UserFunctionLoader¶

UserFunctionLoader uses Function Loaders to loadFunctions.

Creating Instance¶

UserFunctionLoader takes the following to be created:

• MutableFunctionRegistry
• Plugin Directory
• Parent ClassLoader
• blacklist
• Metrics
• loadCustomerUdfs flag

UserFunctionLoader is created when:

• UdfLoaderUtil is requested to load
• UserFunctionLoader is requested to newInstance

Function Loaders¶

UserFunctionLoader creates the function loaders when created:

• UdafLoader
• UdfLoader
• UdtfLoader

The loaders are used to loadFunctions.

Creating UserFunctionLoader¶

UserFunctionLoader newInstance(
  KsqlConfig config,
  MutableFunctionRegistry metaStore,
  String ksqlInstallDir,
  Metrics metricsRegistry)

With ksql.udf.enable.security.manager enabled, newInstance sets the System security as ExtensionSecurityManager.

In the end, newInstance creates a UserFunctionLoader with the following:

• The given MutableFunctionRegistry
• The plugin directory as ext under the given ksqlInstallDir unless ksql.extension.dir is defined
• A new Blacklist with resource-blacklist.txt under the plugin directory
• The given Metrics if ksql.udf.collect.metrics
• ksql.udfs.enabled

newInstance is used when:

• KsqlContext is used to create a KsqlContext
• KsqlRestApplication is used to build a KsqlRestApplication
• StandaloneExecutorFactory is used to create a StandaloneExecutor

Loading Function Jars¶

void load()

load loadFunctions.

With loadCustomerUdfs enabled, load finds all the jar files in the pluginDir and loadFunctions for every jar file (unless blacklisted).

load is used when:

• KsqlContext is used to create a KsqlContext
• UdfLoaderUtil is requested to load
• KsqlRestApplication is used to build a KsqlRestApplication
• StandaloneExecutor is requested to startAsync

loadFunctions¶

void loadFunctions(
  ClassLoader loader,
  Optional<Path> path)

loadFunctions finds classes with the function annotations and uses the UdfLoader to load them.

Logging¶

Enable ALL logging level for io.confluent.ksql.function.UserFunctionLoader logger to see what happens inside.

Add the following line to config/log4j.properties:

log4j.logger.io.confluent.ksql.function.UserFunctionLoader=ALL

Refer to Logging.