Merge branch '241378_until_executed_deduplication_strategy' into 'master'

Add until_executed deduplication strategy

See merge request gitlab-org/gitlab!42223

app/models/ci/build_trace_chunk.rb

@@ -136,9 +136,10 @@ module Ci
     # We are using optimistic locking combined with Redis locking to ensure
     # that a chunk gets migrated properly.
     #
-    # We are catching an exception related to an exclusive lock not being
-    # acquired because it is creating a lot of noise, and is a result of
-    # duplicated workers running in parallel for the same build trace chunk.
+    # We are using until_executed deduplication strategy for workers,
+    # which should prevent duplicated workers running in parallel for the same build trace,
+    # and causing an exception related to an exclusive lock not being
+    # acquired
     #
     def persist_data!
       in_lock(*lock_params) do         # exclusive Redis lock is acquired first
@@ -150,6 +151,8 @@ module Ci
       end
     rescue FailedToObtainLockError
       metrics.increment_trace_operation(operation: :stalled)
+
+      raise FailedToPersistDataError, 'Data migration failed due to a worker duplication'
     rescue ActiveRecord::StaleObjectError
       raise FailedToPersistDataError, <<~MSG
         Data migration race condition detected

app/workers/ci/build_trace_chunk_flush_worker.rb

@@ -5,6 +5,8 @@ module Ci
     include ApplicationWorker
     include PipelineBackgroundQueue
 
+    deduplicate :until_executed
+
     idempotent!
 
     # rubocop: disable CodeReuse/ActiveRecord

changelogs/unreleased/241378_until_executed_deduplication_strategy.yml

+---
+title: Add until_executed deduplication strategy
+merge_request: 42223
+author:
+type: added

doc/development/sidekiq_style_guide.md

@@ -165,6 +165,22 @@ job. The work is skipped because the same work would be
 done by the job that was scheduled first; by the time the second
 job executed, the first job would do nothing.
 
+#### Strategies
+
+GitLab supports two deduplication strategies:
+
+- `until_executing`
+- `until_executed`
+
+More [deduplication strategies have been
+suggested](https://gitlab.com/gitlab-com/gl-infra/scalability/-/issues/195). If
+you are implementing a worker that could benefit from a different
+strategy, please comment in the issue.
+
+##### Until Executing
+
+This strategy takes a lock when a job is added to the queue, and removes that lock before the job starts.
+
 For example, `AuthorizedProjectsWorker` takes a user ID. When the
 worker runs, it recalculates a user's authorizations. GitLab schedules
 this job each time an action potentially changes a user's
@@ -173,10 +189,47 @@ same time, the second job can be skipped if the first job hasn't
 begun, because when the first job runs, it creates the
 authorizations for both projects.
 
+```ruby
+module AuthorizedProjectUpdate
+  class UserRefreshOverUserRangeWorker
+    include ApplicationWorker
+
+    deduplicate :until_executing
+    idempotent!
+
+    # ...
+  end
+end
+```
+
+##### Until Executed
+
+This strategy takes a lock when a job is added to the queue, and removes that lock after the job finishes.
+It can be used to prevent jobs from running simultaneously multiple times.
+
+```ruby
+module Ci
+  class BuildTraceChunkFlushWorker
+    include ApplicationWorker
+
+    deduplicate :until_executed
+    idempotent!
+
+    # ...
+  end
+end
+```
+
+#### Scheduling jobs in the future
+
 GitLab doesn't skip jobs scheduled in the future, as we assume that
 the state will have changed by the time the job is scheduled to
-execute. If you do want to deduplicate jobs scheduled in the future
-this can be specified on the worker as follows:
+execute. Deduplication of jobs scheduled in the feature is possible
+for both `until_executed` and `until_executing` strategies.
+
+If you do want to deduplicate jobs scheduled in the future,
+this can be specified on the worker by passing `including_scheduled: true` argument
+when defining deduplication strategy:
 
 ```ruby
 module AuthorizedProjectUpdate
@@ -191,11 +244,7 @@ module AuthorizedProjectUpdate
 end
 ```
 
-This strategy is called `until_executing`. More [deduplication
-strategies have been
-suggested](https://gitlab.com/gitlab-com/gl-infra/scalability/-/issues/195). If
-you are implementing a worker that could benefit from a different
-strategy, please comment in the issue.
+#### Troubleshooting
 
