fix: Redis v6 fix from russointroitoa/sidekiq-grouping/check_redis_version_for_lua_script

.github/workflows/test.yml

@@ -34,7 +34,6 @@ jobs:
         with:
           bundler: 2
           ruby-version: ${{ matrix.ruby_version }}
-
       # Appraisal doesn't support vendored install
       # See: https://github.com/thoughtbot/appraisal/issues/173
       #      https://github.com/thoughtbot/appraisal/pull/174

Gemfile

@@ -1,13 +1,17 @@
-source "https://rubygems.org"
+source 'https://rubygems.org'
 
-gem "appraisal"
-gem "bundler", "> 1.5"
-gem "pry"
-gem "rake"
-gem "rspec"
-gem "rspec-sidekiq"
-gem "rubocop"
-gem "rubocop-rspec"
-gem "simplecov"
-gem "timecop"
-gem "activesupport"
+# Specify your gem's dependencies in sidekiq-grouping.gemspec
+gemspec
+
+group :development do
+  gem "appraisal"
+  gem "bundler", "> 1.5"
+  gem "pry"
+  gem "rake"
+  gem "rspec"
+  gem "rspec-sidekiq"
+  gem "rubocop"
+  gem "rubocop-rspec"
+  gem "simplecov"
+  gem "timecop"
+end

lib/sidekiq/grouping/flusher.rb

@@ -38,15 +38,16 @@ def flush_batches(batches)
       def flush_concrete(batches)
         return if batches.empty?
 
-        names = batches.map do |batch|
-          "#{batch.worker_class} in #{batch.queue}"
-        end
-        unless Sidekiq::Grouping::Config.tests_env
-          Sidekiq::Grouping.logger.info(
-            "[Sidekiq::Grouping] Trying to flush batched queues: " \
-            "#{names.join(',')}"
-          )
-        end
+        # Comment out logging code since it can be noisy in production
+        # names = batches.map do |batch|
+        #   "#{batch.worker_class} in #{batch.queue}"
+        # end
+        # unless Sidekiq::Grouping::Config.tests_env
+        #   Sidekiq::Grouping.logger.info(
+        #     "[Sidekiq::Grouping] Trying to flush batched queues: " \
+        #     "#{names.join(',')}"
+        #   )
+        # end
         batches.each(&:flush)
       end
     end

lib/sidekiq/grouping/redis.rb

@@ -7,14 +7,25 @@ module Grouping
     class Redis
       include RedisDispatcher
 
-      PLUCK_SCRIPT = <<-SCRIPT
+      BREAK_VERSION = "6.2.0"
+
+      PLUCK_SCRIPT_GTE_6_2_0 = <<-SCRIPT
         local pluck_values = redis.call('lpop', KEYS[1], ARGV[1]) or {}
         if #pluck_values > 0 then
           redis.call('srem', KEYS[2], unpack(pluck_values))
         end
         return pluck_values
       SCRIPT
 
+      PLUCK_SCRIPT_LT_6_2_0 = <<-SCRIPT
+        local pluck_values = redis.call('lrange', KEYS[1], 0, ARGV[1] - 1)
+        redis.call('ltrim', KEYS[1], ARGV[1], -1)
+        for k, v in pairs(pluck_values) do
+          redis.call('srem', KEYS[2], v)
+        end
+        return pluck_values
+      SCRIPT
+
       def push_msg(name, msg, remember_unique: false)
         redis do |conn|
           conn.multi do |pipeline|
@@ -50,7 +61,7 @@ def pluck(name, limit)
         if new_redis_client?
           redis_call(
             :eval,
-            PLUCK_SCRIPT,
+            pluck_script,
             2,
             ns(name),
             unique_messages_key(name),
@@ -59,7 +70,7 @@ def pluck(name, limit)
         else
           keys = [ns(name), unique_messages_key(name)]
           args = [limit]
-          redis_call(:eval, PLUCK_SCRIPT, keys, args)
+          redis_call(:eval, pluck_script, keys, args)
         end
       end
 
@@ -100,6 +111,31 @@ def unique_messages_key(name)
       def ns(key = nil)
         "batching:#{key}"
       end
+
+      #
+      # Get Redis server version
+      #
+      # @return [String] Redis server version
+      #
+      def server_version
+        Sidekiq.redis do |conn|
+          conn.info["redis_version"]
+        end
+      end
+
+      #
+      # The optimized LUA SCRIPT works from Redis greater than or equal to 6.2.
+      # Check Redis version in use and return the suitable PLUCK_SCRIPT
+      #
+      # @return [String] Lua Script
+      #
+      def pluck_script
+        if Gem::Version.new(server_version) >= Gem::Version.new(BREAK_VERSION)
+          PLUCK_SCRIPT_GTE_6_2_0
+        else
+          PLUCK_SCRIPT_LT_6_2_0
+        end
+      end
     end
   end
 end

spec/modules/redis_spec.rb

@@ -41,4 +41,26 @@
       expect(redis_call(:smembers, unique_key)).to eq []
     end
   end
+
+  describe "#pluck_script" do
+    context "when Redis server version is" do
+      it ">= 6.2.0, selects the corresponding pluck script" do
+        allow_any_instance_of(described_class)
+          .to receive(:server_version)
+          .and_return("6.2.0")
+        expect(redis_service.send(:pluck_script)).to eq(
+          described_class::PLUCK_SCRIPT_GTE_6_2_0
+        )
+      end
+
+      it "< 6.2.0, selects the corresponding pluck script" do
+        allow_any_instance_of(described_class)
+          .to receive(:server_version)
+          .and_return("6.0.0")
+        expect(redis_service.send(:pluck_script)).to eq(
+          described_class::PLUCK_SCRIPT_LT_6_2_0
+        )
+      end
+    end
+  end
 end