Adds tracing messages for slow git pushes

Whenever a git push takes more than 50 seconds the user
will receive a trace from each check performed along with
their timings

app/controllers/projects/git_http_controller.rb

@@ -8,6 +8,7 @@ class Projects::GitHttpController < Projects::GitHttpClientController
   rescue_from Gitlab::GitAccess::UnauthorizedError, with: :render_403
   rescue_from Gitlab::GitAccess::NotFoundError, with: :render_404
   rescue_from Gitlab::GitAccess::ProjectCreationError, with: :render_422
+  rescue_from Gitlab::GitAccess::TimeoutError, with: :render_503
 
   # GET /foo/bar.git/info/refs?service=git-upload-pack (git pull)
   # GET /foo/bar.git/info/refs?service=git-receive-pack (git push)
@@ -62,6 +63,10 @@ class Projects::GitHttpController < Projects::GitHttpClientController
     render plain: exception.message, status: :unprocessable_entity
   end
 
+  def render_503(exception)
+    render plain: exception.message, status: :service_unavailable
+  end
+
   def access
     @access ||= access_klass.new(access_actor, project,
       'http', authentication_abilities: authentication_abilities,

changelogs/unreleased/42790-improve-feedback-for-internal-git-access-checks-timeouts.yml

@@ -0,0 +1,5 @@
+---
+title: Adds trace of each access check when git push times out
+merge_request: 22265
+author:
+type: added

lib/api/internal.rb

@@ -65,6 +65,8 @@ module API
                          result
                        rescue Gitlab::GitAccess::UnauthorizedError => e
                          break response_with_status(code: 401, success: false, message: e.message)
+                       rescue Gitlab::GitAccess::TimeoutError => e
+                         break response_with_status(code: 503, success: false, message: e.message)
                        rescue Gitlab::GitAccess::NotFoundError => e
                          break response_with_status(code: 404, success: false, message: e.message)
                        end

lib/gitlab/checks/change_access.rb

@@ -18,11 +18,24 @@ module Gitlab
         lfs_objects_missing: 'LFS objects are missing. Ensure LFS is properly set up or try a manual "git lfs push --all".'
       }.freeze
 
-      attr_reader :user_access, :project, :skip_authorization, :skip_lfs_integrity_check, :protocol, :oldrev, :newrev, :ref, :branch_name, :tag_name
+      LOG_MESSAGES = {
+        push_checks: "Checking if you are allowed to push...",
+        delete_default_branch_check: "Checking if default branch is being deleted...",
+        protected_branch_checks: "Checking if you are force pushing to a protected branch...",
+        protected_branch_push_checks: "Checking if you are allowed to push to the protected branch...",
+        protected_branch_deletion_checks: "Checking if you are allowed to delete the protected branch...",
+        tag_checks: "Checking if you are allowed to change existing tags...",
+        protected_tag_checks: "Checking if you are creating, updating or deleting a protected tag...",
+        lfs_objects_exist_check: "Scanning repository for blobs stored in LFS and verifying their files have been uploaded to GitLab...",
+        commits_check_file_paths_validation: "Validating commits' file paths...",
+        commits_check: "Validating commits..." # different message in EE
+      }.freeze
+
+      attr_reader :user_access, :project, :skip_authorization, :skip_lfs_integrity_check, :protocol, :oldrev, :newrev, :ref, :branch_name, :tag_name, :logger
 
       def initialize(
         change, user_access:, project:, skip_authorization: false,
-        skip_lfs_integrity_check: false, protocol:
+        skip_lfs_integrity_check: false, protocol:, logger:
       )
         @oldrev, @newrev, @ref = change.values_at(:oldrev, :newrev, :ref)
         @branch_name = Gitlab::Git.branch_name(@ref)
@@ -32,6 +45,9 @@ module Gitlab
         @skip_authorization = skip_authorization
         @skip_lfs_integrity_check = skip_lfs_integrity_check
         @protocol = protocol
+
+        @logger = logger
+        @logger.log << "Running checks for ref: #{@branch_name || @tag_name}"
       end
 
       def exec(skip_commits_check: false)
@@ -49,27 +65,33 @@ module Gitlab
       protected
 
       def push_checks
+        logger.log_timed(LOG_MESSAGES[__method__]) do
           unless can_push?
             raise GitAccess::UnauthorizedError, ERROR_MESSAGES[:push_code]
           end
         end
+      end
 
