client.rb in dalli-3.1.1

- old
+ new

@@ -47,40 +47,55 @@
     #                              pass an alternative implementation using another protocol.
     #
     def initialize(servers = nil, options = {})
       @servers = ::Dalli::ServersArgNormalizer.normalize_servers(servers)
       @options = normalize_options(options)
-      @key_manager = ::Dalli::KeyManager.new(options)
+      @key_manager = ::Dalli::KeyManager.new(@options)
       @ring = nil
     end
 
     #
     # The standard memcached instruction set
     #
 
     ##
-    # Turn on quiet aka noreply support.
-    # All relevant operations within this block will be effectively
-    # pipelined as Dalli will use 'quiet' operations where possible.
-    # Currently supports the set, add, replace and delete operations.
-    def multi
-      old = Thread.current[::Dalli::MULTI_KEY]
-      Thread.current[::Dalli::MULTI_KEY] = true
-      yield
-    ensure
-      @ring&.pipeline_consume_and_ignore_responses
-      Thread.current[::Dalli::MULTI_KEY] = old
+    # Get the value associated with the key.
+    # If a value is not found, then +nil+ is returned.
+    def get(key, req_options = nil)
+      perform(:get, key, req_options)
     end
 
     ##
-    # Get the value associated with the key.
+    # Gat (get and touch) fetch an item and simultaneously update its expiration time.
+    #
     # If a value is not found, then +nil+ is returned.
-    def get(key, options = nil)
-      perform(:get, key, options)
+    def gat(key, ttl = nil)
+      perform(:gat, key, ttl_or_default(ttl))
     end
 
     ##
+    # Touch updates expiration time for a given key.
+    #
+    # Returns true if key exists, otherwise nil.
+    def touch(key, ttl = nil)
+      resp = perform(:touch, key, ttl_or_default(ttl))
+      resp.nil? ? nil : true
+    end
+
+    ##
+    # Get the value and CAS ID associated with the key.  If a block is provided,
+    # value and CAS will be passed to the block.
+    def get_cas(key)
+      (value, cas) = perform(:cas, key)
+      #  TODO: This is odd.  Confirm this is working as expected.
+      value = nil if !value || value == 'Not found'
+      return [value, cas] unless block_given?
+
+      yield value, cas
+    end
+
+    ##
     # Fetch multiple keys efficiently.
     # If a block is given, yields key/value pairs one at a time.
     # Otherwise returns a hash of { 'key' => 'value', 'key2' => 'value1' }
     def get_multi(*keys)
       keys.flatten!
@@ -95,11 +110,25 @@
           pipelined_getter.process(keys) { |k, data| hash[k] = data.first }
         end
       end
     end
 
-    CACHE_NILS = { cache_nils: true }.freeze
+    ##
+    # Fetch multiple keys efficiently, including available metadata such as CAS.
+    # If a block is given, yields key/data pairs one a time.  Data is an array:
+    # [value, cas_id]
+    # If no block is given, returns a hash of
+    #   { 'key' => [value, cas_id] }
+    def get_multi_cas(*keys)
+      if block_given?
+        pipelined_getter.process(keys) { |*args| yield(*args) }
+      else
+        {}.tap do |hash|
+          pipelined_getter.process(keys) { |k, data| hash[k] = data }
+        end
+      end
+    end
 
     # Fetch the value associated with the key.
     # If a value is found, then it is returned.
     #
     # If a value is not found and no block is given, then nil is returned.
@@ -108,25 +137,17 @@
     # and a block is given, the block will be invoked and its return value
     # written to the cache and returned.
     def fetch(key, ttl = nil, req_options = nil)
       req_options = req_options.nil? ? CACHE_NILS : req_options.merge(CACHE_NILS) if cache_nils
       val = get(key, req_options)
-      if not_found?(val) && block_given?
-        val = yield
-        add(key, val, ttl_or_default(ttl), req_options)
-      end
-      val
-    end
+      return val unless block_given? && not_found?(val)
 