 If the automatic deduplication were to cause issues in certain
 queues. This can be temporarily disabled by enabling a feature flag

lib/gitlab/sidekiq_middleware/duplicate_jobs/strategies.rb

@@ -8,6 +8,7 @@ module Gitlab
 
         STRATEGIES = {
           until_executing: UntilExecuting,
+          until_executed: UntilExecuted,
           none: None
         }.freeze
 

lib/gitlab/sidekiq_middleware/duplicate_jobs/strategies/base.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module SidekiqMiddleware
+    module DuplicateJobs
+      module Strategies
+        class Base
+          def initialize(duplicate_job)
+            @duplicate_job = duplicate_job
+          end
+
+          def schedule(job)
+            raise NotImplementedError
+          end
+
+          def perform(_job)
+            raise NotImplementedError
+          end
+
+          private
+
+          attr_reader :duplicate_job
+
+          def strategy_name
+            self.class.name.to_s.demodulize.underscore.humanize.downcase
+          end
+
+          def check!
+            # The default expiry time is the DuplicateJob::DUPLICATE_KEY_TTL already
+            # Only the strategies de-duplicating when scheduling
+            duplicate_job.check!
+          end
+        end
+      end
+    end
+  end
+end

lib/gitlab/sidekiq_middleware/duplicate_jobs/strategies/deduplicates_when_scheduling.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module SidekiqMiddleware
+    module DuplicateJobs
+      module Strategies
+        module DeduplicatesWhenScheduling
+          def initialize(duplicate_job)
+            @duplicate_job = duplicate_job
+          end
+
+          def schedule(job)
+            if deduplicatable_job? && check! && duplicate_job.duplicate?
+              job['duplicate-of'] = duplicate_job.existing_jid
+
+              if duplicate_job.droppable?
+                Gitlab::SidekiqLogging::DeduplicationLogger.instance.log(
+                  job, "dropped #{strategy_name}", duplicate_job.options)
+                return false
+              end
+            end
+
+            yield
+          end
+
+          private
+
+          def deduplicatable_job?
+            !duplicate_job.scheduled? || duplicate_job.options[:including_scheduled]
+          end
+
+          def check!
+            duplicate_job.check!(expiry)
+          end
+
+          def expiry
+            return DuplicateJob::DUPLICATE_KEY_TTL unless duplicate_job.scheduled?
+
+            time_diff = duplicate_job.scheduled_at.to_i - Time.now.to_i
+
+            time_diff > 0 ? time_diff : DuplicateJob::DUPLICATE_KEY_TTL
+          end
+        end
+      end
+    end
+  end
+end

lib/gitlab/sidekiq_middleware/duplicate_jobs/strategies/none.rb

@@ -5,10 +5,7 @@ module Gitlab
     module DuplicateJobs
       module Strategies
         # This strategy will never deduplicate a job
-        class None
-          def initialize(_duplicate_job)
-          end
-
+        class None < Base
           def schedule(_job)
             yield
           end

lib/gitlab/sidekiq_middleware/duplicate_jobs/strategies/until_executed.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module SidekiqMiddleware
+    module DuplicateJobs
+      module Strategies
+        # This strategy takes a lock before scheduling the job in a queue and
+        # removes the lock after the job has executed preventing a new job to be queued
+        # while a job is still executing.
+        class UntilExecuted < Base
+          include DeduplicatesWhenScheduling
+
+          def perform(_job)
+            yield
+
+            duplicate_job.delete!
+          end
+        end
+      end
+    end
+  end
+end

lib/gitlab/sidekiq_middleware/duplicate_jobs/strategies/until_executing.rb

@@ -7,50 +7,14 @@ module Gitlab
         # This strategy takes a lock before scheduling the job in a queue and
         # removes the lock before the job starts allowing a new job to be queued
         # while a job is still executing.
-        class UntilExecuting
-          def initialize(duplicate_job)
-            @duplicate_job = duplicate_job
-          end
-
-          def schedule(job)
-            if deduplicatable_job? && check! && duplicate_job.duplicate?
-              job['duplicate-of'] = duplicate_job.existing_jid
-
-              if duplicate_job.droppable?
-                Gitlab::SidekiqLogging::DeduplicationLogger.instance.log(
-                  job, "dropped until executing", duplicate_job.options)
-                return false
-              end
-            end
-
-            yield
-          end
+        class UntilExecuting < Base
+          include DeduplicatesWhenScheduling
 
           def perform(_job)
             duplicate_job.delete!
 
