Merge branch 'rewind-iid-on-pipelines' into 'master'

Rewind iid on pipelines

Closes #59362

See merge request gitlab-org/gitlab-ce!26490

app/models/concerns/atomic_internal_id.rb

@@ -53,6 +53,20 @@ module AtomicInternalId
         value
       end
+
+      define_method("reset_#{scope}_#{column}") do
+        if value = read_attribute(column)
+          scope_value = association(scope).reader
+          scope_attrs = { scope_value.class.table_name.singularize.to_sym => scope_value }
+          usage = self.class.table_name.to_sym
+
+          if InternalId.reset(self, scope_attrs, usage, value)
+            write_attribute(column, nil)
+          end
+        end
+
+        read_attribute(column)
+      end
     end
   end
 end

app/models/internal_id.rb

@@ -55,7 +55,8 @@ class InternalId < ApplicationRecord
     def track_greatest(subject, scope, usage, new_value, init)
       return new_value unless available?
-      InternalIdGenerator.new(subject, scope, usage, init).track_greatest(new_value)
+      InternalIdGenerator.new(subject, scope, usage)
+        .track_greatest(init, new_value)
     end
     def generate_next(subject, scope, usage, init)
@@ -63,7 +64,15 @@ class InternalId < ApplicationRecord
       # This can be the case in other (unrelated) migration specs
       return (init.call(subject) || 0) + 1 unless available?
-      InternalIdGenerator.new(subject, scope, usage, init).generate
+      InternalIdGenerator.new(subject, scope, usage)
+        .generate(init)
+    end
+
+    def reset(subject, scope, usage, value)
+      return false unless available?
+
+      InternalIdGenerator.new(subject, scope, usage)
+        .reset(value)
     end
     # Flushing records is generally safe in a sense that those
@@ -103,14 +112,11 @@ class InternalId < ApplicationRecord
     # subject: The instance we're generating an internal id for. Gets passed to init if called.
     # scope: Attributes that define the scope for id generation.
     # usage: Symbol to define the usage of the internal id, see InternalId.usages
-    # init: Block that gets called to initialize InternalId record if not present
-    #       Make sure to not throw exceptions in the absence of records (if this is expected).
-    attr_reader :subject, :scope, :init, :scope_attrs, :usage
-    def initialize(subject, scope, usage, init)
+    attr_reader :subject, :scope, :scope_attrs, :usage
+    def initialize(subject, scope, usage)
       @subject = subject
       @scope = scope
-      @init = init
       @usage = usage
       raise ArgumentError, 'Scope is not well-defined, need at least one column for scope (given: 0)' if scope.empty?
@@ -121,23 +127,40 @@ class InternalId < ApplicationRecord
     end
     # Generates next internal id and returns it
-    def generate
+    # init: Block that gets called to initialize InternalId record if not present
+    #       Make sure to not throw exceptions in the absence of records (if this is expected).
+    def generate(init)
       subject.transaction do
         # Create a record in internal_ids if one does not yet exist
         # and increment its last value
         #
         # Note this will acquire a ROW SHARE lock on the InternalId record
-        (lookup || create_record).increment_and_save!
+        (lookup || create_record(init)).increment_and_save!
       end
     end
+    # Reset tries to rewind to `value-1`. This will only succeed,
+    # if `value` stored in database is equal to `last_value`.
+    # value: The expected last_value to decrement
+    def reset(value)
+      return false unless value
+
+      updated =
+        InternalId
+          .where(**scope, usage: usage_value)
+          .where(last_value: value)
+          .update_all('last_value = last_value - 1')
+
+      updated > 0
+    end
+
     # Create a record in internal_ids if one does not yet exist
     # and set its new_value if it is higher than the current last_value
     #
     # Note this will acquire a ROW SHARE lock on the InternalId record
-    def track_greatest(new_value)
+    def track_greatest(init, new_value)
       subject.transaction do
-        (lookup || create_record).track_greatest_and_save!(new_value)
+        (lookup || create_record(init)).track_greatest_and_save!(new_value)
       end
     end
@@ -158,7 +181,7 @@ class InternalId < ApplicationRecord
     # was faster in doing this, we'll realize once we hit the unique key constraint
     # violation. We can safely roll-back the nested transaction and perform
     # a lookup instead to retrieve the record.
-    def create_record
+    def create_record(init)
       subject.transaction(requires_new: true) do
         InternalId.create!(
           **scope,

app/services/ci/create_pipeline_service.rb

@@ -55,6 +55,10 @@ module Ci
         end
       end
+      # If pipeline is not persisted, try to recover IID
+      pipeline.reset_project_iid unless pipeline.persisted? ||
+          Feature.disabled?(:ci_pipeline_rewind_iid, project, default_enabled: true)
+
       pipeline
     end

changelogs/unreleased/rewind-iid-on-pipelines.yml

+---
+title: Rewind IID on Ci::Pipelines
+merge_request: 26490
+author:
+type: fixed

