Make `rake gitlab:workhorse:install` use /workhorse

GitLab-Workhorse is published in two places now:
gitlab-org/gitlab-workhorse (old) and gitlab-org/gitlab/workhorse
(new). This updates the `gitlab:workhorse:instal` Rake task to compile
Workhorse from the new location.

changelogs/unreleased/jv-rake-workhorse-vendored.yml

+---
+title: Let `rake gitlab:workhorse:install` use vendored workhorse
+merge_request: 49250
+author:
+type: changed

doc/update/upgrading_from_source.md

@@ -210,17 +210,12 @@ sudo -u git -H make build
 
 ### 10. Update GitLab Workhorse
 
-Install and compile GitLab Workhorse. GitLab Workhorse uses
-[GNU Make](https://www.gnu.org/software/make/).
-If you are not using Linux you may have to run `gmake` instead of
-`make` below.
+Install and compile GitLab Workhorse.
 
 ```shell
-cd /home/git/gitlab-workhorse
+cd /home/git/gitlab
 
-sudo -u git -H git fetch --all --tags --prune
-sudo -u git -H git checkout v$(</home/git/gitlab/GITLAB_WORKHORSE_VERSION)
-sudo -u git -H make
+sudo -u git -H bundle exec rake "gitlab:workhorse:install[/home/git/gitlab-workhorse]" RAILS_ENV=production
 ```
 
 ### 11. Update Gitaly

lib/tasks/gitlab/workhorse.rake

@@ -8,18 +8,32 @@ namespace :gitlab do
         abort %(Please specify the directory where you want to install gitlab-workhorse:\n  rake "gitlab:workhorse:install[/home/git/gitlab-workhorse]")
       end
 
+      # It used to be the case that the binaries in the target directory match
+      # the source code. An administrator could run `make` to rebuild the
+      # binaries for instance. Or they could read the source code, or run `git
+      # log` to see what changed. Or they could patch workhorse for some
+      # reason and recompile it. None of those things make sense anymore once
+      # the transition in https://gitlab.com/groups/gitlab-org/-/epics/4826 is
+      # done: there would be an outdated copy of the workhorse source code for
+      # the administrator to poke at.
+      #
+      # To prevent this possible confusion and make clear what is going on, we
+      # have created a special branch `workhorse-move-notice` in the old
+      # gitlab-workhorse repository which contains no Go files anymore, just a
+      # README explaining what is going on. See:
+      # https://gitlab.com/gitlab-org/gitlab-workhorse/tree/workhorse-move-notice
+      #
       args.with_defaults(repo: 'https://gitlab.com/gitlab-org/gitlab-workhorse.git')
+      checkout_or_clone_version(version: 'workhorse-move-notice', repo: args.repo, target_dir: args.dir, clone_opts: %w[--depth 1])
 
-      version = Gitlab::Workhorse.version
+      _, which_status = Gitlab::Popen.popen(%w[which gmake])
+      make = which_status == 0 ? 'gmake' : 'make'
+      command = %W[#{make} -C #{Rails.root.join('workhorse')} install PREFIX=#{File.absolute_path(args.dir)}]
 
-      checkout_or_clone_version(version: version, repo: args.repo, target_dir: args.dir, clone_opts: %w[--depth 1])
+      run_command!(command)
 
-      _, status = Gitlab::Popen.popen(%w[which gmake])
-      command = status == 0 ? 'gmake' : 'make'
-
-      Dir.chdir(args.dir) do
-        run_command!([command])
-      end
+      # 'make install' puts the binaries in #{args.dir}/bin but the init script expects them in args.dir
+      FileUtils.mv(Dir["#{args.dir}/bin/*"], args.dir)
     end
   end
 end

scripts/update-workhorse

 #!/bin/sh
 set -e
 WORKHORSE_DIR=workhorse/
-WORKHORSE_REF="v$(cat GITLAB_WORKHORSE_VERSION)"
+WORKHORSE_REF="$(cat GITLAB_WORKHORSE_VERSION)"
 WORKHORSE_URL=${GITLAB_WORKHORSE_URL:-https://gitlab.com/gitlab-org/gitlab-workhorse.git}
 
 if [ $# -gt 1 ] || ([ $# = 1 ] && [ x$1 != xcheck ]); then
@@ -9,6 +9,11 @@ if [ $# -gt 1 ] || ([ $# = 1 ] && [ x$1 != xcheck ]); then
   exit 1
 fi
 