-    def not_found?(val)
-      cache_nils ? val == ::Dalli::NOT_FOUND : val.nil?
+      new_val = yield
+      add(key, new_val, ttl_or_default(ttl), req_options)
+      new_val
     end
 
-    def cache_nils
-      @options[:cache_nils]
-    end
-
     ##
     # compare and swap values using optimistic locking.
     # Fetch the existing value for key.
     # If it exists, yield the value to the block.
     # Add the block's return value as the new value for the key.
@@ -134,45 +155,93 @@
     #
     # Returns:
     # - nil if the key did not exist.
     # - false if the value was changed by someone else.
     # - true if the value was successfully updated.
-    def cas(key, ttl = nil, options = nil, &block)
-      cas_core(key, false, ttl, options, &block)
+    def cas(key, ttl = nil, req_options = nil, &block)
+      cas_core(key, false, ttl, req_options, &block)
     end
 
     ##
     # like #cas, but will yield to the block whether or not the value
     # already exists.
     #
     # Returns:
     # - false if the value was changed by someone else.
     # - true if the value was successfully updated.
-    def cas!(key, ttl = nil, options = nil, &block)
-      cas_core(key, true, ttl, options, &block)
+    def cas!(key, ttl = nil, req_options = nil, &block)
+      cas_core(key, true, ttl, req_options, &block)
     end
 
-    def set(key, value, ttl = nil, options = nil)
-      perform(:set, key, value, ttl_or_default(ttl), 0, options)
+    ##
+    # Turn on quiet aka noreply support for a number of
+    # memcached operations.
+    #
+    # All relevant operations within this block will be effectively
+    # pipelined as Dalli will use 'quiet' versions.  The invoked methods
+    # will all return nil, rather than their usual response.  Method
+    # latency will be substantially lower, as the caller will not be
+    # blocking on responses.
+    #
+    # Currently supports storage (set, add, replace, append, prepend),
+    # arithmetic (incr, decr), flush and delete operations.  Use of
+    # unsupported operations inside a block will raise an error.
+    #
+    # Any error replies will be discarded at the end of the block, and
+    # Dalli client methods invoked inside the block will not
+    # have return values
+    def quiet
+      old = Thread.current[::Dalli::QUIET]
+      Thread.current[::Dalli::QUIET] = true
+      yield
+    ensure
+      @ring&.pipeline_consume_and_ignore_responses
+      Thread.current[::Dalli::QUIET] = old
     end
+    alias multi quiet
 
+    def set(key, value, ttl = nil, req_options = nil)
+      set_cas(key, value, 0, ttl, req_options)
+    end
+
     ##
+    # Set the key-value pair, verifying existing CAS.
+    # Returns the resulting CAS value if succeeded, and falsy otherwise.
+    def set_cas(key, value, cas, ttl = nil, req_options = nil)
+      perform(:set, key, value, ttl_or_default(ttl), cas, req_options)
+    end
+
+    ##
     # Conditionally add a key/value pair, if the key does not already exist
     # on the server.  Returns truthy if the operation succeeded.
-    def add(key, value, ttl = nil, options = nil)
-      perform(:add, key, value, ttl_or_default(ttl), options)
+    def add(key, value, ttl = nil, req_options = nil)
+      perform(:add, key, value, ttl_or_default(ttl), req_options)
     end
 
     ##
     # Conditionally add a key/value pair, only if the key already exists
     # on the server.  Returns truthy if the operation succeeded.
-    def replace(key, value, ttl = nil, options = nil)
-      perform(:replace, key, value, ttl_or_default(ttl), 0, options)
+    def replace(key, value, ttl = nil, req_options = nil)
+      replace_cas(key, value, 0, ttl, req_options)
     end
 
+    ##
+    # Conditionally add a key/value pair, verifying existing CAS, only if the
+    # key already exists on the server.  Returns the new CAS value if the
+    # operation succeeded, or falsy otherwise.
+    def replace_cas(key, value, cas, ttl = nil, req_options = nil)
+      perform(:replace, key, value, ttl_or_default(ttl), cas, req_options)
+    end
+
+    # Delete a key/value pair, verifying existing CAS.
+    # Returns true if succeeded, and falsy otherwise.
+    def delete_cas(key, cas = 0)
+      perform(:delete, key, cas)
+    end
+
     def delete(key)
-      perform(:delete, key, 0)
+      delete_cas(key, 0)
     end
 
