Class: SMQueue::StompAdapter

Inherits:
Adapter show all
Defined in:
lib/smqueue/adapters/stomp.rb

Defined Under Namespace

Classes: Configuration

Instance Method Summary collapse

Methods inherited from Adapter

#close, create, #open

Methods inherited from Doodle

#to_hash

Constructor Details

#initialize(*args, &block) ⇒ StompAdapter

Returns a new instance of StompAdapter.



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# File 'lib/smqueue/adapters/stomp.rb', line 133

def initialize(*args, &block)
  super
  restore_remembered_messages
  SMQueue.dbg { [:seen_messages, seen_messages].inspect }
end

Instance Method Details

#ack(subscription_headers, message) ⇒ Object

acknowledge message (if headers == “client”)



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# File 'lib/smqueue/adapters/stomp.rb', line 227

def ack(subscription_headers, message)
  #p [:ack, message.headers["message-id"]]
  if message.headers["message-id"].to_s.strip != "" && subscription_headers["ack"].to_s == "client"
    SMQueue.dbg { [:smqueue, :ack, :message, message].inspect }
    connection.ack message.headers["message-id"], { }
  else
    SMQueue.dbg { [:smqueue, :ack, :not_acknowledging, message].inspect }
  end
  if ENV['PAUSE_SMQUEUE']
    $stderr.print "press enter to continue> "
    $stderr.flush
    $stdin.gets
  end
end

#connect(*args, &block) ⇒ Object

connect to message broker



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# File 'lib/smqueue/adapters/stomp.rb', line 146

def connect(*args, &block)
  self.connection = RStomp::Connection.open(configuration.to_hash)   
  # If the connection has swapped hosts, then swap out primary and secondary
  if connection.current_host != configuration.host
    configuration.secondary_host = configuration.host
    configuration.host = connection.current_host
  end

  # If the connection has swapped ports, then swap out primary and secondary
  if connection.current_port != configuration.port
    configuration.secondary_port = configuration.port
    configuration.port = connection.current_port
  end
end

#get(headers = {}, &block) ⇒ Object

get message from queue

  • if block supplied, loop forever and yield(message) for each message received

default headers are:

:ack               => "client"
:client_id         => configuration.client_id
:subscription_name => configuration.subscription_name



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# File 'lib/smqueue/adapters/stomp.rb', line 250

def get(headers = {}, &block)
  self.connect
  SMQueue.dbg { [:smqueue, :get, headers].inspect }
  subscription_headers = {"ack" => "client", "activemq.prefetchSize" => 1 }
  if client_id = configuration.client_id
    subscription_headers["client_id"] = client_id
  end
  if sub_name = configuration.subscription_name
    subscription_headers["subscription_name"] = sub_name
  end
  # if a client_id is supplied, then user wants a durable subscription
  # N.B. client_id must be unique for broker
  subscription_headers.update(headers)
  #p [:subscription_headers_before, subscription_headers]
  subscription_headers = normalize_keys(subscription_headers)
  if configuration.durable and client_id = configuration.client_id || subscription_headers["client_id"]
    subscription_name = configuration.subscription_name || subscription_headers["subscription_name"] || client_id
    # activemq only
    subscription_headers["activemq.subscriptionName"] = subscription_name
    # JMS
    subscription_headers["durable-subscriber-name"] = subscription_name
  end
  #p [:subscription_headers_after, subscription_headers]
  
  destination = configuration.name
  SMQueue.dbg { [:smqueue, :get, :subscribing, destination, :subscription_headers, subscription_headers].inspect }
  connection.subscribe destination, subscription_headers
  message = nil
  SMQueue.dbg { [:smqueue, :get, :subscription_headers, subscription_headers].inspect }
  begin
    # TODO: refactor this
    if block_given?
      SMQueue.dbg { [:smqueue, :get, :block_given].inspect }
      # todo: change to @running - (and set to false from exception handler)
      # also should check to see if anything left to receive on connection before bailing out
      while true
        SMQueue.dbg { [:smqueue, :get, :receive].inspect }
        # block until message ready
        message = connection.receive
        SMQueue.dbg { [:smqueue, :get, :received, message].inspect }
        case message.command
        when "ERROR"
          SMQueue.dbg { [:smqueue, :get, :ERROR, message].inspect }
        when "RECEIPT"
          SMQueue.dbg { [:smqueue, :get, :RECEIPT, message].inspect }
        else
          SMQueue.dbg { [:smqueue, :get, :yielding].inspect }
          if !message_seen?(message.headers["message-id"])
            yield(message)
          end
          SMQueue.dbg { [:smqueue, :get, :message_seen, message.headers["message-id"]].inspect }
          message_seen message.headers["message-id"]
          SMQueue.dbg { [:smqueue, :get, :returned_from_yield_now_calling_ack].inspect }
          ack(subscription_headers, message)
          SMQueue.dbg { [:smqueue, :get, :returned_from_ack].inspect }
        end
      end
    else
      SMQueue.dbg { [:smqueue, :get, :single_shot].inspect }
      message = connection.receive
      SMQueue.dbg { [:smqueue, :get, :received, message].inspect }
      if !(message.command == "ERROR" or message.command == "RECEIPT")
        SMQueue.dbg { [:smqueue, :get, :message_seen, message.headers["message-id"]].inspect }
        message_seen message.headers["message-id"]
        SMQueue.dbg { [:smqueue, :get, :ack, message].inspect }
        ack(subscription_headers, message)
        SMQueue.dbg { [:smqueue, :get, :returned_from_ack].inspect }
      end
    end
  rescue Object => e
    SMQueue.dbg { [:smqueue, :get, :exception, e].inspect }
    handle_error e, "Exception in SMQueue#get: #{e.message}", caller
  ensure
    SMQueue.dbg { [:smqueue, :get, :ensure].inspect }
    SMQueue.dbg { [:smqueue, :unsubscribe, destination, subscription_headers].inspect }
    connection.unsubscribe destination, subscription_headers
    SMQueue.dbg { [:smqueue, :disconnect].inspect }
    connection.disconnect
  end
  SMQueue.dbg { [:smqueue, :get, :return].inspect }
  message
end

