Add daemonization options to Lita::CLI.

lib/lita/cli.rb

@@ -1,3 +1,5 @@
+require "fileutils"
+
 require "thor"
 
 module Lita
@@ -14,18 +16,67 @@ def self.source_root
     class_option :config,
       aliases: "-c",
       banner: "PATH",
-      default: "lita_config.rb",
+      default: File.expand_path("lita_config.rb", Dir.pwd),
       desc: "Path to the configuration file to use"
 
+    class_option :daemonize,
+      aliases: "-d",
+      default: false,
+      desc: "Run Lita as a daemon",
+      type: :boolean
+
+    class_option :log_file,
+      aliases: "-l",
+      banner: "PATH",
+      default: Process.euid == 0 ?
+        "/var/log/lita.log" : File.expand_path("lita.log", ENV["HOME"]),
+      desc: "Path where the log file should be written when daemonized"
+
+    class_option :pid_file,
+      aliases: "-p",
+      banner: "PATH",
+      default: Process.euid == 0 ?
+        "/var/run/lita.pid" : File.expand_path("lita.pid", ENV["HOME"]),
+      desc: "Path where the PID file should be written when daemonized"
+
     desc "start", "Starts Lita"
     def start
       Bundler.require
+      daemonize if options[:daemonize]
       Lita.run(options[:config])
     end
 
     desc "new NAME", "Generates a new Lita project (default name: lita)"
     def new(name = "lita")
       directory "skeleton", name
     end
+
+    private
+
+    def daemonize
+      ensure_not_running
+      Process.daemon(true)
+      File.open(options[:pid_file], "w") { |f| f.write(Process.pid) }
+      set_up_logs
+      at_exit do
+        FileUtils.rm(options[:pid_file]) if File.exist?(options[:pid_file])
+      end
+    end
+
+    def ensure_not_running
+      if File.exist?(options[:pid_file])
+        abort <<-FATAL.chomp
+PID file exists at #{options[:pid_file]}. Lita may already be running. \
+Kill the existing process or remove the PID file and then start Lita.
+FATAL
+      end
+    end
+
+    def set_up_logs
+      log_file = File.new(options[:log_file], "a")
+      $stdout.reopen(log_file)
+      $stderr.reopen(log_file)
+      $stderr.sync = $stdout.sync = true
+    end
   end
 end