     ##
     # Append value to the value already stored on the server for 'key'.
     # Appending only works for values stored with :raw => true.
@@ -185,17 +254,10 @@
     # Prepending only works for values stored with :raw => true.
     def prepend(key, value)
       perform(:prepend, key, value.to_s)
     end
 
-    def flush(delay = 0)
-      time = -delay
-      ring.servers.map { |s| s.request(:flush, time += delay) }
-    end
-
-    alias flush_all flush
-
     ##
     # Incr adds the given amount to the counter on the memcached server.
     # Amt must be a positive integer value.
     #
     # If default is nil, the counter must already exist or the operation
@@ -203,12 +265,14 @@
     # the new value for the counter.
     #
     # Note that the ttl will only apply if the counter does not already
     # exist.  To increase an existing counter and update its TTL, use
     # #cas.
+    #
+    # If the value already exists, it must have been set with raw: true
     def incr(key, amt = 1, ttl = nil, default = nil)
-      raise ArgumentError, "Positive values only: #{amt}" if amt.negative?
+      check_positive!(amt)
 
       perform(:incr, key, amt.to_i, ttl_or_default(ttl), default)
     end
 
     ##
@@ -223,39 +287,35 @@
     # the new value for the counter.
     #
     # Note that the ttl will only apply if the counter does not already
     # exist.  To decrease an existing counter and update its TTL, use
     # #cas.
+    #
+    # If the value already exists, it must have been set with raw: true
     def decr(key, amt = 1, ttl = nil, default = nil)
-      raise ArgumentError, "Positive values only: #{amt}" if amt.negative?
+      check_positive!(amt)
 
       perform(:decr, key, amt.to_i, ttl_or_default(ttl), default)
     end
 
     ##
-    # Touch updates expiration time for a given key.
-    #
-    # Returns true if key exists, otherwise nil.
-    def touch(key, ttl = nil)
-      resp = perform(:touch, key, ttl_or_default(ttl))
-      resp.nil? ? nil : true
-    end
-
+    # Flush the memcached server, at 'delay' seconds in the future.
+    # Delay defaults to zero seconds, which means an immediate flush.
     ##
-    # Gat (get and touch) fetch an item and simultaneously update its expiration time.
-    #
-    # If a value is not found, then +nil+ is returned.
-    def gat(key, ttl = nil)
-      perform(:gat, key, ttl_or_default(ttl))
+    def flush(delay = 0)
+      ring.servers.map { |s| s.request(:flush, delay) }
     end
+    alias flush_all flush
 
+    ALLOWED_STAT_KEYS = %i[items slabs settings].freeze
+
     ##
     # Collect the stats for each server.
     # You can optionally pass a type including :items, :slabs or :settings to get specific stats
     # Returns a hash like { 'hostname:port' => { 'stat1' => 'value1', ... }, 'hostname2:port' => { ... } }
     def stats(type = nil)
-      type = nil unless [nil, :items, :slabs, :settings].include? type
+      type = nil unless ALLOWED_STAT_KEYS.include? type
       values = {}
       ring.servers.each do |server|
         values[server.name.to_s] = server.alive? ? server.request(:stats, type.to_s) : nil
       end
       values
@@ -268,102 +328,68 @@
         server.alive? ? server.request(:reset_stats) : nil
       end
     end
 
     ##
-    ## Make sure memcache servers are alive, or raise an Dalli::RingError
-    def alive!
-      ring.server_for_key('')
-    end
-
-    ##
     ## Version of the memcache servers.
     def version
       values = {}
       ring.servers.each do |server|
         values[server.name.to_s] = server.alive? ? server.request(:version) : nil
       end
       values
     end
 
