Add ignore_nil config for saving memory

Author: w-masahiro-ct

lib/splitclient-rb/cache/adapters/cache_adapter.rb

@@ -8,7 +8,7 @@ class CacheAdapter
         def_delegators :@adapter, :initialize_set, :set_bool, :pipelined
 
         def initialize(config)
-          @cache = LruRedux::TTL::ThreadSafeCache.new(config.max_cache_size, config.cache_ttl)
+          @cache = LruRedux::TTL::ThreadSafeCache.new(config.max_cache_size, config.cache_ttl, config.ignore_empty_cache)
           @adapter = config.cache_adapter
         end
 

lib/splitclient-rb/cache/observers/impression_observer.rb

@@ -4,13 +4,13 @@ class ImpressionObserver
       LAST_SEEN_CACHE_SIZE = 500000
 
       def initialize
-        @cache = LruRedux::TTL::ThreadSafeCache.new(LAST_SEEN_CACHE_SIZE)
+        @cache = LruRedux::TTL::ThreadSafeCache.new(LAST_SEEN_CACHE_SIZE, true)
         @impression_hasher = Hashers::ImpressionHasher.new
       end
 
       def test_and_set(impression)
         return if impression.nil?
-        
+
         hash = @impression_hasher.process(impression)
         previous = @cache[hash]
         @cache[hash] = impression[:m]

lib/splitclient-rb/split_config.rb

@@ -23,6 +23,7 @@ class SplitConfig
     # @option opts [Int] :impressions_queue_size Size of the impressions queue in the memory repository. Once reached, newer impressions will be dropped
     # @option opts [Int] :impressions_bulk_size Max number of impressions to be sent to the backend on each post
     # @option opts [#log] :impression_listener this object will capture all impressions and process them through `#log`
+    # @option opts [Boolean] :ignore_empty_cache (true) The value to enable or disable caching nil values.
     # @option opts [Int] :cache_ttl Time to live in seconds for the memory cache values when using Redis.
     # @option opts [Int] :max_cache_size Max number of items to be held in the memory cache before prunning when using Redis.
     # @return [type] SplitConfig with configuration options
@@ -70,6 +71,7 @@ def initialize(opts = {})
       @machine_name = SplitConfig.machine_hostname(@ip_addresses_enabled, opts[:machine_name], opts[:cache_adapter] || SplitConfig.default_cache_adapter)
       @machine_ip = SplitConfig.machine_ip(@ip_addresses_enabled, opts[:machine_ip], opts[:cache_adapter] || SplitConfig.default_cache_adapter)
 
+      @ignore_empty_cache = opts[:ignore_empty_cache] || SplitConfig.ignore_empty_cache
       @cache_ttl = opts[:cache_ttl] || SplitConfig.cache_ttl
       @max_cache_size = opts[:max_cache_size] || SplitConfig.max_cache_size
 
@@ -221,6 +223,7 @@ def initialize(opts = {})
     attr_accessor :machine_ip
     attr_accessor :machine_name
 
+    attr_accessor :ignore_empty_cache
     attr_accessor :cache_ttl
     attr_accessor :max_cache_size
 
@@ -591,6 +594,14 @@ def self.transport_debug
       false
     end
 
+    #
+    # The default ignore_empty_cache value
+    #
+    # @return [boolean]
+    def self.ignore_empty_cache
+      true
+    end
+
     #
     # The default cache time to live
     #
@@ -599,13 +610,15 @@ def self.cache_ttl
       5
     end
 
+    #
     # The default max cache size
     #
     # @return [int]
     def self.max_cache_size
       500
     end
 
+    #
     # The default max key size
     #
     # @return [int]