org.apache.beam.runners.core.fn.SdkHarnessClient.java Source code

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Here is the source code for org.apache.beam.runners.core.fn.SdkHarnessClient.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * 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,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.beam.runners.core.fn;

import com.google.auto.value.AutoValue;
import com.google.common.base.Function;
import com.google.common.util.concurrent.Futures;
import com.google.common.util.concurrent.ListenableFuture;
import java.io.IOException;
import java.util.concurrent.Future;
import java.util.concurrent.atomic.AtomicLong;
import org.apache.beam.fn.v1.BeamFnApi;

/**
 * A high-level client for an SDK harness.
 *
 * <p>This provides a Java-friendly wrapper around {@link FnApiControlClient} and {@link
 * FnDataReceiver}, which handle lower-level gRPC message wrangling.
 */
public class SdkHarnessClient {

    /**
     * A supply of unique identifiers, used internally. These must be unique across all Fn API
     * clients.
     */
    public interface IdGenerator {
        String getId();
    }

    /** A supply of unique identifiers that are simply incrementing longs. */
    private static class CountingIdGenerator implements IdGenerator {
        private final AtomicLong nextId = new AtomicLong(0L);

        @Override
        public String getId() {
            return String.valueOf(nextId.incrementAndGet());
        }
    }

    /**
     * An active bundle for a particular {@link
     * org.apache.beam.fn.v1.BeamFnApi.ProcessBundleDescriptor}.
     */
    @AutoValue
    public abstract static class ActiveBundle<InputT> {
        public abstract String getBundleId();

        public abstract Future<BeamFnApi.ProcessBundleResponse> getBundleResponse();

        public abstract FnDataReceiver<InputT> getInputReceiver();

        public static <InputT> ActiveBundle<InputT> create(String bundleId,
                Future<BeamFnApi.ProcessBundleResponse> response, FnDataReceiver<InputT> dataReceiver) {
            return new AutoValue_SdkHarnessClient_ActiveBundle(bundleId, response, dataReceiver);
        }
    }

    private final IdGenerator idGenerator;
    private final FnApiControlClient fnApiControlClient;

    private SdkHarnessClient(FnApiControlClient fnApiControlClient, IdGenerator idGenerator) {
        this.idGenerator = idGenerator;
        this.fnApiControlClient = fnApiControlClient;
    }

    /**
     * Creates a client for a particular SDK harness. It is the responsibility of the caller to ensure
     * that these correspond to the same SDK harness, so control plane and data plane messages can be
     * correctly associated.
     */
    public static SdkHarnessClient usingFnApiClient(FnApiControlClient fnApiControlClient) {
        return new SdkHarnessClient(fnApiControlClient, new CountingIdGenerator());
    }

    public SdkHarnessClient withIdGenerator(IdGenerator idGenerator) {
        return new SdkHarnessClient(fnApiControlClient, idGenerator);
    }

    /**
     * Registers a {@link org.apache.beam.fn.v1.BeamFnApi.ProcessBundleDescriptor} for future
     * processing.
     *
     * <p>A client may block on the result future, but may also proceed without blocking.
     */
    public Future<BeamFnApi.RegisterResponse> register(
            Iterable<BeamFnApi.ProcessBundleDescriptor> processBundleDescriptors) {

        // TODO: validate that all the necessary data endpoints are known

        ListenableFuture<BeamFnApi.InstructionResponse> genericResponse = fnApiControlClient
                .handle(BeamFnApi.InstructionRequest
                        .newBuilder().setInstructionId(idGenerator.getId()).setRegister(BeamFnApi.RegisterRequest
                                .newBuilder().addAllProcessBundleDescriptor(processBundleDescriptors).build())
                        .build());

        return Futures.transform(genericResponse,
                new Function<BeamFnApi.InstructionResponse, BeamFnApi.RegisterResponse>() {
                    @Override
                    public BeamFnApi.RegisterResponse apply(BeamFnApi.InstructionResponse input) {
                        return input.getRegister();
                    }
                });
    }

    /**
     * Start a new bundle for the given {@link
     * org.apache.beam.fn.v1.BeamFnApi.ProcessBundleDescriptor} identifier.
     *
     * <p>The input channels for the returned {@link ActiveBundle} are derived from the
     * instructions in the {@link org.apache.beam.fn.v1.BeamFnApi.ProcessBundleDescriptor}.
     */
    public ActiveBundle newBundle(String processBundleDescriptorId) {
        String bundleId = idGenerator.getId();

        // TODO: acquire an input receiver from appropriate FnDataService
        FnDataReceiver dataReceiver = new FnDataReceiver() {
            @Override
            public void accept(Object input) throws Exception {
                throw new UnsupportedOperationException("Placeholder FnDataReceiver cannot accept data.");
            }

            @Override
            public void close() throws IOException {
                // noop
            }
        };

        ListenableFuture<BeamFnApi.InstructionResponse> genericResponse = fnApiControlClient
                .handle(BeamFnApi.InstructionRequest.newBuilder().setProcessBundle(BeamFnApi.ProcessBundleRequest
                        .newBuilder().setProcessBundleDescriptorReference(processBundleDescriptorId)).build());

        ListenableFuture<BeamFnApi.ProcessBundleResponse> specificResponse = Futures.transform(genericResponse,
                new Function<BeamFnApi.InstructionResponse, BeamFnApi.ProcessBundleResponse>() {
                    @Override
                    public BeamFnApi.ProcessBundleResponse apply(BeamFnApi.InstructionResponse input) {
                        return input.getProcessBundle();
                    }
                });

        return ActiveBundle.create(bundleId, specificResponse, dataReceiver);
    }
}