Add submodule update API endpoint

This new endpoint allow users to update a submodule's reference.

The MR involves adding a new operation RPC operation in gitaly-proto
(see gitlab-org/gitaly-proto!233) and change Gitaly to use this
new version (see gitlab-org/gitaly!936).

See gitlab-org/gitlab-ce!20949

4 files changed, 88 insertions, 0 deletions

diff --git a/lib/api/api.rb b/lib/api/api.rb
index c49c52213bf..8e259961828 100644
--- a/lib/api/api.rb
+++ b/lib/api/api.rb
@@ -143,6 +143,7 @@ module API
     mount ::API::Settings
     mount ::API::SidekiqMetrics
     mount ::API::Snippets
+    mount ::API::Submodules
     mount ::API::Subscriptions
     mount ::API::SystemHooks
     mount ::API::Tags
diff --git a/lib/api/submodules.rb b/lib/api/submodules.rb
new file mode 100644
index 00000000000..72d7d994102
--- /dev/null
+++ b/lib/api/submodules.rb
@@ -0,0 +1,47 @@
+# frozen_string_literal: true
+
+module API
+  class Submodules < Grape::API
+    before { authenticate! }
+
+    helpers do
+      def commit_params(attrs)
+        {
+          submodule: attrs[:submodule],
+          commit_sha: attrs[:commit_sha],
+          branch_name: attrs[:branch],
+          commit_message: attrs[:commit_message]
+        }
+      end
+    end
+
+    params do
+      requires :id, type: String, desc: 'The project ID'
+    end
+    resource :projects, requirements: Files::FILE_ENDPOINT_REQUIREMENTS do
+      desc 'Update existing submodule reference in repository' do
+        success Entities::Commit
+      end
+      params do
+        requires :submodule, type: String, desc: 'Url encoded full path to submodule.'
+        requires :commit_sha, type: String, desc: 'Commit sha to update the submodule to.'
+        requires :branch, type: String, desc: 'Name of the branch to commit into.'
+        optional :commit_message, type: String, desc: 'Commit message. If no message is provided a default one will be set.'
+      end
+      put ":id/repository/submodules/:submodule", requirements: Files::FILE_ENDPOINT_REQUIREMENTS do
+        authorize! :push_code, user_project
+
+        submodule_params = declared_params(include_missing: false)
+
+        result = ::Submodules::UpdateService.new(user_project, current_user, commit_params(submodule_params)).execute
+
+        if result[:status] == :success
+          commit_detail = user_project.repository.commit(result[:result])
+          present commit_detail, with: Entities::CommitDetail
+        else
+          render_api_error!(result[:message], result[:http_status] || 400)
+        end
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/git/repository.rb b/lib/gitlab/git/repository.rb
index 20cd257bb98..1642c4c5687 100644
--- a/lib/gitlab/git/repository.rb
+++ b/lib/gitlab/git/repository.rb
@@ -571,6 +571,20 @@ module Gitlab
         end
       end
 
+      def update_submodule(user:, submodule:, commit_sha:, message:, branch:)
+        args = {
+          user: user,
+          submodule: submodule,
+          commit_sha: commit_sha,
+          branch: branch,
+          message: message
+        }
+
+        wrapped_gitaly_errors do
+          gitaly_operation_client.user_update_submodule(args)
+        end
+      end
+
       # Delete the specified branch from the repository
       def delete_branch(branch_name)
         wrapped_gitaly_errors do
diff --git a/lib/gitlab/gitaly_client/operation_service.rb b/lib/gitlab/gitaly_client/operation_service.rb
index 0f148614b20..1f42f657f68 100644
--- a/lib/gitlab/gitaly_client/operation_service.rb
+++ b/lib/gitlab/gitaly_client/operation_service.rb
@@ -230,6 +230,32 @@ module Gitlab
         response.squash_sha
       end
 
+      def user_update_submodule(user:, submodule:, commit_sha:, branch:, message:)
+        request = Gitaly::UserUpdateSubmoduleRequest.new(
+          repository: @gitaly_repo,
+          user: Gitlab::Git::User.from_gitlab(user).to_gitaly,
+          commit_sha: commit_sha,
+          branch: encode_binary(branch),
+          submodule: encode_binary(submodule),
+          commit_message: encode_binary(message)
+        )
+
+        response = GitalyClient.call(
+          @repository.storage,
+          :operation_service,
+          :user_update_submodule,
+          request
+        )
+
+        if response.pre_receive_error.present?
+          raise Gitlab::Git::PreReceiveError, response.pre_receive_error
+        elsif response.commit_error.present?
+          raise Gitlab::Git::CommitError, response.commit_error
+        else
+          Gitlab::Git::OperationService::BranchUpdate.from_gitaly(response.branch_update)
+        end
+      end
+
       def user_commit_files(
         user, branch_name, commit_message, actions, author_email, author_name,
         start_branch_name, start_repository)