THREESCALE-11062: Redis config: extract DB from URL (#3800)

* Redis config: extract DB from URL

* Add a unit test

* Remove `#db`

app/lib/three_scale/redis_config.rb

@@ -7,21 +7,14 @@ def initialize(redis_config = {})
       sentinels = raw_config.delete(:sentinels).presence
       raw_config.delete_if { |key, value| value.blank? }
       raw_config[:size] ||= raw_config.delete(:pool_size) if raw_config.key?(:pool_size)
+      raw_config[:db] ||= URI.parse(raw_config[:url].to_s).path[1..]
 
       @config = ActiveSupport::OrderedOptions.new.merge(raw_config)
       config.sentinels = parse_sentinels(sentinels) if sentinels
     end
 
     attr_reader :config
 
-    def db
-      value = config.db.presence
-      return value.to_i if value
-      url = config.url.presence
-      return unless url
-      URI.parse(url).path[1..-1].to_s.to_i
-    end
-
     def reverse_merge(other)
       other.merge(config)
     end

test/unit/three_scale/redis_config_test.rb

@@ -4,12 +4,6 @@
 
 module ThreeScale
   class RedisConfigTest < ActiveSupport::TestCase
-    test '#db' do
-      assert_equal 4, RedisConfig.new(db: 4).db
-      assert_equal 3, RedisConfig.new(url: 'redis://my-redis/3').db
-      assert_equal 0, RedisConfig.new(url: 'redis://my-redis').db
-    end
-
     test '#reverse_merge' do
       config_1 = RedisConfig.new(host: 'localhost', db: 1)
       config_2 = RedisConfig.new(db: 2, password: 'passwd')
@@ -37,6 +31,14 @@ class RedisConfigTest < ActiveSupport::TestCase
       assert_equal expected_sentinels, config.sentinels
     end
 
+    test 'extracts the Redis logical DB from the URL' do
+      config = RedisConfig.new(url: 'redis://localhost:6379/6')
+
+      assert config.key? :db
+      assert_equal '6', config[:db]
+      assert_equal '6', config.db
+    end
+
     test ':pool_size is renamed to :size' do
       config = RedisConfig.new(pool_size: 5)