       def branch_checks
         return unless branch_name
 
+        logger.log_timed(LOG_MESSAGES[:delete_default_branch_check]) do
           if deletion? && branch_name == project.default_branch
             raise GitAccess::UnauthorizedError, ERROR_MESSAGES[:delete_default_branch]
           end
+        end
 
         protected_branch_checks
       end
 
       def protected_branch_checks
-        return unless ProtectedBranch.protected?(project, branch_name)
+        logger.log_timed(LOG_MESSAGES[__method__]) do
+          return unless ProtectedBranch.protected?(project, branch_name) # rubocop:disable Cop/AvoidReturnFromBlocks
 
           if forced_push?
             raise GitAccess::UnauthorizedError, ERROR_MESSAGES[:force_push_protected_branch]
           end
+        end
 
         if deletion?
           protected_branch_deletion_checks
@@ -79,6 +101,7 @@ module Gitlab
       end
 
       def protected_branch_deletion_checks
+        logger.log_timed(LOG_MESSAGES[__method__]) do
           unless user_access.can_delete_branch?(branch_name)
             raise GitAccess::UnauthorizedError, ERROR_MESSAGES[:non_master_delete_protected_branch]
           end
@@ -87,8 +110,10 @@ module Gitlab
             raise GitAccess::UnauthorizedError, ERROR_MESSAGES[:non_web_delete_protected_branch]
           end
         end
+      end
 
       def protected_branch_push_checks
+        logger.log_timed(LOG_MESSAGES[__method__]) do
           if matching_merge_request?
             unless user_access.can_merge_to_branch?(branch_name) || user_access.can_push_to_branch?(branch_name)
               raise GitAccess::UnauthorizedError, ERROR_MESSAGES[:merge_protected_branch]
@@ -99,19 +124,23 @@ module Gitlab
             end
           end
         end
+      end
 
       def tag_checks
         return unless tag_name
 
+        logger.log_timed(LOG_MESSAGES[__method__]) do
           if tag_exists? && user_access.cannot_do_action?(:admin_project)
             raise GitAccess::UnauthorizedError, ERROR_MESSAGES[:change_existing_tags]
           end
+        end
 
         protected_tag_checks
       end
 
       def protected_tag_checks
-        return unless ProtectedTag.protected?(project, tag_name)
+        logger.log_timed(LOG_MESSAGES[__method__]) do
+          return unless ProtectedTag.protected?(project, tag_name) # rubocop:disable Cop/AvoidReturnFromBlocks
 
           raise(GitAccess::UnauthorizedError, ERROR_MESSAGES[:update_protected_tag]) if update?
           raise(GitAccess::UnauthorizedError, ERROR_MESSAGES[:delete_protected_tag]) if deletion?
@@ -120,20 +149,25 @@ module Gitlab
             raise GitAccess::UnauthorizedError, ERROR_MESSAGES[:create_protected_tag]
           end
         end
+      end
 
       def commits_check
         return if deletion? || newrev.nil?
         return unless should_run_commit_validations?
 
+        logger.log_timed(LOG_MESSAGES[__method__]) do
           # n+1: https://gitlab.com/gitlab-org/gitlab-ee/issues/3593
           ::Gitlab::GitalyClient.allow_n_plus_1_calls do
             commits.each do |commit|
               commit_check.validate(commit, validations_for_commit(commit))
             end
           end
+        end
 
+        logger.log_timed(LOG_MESSAGES[:commits_check_file_paths_validation]) do
           commit_check.validate_file_paths
         end
+      end
 
       # Method overwritten in EE to inject custom validations
       def validations_for_commit(_)
@@ -194,12 +228,14 @@ module Gitlab
       end
 
       def lfs_objects_exist_check
-        lfs_check = Checks::LfsIntegrity.new(project, newrev)
+        logger.log_timed(LOG_MESSAGES[__method__]) do
+          lfs_check = Checks::LfsIntegrity.new(project, newrev, logger.time_left)
 
           if lfs_check.objects_missing?
             raise GitAccess::UnauthorizedError, ERROR_MESSAGES[:lfs_objects_missing]
           end
         end
+      end
 
       def commit_check
         @commit_check ||= Gitlab::Checks::CommitCheck.new(project, user_access.user, newrev, oldrev)

lib/gitlab/checks/lfs_integrity.rb

@@ -3,9 +3,10 @@
 module Gitlab
   module Checks
     class LfsIntegrity
-      def initialize(project, newrev)
+      def initialize(project, newrev, time_left)
         @project = project
         @newrev = newrev
+        @time_left = time_left
       end
 
