Struct arrow_flight::encode::FlightDataEncoderBuilder

pub struct FlightDataEncoderBuilder { /* private fields */ }

Creates a Stream of FlightDatas from a Stream of Result<RecordBatch, FlightError>.

This can be used to implement FlightService::do_get in an Arrow Flight implementation;

Caveats

1. DictionaryArrays are converted to their underlying types prior to transport, due to https://github.com/apache/arrow-rs/issues/3389.

Example

use arrow_flight::encode::FlightDataEncoderBuilder;

// Get an input stream of Result<RecordBatch, FlightError>
let input_stream = futures::stream::iter(vec![Ok(record_batch)]);

// Build a stream of `Result<FlightData>` (e.g. to return for do_get)
let flight_data_stream = FlightDataEncoderBuilder::new()
 .build(input_stream);

// Create a tonic `Response` that can be returned from a Flight server
let response = tonic::Response::new(flight_data_stream);

Implementations

impl FlightDataEncoderBuilder

pub fn new() -> Self

pub fn with_max_flight_data_size(self, max_flight_data_size: usize) -> Self

Set the (approximate) maximum size, in bytes, of the FlightData produced by this encoder. Defaults to 2MB.

Since there is often a maximum message size for gRPC messages (typically around 4MB), this encoder splits up RecordBatchs (preserving order) into multiple FlightData objects to limit the size individual messages sent via gRPC.

The size is approximate because of the additional encoding overhead on top of the underlying data buffers themselves.

pub fn with_metadata(self, app_metadata: Bytes) -> Self

Specify application specific metadata included in the FlightData::app_metadata field of the the first Schema message

pub fn with_options(self, options: IpcWriteOptions) -> Self

Set the IpcWriteOptions used to encode the RecordBatches for transport.

pub fn with_schema(self, schema: SchemaRef) -> Self

Specify a schema for the RecordBatches being sent. If a schema is not specified, an encoded Schema message will be sent when the first RecordBatch, if any, is encoded. Some clients expect a Schema message even if there is no data sent.

pub fn with_flight_descriptor( self, descriptor: Option<FlightDescriptor> ) -> Self

Specify a flight descriptor in the first FlightData message.

pub fn build<S>(self, input: S) -> FlightDataEncoderwhere S: Stream<Item = Result<RecordBatch>> + Send + 'static,

Return a Stream of FlightData, consuming self. More details on FlightDataEncoder

Trait Implementations

impl Debug for FlightDataEncoderBuilder

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for FlightDataEncoderBuilder

fn default() -> Self

Returns the “default value” for a type.