refactor: parsing cluster node command reply (#201)

Author: supercaracal

lib/redis_client/cluster/node.rb

@@ -18,6 +18,9 @@ class Node
       MAX_STARTUP_SAMPLE = 37
       MAX_THREADS = Integer(ENV.fetch('REDIS_CLIENT_MAX_THREADS', 5))
       IGNORE_GENERIC_CONFIG_KEYS = %i[url host port path].freeze
+      DEAD_FLAGS = %w[fail? fail handshake noaddr noflags].freeze
+      ROLE_FLAGS = %w[master slave].freeze
+      EMPTY_ARRAY = [].freeze
 
       ReloadNeeded = Class.new(::RedisClient::Error)
 
@@ -132,26 +135,32 @@ def load_info(options, **kwargs) # rubocop:disable Metrics/AbcSize, Metrics/Cycl
         # @see https://redis.io/commands/cluster-nodes/
         # @see https://github.com/redis/redis/blob/78960ad57b8a5e6af743d789ed8fd767e37d42b8/src/cluster.c#L4660-L4683
         def parse_cluster_node_reply(reply) # rubocop:disable Metrics/AbcSize, Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity
-          rows = reply.split("\n").map(&:split)
-          rows.each { |arr| arr[2] = arr[2].split(',') }
-          rows.select! { |arr| arr[7] == 'connected' && (arr[2] & %w[fail? fail handshake noaddr noflags]).empty? }
-          rows.each do |arr|
-            arr[1] = arr[1].split('@').first
-            arr[2] = (arr[2] & %w[master slave]).first
-            if arr[8].nil?
-              arr[8] = []
-              next
-            end
-            arr[8] = arr[8..].filter_map { |str| str.start_with?('[') ? nil : str.split('-').map { |s| Integer(s) } }
-                             .map { |a| a.size == 1 ? a << a.first : a }.map(&:sort)
-          end
-
-          rows.map do |arr|
-            ::RedisClient::Cluster::Node::Info.new(
-              id: arr[0], node_key: arr[1], role: arr[2], primary_id: arr[3], ping_sent: arr[4],
-              pong_recv: arr[5], config_epoch: arr[6], link_state: arr[7], slots: arr[8]
+          reply.each_line("\n", chomp: true).with_object(Array.new(reply.count("\n"))) do |line, acc|
+            fields = line.split
+            flags = fields[2].split(',')
+            next unless fields[7] == 'connected' && (flags & DEAD_FLAGS).empty?
+
+            slots = if fields[8].nil?
+                      EMPTY_ARRAY
+                    else
+                      fields[8..].reject { |str| str.start_with?('[') }
+                                 .map { |str| str.split('-').map { |s| Integer(s) } }
+                                 .map { |a| a.size == 1 ? a << a.first : a }
+                                 .map(&:sort)
+                    end
+
+            acc << ::RedisClient::Cluster::Node::Info.new(
+              id: fields[0],
+              node_key: fields[1].split('@').first,
+              role: (flags & ROLE_FLAGS).first,
+              primary_id: fields[3],
+              ping_sent: fields[4],
+              pong_recv: fields[5],
+              config_epoch: fields[6],
+              link_state: fields[7],
+              slots: slots
             )
-          end
+          end.compact
         end
       end