       # rubocop: disable CodeReuse/ActiveRecord
@@ -13,7 +14,7 @@ module Gitlab
         return false unless @newrev && @project.lfs_enabled?
 
         new_lfs_pointers = Gitlab::Git::LfsChanges.new(@project.repository, @newrev)
-                                                  .new_pointers(object_limit: ::Gitlab::Git::Repository::REV_LIST_COMMIT_LIMIT)
+                                                  .new_pointers(object_limit: ::Gitlab::Git::Repository::REV_LIST_COMMIT_LIMIT, dynamic_timeout: @time_left)
 
         return false unless new_lfs_pointers.present?
 

lib/gitlab/checks/timed_logger.rb

@@ -0,0 +1,69 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Checks
+    class TimedLogger
+      TimeoutError = Class.new(StandardError)
+
+      attr_reader :start_time
+      attr_accessor :log, :timeout
+
+      def initialize(start_time: Time.now, log: [], timeout:)
+        @start_time = start_time
+        @timeout = timeout
+        @log = log
+      end
+
+      def log_timed(log_message, start = Time.now)
+        check_timeout_reached
+
+        timed = true
+
+        yield
+
+        log << log_message + time_suffix_message(start: start)
+      rescue GRPC::DeadlineExceeded, TimeoutError
+        args = { cancelled: true }
+        args[:start] = start if timed
+
+        log << log_message + time_suffix_message(args)
+
+        raise TimeoutError
+      end
+
+      def check_timeout_reached
+        return unless time_expired?
+
+        raise TimeoutError
+      end
+
+      def time_left
+        (start_time + timeout.seconds) - Time.now
+      end
+
+      private
+
+      def time_expired?
+        time_left <= 0
+      end
+
+      def time_suffix_message(cancelled: false, start: nil)
+        return " (#{elapsed_time(start)}ms)" unless cancelled
+
+        if start
+          " (cancelled after #{elapsed_time(start)}ms)"
+        else
+          " (cancelled)"
+        end
+      end
+
+      def elapsed_time(start)
+        to_ms(Time.now - start)
+      end
+
+      def to_ms(elapsed)
+        (elapsed.to_f * 1000).round(2)
+      end
+    end
+  end
+end

lib/gitlab/git/lfs_changes.rb

@@ -6,8 +6,8 @@ module Gitlab
         @newrev = newrev
       end
 
-      def new_pointers(object_limit: nil, not_in: nil)
+      def new_pointers(object_limit: nil, not_in: nil, dynamic_timeout: nil)
-        @repository.gitaly_blob_client.get_new_lfs_pointers(@newrev, object_limit, not_in)
+        @repository.gitaly_blob_client.get_new_lfs_pointers(@newrev, object_limit, not_in, dynamic_timeout)
       end
 
       def all_pointers

lib/gitlab/git_access.rb

@@ -9,6 +9,7 @@ module Gitlab
     UnauthorizedError = Class.new(StandardError)
     NotFoundError = Class.new(StandardError)
     ProjectCreationError = Class.new(StandardError)
+    TimeoutError = Class.new(StandardError)
     ProjectMovedError = Class.new(NotFoundError)
 
     ERROR_MESSAGES = {
@@ -26,11 +27,12 @@ module Gitlab
       cannot_push_to_read_only: "You can't push code to a read-only GitLab instance."
     }.freeze
 
+    INTERNAL_TIMEOUT = 50.seconds.freeze
     DOWNLOAD_COMMANDS = %w{git-upload-pack git-upload-archive}.freeze
     PUSH_COMMANDS = %w{git-receive-pack}.freeze
     ALL_COMMANDS = DOWNLOAD_COMMANDS + PUSH_COMMANDS
 
