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MCollective::Connector::Rabbitmq

Attributes

connection[R]

Public Class Methods

new() click to toggle source
# File plugins/mcollective/connector/rabbitmq.rb, line 53
def initialize
  @config = Config.instance
  @subscriptions = []
  @base64 = false
end

Public Instance Methods

connect(connector = ::Stomp::Connection) click to toggle source

Connects to the RabbitMQ middleware

# File plugins/mcollective/connector/rabbitmq.rb, line 60
def connect(connector = ::Stomp::Connection)
  if @connection
    Log.debug("Already connection, not re-initializing connection")
    return
  end

  begin
    @base64 = get_bool_option("rabbitmq.base64", false)

    pools = @config.pluginconf["rabbitmq.pool.size"].to_i
    hosts = []

    1.upto(pools) do |poolnum|
      host = {}

      host[:host] = get_option("rabbitmq.pool.#{poolnum}.host")
      host[:port] = get_option("rabbitmq.pool.#{poolnum}.port", 6163).to_i
      host[:login] = get_env_or_option("STOMP_USER", "rabbitmq.pool.#{poolnum}.user")
      host[:passcode] = get_env_or_option("STOMP_PASSWORD", "rabbitmq.pool.#{poolnum}.password")
      host[:ssl] = get_bool_option("rabbitmq.pool.#{poolnum}.ssl", false)

      host[:ssl] = ssl_parameters(poolnum, get_bool_option("rabbitmq.pool.#{poolnum}.ssl.fallback", false)) if host[:ssl]

      Log.debug("Adding #{host[:host]}:#{host[:port]} to the connection pool")
      hosts << host
    end

    raise "No hosts found for the RabbitMQ connection pool" if hosts.size == 0

    connection = {:hosts => hosts}

    # Various STOMP gem options, defaults here matches defaults for 1.1.6 the meaning of
    # these can be guessed, the documentation isn't clear
    connection[:initial_reconnect_delay] = Float(get_option("rabbitmq.initial_reconnect_delay", 0.01))
    connection[:max_reconnect_delay] = Float(get_option("rabbitmq.max_reconnect_delay", 30.0))
    connection[:use_exponential_back_off] = get_bool_option("rabbitmq.use_exponential_back_off", true)
    connection[:back_off_multiplier] = Integer(get_option("rabbitmq.back_off_multiplier", 2))
    connection[:max_reconnect_attempts] = Integer(get_option("rabbitmq.max_reconnect_attempts", 0))
    connection[:randomize] = get_bool_option("rabbitmq.randomize", false)
    connection[:backup] = get_bool_option("rabbitmq.backup", false)
    connection[:timeout] = Integer(get_option("rabbitmq.timeout", -1))
    connection[:connect_timeout] = Integer(get_option("rabbitmq.connect_timeout", 30))
    connection[:reliable] = true

    # RabbitMQ and Stomp supports vhosts, this sets it in a way compatible with RabbitMQ and
    # force the version to 1.0, 1.1 support will be added in future
    connection[:connect_headers] = {"accept-version" => '1.0', "host" => get_option("rabbitmq.vhost", "/")}

    connection[:logger] = EventLogger.new

    @connection = connector.new(connection)
  rescue Exception => e
    raise("Could not connect to RabbitMQ Server: #{e}")
  end
end
disconnect() click to toggle source

Disconnects from the RabbitMQ connection

# File plugins/mcollective/connector/rabbitmq.rb, line 264
def disconnect
  Log.debug("Disconnecting from RabbitMQ")
  @connection.disconnect
end
get_bool_option(opt, default) click to toggle source

gets a boolean option from the config, supports y/n/true/false/1/0

# File plugins/mcollective/connector/rabbitmq.rb, line 292
def get_bool_option(opt, default)
  return default unless @config.pluginconf.include?(opt)

  val = @config.pluginconf[opt]

  if val =~ /^1|yes|true/
    return true
  elsif val =~ /^0|no|false/
    return false
  else
    return default
  end
end
get_env_or_option(env, opt, default=nil) click to toggle source

looks in the environment first then in the config file for a specific option, accepts an optional default.

raises an exception when it cant find a value anywhere

# File plugins/mcollective/connector/rabbitmq.rb, line 273
def get_env_or_option(env, opt, default=nil)
  return ENV[env] if ENV.include?(env)
  return @config.pluginconf[opt] if @config.pluginconf.include?(opt)
  return default if default

  raise("No #{env} environment or plugin.#{opt} configuration option given")
end
get_option(opt, default=nil) click to toggle source

looks for a config option, accepts an optional default

raises an exception when it cant find a value anywhere

# File plugins/mcollective/connector/rabbitmq.rb, line 284
def get_option(opt, default=nil)
  return @config.pluginconf[opt] if @config.pluginconf.include?(opt)
  return default unless default.nil?

