Implement active pipelines limit

ee/lib/ee/gitlab/ci/limit.rb

+module EE
+  module Gitlab
+    module Ci
+      ##
+      # Abstract base class for CI/CD Quotas
+      #
+      class Limit
+        def initialize(_context, _resource)
+        end
+
+        def enabled?
+          raise NotImplementedError
+        end
+
+        def exceeded?
+          raise NotImplementedError
+        end
+
+        def message
+          raise NotImplementedError
+        end
+      end
+    end
+  end
+end

ee/lib/ee/gitlab/ci/pipeline/quota/activity.rb

+module EE
+  module Gitlab
+    module Ci
+      module Pipeline
+        module Quota
+          class Activity < Ci::Limit
+            include ActionView::Helpers::TextHelper
+
+            def initialize(namespace, project)
+              @namespace = namespace
+              @project = project
+            end
+
+            def enabled?
+              @namespace.max_active_pipelines > 0
+            end
+
+            def exceeded?
+              return false unless enabled?
+
+              excessive_pipelines_count > 0
+            end
+
+            def message
+              return unless exceeded?
+
+              'Active pipelines limit exceeded by ' \
+                "#{pluralize(excessive_pipelines_count, 'pipeline')}!"
+            end
+
+            private
+
+            def excessive_pipelines_count
+              @excessive ||= alive_pipelines_count - max_active_pipelines_count
+            end
+
+            def alive_pipelines_count
+              @project.pipelines.alive.count
+            end
+
+            def max_active_pipelines_count
+              @namespace.max_active_pipelines
+            end
+          end
+        end
+      end
+    end
+  end
+end

spec/ee/spec/lib/gitlab/ci/pipeline/quota/activity_spec.rb

+require 'spec_helper'
+
+describe EE::Gitlab::Ci::Pipeline::Quota::Activity do
+  set(:namespace) { create(:namespace, plan: EE::Namespace::GOLD_PLAN) }
+  set(:project) { create(:project, namespace: namespace) }
+
+  let(:limit) { described_class.new(namespace, project) }
+
+  shared_context 'pipeline activity limit exceeded' do
+    before do
+      create(:ci_pipeline, project: project, status: 'created')
+      create(:ci_pipeline, project: project, status: 'pending')
+      create(:ci_pipeline, project: project, status: 'running')
+
+      namespace.plan.update_column(:active_pipelines_limit, 1)
+    end
+  end
+
+  shared_context 'pipeline activity limit not exceeded' do
+    before do
+      namespace.plan.update_column(:active_pipelines_limit, 2)
+    end
+  end
+
+  describe '#enabled?' do
+    context 'when limit is enabled in plan' do
+      before do
+        namespace.plan.update_column(:active_pipelines_limit, 10)
+      end
+
+      it 'is enabled' do
+        expect(limit).to be_enabled
+      end
+    end
+
+    context 'when limit is not enabled' do
+      before do
+        namespace.plan.update_column(:active_pipelines_limit, 0)
+      end
+
+      it 'is not enabled' do
+        expect(limit).not_to be_enabled
+      end
+    end
+  end
+
+  describe '#exceeded?' do
+    context 'when limit is exceeded' do
+      include_context 'pipeline activity limit exceeded'
+
+      it 'is exceeded' do
+        expect(limit).to be_exceeded
+      end
+    end
+
+    context 'when limit is not exceeded' do
+      include_context 'pipeline activity limit not exceeded'
+
+      it 'is not exceeded' do
+        expect(limit).not_to be_exceeded
+      end
+    end
+  end
+
+  describe '#message' do
+    context 'when limit is exceeded' do
+      include_context 'pipeline activity limit exceeded'
+
+      it 'returns info about pipeline activity limit exceeded' do
+        expect(limit.message)
+          .to eq "Active pipelines limit exceeded by 2 pipelines!"
+      end
+    end
+  end
+end