-    attr_reader :actor, :project, :protocol, :authentication_abilities, :namespace_path, :project_path, :redirected_path, :auth_result_type, :changes
+    attr_reader :actor, :project, :protocol, :authentication_abilities, :namespace_path, :project_path, :redirected_path, :auth_result_type, :changes, :logger
 
     def initialize(actor, project, protocol, authentication_abilities:, namespace_path: nil, project_path: nil, redirected_path: nil, auth_result_type: nil)
       @actor    = actor
@@ -44,6 +46,7 @@ module Gitlab
     end
 
     def check(cmd, changes)
+      @logger = Checks::TimedLogger.new(timeout: INTERNAL_TIMEOUT)
       @changes = changes
 
       check_protocol!
@@ -269,14 +272,25 @@ module Gitlab
     end
 
     def check_single_change_access(change, skip_lfs_integrity_check: false)
-      Checks::ChangeAccess.new(
+      change_access = Checks::ChangeAccess.new(
         change,
         user_access: user_access,
         project: project,
         skip_authorization: deploy_key?,
         skip_lfs_integrity_check: skip_lfs_integrity_check,
-        protocol: protocol
+        protocol: protocol,
-      ).exec
+        logger: logger
+      )
+
+      change_access.exec
+    rescue Checks::TimedLogger::TimeoutError
+      header = <<~MESSAGE
+      Push operation timed out
+
+      Timing information for debugging purposes:
+      MESSAGE
+
+      raise TimeoutError, header + logger.log.join("\n")
     end
 
     def deploy_key

lib/gitlab/gitaly_client/blob_service.rb

@@ -72,7 +72,7 @@ module Gitlab
         GitalyClient::BlobsStitcher.new(response)
       end
 
-      def get_new_lfs_pointers(revision, limit, not_in)
+      def get_new_lfs_pointers(revision, limit, not_in, dynamic_timeout = nil)
         request = Gitaly::GetNewLFSPointersRequest.new(
           repository: @gitaly_repo,
           revision: encode_binary(revision),
@@ -85,7 +85,20 @@ module Gitlab
           request.not_in_refs += not_in
         end
 
-        response = GitalyClient.call(@gitaly_repo.storage_name, :blob_service, :get_new_lfs_pointers, request, timeout: GitalyClient.medium_timeout)
+        timeout =
+          if dynamic_timeout
+            [dynamic_timeout, GitalyClient.medium_timeout].min
+          else
+            GitalyClient.medium_timeout
+          end
+
+        response = GitalyClient.call(
+          @gitaly_repo.storage_name,
+          :blob_service,
+          :get_new_lfs_pointers,
+          request,
+          timeout: timeout
+        )
 
         map_lfs_pointers(response)
       end

spec/lib/gitlab/checks/change_access_spec.rb

@@ -10,13 +10,16 @@ describe Gitlab::Checks::ChangeAccess do
     let(:ref) { 'refs/heads/master' }
     let(:changes) { { oldrev: oldrev, newrev: newrev, ref: ref } }
     let(:protocol) { 'ssh' }
+    let(:timeout) { Gitlab::GitAccess::INTERNAL_TIMEOUT }
+    let(:logger) { Gitlab::Checks::TimedLogger.new(timeout: timeout) }
 
     subject(:change_access) do
       described_class.new(
         changes,
         project: project,
         user_access: user_access,
-        protocol: protocol
+        protocol: protocol,
+        logger: logger
       )
     end
 
@@ -30,6 +33,19 @@ describe Gitlab::Checks::ChangeAccess do
       end
     end
 
+    context 'when time limit was reached' do
+      it 'raises a TimeoutError' do
+        logger = Gitlab::Checks::TimedLogger.new(start_time: timeout.ago, timeout: timeout)
+        access = described_class.new(changes,
+                                     project: project,
+                                     user_access: user_access,
+                                     protocol: protocol,
+                                     logger: logger)
+
+        expect { access.exec }.to raise_error(Gitlab::Checks::TimedLogger::TimeoutError)
+      end
+    end
+
     context 'when the user is not allowed to push to the repo' do
       it 'raises an error' do
         expect(user_access).to receive(:can_do_action?).with(:push_code).and_return(false)

spec/lib/gitlab/checks/lfs_integrity_spec.rb

@@ -3,6 +3,7 @@ require 'spec_helper'
 describe Gitlab::Checks::LfsIntegrity do
   include ProjectForksHelper
 
+  let!(:time_left) { 50 }
   let(:project) { create(:project, :repository) }
   let(:repository) { project.repository }
   let(:newrev) do
@@ -15,7 +16,7 @@ describe Gitlab::Checks::LfsIntegrity do
     operations.commit_tree('8856a329dd38ca86dfb9ce5aa58a16d88cc119bd', "New LFS objects")
   end
 
