Using the Avro to Tuple Operator

Introduction

The Avro to Tuple Java operator converts binary Apache Avro Records to StreamBase tuples. The operator's input port must contain a blob field containing a single Avro Record. All other fields are ignored or passed along if pass through fields are enabled.

Properties View Settings

This section describes the properties you can set for a Avro to Tuple 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 from an Avro Record, this field must be a blob.
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.
Schema The schema to use when converting the Avro Record.
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.

Edit Schema Tab

Use the Edit Schema tab to specify the schema of the output tuple for this adapter. For general instructions on using the Edit Schema tab, see the Properties: Edit Schema Tab section of the Defining Input Streams page.

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

  • TupleIn: The Avro message to be converted to a tuple. The TupleIn port can have any schema but must contain at least the field specified by the Avro Field Name property.

  • TupleOut: This output port contains the converted Avro record and if enabled pass through fields then a copy of the input tuple.