Query ActiveMQ Broker Statistics with Delphi

Broker Configuration

To configure ActiveMQ to use the statistics plugin add the following to the ActiveMQ XML configuration:

<plugins>
  <statisticsBrokerPlugin/>
</plugins>

The statistics plugin looks for messages sent to particular destinations.

Query running broker statistics

To query the running statistics of the message broker, the client sends an empty message to a Destination named ActiveMQ.Statistics.Broker, and sets the replyto field with the Destination you want to receive the result on. The statistics plugin will send a  MapMessage filled with the statistics for the running ActiveMQ broker.

Source code

program DestStatistics;

(**
  Requires ActiveMQ 5.3 or higher
  To configure ActiveMQ to use the statistics plugin, add the following to the ActiveMQ XML configuration:
  <broker>
  ...
    <plugins>
      <statisticsBrokerPlugin/>
    </plugins>
  ...
  </broker>

  Usage:
  ------
  DestStatistics [destination]
  If no destination is specified, the program returns the broker statistics

  Reference
  ---------
  http://activemq.apache.org/statisticsplugin.html
  https://issues.apache.org/activemq/browse/AMQ-2379
  http://rajdavies.blogspot.com/2009/10/query-statistics-for-apache-activemq.html

  You can also use wildcards too, and receive a separate message for every destination matched.
*)

{$APPTYPE CONSOLE}

uses
  SysUtils,
  BTCommAdapterIndy, BTMessageTransformerXMLMapOmni,
  BTJMSInterfaces, BTJMSConnection, BTSessionIntf, BTSerialIntf,
  BTStompTypes, BTTypes,
  Classes;

var
  Connection: IConnection;
  Session: ISession;
  Producer: IMessageProducer;
  Consumer: IMessageConsumer;
  Destination, ReplyQueue: IQueue;
  JMSMessage: ITextMessage;
  Reply: IMapMessage;
  MapNames: PMStrings;
  I: Integer;
  Key: string;

begin
  Connection := TBTJMSConnection.MakeConnection;
  try
    try
      // Create and assign the message transformer
      SetTransformer(Connection, TBTMessageTransformerXMLMapOmni.Create(nil));

      Connection.Start;
      Session := Connection.CreateSession(False, amAutoAcknowledge);

      // listen on reply queue
      ReplyQueue := Session.CreateQueue('Habari' + '?' +
        BTStompTypes.SH_TRANSFORMATION + '=' + TRANSFORMER_ID_MAP_XML);
      Consumer := Session.CreateConsumer(ReplyQueue);

      // create the pseudo destination
      if ParamCount = 0 then
      begin
        Destination := Session.CreateQueue('ActiveMQ.Statistics.Broker');
      end
      else
      begin
        Destination := Session.CreateQueue('ActiveMQ.Statistics.Destination.' + ParamStr(1));
      end;

      // display destination name
      WriteLn('Request statistics for ' + Destination.QueueName + ' ...');

      // create the message and set reply queue name
      JMSMessage := Session.CreateTextMessage;
      JMSMessage.JMSReplyTo := ReplyQueue;
      Producer := Session.CreateProducer(Destination);
      Producer.Send(JMSMessage);

      // read the result message
      Reply := Consumer.Receive(1000) as IMapMessage;

      // list the map key/values
      while Assigned(Reply) do
      begin
        MapNames := Reply.GetMapNames;
        for I := 0 to Length(MapNames) - 1 do
        begin
          Key := MapNames[I];
          WriteLn(Key + '=' + Reply.GetString(Key));
        end;
        WriteLn;
        Reply := Consumer.Receive(1000) as IMapMessage;
      end;

      WriteLn('No more message on queue ' + ReplyQueue.QueueName);

      Connection.Stop;

    except
      on E: Exception do
        WriteLn(E.Message);
    end;
  finally
    Connection.Close;
  end;

  WriteLn('Press any key');
  ReadLn;
end.