Adds plan limits for feature flags

**app/models/operations/feature_flag.rb:**

- Adds limitable concern.

**spec/models/operations/feature_flag_spec.rb:**

- Adds tests for limits.

**changelogs/unreleased/feature-flag-plan-limits.yml:**

- the changelog

**db/migrate/
20200831204646_add_project_feature_flags_to_plan_limits.rb:**

- the column

**db/migrate/
20200831222347_insert_project_feature_flags_plan_limits.rb:**

- the settings

**db/schema_migrations/20200831204646:**

- migration artifact

**db/schema_migrations/20200831222347:**

- migration artifact

**db/structure.sql:**

- structure update

**spec/migrations/
insert_project_feature_flags_plan_limits_spec.rb:**

- spec tests for the migration

app/models/operations/feature_flag.rb

@@ -4,8 +4,11 @@ module Operations
   class FeatureFlag < ApplicationRecord
     include AtomicInternalId
     include IidRoutes
+    include Limitable
 
     self.table_name = 'operations_feature_flags'
+    self.limit_scope = :project
+    self.limit_name = 'project_feature_flags'
 
     belongs_to :project
 

changelogs/unreleased/feature-flag-plan-limits.yml

+---
+title: Adds feature flags plan limits
+merge_request:
+author:
+type: security

db/migrate/20200831204646_add_project_feature_flags_to_plan_limits.rb

+# frozen_string_literal: true
+
+class AddProjectFeatureFlagsToPlanLimits < ActiveRecord::Migration[6.0]
+  DOWNTIME = false
+
+  def change
+    add_column(:plan_limits, :project_feature_flags, :integer, default: 200, null: false)
+  end
+end

db/migrate/20200831222347_insert_project_feature_flags_plan_limits.rb

+# frozen_string_literal: true
+
+class InsertProjectFeatureFlagsPlanLimits < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  def up
+    return unless Gitlab.com?
+
+    create_or_update_plan_limit('project_feature_flags', 'free', 50)
+    create_or_update_plan_limit('project_feature_flags', 'bronze', 100)
+    create_or_update_plan_limit('project_feature_flags', 'silver', 150)
+    create_or_update_plan_limit('project_feature_flags', 'gold', 200)
+  end
+
+  def down
+    return unless Gitlab.com?
+
+    create_or_update_plan_limit('project_feature_flags', 'free', 0)
+    create_or_update_plan_limit('project_feature_flags', 'bronze', 0)
+    create_or_update_plan_limit('project_feature_flags', 'silver', 0)
+    create_or_update_plan_limit('project_feature_flags', 'gold', 0)
+  end
+end

db/schema_migrations/20200831204646

+06e87d83d5520e6ffbfb839d15a6dd02ad2caf5737136441d496e29e03a07e64
\ No newline at end of file

db/schema_migrations/20200831222347

+00af22b19af29b453f0022ded835bd9246c602c63a04a51ef93cbedd47047753
\ No newline at end of file

db/structure.sql

@@ -14367,6 +14367,7 @@ CREATE TABLE plan_limits (
     nuget_max_file_size bigint DEFAULT 524288000 NOT NULL,
     pypi_max_file_size bigint DEFAULT '3221225472'::bigint NOT NULL,
     generic_packages_max_file_size bigint DEFAULT '5368709120'::bigint NOT NULL,
+    project_feature_flags integer DEFAULT 200 NOT NULL,
     golang_max_file_size bigint DEFAULT 104857600 NOT NULL
 );
 

spec/migrations/insert_project_feature_flags_plan_limits_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+require Rails.root.join(
+  'db',
+  'migrate',
+  '20200831222347_insert_project_feature_flags_plan_limits.rb'
+)
+
+RSpec.describe InsertProjectFeatureFlagsPlanLimits do
+  let(:migration) { described_class.new }
+  let(:plans) { table(:plans) }
+  let(:plan_limits) { table(:plan_limits) }
+  let!(:default_plan) { plans.create!(name: 'default') }
+  let!(:free_plan) { plans.create!(name: 'free') }
+  let!(:bronze_plan) { plans.create!(name: 'bronze') }
+  let!(:silver_plan) { plans.create!(name: 'silver') }
+  let!(:gold_plan) { plans.create!(name: 'gold') }
+  let!(:default_plan_limits) do
+    plan_limits.create!(plan_id: default_plan.id, project_feature_flags: 200)
+  end
+
+  context 'when on Gitlab.com' do
+    before do
+      expect(Gitlab).to receive(:com?).at_most(:twice).and_return(true)
+    end
+
+    describe '#up' do
+      it 'updates the project_feature_flags plan limits' do
+        migration.up
+
+        expect(plan_limits.pluck(:plan_id, :project_feature_flags)).to contain_exactly(
+          [default_plan.id, 200],
+          [free_plan.id, 50],
+          [bronze_plan.id, 100],
+          [silver_plan.id, 150],
+          [gold_plan.id, 200]
+        )
+      end
+    end
+
+    describe '#down' do
+      it 'removes the project_feature_flags plan limits' do
+        migration.up
+        migration.down
+
+        expect(plan_limits.pluck(:plan_id, :project_feature_flags)).to contain_exactly(
+          [default_plan.id, 200],
+          [free_plan.id, 0],
+          [bronze_plan.id, 0],
+          [silver_plan.id, 0],
+          [gold_plan.id, 0]
+        )
+      end
+    end
+  end
+
+  context 'when on self-hosted' do
+    before do
+      expect(Gitlab).to receive(:com?).at_most(:twice).and_return(false)
+    end
+
+    describe '#up' do
+      it 'does not change the plan limits' do
+        migration.up
+
+        expect(plan_limits.pluck(:project_feature_flags)).to contain_exactly(200)
+      end
+    end
+
+    describe '#down' do
+      it 'does not change the plan limits' do
+        migration.up
+        migration.down
+
+        expect(plan_limits.pluck(:project_feature_flags)).to contain_exactly(200)
+      end
+    end
+  end
+end

spec/models/operations/feature_flag_spec.rb

@@ -7,6 +7,10 @@ RSpec.describe Operations::FeatureFlag do
 
   subject { create(:operations_feature_flag) }
 
+  it_behaves_like 'includes Limitable concern' do
+    subject { build(:operations_feature_flag, project: create(:project)) }
+  end
+
   describe 'associations' do
     it { is_expected.to belong_to(:project) }
     it { is_expected.to have_many(:scopes) }