             yield
           end
-
-          private
-
-          attr_reader :duplicate_job
-
-          def deduplicatable_job?
-            !duplicate_job.scheduled? || duplicate_job.options[:including_scheduled]
-          end
-
-          def check!
-            duplicate_job.check!(expiry)
-          end
-
-          def expiry
-            return DuplicateJob::DUPLICATE_KEY_TTL unless duplicate_job.scheduled?
-
-            time_diff = duplicate_job.scheduled_at.to_i - Time.now.to_i
-
-            time_diff > 0 ? time_diff : DuplicateJob::DUPLICATE_KEY_TTL
-          end
         end
       end
     end

spec/lib/gitlab/sidekiq_middleware/duplicate_jobs/client_spec.rb

@@ -3,6 +3,7 @@
 require 'spec_helper'
 
 RSpec.describe Gitlab::SidekiqMiddleware::DuplicateJobs::Client, :clean_gitlab_redis_queues do
+  shared_context 'deduplication worker class' do |strategy, including_scheduled|
     let(:worker_class) do
       Class.new do
         def self.name
@@ -11,6 +12,10 @@ RSpec.describe Gitlab::SidekiqMiddleware::DuplicateJobs::Client, :clean_gitlab_r
 
         include ApplicationWorker
 
+        deduplicate strategy, including_scheduled: including_scheduled
+
+        include ApplicationWorker
+
         def perform(*args)
         end
       end
@@ -19,8 +24,12 @@ RSpec.describe Gitlab::SidekiqMiddleware::DuplicateJobs::Client, :clean_gitlab_r
     before do
       stub_const('TestDeduplicationWorker', worker_class)
     end
+  end
 
+  shared_examples 'client duplicate job' do |strategy|
     describe '#call' do
+      include_context 'deduplication worker class', strategy, false
+
       it 'adds a correct duplicate tag to the jobs', :aggregate_failures do
         TestDeduplicationWorker.bulk_perform_async([['args1'], ['args2'], ['args1']])
 
@@ -44,23 +53,10 @@ RSpec.describe Gitlab::SidekiqMiddleware::DuplicateJobs::Client, :clean_gitlab_r
       end
 
       context 'with scheduled deduplication' do
-      let(:scheduled_worker_class) do
-        Class.new do
-          def self.name
-            'TestDeduplicationWorker'
-          end
-
-          include ApplicationWorker
-
-          deduplicate :until_executing, including_scheduled: true
-
-          def perform(*args)
-          end
-        end
-      end
+        include_context 'deduplication worker class', strategy, true
 
         before do
-        stub_const('TestDeduplicationWorker', scheduled_worker_class)
+          stub_const('TestDeduplicationWorker', worker_class)
         end
 
         it 'adds a correct duplicate tag to the jobs', :aggregate_failures do
@@ -78,4 +74,13 @@ RSpec.describe Gitlab::SidekiqMiddleware::DuplicateJobs::Client, :clean_gitlab_r
         end
       end
     end
+  end
+
+  context 'with until_executing strategy' do
+    it_behaves_like 'client duplicate job', :until_executing
+  end
+
+  context 'with until_executed strategy' do
+    it_behaves_like 'client duplicate job', :until_executed
+  end
 end

spec/lib/gitlab/sidekiq_middleware/duplicate_jobs/server_spec.rb

@@ -3,6 +3,7 @@
 require 'spec_helper'
 
 RSpec.describe Gitlab::SidekiqMiddleware::DuplicateJobs::Server, :clean_gitlab_redis_queues do
+  shared_context 'server duplicate job' do |strategy|
     let(:worker_class) do
       Class.new do
         def self.name
@@ -11,7 +12,13 @@ RSpec.describe Gitlab::SidekiqMiddleware::DuplicateJobs::Server, :clean_gitlab_r
 
         include ApplicationWorker
 
+        deduplicate strategy
+
         def perform(*args)
+          self.class.work
+        end
+
+        def self.work
         end
       end
     end
@@ -26,16 +33,41 @@ RSpec.describe Gitlab::SidekiqMiddleware::DuplicateJobs::Server, :clean_gitlab_r
         Sidekiq::Testing.inline! { example.run }
       end
     end
+  end
+
+  context 'with until_executing strategy' do
+    include_context 'server duplicate job', :until_executing
 
