Class: DockerPier::LogStream

Inherits:
Object
  • Object
show all
Defined in:
lib/docker-pier/log-stream.rb,
lib/docker-pier/log-stream/palette.rb

Defined Under Namespace

Classes: Palette

Instance Method Summary collapse

Constructor Details

#initialize(pier) ⇒ LogStream

Returns a new instance of LogStream.



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# File 'lib/docker-pier/log-stream.rb', line 17

def initialize(pier)
  @pier = pier
  @palette = DockerPier::LogStream::Palette.new
  @task_colors = Hash.new{ |h,k| h[k] = @palette.draw! }
end

Instance Method Details

#get_path! ⇒ Object 



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# File 'lib/docker-pier/log-stream.rb', line 27

def get_path!
  logs_dir = Pathname.new '/var/log/fluentd'
  logfile_link = logs_dir + 'docker.log'

  # fluentd creates the symlink with an absolute path from inside a container,
  # so the dir the link points to is wrong. We assume the logs dir instead.
  logs_link_dest = Pathname.new(@pier.ssh.exec!("readlink #{logfile_link.to_shell}").chomp)
  logs_dir + logs_link_dest.basename
end

#parse_log_ln(ln) ⇒ Object 



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# File 'lib/docker-pier/log-stream.rb', line 37

def parse_log_ln(ln)
  ts, fluent_source_id, event_json = ln.split(/\s+/, 3)

  ts = DateTime.parse(ts)
  event = JSON.parse(event_json)
  event_type = (event.delete('source') == 'stderr') ? :error : :output

  container_id = event.delete('container_name')[1..-1]
  msg = event.delete('log')

  if msg[0] == '{'
    msg_parts = JSON.parse(msg)
    msg_lns = msg_parts.delete('lines').map{ |ln| ln.chomp }
    msg_parts = OpenStruct.new(msg_parts)
  else
    msg_lns = msg.split("\n")
  end

  service_parts = container_id.match(/^(\w+)\.(\d+)\.(\w+)$/)
  service = service_parts ? [service_parts[1], service_parts[2].to_i] : nil

  task_handle = service ? ("%s[%02d]" % service) : container_id
  task_color = @task_colors[task_handle]

  OpenStruct.new(
    time: ts,
    type: event_type,
    service: service,
    task: OpenStruct.new(name: task_handle, color: task_color),
    location: [:some_node, container_id],
    message: msg_parts,
    lines: msg_lns
  )
end

#path ⇒ Object 



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# File 'lib/docker-pier/log-stream.rb', line 23

def path
  @path ||= get_path!
end

#stream! ⇒ Object 



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# File 'lib/docker-pier/log-stream.rb', line 72

def stream!
  ssh_session = @pier.ssh

  channel = ssh_session.open_channel do |ch|
		ch.exec "tail -f #{self.path.to_shell}" do |ch, success|
      raise "could not tail logs on remote" unless success

      ch.on_data do |_, data|
        data.split("\n").each do |ln|
          event = parse_log_ln(ln)
          yield(event)
        end
      end
    end
  end

  int_pressed = false
  trap("INT") { int_pressed = true }
  ssh_session.loop(0.1) { not int_pressed }

  ssh_session.shutdown!
end