You can use schemas when producing messages with the Event Streams REST producer API. You simply add the following parameters to the API call:
schemaname: The name of the schema you want to use when producing messages.schemaversion: The schema version you want to use when producing messages.
For example, to use cURL to produce messages to a topic with the producer API, and specify the schema to be used, run the curl command as follows:
Using SCRAM Basic Authentication:
curl -H "Authorization: <basic-auth>" -H "Accept: application/json" -H "Content-Type: text/plain" -d '<avro-encoded-message>' --cacert es-cert.pem "https://<producer-endpoint>/topics/<my-topic>/records?schemaname=<schema-name>&schemaversion=<schema-version-name>"
Using TLS Mutual Authentication:
curl -H "Accept: application/json" -H "Content-Type: text/plain" -d '<avro-encoded-message>' --cacert es-cert.pem --key user.key --cert user.crt "https://<producer-endpoint>/topics/<my-topic>/records?schemaname=<schema-name>&schemaversion=<schema-version-name>"
Note: Replace the values in brackets as follows:
<basic-auth>with the SCRAM Basic Authentication token which is generated using the Event Streams UI.<producer-endpoint>with the producer URL which is available from Connect to this cluster or Connect to this topic and copy the URL in the Producer endpoint and credentials section.<my_topic>with your topic name.<schema-name>with the name of your schema that is stored in Apicurio Registry in Event Streams.<schema-version-name>with the version of your schema that is stored in Apicurio Registry in Event Streams.<avro-encoded-message>with your avro encoded message.
The es-cert.pem certificate is downloaded by running the following command:
kubectl es certificates --format pem
The user.key and user.crt files are downloaded in a .zip file by clicking Generate credentials in the Producer endpoint and credentials section of Connect to this cluster or Connect to this topic, selecting Mutual TLS certificate, following the instructions in the wizard and clicking Download certificates.
By adding these parameters to the API call, a lookup is done on the specified schema and its version to check if it is valid. If valid, the correct message headers are set for the produced message.
Important: When using the producer API, the lookup does not validate the data in the request to see if it matches the schema. Ensure the message conforms to the schema, and that it has been encoded in the Apache Avro binary or JSON encoding format. If the message does not conform and is not encoded with either of those formats, consumers will not be able to deserialize the data.
If the message has been encoded in the Apache Avro binary format, ensure the HTTP Content-Type header is set to application/octet-stream.
If the message has been encoded in the Apache Avro JSON format, ensure the HTTP Content-Type header is set to application/json.