     describe '#call' do
-    it 'removes the stored job from redis' do
+      it 'removes the stored job from redis before execution' do
+        bare_job = { 'class' => 'TestDeduplicationWorker', 'args' => ['hello'] }
+        job_definition = Gitlab::SidekiqMiddleware::DuplicateJobs::DuplicateJob.new(bare_job.dup, 'test_deduplication')
+
+        expect(Gitlab::SidekiqMiddleware::DuplicateJobs::DuplicateJob)
+          .to receive(:new).with(a_hash_including(bare_job), 'test_deduplication')
+                .and_return(job_definition).twice # once in client middleware
+
+        expect(job_definition).to receive(:delete!).ordered.and_call_original
+        expect(TestDeduplicationWorker).to receive(:work).ordered.and_call_original
+
+        TestDeduplicationWorker.perform_async('hello')
+      end
+    end
+  end
+
+  context 'with until_executed strategy' do
+    include_context 'server duplicate job', :until_executed
+
+    it 'removes the stored job from redis after execution' do
       bare_job = { 'class' => 'TestDeduplicationWorker', 'args' => ['hello'] }
       job_definition = Gitlab::SidekiqMiddleware::DuplicateJobs::DuplicateJob.new(bare_job.dup, 'test_deduplication')
 
       expect(Gitlab::SidekiqMiddleware::DuplicateJobs::DuplicateJob)
         .to receive(:new).with(a_hash_including(bare_job), 'test_deduplication')
               .and_return(job_definition).twice # once in client middleware
-      expect(job_definition).to receive(:delete!).and_call_original
+
+      expect(TestDeduplicationWorker).to receive(:work).ordered.and_call_original
+      expect(job_definition).to receive(:delete!).ordered.and_call_original
 
       TestDeduplicationWorker.perform_async('hello')
     end

spec/lib/gitlab/sidekiq_middleware/duplicate_jobs/strategies/until_executed_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Gitlab::SidekiqMiddleware::DuplicateJobs::Strategies::UntilExecuted do
+  it_behaves_like 'deduplicating jobs when scheduling', :until_executed do
+    describe '#perform' do
+      let(:proc) { -> {} }
+
+      it 'deletes the lock after executing' do
+        expect(proc).to receive(:call).ordered
+        expect(fake_duplicate_job).to receive(:delete!).ordered
+
+        strategy.perform({}) do
+          proc.call
+        end
+      end
+    end
+  end
+end

spec/lib/gitlab/sidekiq_middleware/duplicate_jobs/strategies/until_executing_spec.rb

 # frozen_string_literal: true
 
-require 'fast_spec_helper'
+require 'spec_helper'
 
