Use the Kafka Producer step and the ProducerV2 API to publish messages

Push data from ServiceNow to Hermes so that the Kafka consumers can read them.

Before you begin

• Role required: integration_hub_admin
• This page is part of the Stream Connect quick start guide.
• This document shows you how to publish messages through your connection to Hermes. To set up and test your connection, see Set up a secure connection to the Hermes Messaging Service and Testing the connection to Hermes through the ADCv2 gateway.
• The first part of this page shows you how to use the Kafka Producer step in Workflow Studio to publish messages to Hermes. For more information about the step, see Kafka Producer step.
• The second part of this page shows you how to use the ProducerV2 API to publish messages. For more information, see ProducerV2 API.
• To receive all the messages, you need to run two consumers for different datacenters. See Consume test messages from a Hermes topic using the Kafka client for details.

Procedure

1. Start two consumers to receive messages.
   1. Run the following commands from the command line to receive the messages.

      bin/kafka-console-consumer.sh --consumer.config config/bootcamp.properties --topic snc.<instance name>.topic1 --group snc.<instance name>.consumer_group1 --from-beginning --bootstrap-server <instance name>.service-now.com:4100,<instance name>.service-now.com:4101,<instance name>.service-now.com:4102,<instance name>.service-now.com:4103

      bin/kafka-console-consumer.sh --consumer.config config/bootcamp.properties --topic snc.<instance name>.topic1 --group snc.<instance name>.consumer_group1 --from-beginning --bootstrap-server <instance name>.service-now.com:4200, <instance name>.service-now.com:4201, <instance name>.service-now.com:4202, <instance name>.service-now.com:4203

      Be sure to replace <instance name> with the name of your instance.
2. Publish messages from the instance using a flow step.
   1. Navigate to All > Process Automation > Flow Designer.
   2. Create a new action by selecting Create new > Action.
   3. In the Action properties form, give your action a name, then select Submit.
      This example uses the name Message Publisher.
   4. Add a Kafka Producer step to the action.

      To add an action step, select the plus sign between the Inputs and Error Evaluation in the Action Outline.

      

   5. In the step, set the Topic field to topic1.
   6. In the Message field, enter a message.

      You don't need to change any other fields.

      

   7. Select Save to save the action.
   8. Select the Test button to test the action.
      Testing the action publishes the message to the topic.
   9. To view the message, go to the command-line consoles created in step 1.
      The message should be present in one of the terminals.
3. Publish messages from the instance using a script.
   1. Run the following script using the scripts background to publish messages to this topic from the instance.

      var producer = new sn_ih_kafka.ProducerV2();
      producer.send('<sys id of the topic record>', gs.generateGUID(), 'Test message from ServiceNow', false, null);
      

      Be sure to replace <sys id of the topic record> with the sys_id of the topic record.
   2. To view the message, go to the command-line consoles created in step 1.
      The message should be present in one of the terminals.