org.apache.beam.fn.harness.data.BeamFnDataClient Maven / Gradle / Ivy
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* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
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*/
package org.apache.beam.fn.harness.data;
import java.util.List;
import java.util.function.Supplier;
import org.apache.beam.model.fnexecution.v1.BeamFnApi.Elements;
import org.apache.beam.model.pipeline.v1.Endpoints;
import org.apache.beam.model.pipeline.v1.Endpoints.ApiServiceDescriptor;
import org.apache.beam.sdk.fn.data.BeamFnDataOutboundAggregator;
import org.apache.beam.sdk.fn.data.CloseableFnDataReceiver;
import org.apache.beam.sdk.fn.data.FnDataReceiver;
/**
* The {@link BeamFnDataClient} is able to forward inbound elements to a {@link FnDataReceiver} and
* provide a receiver of outbound elements. Callers can register themselves as receivers for inbound
* elements or can get a handle for a receiver of outbound elements.
*/
public interface BeamFnDataClient {
/**
* Registers a receiver for the provided instruction id.
*
* The receiver is not required to be thread safe.
*
*
Receivers for successfully processed bundles must be unregistered. See {@link
* #unregisterReceiver} for details.
*
*
Any failure during {@link FnDataReceiver#accept} will mark the provided {@code
* instructionId} as invalid and will ignore any future data. It is expected that if a bundle
* fails during processing then the failure will become visible to the {@link BeamFnDataClient}
* during a future {@link FnDataReceiver#accept} invocation.
*/
void registerReceiver(
String instructionId,
List apiServiceDescriptors,
CloseableFnDataReceiver receiver);
/**
* Receivers are only expected to be unregistered when bundle processing has completed
* successfully.
*
* It is expected that if a bundle fails during processing then the failure will become visible
* to the {@link BeamFnDataClient} during a future {@link FnDataReceiver#accept} invocation or via
* a call to {@link #poisonInstructionId}.
*/
void unregisterReceiver(String instructionId, List apiServiceDescriptors);
/**
* Poisons the instruction id, indicating that future data arriving for it should be discarded.
* Unregisters the receiver if was registered.
*
* @param instructionId
*/
void poisonInstructionId(String instructionId);
/**
* Creates a {@link BeamFnDataOutboundAggregator} for buffering and sending outbound data and
* timers over the data plane. It is important that {@link
* BeamFnDataOutboundAggregator#sendOrCollectBufferedDataAndFinishOutboundStreams()} is called on
* the returned BeamFnDataOutboundAggregator at the end of each bundle. If
* collectElementsIfNoFlushes is set to true, {@link
* BeamFnDataOutboundAggregator#sendOrCollectBufferedDataAndFinishOutboundStreams()} returns the
* buffered elements instead of sending it through the outbound StreamObserver if there's no
* previous flush.
*
* Closing the returned aggregator signals the end of the streams.
*
*
The returned aggregator is not thread safe.
*/
BeamFnDataOutboundAggregator createOutboundAggregator(
Endpoints.ApiServiceDescriptor apiServiceDescriptor,
Supplier processBundleRequestIdSupplier,
boolean collectElementsIfNoFlushes);
}