 RSpec.describe Gitlab::SidekiqMiddleware::DuplicateJobs::Strategies::UntilExecuting do
-  let(:fake_duplicate_job) do
-    instance_double(Gitlab::SidekiqMiddleware::DuplicateJobs::DuplicateJob)
-  end
-
-  subject(:strategy) { described_class.new(fake_duplicate_job) }
-
-  describe '#schedule' do
-    before do
-      allow(Gitlab::SidekiqLogging::DeduplicationLogger.instance).to receive(:log)
-    end
-
-    it 'checks for duplicates before yielding' do
-      expect(fake_duplicate_job).to receive(:scheduled?).twice.ordered.and_return(false)
-      expect(fake_duplicate_job).to(
-        receive(:check!)
-          .with(Gitlab::SidekiqMiddleware::DuplicateJobs::DuplicateJob::DUPLICATE_KEY_TTL)
-          .ordered
-          .and_return('a jid'))
-      expect(fake_duplicate_job).to receive(:duplicate?).ordered.and_return(false)
-
-      expect { |b| strategy.schedule({}, &b) }.to yield_control
-    end
-
-    it 'checks worker options for scheduled jobs' do
-      expect(fake_duplicate_job).to receive(:scheduled?).ordered.and_return(true)
-      expect(fake_duplicate_job).to receive(:options).ordered.and_return({})
-      expect(fake_duplicate_job).not_to receive(:check!)
-
-      expect { |b| strategy.schedule({}, &b) }.to yield_control
-    end
-
-    context 'job marking' do
-      it 'adds the jid of the existing job to the job hash' do
-        allow(fake_duplicate_job).to receive(:scheduled?).and_return(false)
-        allow(fake_duplicate_job).to receive(:check!).and_return('the jid')
-        allow(fake_duplicate_job).to receive(:droppable?).and_return(true)
-        allow(fake_duplicate_job).to receive(:options).and_return({})
-        job_hash = {}
-
-        expect(fake_duplicate_job).to receive(:duplicate?).and_return(true)
-        expect(fake_duplicate_job).to receive(:existing_jid).and_return('the jid')
-
-        strategy.schedule(job_hash) {}
-
-        expect(job_hash).to include('duplicate-of' => 'the jid')
-      end
-
-      context 'scheduled jobs' do
-        let(:time_diff) { 1.minute }
-
-        context 'scheduled in the past' do
-          it 'adds the jid of the existing job to the job hash' do
-            allow(fake_duplicate_job).to receive(:scheduled?).twice.and_return(true)
-            allow(fake_duplicate_job).to receive(:scheduled_at).and_return(Time.now - time_diff)
-            allow(fake_duplicate_job).to receive(:options).and_return({ including_scheduled: true })
-            allow(fake_duplicate_job).to(
-              receive(:check!)
-                .with(Gitlab::SidekiqMiddleware::DuplicateJobs::DuplicateJob::DUPLICATE_KEY_TTL)
-                .and_return('the jid'))
-            allow(fake_duplicate_job).to receive(:droppable?).and_return(true)
-            job_hash = {}
-
-            expect(fake_duplicate_job).to receive(:duplicate?).and_return(true)
-            expect(fake_duplicate_job).to receive(:existing_jid).and_return('the jid')
-
-            strategy.schedule(job_hash) {}
-
-            expect(job_hash).to include('duplicate-of' => 'the jid')
-          end
-        end
-
-        context 'scheduled in the future' do
-          it 'adds the jid of the existing job to the job hash' do
-            freeze_time do
-              allow(fake_duplicate_job).to receive(:scheduled?).twice.and_return(true)
-              allow(fake_duplicate_job).to receive(:scheduled_at).and_return(Time.now + time_diff)
-              allow(fake_duplicate_job).to receive(:options).and_return({ including_scheduled: true })
-              allow(fake_duplicate_job).to(
-                receive(:check!).with(time_diff.to_i).and_return('the jid'))
-              allow(fake_duplicate_job).to receive(:droppable?).and_return(true)
-              job_hash = {}
-
-              expect(fake_duplicate_job).to receive(:duplicate?).and_return(true)
-              expect(fake_duplicate_job).to receive(:existing_jid).and_return('the jid')
-
-              strategy.schedule(job_hash) {}
-
-              expect(job_hash).to include('duplicate-of' => 'the jid')
-            end
-          end
-        end
-      end
-    end
-
-    context "when the job is droppable" do
-      before do
-        allow(fake_duplicate_job).to receive(:scheduled?).and_return(false)
-        allow(fake_duplicate_job).to receive(:check!).and_return('the jid')
-        allow(fake_duplicate_job).to receive(:duplicate?).and_return(true)
-        allow(fake_duplicate_job).to receive(:options).and_return({})
-        allow(fake_duplicate_job).to receive(:existing_jid).and_return('the jid')
-        allow(fake_duplicate_job).to receive(:droppable?).and_return(true)
-      end
-
-      it 'drops the job' do
-        schedule_result = nil
-
-        expect(fake_duplicate_job).to receive(:droppable?).and_return(true)
-
-        expect { |b| schedule_result = strategy.schedule({}, &b) }.not_to yield_control
-        expect(schedule_result).to be(false)
-      end
-
-      it 'logs that the job was dropped' do
-        fake_logger = instance_double(Gitlab::SidekiqLogging::DeduplicationLogger)
-
-        expect(Gitlab::SidekiqLogging::DeduplicationLogger).to receive(:instance).and_return(fake_logger)
-        expect(fake_logger).to receive(:log).with(a_hash_including({ 'jid' => 'new jid' }), 'dropped until executing', {})
-
-        strategy.schedule({ 'jid' => 'new jid' }) {}
-      end
-
-      it 'logs the deduplication options of the worker' do
-        fake_logger = instance_double(Gitlab::SidekiqLogging::DeduplicationLogger)
+  it_behaves_like 'deduplicating jobs when scheduling', :until_executing do
+    describe '#perform' do
+      let(:proc) { -> {} }
 
-        expect(Gitlab::SidekiqLogging::DeduplicationLogger).to receive(:instance).and_return(fake_logger)
-        allow(fake_duplicate_job).to receive(:options).and_return({ foo: :bar })
-        expect(fake_logger).to receive(:log).with(a_hash_including({ 'jid' => 'new jid' }), 'dropped until executing', { foo: :bar })
+      it 'deletes the lock before executing' do
+        expect(fake_duplicate_job).to receive(:delete!).ordered
+        expect(proc).to receive(:call).ordered
 
