Event Monitoring in Message Broker

1. OVERVIEW:

1.1  INTRODUCTION :

Ø  Event monitoring is feature which lets you configure a message flow to emit monitoring events without any coding. As the configured events occur in the message flow, XML documents are generated and published as pre-defined topics by the broker on which the message flow is deployed.     

            1.2  PURPOSE OF EVENT MONITORING:

Ø  Message flows can be configured to emit events. The events can be read and used by other applications for transaction monitoring, transaction auditing, and business process monitoring.

Ø  An event is a message that a message flow publishes when something interesting or desired happens.

Ø  The message contains information about the source of the event, the time of the event, and the reason for the event. The event can include the message bit stream, and can also include selected elements from the message body. These fields can be used to  convey business data to a monitoring application.

              

2. SYSYTEM REQUIREMENTS:

COMPONENTS	VERSIONS
Websphere MQ Explorer	Websphere MQ Explorer V6.1 or later
Websphere Message Broker components	Websphere Message Broker V6.1.0.3 or later

3 PRE REQUISITES:

 

  3.1 CONCEPTS :

The concepts that we need to know

Ø  Publish/subscribe.

Ø  Monitoring Events:- A monitoring event is an XML document that conforms to the monitoring event schema. Each event contains source of the event ,name of the event ,sequence number and creation time ,correlation id for events emitted by the same transaction or unit of work ,application data extracted from the message .

Ø  Types of Events.

Ø  Transaction Events:Transaction events are emitted only from input nodes.

Ø  Transaction start :The event is emitted when the message is read from the transport.

Ø  Transaction end :The event is emitted when WebSphere Message Broker has completed all processing of the message.

Ø  Transaction rollback :The event is emitted instead of transaction end if the message flow throws an exception which is not caught and processed within the message flow.

Ø  Terminal Events:Terminal events are emitted from any terminal of any node, including input nodes(Failure,Catch,Out).

4.FUNCTIONALITY AND SCENARIO:

    4.1 ILLUSTRATION:

           4.1.1 CONFIGURING A MESSAGE FLOW TO GENERATE MONITORING EVENTS

Ø  We can configure monitoring events to emit without any coding as follows:

Ø  In the node properties we can find a property called monitoring, which needs to be set inorder to emit an event.

Ø  We need to select event source, event name and the event pay load .

Ø  Event Payload is where we will be writing an X-path expression , whose value needs to be extracted from the message.

Ø  As the event occurs an XML document is generated and published in a predefined topic by the broker in the flow is deployed.

       

            4.1.2 COMMAND FOR ACTIVATING THE EVENTS:

Ø   command to activate:

mqsichangeflowmonitoring brokername -e executaiongroupname -f flowname -c active

Ø  Use -c inactive to inactivate.

Ø  Status for monitoring:

mqsireportflowmonitoring brokername -e executaiongroupname -f flowname -a

 

           4.1.3 SUBSCRIBING AND RETRIVING THE MESSAGE:

Ø  As the event message is generated and published in the topic , we need to subscribe it to retrive the event message.

Ø  This subscription can be done by directly subscribing from the MQ or through a subscription flow.

         

          4.1.4 Topics:

Ø  The format of the topic string is

$SYS/Broker/<BrokerName>/Monitoring/<ExecutionGroupName>/<MessageFlowName>

Ø  Topic string for a specfic message flow and specific execution group is

$SYS/Broker/BRK1/Monitoring/default/MonitoringEvents_MF

Ø  Topic string for allmessage flow among all execution group is

$SYS/Broker/BRK1/Monitoring/#/#.

Where # is a wild card indicating all .

         4.1.5  FLOWS ACROSS DIFFERENT BROKERS:            

Ø  By using distribution queueing we can place the event messages of  all flows across different brokers.

Ø  For instance if we have two brokers say brk1 and brk2 .

Ø  We need to place all the event messages of all the flows from two brokers  in  a queue of brk1.

Ø  Hence queue's from different brokers queue manager will subscribe indvidually and then we need to create a distribution queueing between two queue managers.

4.2 EXECUTION:

  

     4.2.1 CONFIGURING A MESSAGE FLOW TO GENERATE MONITORING EVENTS:

Ø  selcet monitoring property and click on add.

Ø  select the basic tab ,set event source,event name, select event payload and click add to add an X-path expression .

Ø  Adding an X path expression in event payload

Ø   Different kinds of expressions.

  4.2.2 COMMAND FOR ACTIVATING THE EVENTS:

              

                     Command for activating :

Ø  "mqsichangeflowmonitoring brokername -e ExecutionGroupname -f Flowname -c active"

Command for status:

Ø  “mqsireportflowmonitoring brokername -e executiongroupname -f flowname –a”

Ø   

  4.2.3 SUBSCRIBING  THE TOPIC:

       

Ø   select the subscription object in the queue manager.

Ø  Select new and subscription

 

Ø  Now we give topic string and queue name to which needs to be subscribed .

Ø  Topic string for a specific flow and execution group.

Ø  Topic string for all flows across all execution group.

Ø  Event message :

      

Ø  Where the XML message consists of broker name, execution group name , flow name and the MsId which is extracted from the message.

Ø  This message is produced when then third property of the event pay load is ocured .

Ø  The value will be true when the condition is meet, else it will be false.