spec/models/internal_id_spec.rb

@@ -107,6 +107,57 @@ describe InternalId do
     end
   end
+  describe '.reset' do
+    subject { described_class.reset(issue, scope, usage, value) }
+
+    context 'in the absence of a record' do
+      let(:value) { 2 }
+
+      it 'does not revert back the value' do
+        expect { subject }.not_to change { described_class.count }
+        expect(subject).to be_falsey
+      end
+    end
+
+    context 'when valid iid is used to reset' do
+      let!(:value) { generate_next }
+
+      context 'and iid is a latest one' do
+        it 'does rewind and next generated value is the same' do
+          expect(subject).to be_truthy
+          expect(generate_next).to eq(value)
+        end
+      end
+
+      context 'and iid is not a latest one' do
+        it 'does not rewind' do
+          generate_next
+
+          expect(subject).to be_falsey
+          expect(generate_next).to be > value
+        end
+      end
+
+      def generate_next
+        described_class.generate_next(issue, scope, usage, init)
+      end
+    end
+
+    context 'with an insufficient schema version' do
+      let(:value) { 2 }
+
+      before do
+        described_class.reset_column_information
+        # Project factory will also call the current_version
+        expect(ActiveRecord::Migrator).to receive(:current_version).twice.and_return(InternalId::REQUIRED_SCHEMA_VERSION - 1)
+      end
+
+      it 'does not reset any of the iids' do
+        expect(subject).to be_falsey
+      end
+    end
+  end
+
   describe '.track_greatest' do
     let(:value) { 9001 }
     subject { described_class.track_greatest(issue, scope, usage, value, init) }

spec/services/ci/create_pipeline_service_spec.rb

@@ -25,7 +25,8 @@ describe Ci::CreatePipelineService do
       merge_request: nil,
       push_options: nil,
       source_sha: nil,
-      target_sha: nil)
+      target_sha: nil,
+      save_on_errors: true)
       params = { ref: ref,
                  before: '00000000',
                  after: after,
@@ -36,7 +37,7 @@ describe Ci::CreatePipelineService do
                  target_sha: target_sha }
       described_class.new(project, user, params).execute(
-        source, trigger_request: trigger_request, merge_request: merge_request)
+        source, save_on_errors: save_on_errors, trigger_request: trigger_request, merge_request: merge_request)
     end
     # rubocop:enable Metrics/ParameterLists
@@ -57,6 +58,7 @@ describe Ci::CreatePipelineService do
         expect(pipeline).to eq(project.ci_pipelines.last)
         expect(pipeline).to have_attributes(user: user)
         expect(pipeline).to have_attributes(status: 'pending')
+        expect(pipeline.iid).not_to be_nil
         expect(pipeline.repository_source?).to be true
         expect(pipeline.builds.first).to be_kind_of(Ci::Build)
       end
@@ -446,6 +448,43 @@ describe Ci::CreatePipelineService do
         expect(Ci::Build.all).to be_empty
         expect(Ci::Pipeline.count).to eq(0)
       end
+
+      describe '#iid' do
+        let(:internal_id) do
+          InternalId.find_by(project_id: project.id, usage: :ci_pipelines)
+        end
+
+        before do
+          expect_any_instance_of(Ci::Pipeline).to receive(:ensure_project_iid!)
+            .and_call_original
+        end
+
+        context 'when ci_pipeline_rewind_iid is enabled' do
+          before do
+            stub_feature_flags(ci_pipeline_rewind_iid: true)
+          end
+
+          it 'rewinds iid' do
+            result = execute_service
+
+            expect(result).not_to be_persisted
+            expect(internal_id.last_value).to eq(0)
+          end
+        end
+
+        context 'when ci_pipeline_rewind_iid is disabled' do
+          before do
+            stub_feature_flags(ci_pipeline_rewind_iid: false)
+          end
+
+          it 'does not rewind iid' do
+            result = execute_service
+
+            expect(result).not_to be_persisted
+            expect(internal_id.last_value).to eq(1)
+          end
+        end
+      end
     end
     context 'with manual actions' do

spec/support/shared_examples/models/atomic_internal_id_spec.rb

@@ -52,20 +52,20 @@ shared_examples_for 'AtomicInternalId' do |validate_presence: true|
         expect(InternalId).to receive(:generate_next).with(instance, scope_attrs, usage, any_args).and_return(iid)
         subject
-        expect(instance.public_send(internal_id_attribute)).to eq(iid)
+        expect(read_internal_id).to eq(iid)
       end
       it 'does not overwrite an existing internal id' do
-        instance.public_send("#{internal_id_attribute}=", 4711)
-        expect { subject }.not_to change { instance.public_send(internal_id_attribute) }
+        write_internal_id(4711)
+        expect { subject }.not_to change { read_internal_id }
       end
       context 'when the instance has an internal ID set' do
         let(:internal_id) { 9001 }
         it 'calls InternalId.update_last_value and sets the `last_value` to that of the instance' do
-          instance.send("#{internal_id_attribute}=", internal_id)
+          write_internal_id(internal_id)
           expect(InternalId)
             .to receive(:track_greatest)
@@ -75,5 +75,39 @@ shared_examples_for 'AtomicInternalId' do |validate_presence: true|
         end
       end
     end
+
+    describe "#reset_scope_internal_id_attribute" do
+      it 'rewinds the allocated IID' do
+        expect { ensure_scope_attribute! }.not_to raise_error
+        expect(read_internal_id).not_to be_nil
+
+        expect(reset_scope_attribute).to be_nil
+        expect(read_internal_id).to be_nil
+      end
+
+      it 'allocates the same IID' do
+        internal_id = ensure_scope_attribute!
+        reset_scope_attribute
+        expect(read_internal_id).to be_nil
+
+        expect(ensure_scope_attribute!).to eq(internal_id)
+      end
+    end
+
+    def ensure_scope_attribute!
+      instance.public_send(:"ensure_#{scope}_#{internal_id_attribute}!")
+    end
+
+    def reset_scope_attribute
+      instance.public_send(:"reset_#{scope}_#{internal_id_attribute}")
+    end
+
+    def read_internal_id
+      instance.public_send(internal_id_attribute)
+    end
+
+    def write_internal_id(value)
+      instance.public_send(:"#{internal_id_attribute}=", value)
+    end
   end
 end