Class: VCAP::Component

Inherits:
Object
  • Object
show all
Defined in:
lib/vcap/component.rb

Overview

Common component setup for discovery and monitoring

Defined Under Namespace

Classes: SafeHash

Class Attribute Summary collapse

Class Method Summary collapse

Class Attribute Details

.healthz ⇒ Object

Returns the value of attribute healthz.



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# File 'lib/vcap/component.rb', line 90

def healthz
  @healthz
end

Class Method Details

.register(opts) ⇒ Object

Announces the availability of this component to NATS. Returns the published configuration of the component, including the ephemeral port and credentials.



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# File 'lib/vcap/component.rb', line 154

def register(opts)
  disallow_exposing_of_config!(opts)

  uuid = VCAP.secure_uuid
  type = opts[:type]
  index = opts[:index]
  uuid = "#{index}-#{uuid}" if index
  host = opts[:host] || VCAP.local_ip
  port = opts[:port] || VCAP.grab_ephemeral_port
  nats = opts[:nats] || NATS
  auth = [opts[:user] || VCAP.secure_uuid, opts[:password] || VCAP.secure_uuid]
  logger = opts[:logger] || Logger.new(nil)
  log_counter = opts[:log_counter]

  # Discover message limited
  @discover = {
    :type => type,
    :index => index,
    :uuid => uuid,
    :host => "#{host}:#{port}",
    :credentials => auth,
    :start => Time.now
  }

  # Varz is customizable
  varz.synchronize do
    varz.merge!(@discover.dup)
    varz[:num_cores] = VCAP.num_cores
    varz[:log_counts] = log_counter if log_counter
  end

  @healthz = "ok\n".freeze

  # Next steps require EM
  raise "EventMachine reactor needs to be running" if !EventMachine.reactor_running?

  # Startup the http endpoint for /varz and /healthz
  start_http_server(host, port, auth, logger)

  # Listen for discovery requests
  nats.subscribe('vcap.component.discover') do |msg, reply|
    update_discover_uptime
    nats.publish(reply, @discover.to_json)
  end

  # Also announce ourselves on startup..
  nats.publish('vcap.component.announce', @discover.to_json)

  @discover
end

.start_http_server(host, port, auth, logger) ⇒ Object 



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# File 'lib/vcap/component.rb', line 131

def start_http_server(host, port, auth, logger)
  http_server = Thin::Server.new(host, port, :signals => false) do
    Thin::Logging.silent = true
    use Rack::Auth::Basic do |username, password|
      [username, password] == auth
    end
    map '/healthz' do
      run Healthz.new(logger)
    end
    map '/varz' do
      run Varz.new(logger)
    end
  end
  http_server.start!
end

.update_discover_uptime ⇒ Object 



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# File 'lib/vcap/component.rb', line 205

def update_discover_uptime
  @discover[:uptime] = VCAP.uptime_string(Time.now - @discover[:start])
end

.updated_healthz ⇒ Object 



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# File 'lib/vcap/component.rb', line 121

def updated_healthz
  @last_healthz_update ||= 0

  if Time.now.to_f - @last_healthz_update >= 1
    @last_healthz_update = Time.now.to_f
  end

  healthz.dup
end

.updated_varz ⇒ Object 



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# File 'lib/vcap/component.rb', line 92

def updated_varz
  @last_varz_update ||= 0

  if Time.now.to_f - @last_varz_update >= 1
    rss_bytes, pcpu = Stats.process_memory_bytes_and_cpu

    # Update varz
    varz.synchronize do
      @last_varz_update = Time.now.to_f

      varz[:uptime] = VCAP.uptime_string(Time.now - varz[:start])
      varz[:cpu] = pcpu.to_f
      varz[:cpu_load_avg] = Stats.cpu_load_average

      varz[:mem_bytes] = rss_bytes.to_i
      varz[:mem_used_bytes] = Stats.memory_used_bytes
      varz[:mem_free_bytes] = Stats.memory_free_bytes

      # Return duplicate while holding lock
      return varz.dup
    end
  else
    # Return duplicate while holding lock
    varz.synchronize do
      return varz.dup
    end
  end
end

.uuid ⇒ Object 



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# File 'lib/vcap/component.rb', line 147

def uuid
  @discover[:uuid]
end

.varz ⇒ Object 



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# File 'lib/vcap/component.rb', line 86

def varz
  @varz ||= SafeHash.new
end