Class: FireflyServer

Inherits:
Object
  • Object
show all
Defined in:
lib/firefly_server.rb,
lib/firefly_server/version.rb,
lib/firefly_server/file_watcher.rb,
lib/firefly_server/configuration.rb

Defined Under Namespace

Classes: Configuration, FileWatcher

Constant Summary collapse

VERSION = 
"0.1.8"

Instance Method Summary collapse

Constructor Details

#initialize(params = {}) ⇒ FireflyServer

Returns a new instance of FireflyServer.



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# File 'lib/firefly_server.rb', line 8

def initialize(params = {})
  self.configuration = Configuration.new
  self.file_watcher = FileWatcher.new(configuration)
end

Instance Method Details

#configure {|configuration| ... } ⇒ Object

Yields:

  • (configuration) 


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# File 'lib/firefly_server.rb', line 13

def configure
  yield(configuration)
  self
end

#process_exists?(pid) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/firefly_server.rb', line 18

def process_exists?(pid)
  Process.kill(0, pid)
  true
rescue Errno::ESRCH
  false
end

#start! ⇒ Object 



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# File 'lib/firefly_server.rb', line 25

def start!
  server_pid = nil
  configuration.validate!
  # stop server if it is running
  %x(#{configuration.stop_server})
  # trap signals and exit
  configuration.exit_signals.each do |signal|
    Signal.trap(signal) do
      # attempt to stop server
      if server_pid && process_exists?(server_pid)
        puts "Stopping Server: #{configuration.stop_server}"
        %x(#{configuration.stop_server})
        # give server a moment to exit
        begin
          Timeout.timeout(2) do
            Process.wait(server_pid)
          end
        rescue Timeout::Error
        end
      end
      # reset shell in case of server crash messing with prompt (common byebug problem)
      if server_pid && process_exists?(server_pid)
        %x{reset}
        puts 'Server Stop Failed: Shell was "reset" to ensure access after possible crash'
      end
      puts "\rStopping Firefly Server"
      exit 130
    end
  end
  # file_watcher loop
  file_watcher.watch! do |files|
    puts "Ignored: #{files.ignored.join(", ")}"   if files.ignored?
    puts "Modified: #{files.modified.join(", ")}" if files.modified?
    puts "Added: #{files.added.join(", ")}"       if files.added?
    puts "Removed: #{files.removed.join(", ")}"   if files.removed?
    # stop server
    if files.added? || files.removed?
      puts "Stopping Server: #{configuration.stop_server}"
      %x(#{configuration.stop_server})
    elsif files.modified? && configuration.reload_server && files.modified.map { |f| f.end_with?(".rb") }.uniq == [true]
      puts "Reloading Server: #{configuration.reload_server}"
      ENV["FIREFLY_MODIFIED_FILES"] = files.modified.join(",")
      %x(#{configuration.reload_server})
    elsif files.modified?
      puts "Stopping Server: #{configuration.stop_server}"
      %x(#{configuration.stop_server})
    end
  end
  # on_start callbacks
  configuration.on_start_callbacks.each do |on_start_callback|
    on_start_callback.call(self)
  end
  # server loop
  restart_attempt = 0
  loop do
    # delete stale PID file
    File.delete(configuration.pid_file) if File.file?(configuration.pid_file)
    # start server
    puts "Starting Server: #{configuration.start_server}"
    # new fork will have nil initial pid
    server_pid = fork
    # new fork
    if server_pid == nil
      exec(configuration.start_server)
    else
      Process.wait(server_pid)
      server_pid_status = $? # Process.wait sets $? to pid status
    end
    # normal restart
    if server_pid_status.success?
      restart_attempt = 0
    # failed restart
    else
      restart_attempt += 1
      # throttle restart attempts to prevent high CPU usage
      if restart_attempt >= configuration.restart_attempt_throttle_threshold
        puts "Throttling restart attempts by sleeping #{configuration.restart_attempt_throttle_sleep} seconds"
        sleep(configuration.restart_attempt_throttle_sleep)
      end
    end
  end
end