_entry(key, options)
+ entry = super
+ if options[:raw] && local_cache && entry
+ entry = deserialize_entry(entry.value)
+ end
+ entry
+ end
+
+ def write_entry(key, entry, options)
+ if options[:raw] && local_cache
+ raw_entry = Entry.new(entry.value.to_s)
+ raw_entry.expires_at = entry.expires_at
+ super(key, raw_entry, options)
+ else
+ super
+ end
+ end
+ end
+
+ # Advertise cache versioning support.
+ def self.supports_cache_versioning?
+ true
+ end
+
+ prepend Strategy::LocalCache
+ prepend LocalCacheWithRaw
+
+ ESCAPE_KEY_CHARS = /[\x00-\x20%\x7F-\xFF]/n
+
+ # Creates a new Dalli::Client instance with specified addresses and options.
+ # By default address is equal localhost:11211.
+ #
+ # ActiveSupport::Cache::MemCacheStore.build_mem_cache
+ # # => #<Dalli::Client:0x007f98a47d2028 @servers=["localhost:11211"], @options={}, @ring=nil>
+ # ActiveSupport::Cache::MemCacheStore.build_mem_cache('localhost:10290')
+ # # => #<Dalli::Client:0x007f98a47b3a60 @servers=["localhost:10290"], @options={}, @ring=nil>
+ def self.build_mem_cache(*addresses) # :nodoc:
+ addresses = addresses.flatten
+ options = addresses.extract_options!
+ addresses = ["localhost:11211"] if addresses.empty?
+ pool_options = retrieve_pool_options(options)
+
+ if pool_options.empty?
+ Dalli::Client.new(addresses, options)
+ else
+ ensure_connection_pool_added!
+ ConnectionPool.new(pool_options) { Dalli::Client.new(addresses, options.merge(threadsafe: false)) }
+ end
+ end
+
+ # Creates a new MemCacheStore object, with the given memcached server
+ # addresses. Each address is either a host name, or a host-with-port string
+ # in the form of "host_name:port". For example:
+ #
+ # ActiveSupport::Cache::MemCacheStore.new("localhost", "server-downstairs.localnetwork:8229")
+ #
+ # If no addresses are specified, then MemCacheStore will connect to
+ # localhost port 11211 (the default memcached port).
+ def initialize(*addresses)
+ addresses = addresses.flatten
+ options = addresses.extract_options!
+ super(options)
+
+ unless [String, Dalli::Client, NilClass].include?(addresses.first.class)
+ raise ArgumentError, "First argument must be an empty array, an array of hosts or a Dalli::Client instance."
+ end
+ if addresses.first.is_a?(Dalli::Client)
+ @data = addresses.first
+ else
+ mem_cache_options = options.dup
+ UNIVERSAL_OPTIONS.each { |name| mem_cache_options.delete(name) }
+ @data = self.class.build_mem_cache(*(addresses + [mem_cache_options]))
+ end
+ end
+
+ # Increment a cached value. This method uses the memcached incr atomic
+ # operator and can only be used on values written with the :raw option.
+ # Calling it on a value not stored with :raw will initialize that value
+ # to zero.
+ def increment(name, amount = 1, options = nil)
+ options = merged_options(options)
+ instrument(:increment, name, amount: amount) do
+ rescue_error_with nil do
+ @data.with { |c| c.incr(normalize_key(name, options), amount, options[:expires_in]) }
+ end
+ end
+ end
+
+ # Decrement a cached value. This method uses the memcached decr atomic
+ # operator and can only be used on values written with the :raw option.
+ # Calling it on a value not stored with :raw will initialize that value
+ # to zero.
+ def decrement(name, amount = 1, options = nil)
+ options = merged_options(options)
+ instrument(:decrement, name, amount: amount) do
+ rescue_error_with nil do
+ @data.with { |c| c.decr(normalize_key(name, options), amount, options[:expires_in]) }
+ end
+ end
+ end
+
+ # Clear the entire cache on all memcached servers. This method should
+ # be used with care when shared cache is being used.
+ def clear(options = nil)
+ rescue_error_with(nil) { @data.with { |c| c.flush_all } }
+ end
+
+ # Get the statistics from the memcached servers.
+ def stats
+ @data.with { |c| c.stats }
+ end
+
+ private
+ # Read an entry from the cache.
+ def read_entry(key, options)
+ rescue_error_with(nil) { deserialize_entry(@data.with { |c| c.get(key, options) }) }
+ end
+
+ # Write an entry to the cache.
+ def write_entry(key, entry, options)
+ method = options && options[:unless_exist] ? :add : :set
+ value = options[:raw] ? entry.value.to_s : entry
+ expires_in = options[:expires_in].to_i
+ if expires_in > 0 && !options[:raw]
+ # Set the memcache expire a few minutes in the future to support race condition ttls on read
+ expires_in += 5.minutes
+ end
+ rescue_error_with false do
+ @data.with { |c| c.send(method, key, value, expires_in, options) }
+ end
+ end
+
+ # Reads multiple entries from the cache implementation.
+ def read_multi_entries(names, options)
+ keys_to_names = Hash[names.map { |name| [normalize_key(name, options), name] }]
+
+ raw_values = @data.with { |c| c.get_multi(keys_to_names.keys) }
+ values = {}
+
+ raw_values.each do |key, value|
+ entry = deserialize_entry(value)
+
+ unless entry.expired? || entry.mismatched?(normalize_version(keys_to_names[key], options))
+ values[keys_to_names[key]] = entry.value
+ end
+ end
+
+ values
+ end
+
+ # Delete an entry from the cache.
+ def delete_entry(key, options)
+ rescue_error_with(false) { @data.with { |c| c.delete(key) } }
+ end
+
+ # Memcache keys are binaries. So we need to force their encoding to binary
+ # before applying the regular expression to ensure we are escaping all
+ # characters properly.
+ def normalize_key(key, options)
+ key = super.dup
+ key = key.force_encoding(Encoding::ASCII_8BIT)
+ key = key.gsub(ESCAPE_KEY_CHARS) { |match| "%#{match.getbyte(0).to_s(16).upcase}" }
+ key = "#{key[0, 213]}:md5:#{ActiveSupport::Digest.hexdigest(key)}" if key.size > 250
+ key
+ end
+
+ def deserialize_entry(raw_value)
+ if raw_value
+ entry = Marshal.load(raw_value) rescue raw_value
+ entry.is_a?(Entry) ? entry : Entry.new(entry)
+ end
+ end
+
+ def rescue_error_with(fallback)
+ yield
+ rescue Dalli::DalliError => e
+ logger.error("DalliError (#{e}): #{e.message}") if logger
+ fallback
+ end
+ end
+ end
+end
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