1 files changed, 59 insertions, 0 deletions
diff --git a/rubocop/cop/scalability/idempotent_worker.rb b/rubocop/cop/scalability/idempotent_worker.rb
new file mode 100644
index 00000000000..a38b457b7c7
--- /dev/null
+++ b/rubocop/cop/scalability/idempotent_worker.rb
@@ -0,0 +1,59 @@
+# frozen_string_literal: true
+
+require_relative '../../code_reuse_helpers.rb'
+
+module RuboCop
+  module Cop
+    module Scalability
+      # This cop checks for the `idempotent!` call in the worker scope.
+      #
+      # @example
+      #
+      # # bad
+      # class TroubleMakerWorker
+      #   def perform
+      #   end
+      # end
+      #
+      # # good
+      # class NiceWorker
+      #   idempotent!
+      #
+      #   def perform
+      #   end
+      # end
+      #
+      class IdempotentWorker < RuboCop::Cop::Cop
+        include CodeReuseHelpers
+
+        HELP_LINK = 'https://github.com/mperham/sidekiq/wiki/Best-Practices#2-make-your-job-idempotent-and-transactional'
+
+        MSG = <<~MSG
+          Avoid adding not idempotent workers.
+
+          A worker is considered idempotent if:
+
+          1. It can safely run multiple times with the same arguments
+          2. The application side-effects are expected to happen once (or side-effects of a second run are not impactful)
+          3. It can safely be skipped if another job with the same arguments is already in the queue
+
+          If all the above is true, make sure to mark it as so by calling the `idempotent!`
+          method in the worker scope.
+
+          See #{HELP_LINK}
+        MSG
+
+        def_node_search :idempotent?, <<~PATTERN
+          (send nil? :idempotent!)
+        PATTERN
+
+        def on_class(node)
+          return unless in_worker?(node)
+          return if idempotent?(node)
+
+          add_offense(node, location: :expression)
+        end
+      end
+    end
+  end
+end