     ##
-    # Get the value and CAS ID associated with the key.  If a block is provided,
-    # value and CAS will be passed to the block.
-    def get_cas(key)
-      (value, cas) = perform(:cas, key)
-      value = nil if !value || value == 'Not found'
-      if block_given?
-        yield value, cas
-      else
-        [value, cas]
-      end
+    ## Make sure memcache servers are alive, or raise an Dalli::RingError
+    def alive!
+      ring.server_for_key('')
     end
 
     ##
-    # Fetch multiple keys efficiently, including available metadata such as CAS.
-    # If a block is given, yields key/data pairs one a time.  Data is an array:
-    # [value, cas_id]
-    # If no block is given, returns a hash of
-    #   { 'key' => [value, cas_id] }
-    def get_multi_cas(*keys)
-      if block_given?
-        pipelined_getter.process(keys) { |*args| yield(*args) }
-      else
-        {}.tap do |hash|
-          pipelined_getter.process(keys) { |k, data| hash[k] = data }
-        end
-      end
-    end
-
-    ##
-    # Set the key-value pair, verifying existing CAS.
-    # Returns the resulting CAS value if succeeded, and falsy otherwise.
-    def set_cas(key, value, cas, ttl = nil, options = nil)
-      ttl ||= @options[:expires_in].to_i
-      perform(:set, key, value, ttl, cas, options)
-    end
-
-    ##
-    # Conditionally add a key/value pair, verifying existing CAS, only if the
-    # key already exists on the server.  Returns the new CAS value if the
-    # operation succeeded, or falsy otherwise.
-    def replace_cas(key, value, cas, ttl = nil, options = nil)
-      ttl ||= @options[:expires_in].to_i
-      perform(:replace, key, value, ttl, cas, options)
-    end
-
-    # Delete a key/value pair, verifying existing CAS.
-    # Returns true if succeeded, and falsy otherwise.
-    def delete_cas(key, cas = 0)
-      perform(:delete, key, cas)
-    end
-
-    ##
     # Close our connection to each server.
     # If you perform another operation after this, the connections will be re-established.
     def close
       @ring&.close
       @ring = nil
     end
     alias reset close
 
+    CACHE_NILS = { cache_nils: true }.freeze
+
+    def not_found?(val)
+      cache_nils ? val == ::Dalli::NOT_FOUND : val.nil?
+    end
+
+    def cache_nils
+      @options[:cache_nils]
+    end
+
     # Stub method so a bare Dalli client can pretend to be a connection pool.
     def with
       yield self
     end
 
     private
 
-    def cas_core(key, always_set, ttl = nil, options = nil)
+    def check_positive!(amt)
+      raise ArgumentError, "Positive values only: #{amt}" if amt.negative?
+    end
+
+    def cas_core(key, always_set, ttl = nil, req_options = nil)
       (value, cas) = perform(:cas, key)
       value = nil if !value || value == 'Not found'
       return if value.nil? && !always_set
 
       newvalue = yield(value)
-      perform(:set, key, newvalue, ttl_or_default(ttl), cas, options)
+      perform(:set, key, newvalue, ttl_or_default(ttl), cas, req_options)
     end
 
+    ##
+    # Uses the argument TTL or the client-wide default.  Ensures
+    # that the value is an integer
+    ##
     def ttl_or_default(ttl)
       (ttl || @options[:expires_in]).to_i
     rescue NoMethodError
       raise ArgumentError, "Cannot convert ttl (#{ttl}) to an integer"
     end
@@ -380,10 +406,19 @@
 
     def protocol_implementation
       @protocol_implementation ||= @options.fetch(:protocol_implementation, Dalli::Protocol::Binary)
     end
 
-    # Chokepoint method for instrumentation
+    ##
+    # Chokepoint method for memcached methods with a key argument.
+    # Validates the key, resolves the key to the appropriate server
+    # instance, and invokes the memcached method on the appropriate
+    # server.
+    #
+    # This method also forces retries on network errors - when
+    # a particular memcached instance becomes unreachable, or the
+    # operational times out.
+    ##
     def perform(*all_args)
       return yield if block_given?
 
       op, key, *args = all_args
 