Page tree
Skip to end of metadata
Go to start of metadata

Messaging has three fundamental components:

  • Topic
  • Publisher
  • Subscriber

 

topic is a distribution mechanism that creates messages in a message queue. Security permissions manage the people that can access a topic.

A publisher is an authorised connection to a topic and is permitted to submit messages to the topic.

A subscriber is an authorised connection to a topic and is permitted to read messages from the topic.

Topics are configured on the messaging server, and publishers and subscribers are clients connected to the messaging server. This means that publishers and subscribers do not have to be local to the messaging server, and can reside in different locations. In addition, the publisher and subscriber do not need to be aware of each other for messaging to complete successfully.

Although this tutorial demonstrates all tasks on a single messaging server, in a real-world implementation the possibilities and designs of message queues are vast and you will more than likely use a client-server relationship.

Looking at the requirements for Widget Ltd to send data to Tucker Inc., once the components required for this tutorial are configured, the data between the two Widget Ltd and Tucker Inc.’s ERP systems will follow the process:

So, to successfully complete the tasks in this tutorial, you must configure the following messaging components:

  • Topic_WidgetSales – this topic creates messages from the sales division of Widget Ltd’s Food Chain ERP system.
  • Publisher_WidgetSales – this publisher submits messages in the queue from the sales division of Widget Ltd’s Food Chain ERP system.
  • Subscriber_TuckerSales – this subscriber reads messages in Tucker Inc.’s  JD Edwards ERP system, received from the sales division of Widget Ltd’s Food Chain ERP system, via the message queue.

In order for components to successfully communicate with the ESB system, all components must use the common user account to access data. Since you may have multiple user accounts requiring access, the best way to achieve this is by giving each component read and write permissions at a role level.

So let’s continue and create some components!

 Adding a topic component

In this tutorial, Tucker Inc. requires all sales information from Widget Ltd. This means you must create a topic for the sales data stream. 

To add a topic:

  1. Open Information Bus in a browser tab.
  2. Select Topics. The Topics screen is displayed.
  3. Click Add.
  4. Select Universal Topic from the list of extensions. The Topic Details screen is displayed.
  5. On the General tab, configure the topic as follows:
    • Name: Topic_WidgetSales
    • Spot: Universal Platform
    • Read Roles: universal-users
    • Write Roles: universal-users
  6. Click Save & Close.

     

 

Great! Now let’s create the publisher component.

 Adding a publisher component

A publisher component submits messages in the messaging queue to the receiving ERP system.

Since you are configuring messaging for the sales data stream between Widget Ltd and Tucker Inc. you must configure a publisher for this stream.  

To add a publisher:

  1. Select Publishers on the Information Bus browser tab. The Publisher screen is displayed.
  2. Click Add.
  3. Select Universal Publisher from the list of extensions. The Publisher Details screen is displayed.
  4. On the General tab, configure the publisher as follows:
    • Name: Publisher_WidgetSales
    • Spot: Universal Platform
    • Topic: Topic_WidgetSales
    • User Credential: ClientLogin_User

      • Replace port_number with the port number of the messaging server. As this tutorial is structured on a single messaging server, we will listen on the localhost loopback service. The default port number for this is 61616.
      • If you are sitting in instructor-led training with other users, your presenter will provide this information to you. If you get an error for the port number, try entering another port, with the number incremented by one. For example, 61617.

       

  5. Click Save & Close.

     

 

Now let’s create the subscriber component.

 Adding a subscriber component

A subscriber component reads messages in the messaging queue in the receiving ERP system.

As for the topics and publishers you configured in previous tasks of this tutorial, you must configure a subscriber for the sales data stream.

To add a subscriber:

  1. Select Subscribers on the Information Bus browser tab. The Subscriber screen is displayed.
  2. Click Add.
  3. Select Universal Subscriber from the list of extensions. The Subscriber Details screen is displayed.
  4. On the General tab, configure the subscriber as follows:
    • Name: Subscriber_TuckerSales
    • Spot: Universal Platform
    • Topic: Topic_WidgetSales
    • User Credential: ClientLogin_User

      • Replace port_number with the port number of the messaging server. As this tutorial is structured on a single messaging server, we will listen on the localhost loopback service. The default port number for this is 61616.
      • If you are sitting in instructor-led training with other users, your presenter will provide this information to you. If you get an error for the port number, try entering another port, with the number incremented by one. For example, 61617.

       

  5. Click Save & Close.

     

Now that you have configured all the required messaging components, let’s ensure these changes are updated in the ESB.

 Applying updates to publishers and subscribers

The Universal Platform ESB services must be restarted in order to load the new configuration information. This is essential as the service loads the configuration at start-up and will not dynamically refresh this information until the service is restarted.

To re-start the messaging queue service:

  1. Go to the browser tab that has Universal Console open.
  2. Select Messaging. The Messaging Queue screen is displayed.
  3. Click Stop. Wait for the service to stop.
  4. Click Start and check that the service starts successfully.

    The refresh button will also show the status of all the queues.


     

Next you must check the status of a publisher or subscriber to ensure that the service is started.

 Checking the status of a publisher or subscriber

You can view the status of a publisher or subscriber to ensure that the messaging service is running and so messages can be processed.

To check the status of the messaging service for a publisher or subscriber:

  1. Go to the browser tab that has Information Bus open.
  2. Click one of the publishers or subscribers you created in the Adding a publisher component and Adding a subscriber component tasks.
  3. Click Status in the Publisher section and check the information message to see if the publisher is started. If the publisher is stopped or you get an error, check your settings and try again.
  4. Click Save & Close.

     
 And that's a wrap

And that’s a wrap - congratulations on completing this module! Before we finish, let’s have a quick look at what you have done:

  • No labels