Data Transforms API

Technical Preview

API reference documentation for Redpanda data transforms.

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Data transforms functions


func OnRecordWritten(fn OnRecordWrittenCallback)

The OnRecordWritten function registers a callback of type OnRecordWrittenCallback, which is invoked when a record is written to the input topic.

The function should be called in a package’s main function to register the transform function that will be applied.

Data transforms types


type OnRecordWrittenCallback func(e WriteEvent) ([]Record, error)

The OnRecordWrittenCallback type is a callback to transform records after a write event happens in the input topic. It’s the type of the parameter for the OnRecordWritten function.


type Record struct {
	// Key is an optional field.
	Key []byte
	// Value is the blob of data that is written to Redpanda.
	Value []byte
	// Headers are client specified key/value pairs that are
	// attached to a record.
	Headers []RecordHeader
	// Attrs is the attributes of a record.
	// Output records should leave these unset.
	Attrs RecordAttrs
	// The timestamp associated with this record.
	// For output records this can be left unset as it will
	// always be the same value as the input record.
	Timestamp time.Time
	// The offset of this record in the partition.
	// For output records this field is left unset,
	// as it will be set by Redpanda.
	Offset int64

The Record type is a record that has been written to Redpanda.


type RecordAttrs struct {
	// contains filtered or unexported fields


func (a RecordAttrs) TimestampType() int8


type RecordHeader struct {
	Key   []byte
	Value []byte

The RecordHeader type is an optional key/value pair that is passed along with records.


type WriteEvent interface {
	// Access the record associated with this event
	Record() Record

The WriteEvent type contains information about a record that was written.