Manifest content-type to be stored in obj storage

Update dependency proxy uploader to set the
content-type based on what is returned from
the original request.

app/controllers/groups/dependency_proxy_for_containers_controller.rb

@@ -20,8 +20,14 @@ class Groups::DependencyProxyForContainersController < Groups::ApplicationContro
       response.headers['Content-Length'] = result[:manifest].size
       response.headers['Docker-Distribution-Api-Version'] = DependencyProxy::DISTRIBUTION_API_VERSION
       response.headers['Etag'] = "\"#{result[:manifest].digest}\""
-
-      send_upload(result[:manifest].file, send_params: { type: result[:manifest].content_type })
+      content_type = result[:manifest].content_type
+
+      send_upload(
+        result[:manifest].file,
+        proxy: true,
+        redirect_params: { query: { 'response-content-type' => content_type } },
+        send_params: { type: content_type }
+      )
     else
       render status: result[:http_status], json: result[:message]
     end

app/uploaders/dependency_proxy/file_uploader.rb

@@ -3,6 +3,7 @@
 class DependencyProxy::FileUploader < GitlabUploader
   include ObjectStorage::Concern
 
+  before :cache, :set_content_type
   storage_options Gitlab.config.dependency_proxy
 
   alias_method :upload, :model
@@ -17,6 +18,17 @@ class DependencyProxy::FileUploader < GitlabUploader
 
   private
 
+  # Docker manifests return a custom content type
+  # GCP will only use the content-type that is stored with the file
+  # and will not allow it to be overwritten when downloaded
+  # so we must store the custom content type in object storage.
+  # This does not apply to DependencyProxy::Blob uploads.
+  def set_content_type(file)
+    return unless model.class == DependencyProxy::Manifest
+
+    file.content_type = model.content_type
+  end
+
   def dynamic_segment
     Gitlab::HashedPath.new('dependency_proxy', model.group_id, 'files', model.id, root_hash: model.group_id)
   end

spec/uploaders/dependency_proxy/file_uploader_spec.rb

@@ -2,25 +2,43 @@
 require 'spec_helper'
 
 RSpec.describe DependencyProxy::FileUploader do
-  let(:blob) { create(:dependency_proxy_blob) }
-  let(:uploader) { described_class.new(blob, :file) }
-  let(:path) { Gitlab.config.dependency_proxy.storage_path }
+  describe 'DependencyProxy::Blob uploader' do
+    let_it_be(:blob) { create(:dependency_proxy_blob) }
+    let_it_be(:path) { Gitlab.config.dependency_proxy.storage_path }
+    let(:uploader) { described_class.new(blob, :file) }
 
-  subject { uploader }
+    subject { uploader }
 
-  it_behaves_like "builds correct paths",
-                  store_dir: %r[\h{2}/\h{2}],
-                  cache_dir: %r[/dependency_proxy/tmp/cache],
-                  work_dir: %r[/dependency_proxy/tmp/work]
+    it_behaves_like "builds correct paths",
+                    store_dir: %r[\h{2}/\h{2}],
+                    cache_dir: %r[/dependency_proxy/tmp/cache],
+                    work_dir: %r[/dependency_proxy/tmp/work]
+
+    context 'object store is remote' do
+      before do
+        stub_dependency_proxy_object_storage
+      end
 
-  context 'object store is remote' do
-    before do
-      stub_dependency_proxy_object_storage
+      include_context 'with storage', described_class::Store::REMOTE
+
+      it_behaves_like "builds correct paths",
+                      store_dir: %r[\h{2}/\h{2}]
     end
+  end
 
-    include_context 'with storage', described_class::Store::REMOTE
+  describe 'DependencyProxy::Manifest uploader' do
+    let_it_be(:manifest) { create(:dependency_proxy_manifest) }
+    let_it_be(:initial_content_type) { 'application/json' }
+    let_it_be(:fixture_file) { fixture_file_upload('spec/fixtures/dependency_proxy/manifest', initial_content_type) }
+    let(:uploader) { described_class.new(manifest, :file) }
 
-    it_behaves_like "builds correct paths",
-                    store_dir: %r[\h{2}/\h{2}]
+    subject { uploader }
+
+    it 'will change upload file content type to match the model content type', :aggregate_failures do
+      uploader.cache!(fixture_file)
+
+      expect(uploader.file.content_type).to eq(manifest.content_type)
+      expect(uploader.file.content_type).not_to eq(initial_content_type)
+    end
   end
 end