Split cluster support in a separate gem

Author: byroot

.github/workflows/test.yaml

@@ -197,7 +197,7 @@ jobs:
       LOW_TIMEOUT: "0.14"
       DRIVER: ruby
       REDIS_BRANCH: "7.0"
-      REDIS_CLUSTER: "true"
+      BUNDLE_GEMFILE: redis_cluster/Gemfile
     steps:
       - name: Check out code
         uses: actions/checkout@v3

.rubocop.yml

@@ -148,3 +148,7 @@ Style/SymbolProc:
 
 Bundler/OrderedGems:
   Enabled: false
+
+Gemspec/RequiredRubyVersion:
+  Exclude:
+    - redis_cluster/redis_cluster.gemspec

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 # Unreleased 5.0.0
 
+- Cluster support has been moved to a `redis_cluster` companion gem.
 - `select` no longer record the current database. If the client has to reconnect after `select` was used, it will reconnect to the original database.
 - Removed `logger` option.
 - Removed `reconnect_delay_max` and `reconnect_delay`, you can pass precise sleep durations to `reconnect_attempts` instead.

Gemfile

@@ -11,4 +11,3 @@ gem 'mocha'
 
 gem 'redis-client', github: 'redis-rb/redis-client'
 gem 'hiredis-client'
-gem 'redis-cluster-client', github: 'redis-rb/redis-cluster-client' if ENV['REDIS_CLUSTER']

README.md

@@ -116,59 +116,7 @@ redis = Redis.new(name: 'mymaster', sentinels: SENTINELS, role: :master)
 
 ## Cluster support
 
-`redis-rb` supports [clustering](https://redis.io/topics/cluster-spec).
-
-```ruby
-# Nodes can be passed to the client as an array of connection URLs.
-nodes = (7000..7005).map { |port| "redis://127.0.0.1:#{port}" }
-redis = Redis.new(cluster: nodes)
-
-# You can also specify the options as a Hash. The options are the same as for a single server connection.
-(7000..7005).map { |port| { host: '127.0.0.1', port: port } }
-```
-
-You can also specify only a subset of the nodes, and the client will discover the missing ones using the [CLUSTER NODES](https://redis.io/commands/cluster-nodes) command.
-
-```ruby
-Redis.new(cluster: %w[redis://127.0.0.1:7000])
-```
-
-If you want [the connection to be able to read from any replica](https://redis.io/commands/readonly), you must pass the `replica: true`. Note that this connection won't be usable to write keys.
-
-```ruby
-Redis.new(cluster: nodes, replica: true)
-```
-
-The calling code is responsible for [avoiding cross slot commands](https://redis.io/topics/cluster-spec#keys-distribution-model).
-
-```ruby
-redis = Redis.new(cluster: %w[redis://127.0.0.1:7000])
-
-redis.mget('key1', 'key2')
-#=> Redis::CommandError (CROSSSLOT Keys in request don't hash to the same slot)
-
-redis.mget('{key}1', '{key}2')
-#=> [nil, nil]
-```
-
-* The client automatically reconnects after a failover occurred, but the caller is responsible for handling errors while it is happening.
-* The client support permanent node failures, and will reroute requests to promoted slaves.
-* The client supports `MOVED` and `ASK` redirections transparently.
-
-## Cluster mode with SSL/TLS
-Since Redis can return FQDN of nodes in reply to client since `7.*` with CLUSTER commands, we can use cluster feature with SSL/TLS connection like this:
-
-```ruby
-Redis.new(cluster: %w[rediss://foo.example.com:6379])
-```
-
-On the other hand, in Redis versions prior to `6.*`, you can specify options like the following if cluster mode is enabled and client has to connect to nodes via single endpoint with SSL/TLS.
-
-```ruby
-Redis.new(cluster: %w[rediss://foo-endpoint.example.com:6379], fixed_hostname: 'foo-endpoint.example.com')
-```
-
-In case of the above architecture, if you don't pass the `fixed_hostname` option to the client and servers return IP addresses of nodes, the client may fail to verify certificates.
+[Clustering](https://redis.io/topics/cluster-spec). is supported via the [`redis_cluster` gem](redis_cluster/).
 
 ## Storing objects
 

Rakefile

@@ -1,10 +1,12 @@
 # frozen_string_literal: true
 
 require 'bundler/gem_tasks'
+Bundler::GemHelper.install_tasks(dir: "redis_cluster", name: "redis_cluster")
+
 require 'rake/testtask'
 
 namespace :test do
-  groups = %i(redis distributed sentinel cluster)
+  groups = %i(redis distributed sentinel)
   groups.each do |group|
     Rake::TestTask.new(group) do |t|
       t.libs << "test"
@@ -18,6 +20,13 @@ namespace :test do
   unless lost_tests.empty?
     abort "The following test files are in no group:\n#{lost_tests.join("\n")}"
   end
+
+  Rake::TestTask.new(:cluster) do |t|
+    t.libs << "redis_cluster/test" << "test"
+    t.libs << "redis_cluster/lib" << "lib"
+    t.test_files = FileList["redis_cluster/test/**/*_test.rb"]
+    t.options = '-v' if ENV['CI'] || ENV['VERBOSE']
+  end
 end
 
 task test: ["test:redis", "test:distributed", "test:sentinel", "test:cluster"]

bin/cluster_creator

@@ -5,7 +5,7 @@ puts ARGV.join(" ")
 require 'bundler/setup'
 