  raise("No plugin.#{opt} configuration option given")
end
make_target(agent, type, collective, reply_to=nil, node=nil) click to toggle source
# File plugins/mcollective/connector/rabbitmq.rb, line 203
def make_target(agent, type, collective, reply_to=nil, node=nil)
  raise("Unknown target type #{type}") unless [:directed, :broadcast, :reply, :request, :direct_request].include?(type)
  raise("Unknown collective '#{collective}' known collectives are '#{@config.collectives.join ', '}'") unless @config.collectives.include?(collective)

  target = {:name => "", :headers => {}, :id => nil}

  case type
    when :reply # receiving replies on a temp queue
      target[:name] = "/temp-queue/mcollective_reply_%s" % agent
      target[:id] = "mcollective_%s_replies" % agent

    when :broadcast, :request # publishing a request to all nodes with an agent
      target[:name] = "/exchange/%s_broadcast/%s" % [collective, agent]
      if reply_to
        target[:headers]["reply-to"] = reply_to
      else
        target[:headers]["reply-to"] = "/temp-queue/mcollective_reply_%s" % agent
      end
      target[:id] = "%s_broadcast_%s" % [collective, agent]

    when :direct_request # a request to a specific node
      raise "Directed requests need to have a node identity" unless node

      target[:name] = "/exchange/%s_directed/%s" % [ collective, node]
      target[:headers]["reply-to"] = "/temp-queue/mcollective_reply_%s" % agent

    when :directed # subscribing to directed messages
      target[:name] = "/exchange/%s_directed/%s" % [ collective, @config.identity ]
      target[:id] = "%s_directed_to_identity" % @config.identity
  end

  target
end
publish(msg) click to toggle source

Sends a message to the RabbitMQ connection

# File plugins/mcollective/connector/rabbitmq.rb, line 168
def publish(msg)
  msg.base64_encode! if @base64

  if msg.type == :direct_request
    msg.discovered_hosts.each do |node|
      target = target_for(msg, node)

      Log.debug("Sending a direct message to RabbitMQ target '#{target[:name]}' with headers '#{target[:headers].inspect}'")

      @connection.publish(target[:name], msg.payload, target[:headers])
    end
  else
    target = target_for(msg)

    Log.debug("Sending a broadcast message to RabbitMQ target '#{target[:name]}' with headers '#{target[:headers].inspect}'")

    @connection.publish(target[:name], msg.payload, target[:headers])
  end
end
receive() click to toggle source

Receives a message from the RabbitMQ connection

# File plugins/mcollective/connector/rabbitmq.rb, line 148
def receive
  Log.debug("Waiting for a message from RabbitMQ")

  # When the Stomp library > 1.2.0 is mid reconnecting due to its reliable connection
  # handling it sets the connection to closed.  If we happen to be receiving at just
  # that time we will get an exception warning about the closed connection so handling
  # that here with a sleep and a retry.
  begin
    msg = @connection.receive
  rescue ::Stomp::Error::NoCurrentConnection
    sleep 1
    retry
  end

  raise "Received a processing error from RabbitMQ: '%s'" % msg.body.chomp if msg.body =~ /Processing error/

  Message.new(msg.body, msg, :base64 => @base64, :headers => msg.headers)
end
ssl_parameters(poolnum, fallback) click to toggle source

Sets the SSL paramaters for a specific connection

# File plugins/mcollective/connector/rabbitmq.rb, line 117
def ssl_parameters(poolnum, fallback)
  params = {:cert_file => get_option("rabbitmq.pool.#{poolnum}.ssl.cert", false),
            :key_file  => get_option("rabbitmq.pool.#{poolnum}.ssl.key", false),
            :ts_files  => get_option("rabbitmq.pool.#{poolnum}.ssl.ca", false)}

  raise "cert, key and ca has to be supplied for verified SSL mode" unless params[:cert_file] && params[:key_file] && params[:ts_files]

  raise "Cannot find certificate file #{params[:cert_file]}" unless File.exist?(params[:cert_file])
  raise "Cannot find key file #{params[:key_file]}" unless File.exist?(params[:key_file])

  params[:ts_files].split(",").each do |ca|
    raise "Cannot find CA file #{ca}" unless File.exist?(ca)
  end

  begin
    Stomp::SSLParams.new(params)
  rescue NameError
    raise "Stomp gem >= 1.2.2 is needed"
  end

rescue Exception => e
  if fallback
    Log.warn("Failed to set full SSL verified mode, falling back to unverified: #{e.class}: #{e}")
    return true
  else
    Log.error("Failed to set full SSL verified mode: #{e.class}: #{e}")
    raise(e)
  end
end
subscribe(agent, type, collective) click to toggle source

Subscribe to a topic or queue

# File plugins/mcollective/connector/rabbitmq.rb, line 238
def subscribe(agent, type, collective)
  return if type == :reply

  source = make_target(agent, type, collective)

  unless @subscriptions.include?(source[:id])
    Log.debug("Subscribing to #{source[:name]} with headers #{source[:headers].inspect.chomp}")
    @connection.subscribe(source[:name], source[:headers], source[:id])
    @subscriptions << source[:id]
  end
rescue ::Stomp::Error::DuplicateSubscription
  Log.error("Received subscription request for #{source.inspect.chomp} but already had a matching subscription, ignoring")
end
target_for(msg, node=nil) click to toggle source
# File plugins/mcollective/connector/rabbitmq.rb, line 188
def target_for(msg, node=nil)
  if msg.type == :reply
    target = {:name => msg.request.headers["reply-to"], :headers => {}, :id => ""}

  elsif [:request, :direct_request].include?(msg.type)
    target = make_target(msg.agent, msg.type, msg.collective, msg.reply_to, node)

  else
    raise "Don't now how to create a target for message type #{msg.type}"

  end

  return target
end
unsubscribe(agent, type, collective) click to toggle source

Subscribe to a topic or queue

# File plugins/mcollective/connector/rabbitmq.rb, line 253
def unsubscribe(agent, type, collective)
  return if type == :reply

  source = make_target(agent, type, collective)

  Log.debug("Unsubscribing from #{source[:name]}")
  @connection.unsubscribe(source[:name], source[:headers], source[:id])
  @subscriptions.delete(source[:id])
end

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