Managing topics

After adding a Kafka topic as an event source to Event Endpoint Management, you can use the Topic Detail page to subsequently edit the details you provide about the topic, socialize it, and find out more about its usage. You can also manage a topic’s lifecycle state and remove a topic from the catalog from this page.

To access the Topic Detail page:

1. Log in to the Event Endpoint Management UI by using your login credentials.
2. In the navigation pane, click Topics.
3. Find the topic you want to work with in the list, and click the name of the topic.

The details of your topic appear in two sections:

• The Information section: displays all the possible information presented to a user when a topic is socialized in the catalog. These can be provided or removed by editing your topic.
• The Manage section: displays the current lifecycle status of your topic in Event Endpoint Management, including the ability for users to subscribe and discover your topic and the current set of subscribed users of your topic.

You can also delete your topic from this page, or export this topic for use with IBM API Connect.

Editing a topic

To edit the event source details that represent a topic:

1. Click the Edit Information button found in the header of the Topic Detail page.

   Click the Information tab on the Topic Detail page, and then select Edit Information.

2. Edit the fields you want to change in the Overview information section.
3. In the side bar, click Event Information to navigate to this section.
4. Edit the fields and values in the Event Information section that you want to change.
5. After you make changes, save your changes by clicking the blue Save button in the footer.
6. You can cancel any changes by clicking the Cancel button in the footer or the cross icon in the top corner.

Refer to the following sections for more information about the fields that can be edited in Overview information and Event Information.

Overview information

You can edit the following information on this page. Restrictions and validation checks ensure each field meets requirements for Kafka event sources.

• Topic alias is editable only when the topic is in an unpublished state. The topic alias must meet the following conditions:

  • Be less than 200 characters in length,
  • Have no white space included,
  • Must not use invalid characters: '/', '\\', ',', '\u0000', ':', '"', '\'', ';', '*', '?', ' ', '\t', '\r', '\n', '='
• Topic name is set when the event source is created and cannot be edited.
• Description can be edited to describe your topic.
• Tags can be added in a comma separated list. For example: Product,Returns,Damage Returns. You can use tags to make discovering the topic easier to identify in the catalog.
• Contact must follow an email address format.

Event information

The event information provides details to help consume the events from the topic.

• Upload Schema: you can provide an Avro Schema in JavaScript Object Notation (JSON) document format. Checks are made to ensure valid JSON and valid Avro schemas have been uploaded. If a valid file has been uploaded, a code snippet preview of the schema is displayed. If the formatting is incorrect, the schema is not saved with a validation failure. Note: The schema must also be saved as a .avsc or .avro file. Invalid file formats will not be saved when uploaded, and the topic will not have a schema.
• Schema description: you can add detailed information about the schema.
• Sample messages: you can provide examples of the messages that are emitted by the event source. In addition, if the event source does not follow an Avro schema, you can use the sample messages field. The sample messages will then be used to infer the schema of messages sent on the topic. The sample messages do not follow a required format. You can use this to document to check how the sample messages are structured.

Saving changes

The save button is disabled if the edits made do not meet the requirements for a Kafka topic. When you are finished with editing the event source, you can either:

• Click the blue Save button, which will be visible in the footer if the validation checks pass.
• Click the Cancel button in the footer or the cross icon in the top corner to cancel any unwanted changes.

Deleting a topic

Unpublished topics can be deleted from Event Endpoint Management. Deleting a topic removes all details about your topic. To get your topic into a state where it can be deleted, see how you can manage its lifecycle state.

To delete a topic from Event Endpoint Management, complete the following steps.

1. In the header of the Topic Detail page for your Unpublished topic, click Delete topic.

   Open the Manage tab within the Topic Detail page for your Unpublished topic, and select Delete topic.

2. Confirm the topic that you want to delete by entering the topic name.
3. Click the red Delete button, this will be visible in the footer if you have entered the topic name that you want to delete correctly.

Topics can also be deleted from the Topics page. All Unpublished topics will contain a delete icon in their row in the topic table. You can delete a topic from the Topics page by clicking the delete icon and following steps 2-3 above.

Topic lifecycle state

After adding the Kafka topic as an event source to Event Endpoint Management, it can have different lifecycle states. The lifecycle state of your event source determines whether it can be subscribed to by users, socialized in the Catalog, and available to perform any other operations.

The lifecycle a Kafka topic in Event Endpoint Management progresses through is as follows:

• Unpublished: this topic is not socialized in the Catalog, cannot be subscribed to by other users, and has no current subscriptions.
• Published: this topic is socialized in the Catalog, and users can create new subscriptions to use it.
• Archived: this topic is socialized in the Catalog and has existing subscriptions, but users cannot create new subscriptions.

The Manage tab on the Topic Detail page allows users to manage a topic’s lifecycle state. You can see both the topic’s current state and a button to advance it to the next state on this page.

You can change the lifecycle state of an event source as follows:

• To change the Unpublished state to Published, click the Publish topic button.
• To change the Published state to Archived, click the Archive topic button.
  • Note: This option is only available if a published topic has subscribers.
• To change the Archived state to Published, click the Publish topic button.
• To change the Published state to Unpublished, click the Unpublish topic button.
  • Note: This option is only available if a published topic has no current subscribers.

Note: Archived topics automatically return to the Unpublished state when all subscribers have their subscriptions revoked from using this topic.

A topic can be edited in any lifecycle state. However, the set of fields that can be edited is restricted when in Published or Archived states to prevent changes that cause runtime issues for subscribed users.

Note: Only Unpublished topics can be deleted from Event Endpoint Management.