SchemaRegistryClient properties reference

Review the following reference for a comprehensive list of the SchemaRegistryClient properties.

Table 1. SchemaRegistryClient properties
Property Name	Description	Type	Default Value
`schema.registry.url`	The URL of the Schema Registry server which this client connects to.	String	`http://localhost:9090/api/v1`
`schema.registry.client.local.jars.path`	The local directory path to which downloaded JARs are copied to.	String	`/tmp/schema-registry/local-jars`
`schema.registry.client.class.loader.cache.size`	The maximum size of the classloader cache.	Int	1024
`schema.registry.client.class.loader.cache.expiry.interval.secs`	The expiry interval (in seconds) of an entry in the classloader cache.	Int	3600 sec
`schema.registry.client.schema.version.cache.size`	The maximum size of schema text cache.	Int	1024
`schema.registry.client.schema.version.cache.expiry.interval.secs`	The expiry interval (in seconds) of an entry in schema version cache.	Int	300 sec
`schema.registry.client.schema.metadata.cache.size`	Maximum size of schema metadata cache.	Int	1024
`schema.registry.client.schema.metadata.cache.expiry.interval.secs`	Expiry interval (in seconds) of an entry in schema metadata cache.	Int	300 sec
`schema.registry.client.schema.text.cache.size`	Maximum size of schema text cache.	Int	1024
`schema.registry.client.schema.text.cache.expiry.interval.secs`	Expiry interval (in seconds) of an entry in schema text cache.	Int	300 sec
`schema.registry.client.url.selector`	Schema Registry URL selector class.	String	com.hortonworks.registries.schemaregistry.client.FailoverUrlSelector
`sasl.jaas.config`	Schema Registry Dynamic JAAS configuration for SASL connection.	String	null
`schema.registry.auth.username`	Username for basic authentication.	String	null
`schema.registry.auth.password`	Password for basic authentication.	String	null
`schema.registry.hash.function`	Hashing algorithm for generating schema fingerprints.	String	MD5
`schema.registry.auth.type`	The type of authentication the client should use. If the value is `oauth2`, it will be configured for oauth login, otherwise it will use Kerberos.	String	kerberos
`schema.registry.oauth.client.id`	Client ID for OAuth server in case of oauth login.	String	empty
`schema.registry.oauth.secret`	Secret for OAuth server in case of oauth login.	String	empty
`schema.registry.oauth.server.url`	OAuth server URL in case of oauth login.	String	empty
`schema.registry.oauth.scope`	OAuth scope in case of oauth login.	String	empty
`schema.registry.oauth.request.method`	HTTP method for requesting the oauth token.	String	post
`connector.provider.class`	Classname of a Jersey connector provider. (For example: org.glassfish.jersey.apache.connector.ApacheConnectorProvider) Make sure the class is on classpath. If this is set, Backoff policy might need to be set to `com.hortonworks.registries.schemaregistry.retry.policy.ExponentialBackoffPolicy`.	String	empty
`schema.registry.client.ssl`	Schema Registry SSL configuration. Expects a map of SSL properties. For available properties, see SSL configuration properties.	Object	null
`schema.registry.client.retry.policy`	Expects a map containing the retry policy configuration. The map accepts a `className` key to specify the policy class and a `config` key for policy-specific properties. Both keys are optional. `className` defaults to ExponentialBackoffPolicy if omitted, and `config` uses policy defaults if omitted. For available policies and properties, see Retry policies and retry policy configuration properties.	Object	ExponentialBackoffPolicy with the following default properties: `sleepTimeMs=1000 maxAttempts=5 timeoutMs=90000`
`schema.registry.client.doAs`	The user principal to send requests on behalf of. When configured, the principal name is included in the `doAs` query parameter for every request.	String	empty

SSL configuration properties

The schema.registry.client.ssl property expects a map of SSL properties that control SSL/TLS connections between the Schema Registry client and server.

