Added has_valid_deployment? to Ci::Build

Added method to check whether a deployment is valid.
Used method as check to drop a build.
Added tests for this new method.

app/models/commit_status_enums.rb

@@ -18,6 +18,7 @@ module CommitStatusEnums
       unmet_prerequisites: 10,
       scheduler_failure: 11,
       data_integrity_failure: 12,
+      forward_deployment_failure: 13,
       insufficient_bridge_permissions: 1_001,
       downstream_bridge_project_not_found: 1_002,
       invalid_bridge_trigger: 1_003,

app/models/deployment.rb

@@ -41,6 +41,9 @@ class Deployment < ApplicationRecord
 
   scope :visible, -> { where(status: %i[running success failed canceled]) }
   scope :stoppable, -> { where.not(on_stop: nil).where.not(deployable_id: nil).success }
+  scope :active, -> { where(status: %i[created running]) }
+  scope :older_than, -> (deployment) { where('id < ?', deployment.id) }
+  scope :with_deployable, -> { includes(:deployable).where('deployable_id IS NOT NULL') }
 
   state_machine :status, initial: :created do
     event :run do
@@ -74,6 +77,14 @@ class Deployment < ApplicationRecord
         Deployments::FinishedWorker.perform_async(id)
       end
     end
+
+    after_transition any => :running do |deployment|
+      next unless deployment.project.forward_deployment_enabled?
+
+      deployment.run_after_commit do
+        Deployments::ForwardDeploymentWorker.perform_async(id)
+      end
+    end
   end
 
   enum status: {

app/models/environment.rb

@@ -12,6 +12,7 @@ class Environment < ApplicationRecord
 
   has_many :deployments, -> { visible }, dependent: :destroy # rubocop:disable Cop/ActiveRecordDependent
   has_many :successful_deployments, -> { success }, class_name: 'Deployment'
+  has_many :active_deployments, -> { active }, class_name: 'Deployment'
   has_many :prometheus_alerts, inverse_of: :environment
 
   has_one :last_deployment, -> { success.order('deployments.id DESC') }, class_name: 'Deployment'

app/models/project.rb

@@ -343,6 +343,7 @@ class Project < ApplicationRecord
   delegate :last_pipeline, to: :commit, allow_nil: true
   delegate :external_dashboard_url, to: :metrics_setting, allow_nil: true, prefix: true
   delegate :default_git_depth, :default_git_depth=, to: :ci_cd_settings, prefix: :ci
+  delegate :forward_deployment_enabled, :forward_deployment_enabled=, :forward_deployment_enabled?, to: :ci_cd_settings
 
   # Validations
   validates :creator, presence: true, on: :create

app/models/project_ci_cd_setting.rb

@@ -18,6 +18,8 @@ class ProjectCiCdSetting < ApplicationRecord
     },
     allow_nil: true
 
+  default_value_for :forward_deployment_enabled, true
+
   def self.available?
     @available ||=
       ActiveRecord::Migrator.current_version >= MINIMUM_SCHEMA_VERSION
@@ -28,6 +30,10 @@ class ProjectCiCdSetting < ApplicationRecord
     super
   end
 
+  def forward_deployment_enabled?
+    super && ::Feature.enabled?(:forward_deployment_enabled, project)
+  end
+
   private
 
   def set_default_git_depth

app/presenters/commit_status_presenter.rb

@@ -14,6 +14,7 @@ class CommitStatusPresenter < Gitlab::View::Presenter::Delegated
     unmet_prerequisites: 'The job failed to complete prerequisite tasks',
     scheduler_failure: 'The scheduler failed to assign job to the runner, please try again or contact system administrator',
     data_integrity_failure: 'There has been a structural integrity problem detected, please contact system administrator',
+    forward_deployment_failure: 'The deployment job is older than the previously succeeded deployment job, and therefore cannot be run',
     invalid_bridge_trigger: 'This job could not be executed because downstream pipeline trigger definition is invalid',
     downstream_bridge_project_not_found: 'This job could not be executed because downstream bridge project could not be found',
     insufficient_bridge_permissions: 'This job could not be executed because of insufficient permissions to create a downstream pipeline',

app/services/deployments/older_deployments_drop_service.rb

+# frozen_string_literal: true
+
+module Deployments
+  class OlderDeploymentsDropService
+    attr_reader :deployment
+
+    def initialize(deployment_id)
+      @deployment = Deployment.find_by_id(deployment_id)
+    end
+
+    def execute
+      return unless @deployment&.running?
+
+      older_deployments.find_each do |older_deployment|
+        older_deployment.deployable&.drop!(:forward_deployment_failure)
+      rescue => e
+        Gitlab::ErrorTracking.track_exception(e, subject_id: @deployment.id, deployment_id: older_deployment.id)
+      end
+    end
+
+    private
+
+    def older_deployments
+      @deployment
+        .environment
+        .active_deployments
+        .older_than(@deployment)
+        .with_deployable
+    end
+  end
+end

app/workers/all_queues.yml

@@ -225,6 +225,12 @@
   :latency_sensitive: 
   :resource_boundary: :cpu
   :weight: 3
+- :name: deployment:deployments_forward_deployment
+  :feature_category: :continuous_delivery
+  :has_external_dependencies: 
+  :latency_sensitive: 
+  :resource_boundary: :unknown
+  :weight: 3
 - :name: deployment:deployments_success
   :feature_category: :continuous_delivery
   :has_external_dependencies: 

app/workers/deployments/forward_deployment_worker.rb

+# frozen_string_literal: true
+
+module Deployments
+  class ForwardDeploymentWorker
+    include ApplicationWorker
+
+    queue_namespace :deployment
+    feature_category :continuous_delivery
+
+    def perform(deployment_id)
+      Deployments::OlderDeploymentsDropService.new(deployment_id).execute
+    end
+  end
+end

changelogs/unreleased/25276-allow-forward-deploys-only.yml

+---
+title: Allow to deploy only forward deployments
+merge_request: 22959
+author:
+type: changed

db/migrate/20200124143014_add_restrict_deployment_order_to_project_ci_cd_settings.rb