#handle_error(exception_class, error_message, caller) ⇒ Object

handle an error

Raises:

  • (exception_class) 


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# File 'lib/smqueue/adapters/stomp.rb', line 140

def handle_error(exception_class, error_message, caller)
  #configuration.logger.warn error_message
  raise exception_class, error_message, caller
end

#message_seen(message_id) ⇒ Object

remember the message_id



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# File 'lib/smqueue/adapters/stomp.rb', line 179

def message_seen(message_id)
  message_id = message_id.to_s.strip
  if message_id != ""
    self.seen_messages << message_id
    SMQueue.dbg { [:smqueue, :ack, :message_seen, message_id].inspect }
    if self.seen_messages.size > self.seen_message_count
      self.seen_messages.shift
    end
    store_remembered_messages
  else
    SMQueue.dbg { [:smqueue, :ack, :message_seen, message_id].inspect }
  end
end

#message_seen?(message_id) ⇒ Boolean

true if the message with this message_id has already been seen

Returns:

  • (Boolean) 


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# File 'lib/smqueue/adapters/stomp.rb', line 174

def message_seen?(message_id)
  self.seen_messages.include?(message_id)
end

#normalize_keys(hash, method = :to_s) ⇒ Object

normalize hash keys (top level only)

  • normalizes keys to strings by default

  • optionally pass in name of method to use (e.g. :to_sym) to normalize keys



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# File 'lib/smqueue/adapters/stomp.rb', line 164

def normalize_keys(hash, method = :to_s)
  hash = hash.dup
  hash.keys.each do |k|
    normalized_key = k.respond_to?(method) ? k.send(method) : k
    hash[normalized_key] = hash.delete(k)
  end
  hash
end

#put(body, headers = { }) ⇒ Object

put a message on the queue default headers are:

:persistent => true
:ack        => "auto"
:expires    => configuration.expires



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# File 'lib/smqueue/adapters/stomp.rb', line 338

def put(body, headers = { })
  SMQueue.dbg { [:smqueue, :put, body, headers].inspect }
  begin
    self.connect
    headers = {:persistent => true, :ack => "auto", :expires => SMQueue.calc_expiry_time(configuration.expires) }.merge(headers)
    destination = configuration.name
    SMQueue.dbg { [:smqueue, :send, body, headers].inspect }
    connection.send destination, body, headers
  rescue Exception => e
    SMQueue.dbg { [:smqueue, :exception, e].inspect }
    handle_error e, "Exception in SMQueue#put - #{e.message}", caller
    #connection.disconnect
  ensure
    connection.disconnect
  end
end

#restore_remembered_messages ⇒ Object

reload remembered message ids from a yaml file



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# File 'lib/smqueue/adapters/stomp.rb', line 203

def restore_remembered_messages
  if configuration.single_delivery
    yaml = default_yaml = "--- []"
    begin
      File.open(seen_messages_file, 'r') do |file|
        yaml = file.read
      end
    rescue Object
      yaml = default_yaml
    end
    buffer = []
    begin
      buffer = YAML.load(yaml)
      if !buffer.kind_of?(Array) or !buffer.all?{ |x| x.kind_of?(String)}
        raise Exception, "Invalid seen_messages.yml file"
      end
    rescue Object
      buffer = []
    end
    self.seen_messages = buffer
  end
end

#store_remembered_messages ⇒ Object

store the remembered message ids in a yaml file



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# File 'lib/smqueue/adapters/stomp.rb', line 194

def store_remembered_messages
  if configuration.single_delivery
    File.open(seen_messages_file, 'w') do |file|
      file.write seen_messages.to_yaml
    end
  end
end