-        strategy.schedule({ 'jid' => 'new jid' }) {}
-      end
+        strategy.perform({}) do
+          proc.call
         end
       end
-
-  describe '#perform' do
-    it 'deletes the lock before executing' do
-      expect(fake_duplicate_job).to receive(:delete!).ordered
-      expect { |b| strategy.perform({}, &b) }.to yield_control
     end
   end
 end

spec/lib/gitlab/sidekiq_middleware/duplicate_jobs/strategies_spec.rb

@@ -8,6 +8,10 @@ RSpec.describe Gitlab::SidekiqMiddleware::DuplicateJobs::Strategies do
       expect(described_class.for(:until_executing)).to eq(described_class::UntilExecuting)
     end
 
+    it 'returns the right class for `until_executed`' do
+      expect(described_class.for(:until_executed)).to eq(described_class::UntilExecuted)
+    end
+
     it 'returns the right class for `none`' do
       expect(described_class.for(:none)).to eq(described_class::None)
     end

spec/models/ci/build_trace_chunk_spec.rb

@@ -594,23 +594,19 @@ RSpec.describe Ci::BuildTraceChunk, :clean_gitlab_redis_shared_state do
           context 'when the chunk is being locked by a different worker' do
             let(:metrics) { spy('metrics') }
 
-            it 'does not raise an exception' do
-              lock_chunk do
-                expect { build_trace_chunk.persist_data! }.not_to raise_error
-              end
-            end
-
             it 'increments stalled chunk trace metric' do
               allow(build_trace_chunk)
                 .to receive(:metrics)
                 .and_return(metrics)
 
-              lock_chunk { build_trace_chunk.persist_data! }
+              expect do
+                subject
 
                 expect(metrics)
                   .to have_received(:increment_trace_operation)
                     .with(operation: :stalled)
                     .once
+              end.to raise_error(described_class::FailedToPersistDataError)
             end
 
             def lock_chunk(&block)

spec/support/shared_examples/lib/gitlab/sidekiq_middleware/strategy_shared_examples.rb

