Attention: This version of Event Streams has reached End of Support. For more information about supported versions, see the support matrix.

Managing schema lifecycle

You can have multiple versions of a schema stored in the Event Streams schema registry. Kafka producers and consumers retrieve the right schema version they use from the registry based on a unique identifier and version.

When a new schema version is added, you can set both the producer and consumer applications to use that version. You then have the following options to handle earlier versions. The lifecycle is as follows:

  1. Add schema
  2. Add new schema version
  3. Deprecate earlier versions or deprecate entire schema
  4. Disable version or entire schema
  5. Remove version or entire schema

Deprecating

If you want your applications to use a new version of a schema, you can set the earlier version to Deprecated. When a version is deprecated, the applications using that version receive a message to warn them to stop using it. Applications can continue to use the schema, but warnings will be written to application logs about the schema version being deprecated. You can customize the message to be provided in the logs.

Deprecated versions are still available in the registry and can be used again.

Note: You can deprecate a entire schema, not just the versions of that schema. If the entire schema is set to deprecated, then all of its versions are reported as deprecated (including any new ones added).

Using the UI

  1. Log in to your Event Streams UI as an administrator from a supported web browser (see how to determine the login URL for your Event Streams UI).
  2. Click Schema Registry in the primary navigation.
  3. Select the schema you want to deprecate from the list.
  4. Set the entire schema or a selected version of the schema to be deprecated:
    • If you want to deprecate the entire schema and all its versions, click the Manage schema tab, and set Mark schema as deprecated to on.
    • To deprecate a specific version, select it from the list, and click the Manage version tab for that version. Then set Mark schema as deprecated to on.

Deprecated schemas and versions are marked with a Deprecated flag on the UI.

You can re-activate a schema or its version by setting Mark schema as deprecated to off.

Using the CLI

  1. Log in to your cluster as an administrator by using the IBM Cloud Private CLI:
    cloudctl login -a https://<cluster-address>:<cluster-router-https-port>
  2. Run the following command to initialize the Event Streams CLI on the cluster:
    cloudctl es init

  3. Run the following command to deprecate a schema version:
    cloudctl es schema-modify --deprecate --name <schema-name> --version <schema-version>

    To deprecate an entire schema, do not specify the --version <schema-version> option.

    To re-activate a schema version:
    cloudctl es schema-modify --activate --name <schema-name> --version <schema-version>

    To re-activate an entire schema, do not specify the --version <schema-version> option.

Disabling

If you want your applications to stop using a specific schema, you can set the schema version to Disabled. If you disable a version, applications will be prevented from producing and consuming messages using it. You can re-enable it again to allow applications to use the schema again.

When a schema is disabled, applications that want to use the schema receive an ERROR.

Java producers using the Event Streams schema registry serdes library will throw a SchemaDisabledException when attempting to produce messages using a disabled schema version.

For example, the message and stack trace for a disabled schema named Test_Schema would look like this:

com.ibm.eventstreams.serdes.exceptions.SchemaDisabledException: Schema "Test_Schema" version "1.0.0" is disabled.
	at com.ibm.eventstreams.serdes.EventStreamsSerializer.serialize(EventStreamsSerializer.java:174)
	at com.ibm.eventstreams.serdes.EventStreamsSerializer.serialize(EventStreamsSerializer.java:41)
	at org.apache.kafka.clients.producer.KafkaProducer.doSend(KafkaProducer.java:884)
	at org.apache.kafka.clients.producer.KafkaProducer.send(KafkaProducer.java:846)
	at org.apache.kafka.clients.producer.KafkaProducer.send(KafkaProducer.java:733)
	at Producer.main(Producer.java:92)

Note: You can disable a entire schema, not just the versions of that schema. If the entire schema is disabled, then all of its versions are disabled as well, which means no version of the schema can be used by applications (including any new ones added).

Using the UI

  1. Log in to your Event Streams UI as an administrator from a supported web browser (see how to determine the login URL for your Event Streams UI).
  2. Click Schema Registry in the primary navigation.
  3. Select the schema you want to disable from the list.
  4. Set the entire schema or a selected version of the schema to be disabled:
    • If you want to disable the entire schema and all its versions, click the Manage schema tab, and click Disable schema, then click Disable.
    • To disable a specific version, select it from the list, and click the Manage version tab for that version. Then click Disable version, then click Disable.
      You can re-enable a schema by clicking Enable schema, and re-enable a schema version by clicking Re-enable version.

Using the CLI

  1. Log in to your cluster as an administrator by using the IBM Cloud Private CLI:
    cloudctl login -a https://<cluster-address>:<cluster-router-https-port>
  2. Run the following command to initialize the Event Streams CLI on the cluster:
    cloudctl es init

  3. Run the following command to disable a schema version:
    cloudctl es schema-modify --disable --name <schema-name> --version <schema-version>

    To disable an entire schema, do not specify the --version <schema-version> option.

    To re-enable a schema version:
    cloudctl es schema-modify --enable --name <schema-name> --version <schema-version>

    To re-enable an entire schema, do not specify the --version <schema-version> option.

Removing

If a schema version has not been used for a period of time, you can remove it from the schema registry. Removing a schema version means it will be permanently deleted from the schema registry of your Event Streams instance, and applications will be prevented from producing and consuming messages using it.

If a schema is no longer available in the registry, Java applications that want to use the schema receive a SchemaNotFoundException message.

For example, the message and stack trace when producing a message with a missing schema named Test_Schema would look like this:

com.ibm.eventstreams.serdes.exceptions.SchemaNotFoundException: Schema "Test_Schema" not found
    at com.ibm.eventstreams.serdes.SchemaRegistryRestAPIClient.handleErrorResponse(SchemaRegistryRestAPIClient.java:145)
    at com.ibm.eventstreams.serdes.SchemaRegistryRestAPIClient.get(SchemaRegistryRestAPIClient.java:120)
    at com.ibm.eventstreams.serdes.SchemaRegistry.downloadSchema(SchemaRegistry.java:253)
    at com.ibm.eventstreams.serdes.SchemaRegistry.getSchema(SchemaRegistry.java:239)

Important: You cannot reverse the removal of a schema. This action is permanent.

Note: You can remove a entire schema, including all of its versions. If the entire schema is removed, then all of its versions are permanently deleted from the schema registry of your Event Streams instance.

Using the UI

  1. Log in to your Event Streams UI as an administrator from a supported web browser (see how to determine the login URL for your Event Streams UI).
  2. Click Schema Registry in the primary navigation.
  3. Select the schema you want to remove from the list.
  4. Remove the entire schema or a selected version of the schema:
    • If you want to remove the entire schema and all its versions, click the Manage schema tab, and click Remove schema, then click Remove.
    • To remove a specific version, select it from the list, and click the Manage version tab for that version. Then click Remove version, then click Remove.

    Important: This action is permanent and cannot be reversed.

Using the CLI

  1. Log in to your cluster as an administrator by using the IBM Cloud Private CLI:
    cloudctl login -a https://<cluster-address>:<cluster-router-https-port>
  2. Run the following command to initialize the Event Streams CLI on the cluster:
    cloudctl es init

  3. Run the following command to remove a schema version:
    cloudctl es schema-remove --name <schema-name> --version <schema-version>

    To remove an entire schema, do not specify the --version <schema-version> option.

    Important: This action is permanent and cannot be reversed.