+if echo "$WORKHORSE_REF" | grep -q '^[0-9]\+\.[0-9]\+\.[0-9]\+' ; then
+  # Assume this is a tagged release
+  WORKHORSE_REF="v${WORKHORSE_REF}"
+fi
+
 clean="$(git status --porcelain)"
 if [ -n "$clean" ] ; then
   echo 'error: working directory is not clean:'

spec/tasks/gitlab/workhorse_rake_spec.rb

@@ -10,7 +10,7 @@ RSpec.describe 'gitlab:workhorse namespace rake task' do
   describe 'install' do
     let(:repo) { 'https://gitlab.com/gitlab-org/gitlab-workhorse.git' }
     let(:clone_path) { Rails.root.join('tmp/tests/gitlab-workhorse').to_s }
-    let(:version) { File.read(Rails.root.join(Gitlab::Workhorse::VERSION_FILE)).chomp }
+    let(:workhorse_source) { Rails.root.join('workhorse').to_s }
 
     context 'no dir given' do
       it 'aborts and display a help message' do
@@ -30,13 +30,9 @@ RSpec.describe 'gitlab:workhorse namespace rake task' do
     end
 
     describe 'checkout or clone' do
-      before do
-        expect(Dir).to receive(:chdir).with(clone_path)
-      end
-
       it 'calls checkout_or_clone_version with the right arguments' do
         expect(main_object)
-          .to receive(:checkout_or_clone_version).with(version: version, repo: repo, target_dir: clone_path, clone_opts: %w[--depth 1])
+          .to receive(:checkout_or_clone_version).with(version: 'workhorse-move-notice', repo: repo, target_dir: clone_path, clone_opts: %w[--depth 1])
 
         run_rake_task('gitlab:workhorse:install', clone_path)
       end
@@ -45,7 +41,6 @@ RSpec.describe 'gitlab:workhorse namespace rake task' do
     describe 'gmake/make' do
       before do
         FileUtils.mkdir_p(clone_path)
-        expect(Dir).to receive(:chdir).with(clone_path).and_call_original
       end
 
       context 'gmake is available' do
@@ -56,7 +51,7 @@ RSpec.describe 'gitlab:workhorse namespace rake task' do
 
         it 'calls gmake in the gitlab-workhorse directory' do
           expect(Gitlab::Popen).to receive(:popen).with(%w[which gmake]).and_return(['/usr/bin/gmake', 0])
-          expect(main_object).to receive(:run_command!).with(['gmake']).and_return(true)
+          expect(main_object).to receive(:run_command!).with(["gmake", "-C", workhorse_source, "install", "PREFIX=#{clone_path}"]).and_return(true)
 
           run_rake_task('gitlab:workhorse:install', clone_path)
         end
@@ -70,7 +65,7 @@ RSpec.describe 'gitlab:workhorse namespace rake task' do
 
         it 'calls make in the gitlab-workhorse directory' do
           expect(Gitlab::Popen).to receive(:popen).with(%w[which gmake]).and_return(['', 42])
-          expect(main_object).to receive(:run_command!).with(['make']).and_return(true)
+          expect(main_object).to receive(:run_command!).with(["make", "-C", workhorse_source, "install", "PREFIX=#{clone_path}"]).and_return(true)
 
           run_rake_task('gitlab:workhorse:install', clone_path)
         end