Class: ActiveSupport::Cache::MemCacheStore
- Includes:
- DupLocalCache, Strategy::LocalCache
- Defined in:
- lib/active_support/cache/mem_cache_store.rb
Overview
A cache store implementation which stores data in Memcached: 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.
Defined Under Namespace
Modules: Coders, DupLocalCache
Constant Summary collapse
- ESCAPE_KEY_CHARS =
/[\x00-\x20%\x7F-\xFF]/n
Instance Attribute Summary
Attributes inherited from Store
Class Method Summary collapse
-
.build_mem_cache(*addresses) ⇒ Object
Creates a new Dalli::Client instance with specified addresses and options.
-
.supports_cache_versioning? ⇒ Boolean
Advertise cache versioning support.
Instance Method Summary collapse
-
#clear(options = nil) ⇒ Object
Clear the entire cache on all memcached servers.
-
#decrement(name, amount = 1, options = nil) ⇒ Object
Decrement a cached value.
-
#increment(name, amount = 1, options = nil) ⇒ Object
Increment a cached value.
-
#initialize(*addresses) ⇒ MemCacheStore
constructor
Creates a new MemCacheStore object, with the given memcached server addresses.
-
#stats ⇒ Object
Get the statistics from the memcached servers.
Methods included from Strategy::LocalCache
#cleanup, #delete_matched, #middleware, #with_local_cache
Methods inherited from Store
#cleanup, #delete, #delete_matched, #delete_multi, #exist?, #fetch, #fetch_multi, #mute, #new_entry, #read, #read_multi, #silence!, #write, #write_multi
Constructor Details
#initialize(*addresses) ⇒ MemCacheStore
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 provided, but ENV is defined, it will be used instead. Otherwise, MemCacheStore will connect to localhost:11211 (the default memcached port).
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# File 'lib/active_support/cache/mem_cache_store.rb', line 109 def initialize(*addresses) addresses = addresses.flatten = addresses. if .key?(:cache_nils) [:skip_nil] = !.delete(:cache_nils) end super() 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 = .dup # The value "compress: false" prevents duplicate compression within Dalli. [:compress] = false (UNIVERSAL_OPTIONS - %i(compress)).each { |name| .delete(name) } @data = self.class.build_mem_cache(*(addresses + [])) end end |
Class Method Details
.build_mem_cache(*addresses) ⇒ Object
Creates a new Dalli::Client instance with specified addresses and options. If no addresses are provided, we give nil to Dalli::Client, so it uses its fallbacks:
-
ENV (if defined)
-
“127.0.0.1:11211” (otherwise)
ActiveSupport::Cache::MemCacheStore.build_mem_cache
# => #<Dalli::Client:0x007f98a47d2028 @servers=["127.0.0.1:11211"], @options={}, @ring=nil>
ActiveSupport::Cache::MemCacheStore.build_mem_cache(‘localhost:10290’)
# => #<Dalli::Client:0x007f98a47b3a60 @servers=["localhost:10290"], @options={}, @ring=nil>
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# File 'lib/active_support/cache/mem_cache_store.rb', line 87 def self.build_mem_cache(*addresses) # :nodoc: addresses = addresses.flatten = addresses. addresses = nil if addresses.compact.empty? = () if .empty? Dalli::Client.new(addresses, ) else ensure_connection_pool_added! ConnectionPool.new() { Dalli::Client.new(addresses, .merge(threadsafe: false)) } end end |
.supports_cache_versioning? ⇒ Boolean
Advertise cache versioning support.
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# File 'lib/active_support/cache/mem_cache_store.rb', line 30 def self.supports_cache_versioning? true end |
Instance Method Details
#clear(options = nil) ⇒ Object
Clear the entire cache on all memcached servers. This method should be used with care when shared cache is being used.
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# File 'lib/active_support/cache/mem_cache_store.rb', line 159 def clear( = nil) rescue_error_with(nil) { @data.with { |c| c.flush_all } } end |
#decrement(name, amount = 1, options = nil) ⇒ Object
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.
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# File 'lib/active_support/cache/mem_cache_store.rb', line 148 def decrement(name, amount = 1, = nil) = () instrument(:decrement, name, amount: amount) do rescue_error_with nil do @data.with { |c| c.decr(normalize_key(name, ), amount, [:expires_in]) } end end end |
#increment(name, amount = 1, options = nil) ⇒ Object
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.
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# File 'lib/active_support/cache/mem_cache_store.rb', line 135 def increment(name, amount = 1, = nil) = () instrument(:increment, name, amount: amount) do rescue_error_with nil do @data.with { |c| c.incr(normalize_key(name, ), amount, [:expires_in]) } end end end |
#stats ⇒ Object
Get the statistics from the memcached servers.
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# File 'lib/active_support/cache/mem_cache_store.rb', line 164 def stats @data.with { |c| c.stats } end |