+# frozen_string_literal: true
+
+RSpec.shared_examples 'deduplicating jobs when scheduling' do |strategy_name|
+  let(:fake_duplicate_job) do
+    instance_double(Gitlab::SidekiqMiddleware::DuplicateJobs::DuplicateJob)
+  end
+
+  let(:expected_message) { "dropped #{strategy_name.to_s.humanize.downcase}" }
+
+  subject(:strategy) { Gitlab::SidekiqMiddleware::DuplicateJobs::Strategies.for(strategy_name).new(fake_duplicate_job) }
+
+  describe '#schedule' do
+    before do
+      allow(Gitlab::SidekiqLogging::DeduplicationLogger.instance).to receive(:log)
+    end
+
+    it 'checks for duplicates before yielding' do
+      expect(fake_duplicate_job).to receive(:scheduled?).twice.ordered.and_return(false)
+      expect(fake_duplicate_job).to(
+        receive(:check!)
+          .with(Gitlab::SidekiqMiddleware::DuplicateJobs::DuplicateJob::DUPLICATE_KEY_TTL)
+          .ordered
+          .and_return('a jid'))
+      expect(fake_duplicate_job).to receive(:duplicate?).ordered.and_return(false)
+
+      expect { |b| strategy.schedule({}, &b) }.to yield_control
+    end
+
+    it 'checks worker options for scheduled jobs' do
+      expect(fake_duplicate_job).to receive(:scheduled?).ordered.and_return(true)
+      expect(fake_duplicate_job).to receive(:options).ordered.and_return({})
+      expect(fake_duplicate_job).not_to receive(:check!)
+
+      expect { |b| strategy.schedule({}, &b) }.to yield_control
+    end
+
+    context 'job marking' do
+      it 'adds the jid of the existing job to the job hash' do
+        allow(fake_duplicate_job).to receive(:scheduled?).and_return(false)
+        allow(fake_duplicate_job).to receive(:check!).and_return('the jid')
+        allow(fake_duplicate_job).to receive(:droppable?).and_return(true)
+        allow(fake_duplicate_job).to receive(:options).and_return({})
+        job_hash = {}
+
+        expect(fake_duplicate_job).to receive(:duplicate?).and_return(true)
+        expect(fake_duplicate_job).to receive(:existing_jid).and_return('the jid')
+
+        strategy.schedule(job_hash) {}
+
+        expect(job_hash).to include('duplicate-of' => 'the jid')
+      end
+
+      context 'scheduled jobs' do
+        let(:time_diff) { 1.minute }
+
+        context 'scheduled in the past' do
+          it 'adds the jid of the existing job to the job hash' do
+            allow(fake_duplicate_job).to receive(:scheduled?).twice.and_return(true)
+            allow(fake_duplicate_job).to receive(:scheduled_at).and_return(Time.now - time_diff)
+            allow(fake_duplicate_job).to receive(:options).and_return({ including_scheduled: true })
+            allow(fake_duplicate_job).to(
+              receive(:check!)
+                .with(Gitlab::SidekiqMiddleware::DuplicateJobs::DuplicateJob::DUPLICATE_KEY_TTL)
+                .and_return('the jid'))
+            allow(fake_duplicate_job).to receive(:droppable?).and_return(true)
+            job_hash = {}
+
+            expect(fake_duplicate_job).to receive(:duplicate?).and_return(true)
+            expect(fake_duplicate_job).to receive(:existing_jid).and_return('the jid')
+
+            strategy.schedule(job_hash) {}
+
+            expect(job_hash).to include('duplicate-of' => 'the jid')
+          end
+        end
+
+        context 'scheduled in the future' do
+          it 'adds the jid of the existing job to the job hash' do
+            freeze_time do
+              allow(fake_duplicate_job).to receive(:scheduled?).twice.and_return(true)
+              allow(fake_duplicate_job).to receive(:scheduled_at).and_return(Time.now + time_diff)
+              allow(fake_duplicate_job).to receive(:options).and_return({ including_scheduled: true })
+              allow(fake_duplicate_job).to(
+                receive(:check!).with(time_diff.to_i).and_return('the jid'))
+              allow(fake_duplicate_job).to receive(:droppable?).and_return(true)
+              job_hash = {}
+
+              expect(fake_duplicate_job).to receive(:duplicate?).and_return(true)
+              expect(fake_duplicate_job).to receive(:existing_jid).and_return('the jid')
+
+              strategy.schedule(job_hash) {}
+
+              expect(job_hash).to include('duplicate-of' => 'the jid')
+            end
+          end
+        end
+      end
+    end
+
+    context "when the job is droppable" do
+      before do
+        allow(fake_duplicate_job).to receive(:scheduled?).and_return(false)
+        allow(fake_duplicate_job).to receive(:check!).and_return('the jid')
+        allow(fake_duplicate_job).to receive(:duplicate?).and_return(true)
+        allow(fake_duplicate_job).to receive(:options).and_return({})
+        allow(fake_duplicate_job).to receive(:existing_jid).and_return('the jid')
+        allow(fake_duplicate_job).to receive(:droppable?).and_return(true)
+      end
+
+      it 'drops the job' do
+        schedule_result = nil
+
+        expect(fake_duplicate_job).to receive(:droppable?).and_return(true)
+
+        expect { |b| schedule_result = strategy.schedule({}, &b) }.not_to yield_control
+        expect(schedule_result).to be(false)
+      end
+
+      it 'logs that the job was dropped' do
+        fake_logger = instance_double(Gitlab::SidekiqLogging::DeduplicationLogger)
+
+        expect(Gitlab::SidekiqLogging::DeduplicationLogger).to receive(:instance).and_return(fake_logger)
+        expect(fake_logger).to receive(:log).with(a_hash_including({ 'jid' => 'new jid' }), expected_message, {})
+
+        strategy.schedule({ 'jid' => 'new jid' }) {}
+      end
+
+      it 'logs the deduplication options of the worker' do
+        fake_logger = instance_double(Gitlab::SidekiqLogging::DeduplicationLogger)
+
+        expect(Gitlab::SidekiqLogging::DeduplicationLogger).to receive(:instance).and_return(fake_logger)
+        allow(fake_duplicate_job).to receive(:options).and_return({ foo: :bar })
+        expect(fake_logger).to receive(:log).with(a_hash_including({ 'jid' => 'new jid' }), expected_message, { foo: :bar })
+
+        strategy.schedule({ 'jid' => 'new jid' }) {}
+      end
+    end
+  end
+end