Integrate rubocop-daemon

bin/console

@@ -4,6 +4,7 @@
 require 'bundler/setup'
 require 'irb'
 require 'rubocop'
+require 'rubocop/server'
 
 ARGV.clear
 

changelog/new_integrate_rubocop_server.md

@@ -0,0 +1 @@
+* [#10706](https://github.com/rubocop/rubocop/pull/10706): Integrate rubocop-daemon to add server options. ([@koic][])

codespell.txt

@@ -1,4 +1,5 @@
 ba
+creat
 enviromnent
 filetest
 fo

docs/modules/ROOT/nav.adoc

@@ -5,6 +5,7 @@
 ** xref:usage/basic_usage.adoc[Basic Usage]
 ** xref:usage/autocorrect.adoc[Autocorrect]
 ** xref:usage/caching.adoc[Caching]
+** xref:usage/server.adoc[Server]
 * xref:configuration.adoc[Configuration]
 * xref:cops.adoc[Cops]
 * xref:formatters.adoc[Formatters]

docs/modules/ROOT/pages/integration_with_other_tools.adoc

@@ -7,7 +7,7 @@ to do autocorrection for you. In these cases, `rubocop` ends up getting called r
 which may result in some slowness, as `rubocop` has to require its entire environment on
 each call.
 
-You can alleviate some of that boot time by using
+You can alleviate some of that boot time by using xref:server.adoc["Server"] or
 https://github.com/fohte/rubocop-daemon[rubocop-daemon]. `rubocop-daemon` is a
 wrapper around `rubocop` that loads everything into a daemonized process so that
 subsequent runs save on that boot time after the first execution. Please see the

docs/modules/ROOT/pages/usage/server.adoc

@@ -0,0 +1,84 @@
+= Server Mode
+
+You can reduce the RuboCop boot time by using the `--server` option.
+
+The server option speeds up the launch of the `rubocop` command by serverizing
+the process that loaded the RuboCop runtime production files (i.e. `require 'rubocop'`).
+
+NOTE: The feature cannot be used on JRuby and Windows that do not support fork.
+
+== Run with Server
+
+There are two ways to enable server.
+
+- `rubocop --server` ... If server process has not started yet,
+start server process and execute inspection with server.
+- `rubocop --start-server` ... Just start server process.
+
+When server is started, it outputs the host and port.
+
+```console
+% rubocop --start-server
+RuboCop server starting on 127.0.0.1:55772.
+```
+
+NOTE: The `rubocop` command is executed using server process if server is started.
+Whenever server process is not running, it will load the RuboCop runtime files and execute.
+(same behavior as 1.30 and lower)
+
+If server is already running, just display the PID. The new server will not start.
+
+```console
+% rubocop --start-server
+RuboCop server (16060) is already running.
+```
+
+A started server process name is `rubocop --server` with project directory path.
+
+```console
+% ps aux | grep 'rubocop --server'
+user             16060   0.0  0.0  5078568   2264   ??  S     7:54AM   0:00.00 rubocop --server /Users/user/src/github.com/rubocop/rubocop
+user             16337   0.0  0.0  5331560   2396   ??  S    23:51PM   0:00.00 rubocop --server /Users/user/src/github.com/rubocop/rubocop-rails
+```
+
+== Restart Server
+
+The started server does not reload the configuration file.
+You will need to restart server when you upgrade RuboCop or change
+the RuboCop configuration.
+
+```console
+% rubocop --restart-server
+RuboCop server starting on 127.0.0.1:55822.
+```
+
+This may be supported so that no reboot is required in future.
+
+== Command Line Options
+
+These are options for server operations.
+
+* `--server` ... If server process has not started yet, start the
+server process and execute inspection with server. You can specify
+the server host and port with the $RUBOCOP_SERVER_HOST and
+the $RUBOCOP_SERVER_PORT environment variables.
+* `--no-server` ... If server process has been started, stop the
+server process and execute inspection with server.
+* `--restart-server` ... Restart server process.
+* `--start-server` ... Start server process.
+* `--stop-server` ... Stop server process.
+* `--server-status` ... Show server status.
+
+== Environment Variables
+
+You can change the startup host and port of server process with
+environment variables.
+
+* `$RUBOCOP_SERVER_HOST`
+* `$RUBOCOP_SERVER_PORT`
+
+The following is an example:
+
+```console
+% RUBOCOP_SERVER_PORT=98989 rubocop --start-server
+```

exe/rubocop

@@ -3,13 +3,21 @@
 
 $LOAD_PATH.unshift("#{__dir__}/../lib")
 
-require 'rubocop'
-require 'benchmark'
+require 'rubocop/server'
+server_cli = RuboCop::Server::CLI.new
+exit_status = server_cli.run
+exit exit_status if server_cli.exit?
 
-cli = RuboCop::CLI.new
-result = 0
+if RuboCop::Server.running?
+  exit_status = RuboCop::Server::ClientCommand::Exec.new.run
+else
+  require 'rubocop'
+  require 'benchmark'
 
-time = Benchmark.realtime { result = cli.run }
+  cli = RuboCop::CLI.new
 
-puts "Finished in #{time} seconds" if cli.options[:debug] || cli.options[:display_time]
-exit result
+  time = Benchmark.realtime { exit_status = cli.run }
+
+  puts "Finished in #{time} seconds" if cli.options[:debug] || cli.options[:display_time]
+end
+exit exit_status

lib/rubocop/options.rb

@@ -63,6 +63,7 @@ def define_options
 
         add_check_options(opts)
         add_cache_options(opts)
+        add_server_options(opts)
         add_output_options(opts)
         add_autocorrection_options(opts)
         add_config_generation_options(opts)
@@ -201,6 +202,16 @@ def add_cache_options(opts)
       end
     end
 
