org.apache.beam.runners.fnexecution.data.FnDataService 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.runners.fnexecution.data;
import java.util.function.Supplier;
import org.apache.beam.model.fnexecution.v1.BeamFnApi.Elements;
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 FnDataService} is able to forward inbound elements to a consumer and is also a
* consumer of outbound elements. Callers can register themselves as consumers for inbound elements
* or can get a handle for a consumer for outbound elements.
*/
public interface FnDataService {
/**
* 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 FnDataService}
* during a future {@link FnDataReceiver#accept} invocation.
*/
void registerReceiver(String instructionId, CloseableFnDataReceiver observer);
/**
* 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 FnDataService} during a future {@link FnDataReceiver#accept} invocation.
*/
void unregisterReceiver(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(
Supplier processBundleRequestIdSupplier, boolean collectElementsIfNoFlushes);
}