-  subject { described_class.new(project, newrev) }
+  subject { described_class.new(project, newrev, time_left) }
 
   describe '#objects_missing?' do
     let(:blob_object) { repository.blob_at_branch('lfs', 'files/lfs/lfs_object.iso') }

spec/lib/gitlab/checks/timed_logger_spec.rb

@@ -0,0 +1,75 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Gitlab::Checks::TimedLogger do
+  let(:log_messages) do
+    {
+      foo: "Foo message..."
+    }
+  end
+
+  class FooCheck
+    attr_accessor :logger
+
+    INTERNAL_TIMEOUT = 50.seconds.freeze
+
+    def initialize(start_time, ref)
+      @logger = Gitlab::Checks::TimedLogger.new(start_time: start_time, timeout: INTERNAL_TIMEOUT)
+      @logger.log << "Checking ref: #{ref}"
+    end
+
+    def bar_check
+      2 + 2
+    end
+
+    def grpc_check
+      raise GRPC::DeadlineExceeded
+    end
+  end
+
+  describe '#log_timed' do
+    it 'logs message' do
+      start = Time.now
+      check = FooCheck.new(start, "bar")
+
+      Timecop.freeze(start + 30.seconds) do
+        check.logger.log_timed(log_messages[:foo], start) { check.bar_check }
+      end
+
+      expect(check.logger.log).to eq(["Checking ref: bar", "Foo message... (30000.0ms)"])
+    end
+
+    context 'when time limit was reached' do
+      it 'cancels action' do
+        start = Time.now
+        check = FooCheck.new(start, "bar")
+
+        Timecop.freeze(start + 50.seconds) do
+          expect do
+            check.logger.log_timed(log_messages[:foo], start) do
+              check.bar_check
+            end
+          end.to raise_error(described_class::TimeoutError)
+        end
+
+        expect(check.logger.log).to eq(["Checking ref: bar", "Foo message... (cancelled)"])
+      end
+
+      it 'cancels action with time elapsed if work was performed' do
+        start = Time.now
+        check = FooCheck.new(start, "bar")
+
+        Timecop.freeze(start + 30.seconds) do
+          expect do
+            check.logger.log_timed(log_messages[:foo], start) do
+              check.grpc_check
+            end
+          end.to raise_error(described_class::TimeoutError)
+
+          expect(check.logger.log).to eq(["Checking ref: bar", "Foo message... (cancelled after 30000.0ms)"])
+        end
+      end
+    end
+  end
+end

spec/lib/gitlab/git/lfs_changes_spec.rb

@@ -15,5 +15,9 @@ describe Gitlab::Git::LfsChanges do
     it 'limits new_objects using object_limit' do
       expect(subject.new_pointers(object_limit: 1)).to eq([])
     end
+
+    it 'times out if given a small dynamic timeout' do
+      expect { subject.new_pointers(dynamic_timeout: 0.001) }.to raise_error(GRPC::DeadlineExceeded)
+    end
   end
 end

spec/lib/gitlab/git_access_spec.rb

@@ -934,6 +934,16 @@ describe Gitlab::GitAccess do
         # There is still an N+1 query with protected branches
         expect { access.check('git-receive-pack', changes) }.not_to exceed_query_limit(control_count).with_threshold(1)
       end
+
+      it 'raises TimeoutError when #check_single_change_access raises a timeout error' do
+        message = "Push operation timed out\n\nTiming information for debugging purposes:\nRunning checks for ref: wow"
+
+        expect_next_instance_of(Gitlab::Checks::ChangeAccess) do |check|
+          expect(check).to receive(:exec).and_raise(Gitlab::Checks::TimedLogger::TimeoutError)
+        end
+
+        expect { access.check('git-receive-pack', changes) }.to raise_error(described_class::TimeoutError, message)
+      end
     end
   end
 

spec/requests/api/internal_spec.rb

@@ -494,6 +494,24 @@ describe API::Internal do
       end
     end
 
+    context 'request times out' do
+      context 'git push' do
+        it 'responds with a gateway timeout' do
+          personal_project = create(:project, namespace: user.namespace)
+
+          expect_next_instance_of(Gitlab::GitAccess) do |access|
+            expect(access).to receive(:check).and_raise(Gitlab::GitAccess::TimeoutError, "Foo")
+          end
+          push(key, personal_project)
+
+          expect(response).to have_gitlab_http_status(503)
+          expect(json_response['status']).to be_falsey
+          expect(json_response['message']).to eq("Foo")
+          expect(user.reload.last_activity_on).to be_nil
+        end
+      end
+    end
+
     context "archived project" do
       before do
         project.add_developer(user)