+    def add_server_options(opts)
+      section(opts, 'Server Options') do
+        option(opts, '--[no-]server')
+        option(opts, '--restart-server')
+        option(opts, '--start-server')
+        option(opts, '--stop-server')
+        option(opts, '--server-status')
+      end
+    end
+
     def add_additional_modes(opts)
       section(opts, 'Additional Modes') do
         option(opts, '-L', '--list-target-files')
@@ -569,7 +580,17 @@ module OptionsHelp
                                          'parallel. Default is true.'],
       stdin:                            ['Pipe source from STDIN, using FILE in offense',
                                          'reports. This is useful for editor integration.'],
-      init:                             'Generate a .rubocop.yml file in the current directory.'
+      init:                             'Generate a .rubocop.yml file in the current directory.',
+      server:                           ['If server process has not started yet, start the',
+                                         'server process and execute inspection with server.',
+                                         'Default is false.',
+                                         'You can specify server host and port with',
+                                         'the $RUBOCOP_SERVER_HOST and the $RUBOCOP_SERVER_PORT',
+                                         'environment variables.'],
+      restart_server:                   'Restart server process.',
+      start_server:                     'Start server process.',
+      stop_server:                      'Stop server process.',
+      server_status:                    'Show server status.'
     }.freeze
   end
 end

lib/rubocop/server.rb

@@ -0,0 +1,53 @@
+# frozen_string_literal: true
+
+require_relative 'platform'
+
+#
+# This code is based on https://github.com/fohte/rubocop-daemon.
+#
+# Copyright (c) 2018 Hayato Kawai
+#
+# The MIT License (MIT)
+#
+# https://github.com/fohte/rubocop-daemon/blob/master/LICENSE.txt
+#
+module RuboCop
+  # The bootstrap module for server.
+  # @api private
+  module Server
+    TIMEOUT = 20
+
+    autoload :CLI, 'rubocop/server/cli'
+    autoload :Cache, 'rubocop/server/cache'
+    autoload :ClientCommand, 'rubocop/server/client_command'
+    autoload :Helper, 'rubocop/server/helper'
+    autoload :Core, 'rubocop/server/core'
+    autoload :ServerCommand, 'rubocop/server/server_command'
+    autoload :SocketReader, 'rubocop/server/socket_reader'
+
+    class << self
+      def support_server?
+        RUBY_ENGINE == 'ruby' && !RuboCop::Platform.windows?
+      end
+
+      def running?
+        return false unless support_server? # Never running.
+
+        Cache.dir.exist? && Cache.pid_path.file? && Cache.pid_running?
+      end
+
+      def wait_for_running_status!(expected)
+        start_time = Time.now
+        while Server.running? != expected
+          sleep 0.1
+          next unless Time.now - start_time > TIMEOUT
+
+          warn "running? was not #{expected} after #{TIMEOUT} seconds!"
+          exit 1
+        end
+      end
+    end
+  end
+end
+
+require_relative 'server/errors'

lib/rubocop/server/cache.rb

@@ -0,0 +1,101 @@
+# frozen_string_literal: true
+
+require 'pathname'
+
+#
+# This code is based on https://github.com/fohte/rubocop-daemon.
+#
+# Copyright (c) 2018 Hayato Kawai
+#
+# The MIT License (MIT)
+#
+# https://github.com/fohte/rubocop-daemon/blob/master/LICENSE.txt
+#
+module RuboCop
+  module Server
+    # Caches the states of server process.
+    # @api private
+    class Cache
+      GEMFILE_NAMES = %w[Gemfile gems.rb].freeze
+
+      class << self
+        # Searches for Gemfile or gems.rb in the current dir or any parent dirs
+        def project_dir
+          current_dir = Dir.pwd
+          while current_dir != '/'
+            return current_dir if GEMFILE_NAMES.any? do |gemfile|
+              File.exist?(File.join(current_dir, gemfile))
+            end
+
+            current_dir = File.expand_path('..', current_dir)
+          end
+          # If we can't find a Gemfile, just use the current directory
+          Dir.pwd
+        end
+
+        def project_dir_cache_key
+          @project_dir_cache_key ||= project_dir[1..].tr('/', '+')
+        end
+
+        def dir
+          cache_path = File.expand_path('~/.cache/rubocop_cache/server')
+          Pathname.new(File.join(cache_path, project_dir_cache_key)).tap do |d|
+            d.mkpath unless d.exist?
+          end
+        end
+
+        def port_path
+          dir.join('port')
+        end
+
+        def token_path
+          dir.join('token')
+        end
+
+        def pid_path
+          dir.join('pid')
+        end
+
+        def lock_path
+          dir.join('lock')
+        end
+
+        def status_path
+          dir.join('status')
+        end
+
+        def pid_running?
+          Process.kill(0, pid_path.read.to_i) == 1
+        rescue Errno::ESRCH
+          false
+        end
+
+        def acquire_lock
+          lock_file = File.open(lock_path, File::CREAT)
+          # flock returns 0 if successful, and false if not.
+          flock_result = lock_file.flock(File::LOCK_EX | File::LOCK_NB)
+          yield flock_result != false
+        ensure
+          lock_file.flock(File::LOCK_UN)
+          lock_file.close
+        end
+
+        def write_port_and_token_files(port:, token:)
+          port_path.write(port)
+          token_path.write(token)
+        end
+
+        def write_pid_file
+          pid_path.write(Process.pid)
+          yield
+        ensure
+          dir.rmtree
+        end
+
+        def write_status_file(status)
+          status_path.write(status)
+        end
+      end
+    end
+  end
+end