+# frozen_string_literal: true
+
+class AddRestrictDeploymentOrderToProjectCiCdSettings < ActiveRecord::Migration[5.2]
+  DOWNTIME = false
+
+  def change
+    add_column :project_ci_cd_settings, :forward_deployment_enabled, :boolean
+  end
+end

db/schema.rb

@@ -3163,6 +3163,7 @@ ActiveRecord::Schema.define(version: 2020_02_13_204737) do
     t.boolean "group_runners_enabled", default: true, null: false
     t.boolean "merge_pipelines_enabled"
     t.integer "default_git_depth"
+    t.boolean "forward_deployment_enabled"
     t.index ["project_id"], name: "index_project_ci_cd_settings_on_project_id", unique: true
   end
 

lib/gitlab/ci/status/build/failed.rb

@@ -19,6 +19,7 @@ module Gitlab
             unmet_prerequisites: 'unmet prerequisites',
             scheduler_failure: 'scheduler failure',
             data_integrity_failure: 'data integrity failure',
+            forward_deployment_failure: 'forward deployment failure',
             invalid_bridge_trigger: 'downstream pipeline trigger definition is invalid',
             downstream_bridge_project_not_found: 'downstream project could not be found',
             insufficient_bridge_permissions: 'no permissions to trigger downstream pipeline',

spec/factories/projects.rb

@@ -37,6 +37,7 @@ FactoryBot.define do
       group_runners_enabled { nil }
       import_status { nil }
       import_jid { nil }
+      forward_deployment_enabled { nil }
     end
 
     after(:create) do |project, evaluator|

spec/models/deployment_spec.rb

@@ -281,6 +281,45 @@ describe Deployment do
         expect(last_deployments).to match_array(deployments.last(2))
       end
     end
+
+    describe 'active' do
+      subject { described_class.active }
+
+      it 'retrieves the active deployments' do
+        deployment1 = create(:deployment, status: :created )
+        deployment2 = create(:deployment, status: :running )
+        create(:deployment, status: :failed )
+        create(:deployment, status: :canceled )
+
+        is_expected.to contain_exactly(deployment1, deployment2)
+      end
+    end
+
+    describe 'older_than' do
+      let(:deployment) { create(:deployment) }
+
+      subject { described_class.older_than(deployment) }
+
+      it 'retrives the correct older deployments' do
+        older_deployment1 = create(:deployment)
+        older_deployment2 = create(:deployment)
+        deployment
+        create(:deployment)
+
+        is_expected.to contain_exactly(older_deployment1, older_deployment2)
+      end
+    end
+
+    describe 'with_deployable' do
+      subject { described_class.with_deployable }
+
+      it 'retrieves deployments with deployable builds' do
+        with_deployable = create(:deployment)
+        create(:deployment, deployable: nil)
+
+        is_expected.to contain_exactly(with_deployable)
+      end
+    end
   end
 
   describe '#includes_commit?' do

spec/models/project_ci_cd_setting_spec.rb

@@ -32,6 +32,12 @@ describe ProjectCiCdSetting do
     end
   end
 
+  describe '#forward_deployment_enabled' do
+    it 'is true by default' do
+      expect(described_class.new.forward_deployment_enabled).to be_truthy
+    end
+  end
+
   describe '#default_git_depth' do
     let(:default_value) { described_class::DEFAULT_GIT_DEPTH }
 

spec/services/deployments/older_deployments_drop_service_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Deployments::OlderDeploymentsDropService do
+  let(:environment) { create(:environment) }
+  let(:deployment) { create(:deployment, environment: environment) }
+  let(:service) { described_class.new(deployment) }
+
+  describe '#execute' do
+    subject { service.execute }
+
+    shared_examples 'it does not drop any build' do
+      it do
+        expect { subject }.to not_change(Ci::Build.failed, :count)
+      end
+    end
+
+    context 'when deployment is nil' do
+      let(:deployment) { nil }
+
+      it_behaves_like 'it does not drop any build'
+    end
+
+    context 'when a deployment is passed in' do
+      context 'and there is no active deployment for the related environment' do
+        let(:deployment) { create(:deployment, :canceled, environment: environment) }
+        let(:deployment2) { create(:deployment, :canceled, environment: environment) }
+
+        before do
+          deployment
+          deployment2
+        end
+
+        it_behaves_like 'it does not drop any build'
+      end
+
+      context 'and there are active deployment for the related environment' do
+        let(:deployment) { create(:deployment, :running, environment: environment) }
+        let(:deployment2) { create(:deployment, :running, environment: environment) }
+
+        context 'and there is no older deployment than "deployment"' do
+          before do
+            deployment
+            deployment2
+          end
+
+          it_behaves_like 'it does not drop any build'
+        end
+
+        context 'and there is an older deployment than "deployment"' do
+          let(:older_deployment) { create(:deployment, :running, environment: environment) }
+
+          before do
+            older_deployment
+            deployment
+            deployment2
+          end
+
+          it 'drops that older deployment' do
+            deployable = older_deployment.deployable
+            expect(deployable.failed?).to be_falsey
+
+            subject
+
+            expect(deployable.reload.failed?).to be_truthy
+          end
+
+          context 'and there is no deployable for that older deployment' do
+            let(:older_deployment) { create(:deployment, :running, environment: environment, deployable: nil) }
+
+            it_behaves_like 'it does not drop any build'
+          end
+        end
+      end
+    end
+  end
+end