Class: Quartz::GoProcess

Inherits:
Object
  • Object
show all
Defined in:
lib/quartz/go_process.rb

Constant Summary collapse

READ_EXCEPTION = 
IO::EAGAINWaitReadable
MAX_MESSAGE_SIZE =

Bytes

8192

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(opts) ⇒ GoProcess

Returns a new instance of GoProcess.



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# File 'lib/quartz/go_process.rb', line 25

def initialize(opts)
  @seed = SecureRandom.hex
  socket_dir = opts.fetch(:socket_dir) { '/tmp' }
  @socket_path = opts[:socket_path] || File.join(socket_dir, "quartz_#{seed}.sock")
  ENV['QUARTZ_SOCKET'] = @socket_path

  if opts[:file_path]
    Quartz::Validations.check_for_go
    compile_and_run(opts[:file_path])
  elsif opts[:bin_path]
    @go_process = IO.popen(opts[:bin_path])
  elsif opts[:socket_path]
    @external_socket = true
  else
    raise Quartz::ConfigError, 'Missing go binary'
  end

  block_until_server_starts
  self.class.processes << self
end

Instance Attribute Details

#seed ⇒ Object (readonly)

Returns the value of attribute seed.



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# File 'lib/quartz/go_process.rb', line 5

def seed
  @seed
end

#socket_path ⇒ Object (readonly)

Returns the value of attribute socket_path.



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# File 'lib/quartz/go_process.rb', line 5

def socket_path
  @socket_path
end

#temp_file_path ⇒ Object (readonly)

Returns the value of attribute temp_file_path.



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# File 'lib/quartz/go_process.rb', line 5

def temp_file_path
  @temp_file_path
end

Class Method Details

.cleanup ⇒ Object 



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# File 'lib/quartz/go_process.rb', line 163

def self.cleanup
  return unless @processes
  @processes.each(&:cleanup)
  @processes = []
end

.clear_processes ⇒ Object 



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# File 'lib/quartz/go_process.rb', line 11

def self.clear_processes
  @processes = []
end

.processes ⇒ Object 



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# File 'lib/quartz/go_process.rb', line 7

def self.processes
  @processes ||= []
end

Instance Method Details

#block_until_server_starts ⇒ Object 



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# File 'lib/quartz/go_process.rb', line 68

def block_until_server_starts
  max_retries = 20
  retries = 0
  delay = 0.001 # seconds

  loop do
    return if File.exists?(@socket_path)
    raise Quartz::GoServerError, 'RPC server not starting' if retries > max_retries
    sleep(delay * 2**retries)
    retries += 1
  end
end

#call(struct_name, method, args) ⇒ Object 



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# File 'lib/quartz/go_process.rb', line 100

def call(struct_name, method, args)
  payload = {
    'method' => "#{struct_name}.#{method}",
    'params' => [args],
    'id' => 1
  }

  begin
    socket.send(MultiJson.dump(payload), 0)
  rescue Errno::EPIPE
    # Retry send with a new socket. We might trigger this if Go
    # process restarted.  There's a good chance that this raises the
    # exact same error.
    new_socket!
    socket.send(MultiJson.dump(payload), 0)
  end

  read
end

#cleanup ⇒ Object 



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# File 'lib/quartz/go_process.rb', line 144

def cleanup
  # If we've forked, there's no need to cleanup since the parent
  # process will.
  return if @forked

  # If the Go process is managed externally, there's nothing to do.
  return if @external_socket

  unless @killed_go_process
    Process.kill('SIGTERM', pid)
    Process.wait(pid)
    @killed_go_process = true
  end

  if @temp_file_path && File.exists?(@temp_file_path)
    File.delete(@temp_file_path)
  end
end

#compile_and_run(path) ⇒ Object 



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# File 'lib/quartz/go_process.rb', line 46

def compile_and_run(path)
  @temp_file_path = "/tmp/quartz_runner_#{seed}"

  unless system('go', 'build', '-o', @temp_file_path, path)
    raise Quartz::ConfigError, 'Go compilation failed'
  end

  @go_process = IO.popen(@temp_file_path)
end

#forked_mode! ⇒ Object 



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# File 'lib/quartz/go_process.rb', line 15

def forked_mode!
  if @forked.nil?
    @forked = true
  else
    @forked = !@forked
  end

  new_socket! if @forked
end

#get_metadata ⇒ Object 



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# File 'lib/quartz/go_process.rb', line 81

def get_metadata
  payload = {
    'method' => 'Quartz.GetMetadata',
    'params' => [],
    # This parameter isn't needed because we use a different
    # connection for each thread.
    'id' => 1
  }

  socket.send(MultiJson.dump(payload), 0)
  response = read

  if response['error']
    raise Quartz::GoResponseError, "Metadata error: #{response['error']}"
  end

  response['result']
end

#new_socket! ⇒ Object 



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# File 'lib/quartz/go_process.rb', line 60

def new_socket!
  Thread.current["quartz_socket_#{seed}".to_sym] = UNIXSocket.new(@socket_path)
end

#pid ⇒ Object 



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# File 'lib/quartz/go_process.rb', line 56

def pid
  @go_process.pid
end

#read ⇒ Object 



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# File 'lib/quartz/go_process.rb', line 128

def read
  value = ''
  loop do
    begin
      value << socket.recv_nonblock(MAX_MESSAGE_SIZE)
      break if value.end_with?("\n")
    rescue READ_EXCEPTION
      IO.select([socket], [], [])
    rescue Errno::EPIPE
      new_socket!
    end
  end

  MultiJson.load(value)
end

#socket ⇒ Object 



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# File 'lib/quartz/go_process.rb', line 64

def socket
  Thread.current["quartz_socket_#{seed}".to_sym] ||= UNIXSocket.new(@socket_path)
end