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course: Apache Kafka® for Python Developers

Hands On: Use the Python AdminClient Class


Dave Klein

Developer Advocate

Use AdminClient to Create a Topic and Alter its Configuration

In this exercise you will use the AdminClient class to create a new Kafka topic and alter one of its configuration properties.

Project Setup

  1. Open a terminal window and navigate to the kafka-python directory that you created in the previous exercise.

  2. If you are not currently using the kafka-env environment that was created in the last exercise, switch to it with the following command:

    source kafka-env/bin/activate
  3. Create a file called

  4. Open in an IDE of your choice.

Add Required Imports

  1. Add the following import statements to the top of the file:

    from confluent_kafka.admin import (AdminClient, NewTopic, 
    from config import config

Check if Kafka Topic Exists

  1. Add a function that uses list_topics() to check to see if a specific topic already exists:

    # return True if topic exists and False if not
    def topic_exists(admin, topic):
        metadata = admin.list_topics()
        for t in iter(metadata.topics.values()):
            if t.topic == topic:
                return True
        return False

Create a New Kafka Topic

  1. Add a function using a NewTopic instance and the create_topics() function to create a topic:

    # create new topic and return results dictionary
    def create_topic(admin, topic):
        new_topic = NewTopic(topic, num_partitions=6, replication_factor=3) 
        result_dict = admin.create_topics([new_topic])
        for topic, future in result_dict.items():
                future.result()  # The result itself is None
                print("Topic {} created".format(topic))
            except Exception as e:
                print("Failed to create topic {}: {}".format(topic, e))

Describe the New Kafka Topic

  1. Create a function that uses a ConfigResource instance and the describe_configs() function:

    # get max.message.bytes property
    def get_max_size(admin, topic):
        resource = ConfigResource('topic', topic)
        result_dict = admin.describe_configs([resource])
        config_entries = result_dict[resource].result()
        max_size = config_entries['max.message.bytes']
        return max_size.value

Set a Kafka Topic Configuration Property Value

  1. Now add a function using the alter_configs() function to set the max.message.bytes property:

    # set max.message.bytes for topic
    def set_max_size(admin, topic, max_k):
        config_dict = {'max.message.bytes': str(max_k*1024)}
        resource = ConfigResource('topic', topic, config_dict)
        result_dict = admin.alter_configs([resource])

Add Main Block

  1. Add a main block to put the new functions to work:

    if __name__ == '__main__':
        # Create Admin client
        admin = AdminClient(config)
        topic_name = 'my_topic'
        max_msg_k = 50
        # Create topic if it doesn't exist
        if not topic_exists(admin, topic_name):
            create_topic(admin, topic_name)
        # Check max.message.bytes config and set if needed
        current_max = get_max_size(admin, topic_name)
        if current_max != str(max_msg_k * 1024):
            print(f'Topic, {topic_name} max.message.bytes is {current_max}.')
            set_max_size(admin, topic_name, max_msg_k)
        # Verify config was set 
        new_max = get_max_size(admin, topic_name)
        print(f'Now max.message.bytes for topic {topic_name} is {new_max}')


  1. Save the file.

  2. Run from the command line with this command:

  3. Verify that the output is something like this:

    Topic my_topic created
    Topic, my_topic max.message.bytes is currently 2097164.
    Now max.message.bytes for topic my_topic is 51200

Exercise Environment Teardown

After completing the course exercises, you need to tear down the learn-kafka-python environment to avoid unnecessarily accruing cost to the point your promotional credits are exhausted.

  1. In the Confluent Cloud console, navigate to Environments.

  2. Click on the learn-kafka-python environment.

  3. Click the Delete Environment link at the bottom right.

  4. Confirm the delete request and click Continue.

Use the promo code PYTHONKAFKA101 to get $25 of free Confluent Cloud usage

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