Use downcased path to container repository as this is expected path by Docker

CHANGELOG

@@ -21,6 +21,7 @@ v 8.9.0 (unreleased)
   - Fix bug when sorting issues by milestone due date and filtering by two or more labels
   - Remove 'main language' feature
   - Pipelines can be canceled only when there are running builds
+  - Use downcased path to container repository as this is expected path by Docker
   - Projects pending deletion will render a 404 page
   - Measure queue duration between gitlab-workhorse and Rails
   - Make authentication service for Container Registry to be compatible with < Docker 1.11

app/models/project.rb

@@ -313,17 +313,17 @@ class Project < ActiveRecord::Base
     return unless Gitlab.config.registry.enabled
 
     @container_registry_repository ||= begin
-      token = Auth::ContainerRegistryAuthenticationService.full_access_token(path_with_namespace)
+      token = Auth::ContainerRegistryAuthenticationService.full_access_token(path_with_namespace.downcase)
       url = Gitlab.config.registry.api_url
       host_port = Gitlab.config.registry.host_port
       registry = ContainerRegistry::Registry.new(url, token: token, path: host_port)
-      registry.repository(path_with_namespace)
+      registry.repository(path_with_namespace.downcase)
     end
   end
 
   def container_registry_repository_url
     if Gitlab.config.registry.enabled
-      "#{Gitlab.config.registry.host_port}/#{path_with_namespace}"
+      "#{Gitlab.config.registry.host_port}/#{path_with_namespace.downcase}"
     end
   end
 

spec/models/project_spec.rb

@@ -792,6 +792,13 @@ describe Project, models: true do
     subject { project.container_registry_repository }
 
     it { is_expected.not_to be_nil }
+
+    context 'for uppercase project path' do
+      let(:project) { create(:empty_project, path: 'PROJECT') }
+
+      it { expect(subject.path).not_to end_with(project.path) }
+      it { expect(subject.path).to end_with(project.path.downcase) }
+    end
   end
 
   describe '#container_registry_repository_url' do
@@ -810,6 +817,13 @@ describe Project, models: true do
       end
 
       it { is_expected.not_to be_nil }
+
+      context 'for uppercase project path' do
+        let(:project) { create(:empty_project, path: 'PROJECT') }
+
+        it { is_expected.not_to end_with(project.path) }
+        it { is_expected.to end_with(project.path.downcase) }
+      end
     end
 
     context 'for disabled registry' do