 $LOAD_PATH.unshift(File.expand_path('../lib', __dir__))
-require_relative '../test/support/cluster/orchestrator'
+require_relative '../redis_cluster/test/support/orchestrator'
 
 urls = ARGV.map { |host_port| "redis://#{host_port}" }
 orchestrator = ClusterOrchestrator.new(urls, timeout: 3.0)

lib/redis.rb

@@ -8,8 +8,6 @@ class Redis
   BASE_PATH = __dir__
   Deprecated = Class.new(StandardError)
 
-  autoload :ClusterClient, "redis/cluster_client"
-
   class << self
     attr_accessor :silence_deprecations, :raise_deprecations
 
@@ -50,12 +48,6 @@ def deprecate!(message)
   # @option options [Boolean] :inherit_socket (false) Whether to use socket in forked process or not
   # @option options [String] :name The name of the server group to connect to.
   # @option options [Array] :sentinels List of sentinels to contact
-  # @option options [Symbol] :role (:master) Role to fetch via Sentinel, either `:master` or `:slave`
-  # @option options [Array<String, Hash{Symbol => String, Integer}>] :cluster List of cluster nodes to contact
-  # @option options [Boolean] :replica Whether to use readonly replica nodes in Redis Cluster or not
-  # @option options [String] :fixed_hostname Specify a FQDN if cluster mode enabled and
-  #   client has to connect nodes via single endpoint with SSL/TLS
-  # @option options [Class] :connector Class of custom connector
   #
   # @return [Redis] a new client instance
   def initialize(options = {})
@@ -68,34 +60,7 @@ def initialize(options = {})
     inherit_socket = @options.delete(:inherit_socket)
     @subscription_client = nil
 
-    @client = if @cluster_mode = options.key?(:cluster)
-      @options[:nodes] ||= @options.delete(:cluster)
-      cluster_config = RedisClient.cluster(**@options, protocol: 2, client_implementation: ClusterClient)
-      begin
-        cluster_config.new_client
-      rescue ::RedisClient::Error => error
-        raise ClusterClient::ERROR_MAPPING.fetch(error.class), error.message, error.backtrace
-      end
-    elsif @options.key?(:sentinels)
-      if url = @options.delete(:url)
-        uri = URI.parse(url)
-        if !@options.key?(:name) && uri.host
-          @options[:name] = uri.host
-        end
-
-        if !@options.key?(:password) && uri.password && !uri.password.empty?
-          @options[:password] = uri.password
-        end
-
-        if !@options.key?(:username) && uri.user && !uri.user.empty?
-          @options[:username] = uri.user
-        end
-      end
-
-      Client.sentinel(**@options).new_client
-    else
-      Client.config(**@options).new_client
-    end
+    @client = initialize_client(@options)
     @client.inherit_socket! if inherit_socket
   end
 
@@ -145,10 +110,6 @@ def dup
   end
 
   def connection
-    if @cluster_mode
-      raise NotImplementedError, "Redis::Cluster doesn't implement #connection"
-    end
-
     {
       host: @client.host,
       port: @client.port,
@@ -160,6 +121,33 @@ def connection
 
   private
 
+  def initialize_client(options)
+    if options.key?(:cluster)
+      raise "Redis Cluster support was moved to the `redis_cluster` gem."
+    end
+
+    if options.key?(:sentinels)
+      if url = options.delete(:url)
+        uri = URI.parse(url)
+        if !options.key?(:name) && uri.host
+          options[:name] = uri.host
+        end
+
+        if !options.key?(:password) && uri.password && !uri.password.empty?
+          options[:password] = uri.password
+        end
+
+        if !options.key?(:username) && uri.user && !uri.user.empty?
+          options[:username] = uri.user
+        end
+      end
+
+      Client.sentinel(**options).new_client
+    else
+      Client.config(**options).new_client
+    end
+  end
+
   def synchronize
     @monitor.synchronize { yield(@client) }
   end

lib/redis/cluster_client.rb

@@ -12,24 +12,7 @@ module Cluster
       #
       # @return [Object] depends on the subcommand
       def cluster(subcommand, *args)
-        subcommand = subcommand.to_s.downcase
-        block = case subcommand
-        when 'slots'
-          HashifyClusterSlots
-        when 'nodes'
-          HashifyClusterNodes
-        when 'slaves'
-          HashifyClusterSlaves
-        when 'info'
-          HashifyInfo
-        else
-          Noop
-        end
-
-        # @see https://github.com/antirez/redis/blob/unstable/src/redis-trib.rb#L127 raw reply expected
-        block = Noop unless @cluster_mode
-
-        send_command([:cluster, subcommand] + args, &block)
+        send_command([:cluster, subcommand] + args)
       end
 
       # Sends `ASKING` command to random node and returns its reply.