Example configuration in YAML

The following example shows a typical mTLS configuration with both truststore properties (for validating the server) and keystore properties (for client authentication):

#...
schema.registry.client.ssl:
  protocol: [***PROTOCOL NAME***]
  trustStoreType: [***STORE TYPE***]
  trustStorePath: [***TRUSTSTORE PATH***]
  trustStorePassword: [***TRUSTSTORE PASSWORD***]
  keyStoreType: [***STORE TYPE***]
  keyStorePath: [***KEYSTORE PATH***]
  keyStorePassword: [***KEYSTORE PASSWORD***]

Table 2. SchemaRegistryClient SSL configurations properties
Property Name	Description	Type	Default Value
`protocol`	The SSL/TLS protocol name used to create the SSLContext. Using generic protocol names like "SSL" or "TLS" allows the JVM to negotiate the best available protocol version. Specifying a specific version restricts the connection to that protocol.	String	null (uses JVM default)
`hostnameVerifierClass`	Fully qualified class name of a custom `HostnameVerifier` implementation for validating server hostnames during the SSL handshake.	String	null (uses default HTTPS hostname verification)
`keyStoreType`	Format of the client keystore file.	String	null (uses JVM default, typically "JKS")
`keyStorePath`	Absolute or relative file path to the keystore containing the client's private key and certificate. Required for mutual TLS (mTLS) authentication.	String	null (client authentication disabled)
`keyStorePassword`	Password required to access the keystore file specified in `keyStorePath`.	String	null
`keyPassword`	Password for the client's private key within the keystore. Only needed if different from `keyStorePassword`.	String	null (uses `keyStorePassword`)
`keyStoreProvider`	Name of the Java security provider for the keystore.	String	null (uses default provider)
`keyManagerFactoryAlgorithm`	Algorithm used by the KeyManagerFactory for managing client authentication credentials. This is an advanced property that rarely needs to be configured.	String	null (uses default algorithm)
`keyManagerFactoryProvider`	Provider name for the KeyManagerFactory for managing client authentication credentials. This is an advanced property that rarely needs to be configured.	String	null (uses default provider)
`trustStoreType`	Format of the truststore file. Required for validating the server's certificate.	String	null (uses JVM default)
`trustStorePath`	Absolute or relative file path to the truststore containing trusted CA certificates for validating the server's SSL certificate.	String	null (uses JVM's default cacerts)
`trustStorePassword`	Password required to access the truststore file specified in `trustStorePath`.	String	null
`trustStoreProvider`	Name of the Java security provider for the truststore.	String	null (uses default provider)
`trustManagerFactoryAlgorithm`	Algorithm used by the TrustManagerFactory for managing server certificate validation. This is an advanced property that rarely needs to be configured.	String	null (uses default algorithm)
`trustManagerFactoryProvider`	Provider name for the TrustManagerFactory for managing server certificate validation. This is an advanced property that rarely needs to be configured.	String	null (uses default provider)

Retry policies and retry policy configuration properties

The schema.registry.client.retry.policy property expects a map containing the retry policy configuration. The map accepts a className key to specify the policy class and a config key for policy-specific properties. Both keys are optional. className defaults to ExponentialBackoffPolicy if omitted, and config uses policy defaults if omitted. The retry policy controls how the client handles failed requests to the Schema Registry server.

The following retry policies are available:

com.hortonworks.registries.schemaregistry.retry.policy.ExponentialBackoffPolicy – The default policy. Retries with exponentially increasing delays between attempts.
com.hortonworks.registries.schemaregistry.retry.policy.FixedTimeBackoffPolicy – Retries with a fixed delay between attempts.
com.hortonworks.registries.schemaregistry.retry.policy.NOOPBackoffPolicy – No retry attempts are made.

Example configuration in YAML

#...
schema.registry.client.retry.policy:
  className: [***POLICY CLASS***]
  config:
    sleepTimeMs: [***MILLISECONDS***]
    maxAttempts: [***ATTEMPT COUNT***]
    timeoutMs: [***TIMEOUT MILLISECONDS***]

Table 3. SchemaRegistryClient retry policy configuration properties
Property Name	Description	Type	Default Value
`sleepTimeMs`	The initial delay in milliseconds between retry attempts. For ExponentialBackoffPolicy, this value increases exponentially with each retry.	Long	ExponentialBackoffPolicy – 1000
			FixedTimeBackoffPolicy – 1000
			NOOPBackoffPolicy – 0
`maxAttempts`	The maximum number of retry attempts before failing the request.	Int	ExponentialBackoffPolicy – 5
			FixedTimeBackoffPolicy – 5
			NOOPBackoffPolicy – 1
`timeoutMs`	The total timeout in milliseconds for all retry attempts combined. The client will stop retrying once this timeout is exceeded, even if `maxAttempts` has not been reached.	Long	ExponentialBackoffPolicy – 90000
			FixedTimeBackoffPolicy – 60000
			NOOPBackoffPolicy – 0