Using the Tuple to Avro Operator

Introduction

The Tuple to Avro Java operator converts StreamBase tuples to binary Apache Avro Records. The entire input tuple can be converted or a user-defined subtuple.

Properties View Settings

This section describes the properties you can set for a Tuple to Avro operator, using the various tabs of the Properties view in StreamBase Studio.

General Tab

Name: Use this required field to specify or change the name of this instance of this component, which must be unique in the current EventFlow module. The name must contain only alphabetic characters, numbers, and underscores, and no hyphens or other special characters. The first character must be alphabetic or an underscore.

Operator: A read-only field that shows the formal name of the operator.

Start with application: If this field is set to Yes (default) or to a module parameter that evaluates to true, this instance of this operator starts as part of the JVM engine that runs this EventFlow module. If this field is set to No or to a module parameter that evaluates to false, the operator instance is loaded with the engine, but does not start until you send an sbadmin resume command, or until you start the component with StreamBase Manager.

Enable Error Output Port: Select this check box to add an Error Port to this component. In the EventFlow canvas, the Error Port shows as a red output port, always the last port for the component. See Using Error Ports to learn about Error Ports.

Description: Optionally enter text to briefly describe the component's purpose and function. In the EventFlow canvas, you can see the description by pressing Ctrl while the component's tooltip is displayed.

Operator Properties Tab

Property Description
Avro Field Name The name of the field in the input tuple which will be converted to an Avro Record. If blank the entire tuple is converted.
Namespace The namespace to use during the conversion
Enable Pass Through Fields If enabled the input tuple will be copied to the output tuple in a field named passThrough
Log Level Controls the level of verbosity the adapter uses to send notifications to the console. This setting can be higher than the containing application's log level. If set lower, the system log level is used. Available values, in increasing order of verbosity, are: OFF, ERROR, WARN, INFO, DEBUG, TRACE, and ALL.

Concurrency Tab

Use the Concurrency tab to specify parallel regions for this instance of this component, or multiplicity options, or both. The Concurrency tab settings are described in Concurrency Options, and dispatch styles are described in Dispatch Styles.

Caution

Concurrency settings are not suitable for every application, and using these settings requires a thorough analysis of your application. For details, see Execution Order and Concurrency, which includes important guidelines for using the concurrency options.

Operator Ports

The operator has one input port and one output port to communicate with the surrounding application.

The Tuple to Avro operator's ports are used as follows:

  • TupleIn: The tuple to be converted to Avro. The TupleIn port can be any schema but if the Avro Field Name is defined, it must exist in the input tuple.

  • TupleOut: This output port contains the processed tuple containing the Avro binary data and if pass through fields is enabled, a second field which contains a copy of the input tuple.