ruby: Move scripts that generate Proto sources into tools directory

We've got multiple scripts that are required to generate Ruby code from
our Protobuf definitions in the `_support` directory. This has multiple
smells:

    - It's out-of-line with all the other tools, which nowadays are
      located in the `tools` directory.

    - It's hard to discover and find out which parts logically form a
      unit.

    - We are reusing the Gemfile of the Ruby sidecar to pin the
      `grpc-tools` dependency to a specific version.

Move the tooling into its own `tools/protogem` directory that's got its
own Gemfile to fix these points. This also allows us to auto-update
dependencies via the Renovate bot like we do for our other tools.

5 files changed, 135 insertions, 0 deletions

diff --git a/tools/protogem/Gemfile b/tools/protogem/Gemfile
new file mode 100644
index 000000000..9cafb7578
--- /dev/null
+++ b/tools/protogem/Gemfile
@@ -0,0 +1,3 @@
+source 'https://rubygems.org'
+
+gem 'grpc-tools', '~> 1.42.0'
diff --git a/tools/protogem/Gemfile.lock b/tools/protogem/Gemfile.lock
new file mode 100644
index 000000000..57b2bf6f9
--- /dev/null
+++ b/tools/protogem/Gemfile.lock
@@ -0,0 +1,13 @@
+GEM
+  remote: https://rubygems.org/
+  specs:
+    grpc-tools (1.42.0)
+
+PLATFORMS
+  ruby
+
+DEPENDENCIES
+  grpc-tools (~> 1.42.0)
+
+BUNDLED WITH
+   2.3.24
diff --git a/tools/protogem/generate-proto-ruby b/tools/protogem/generate-proto-ruby
new file mode 100755
index 000000000..544da294f
--- /dev/null
+++ b/tools/protogem/generate-proto-ruby
@@ -0,0 +1,44 @@
+#!/usr/bin/env ruby
+
+require 'erb'
+require 'fileutils'
+
+require_relative 'run.rb'
+
+PROTO_INCLUDE = './proto'
+PROTO_FILES = Dir[File.join(PROTO_INCLUDE, '*.proto')].sort.map { |f| File.absolute_path(f) }
+RUBY_PREFIX = 'ruby/proto'
+RUBY_VERSION_FILE = 'gitaly/version.rb'
+
+def main
+  ruby_lib_gitaly = File.join(RUBY_PREFIX, 'gitaly')
+  FileUtils.rm(Dir[File.join(ruby_lib_gitaly, '**/*_pb.rb')])
+  FileUtils.mkdir_p(ruby_lib_gitaly)
+
+  Dir.chdir(File.join(Dir.pwd, 'tools', 'protogem')) do
+    # Using an absolute path make sure the prefixes match, or the passed in file
+    # locations. `protoc` requires this.
+    proto_include_abs = File.absolute_path(File.join('..', '..', PROTO_INCLUDE))
+
+    run!(%W[bundle exec grpc_tools_ruby_protoc -I #{proto_include_abs} --ruby_out=../../#{ruby_lib_gitaly} --grpc_out=../../#{ruby_lib_gitaly}] + PROTO_FILES)
+  end
+
+  write_ruby_requires
+end
+
+def write_ruby_requires
+  requires = Dir.chdir(RUBY_PREFIX) { Dir['gitaly/*_services_pb.rb'] }.sort
+  abort "No auto-generated Ruby service files found" if requires.empty?
+  requires.unshift(RUBY_VERSION_FILE)
+  gem_root = File.join(RUBY_PREFIX, 'gitaly.rb')
+  gem_root_template = ERB.new <<~EOT
+    # This file is generated by #{File.basename($0)}. Do not edit.
+    $:.unshift(File.expand_path('../gitaly', __FILE__))
+    <% requires.each do |f| %>
+    require '<%= f.sub(/\.rb$/, '') %>'
+    <% end %>
+  EOT
+  open(gem_root, 'w') { |f| f.write(gem_root_template.result(binding)) }
+end
+
+main
diff --git a/tools/protogem/publish-gem b/tools/protogem/publish-gem
new file mode 100755
index 000000000..f0a1b138e
--- /dev/null
+++ b/tools/protogem/publish-gem
@@ -0,0 +1,39 @@
+#!/usr/bin/env ruby
+
+require_relative 'run.rb'
+
+def main(tag)
+  version = tag.sub(/^v/, '')
+
+  unless version.match?(/\d+\.\d+\.\d+(-rc\d+)?/)
+    abort "Version string #{version.inspect} does not look like a Gitaly Release tag (e.g. \"v1.0.2\"). Aborting."
+  end
+
+  ref = capture!(%w[git describe --tag]).chomp
+  if ref != "v#{version}"
+    abort "Checkout tag v#{version} to publish.\n\t git checkout v#{version}"
+  end
+
+  puts 'Testing for changed files'
+  run!(%w[git diff --quiet --exit-code])
+
+  puts 'Testing for staged changes'
+  run!(%w[git diff --quiet --cached --exit-code])
+
+  gem = "gitaly-#{version}.gem"
+  run!(['gem', 'build', 'gitaly.gemspec', '--output', gem])
+  abort "gem not found: #{gem}" unless File.exist?(gem)
+
+  puts "Proceed to publish version #{tag}? Enter 'Yes' to continue; Ctrl-C to abort"
+  $stdout.flush
+  abort unless $stdin.gets.chomp == 'Yes'
+
+  run!(%W[gem push #{gem}])
+end
+
+unless ARGV.count == 1
+  warn "Usage: #{$0} TAG"
+  abort
+end
+
+main(ARGV[0])
diff --git a/tools/protogem/run.rb b/tools/protogem/run.rb
new file mode 100644
index 000000000..e7d29a1e8
--- /dev/null
+++ b/tools/protogem/run.rb
@@ -0,0 +1,36 @@
+def run!(cmd, chdir='.')
+  GitalySupport.print_cmd(cmd)
+  unless system(*cmd, chdir: chdir)
+    GitalySupport.fail_cmd!(cmd)
+  end
+end
+
+def run2!(cmd, chdir: '.', out: 1)
+  GitalySupport.print_cmd(cmd)
+  unless system(*cmd, chdir: chdir, out: out)
+    GitalySupport.fail_cmd!(cmd)
+  end
+end
+
+def capture!(cmd, chdir='.')
+  GitalySupport.print_cmd(cmd)
+  output = IO.popen(cmd, chdir: chdir) { |io| io.read }
+  GitalySupport.fail_cmd!(cmd) unless $?.success?
+  output
+end
+
+module GitalySupport
+  class << self
+    def print_cmd(cmd)
+      puts '-> ' + printable_cmd(cmd)
+    end
+
+    def fail_cmd!(cmd)
+      abort "command failed: #{printable_cmd(cmd)}"
+    end
+
+    def printable_cmd(cmd)
+      cmd.join(' ')
+    end
+  end
+end