com.google.cloud.storage.ParallelCompositeUploadBlobWriteSessionConfig Maven / Gradle / Ivy
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/*
* Copyright 2023 Google LLC
*
* Licensed 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 com.google.cloud.storage;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import static java.util.Objects.requireNonNull;
import com.google.api.core.ApiFuture;
import com.google.api.core.ApiFutures;
import com.google.api.core.BetaApi;
import com.google.api.core.InternalApi;
import com.google.api.core.SettableApiFuture;
import com.google.cloud.storage.BufferedWritableByteChannelSession.BufferedWritableByteChannel;
import com.google.cloud.storage.MetadataField.PartRange;
import com.google.cloud.storage.Storage.BlobWriteOption;
import com.google.cloud.storage.TransportCompatibility.Transport;
import com.google.cloud.storage.UnifiedOpts.ObjectTargetOpt;
import com.google.cloud.storage.UnifiedOpts.Opts;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.hash.HashCode;
import com.google.common.hash.HashFunction;
import com.google.common.hash.Hashing;
import com.google.common.util.concurrent.ThreadFactoryBuilder;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.nio.charset.StandardCharsets;
import java.security.SecureRandom;
import java.time.Clock;
import java.util.Base64;
import java.util.Base64.Encoder;
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.atomic.AtomicInteger;
import javax.annotation.concurrent.Immutable;
import org.checkerframework.checker.nullness.qual.NonNull;
/**
* Immutable config builder to configure BlobWriteSession instances to perform Parallel Composite
* Uploads.
*
* Parallel Composite Uploads can yield higher throughput when uploading large objects. However,
* there are some things which must be kept in mind when choosing to use this strategy.
*
*
* - Performing parallel composite uploads costs more money. Class A operations
* are performed to create each part and to perform each compose. If a storage tier other than
*
STANDARD
* is used, early deletion fees apply to deletion of the parts.
* An illustrative example. Upload a 5GiB object using 64MiB as the max size per part.
*
* - 80 Parts will be created (Class A)
*
- 3 compose calls will be performed (Class A)
*
- Delete 80 Parts along with 2 intermediary Compose objects (Free tier as long as
* {@code STANDARD} class)
*
* Once the parts and intermediary compose objects are deleted, there will be no storage
* charges related to those temporary objects.
* - The service account/credentials used to perform the parallel composite upload require {@code
* storage.objects.delete} in order to cleanup the temporary part and intermediary compose
* objects.
* To handle handle part and intermediary compose object deletion out of band passing
* {@link PartCleanupStrategy#never()} to {@link
* ParallelCompositeUploadBlobWriteSessionConfig#withPartCleanupStrategy(PartCleanupStrategy)}
* will prevent automatic cleanup.
* - Please see the
* Parallel composite uploads documentation for a more in depth explanation of the
* limitations of Parallel composite uploads.
*
- A failed upload can leave part and intermediary compose objects behind which will count as
* storage usage, and you will be billed for it.
* By default if an upload fails, an attempt to cleanup the part and intermediary compose will
* be made. However if the program were to crash there is no means for the client to perform
* the cleanup.
* Every part and intermediary compose object will be created with a name which ends in {@code
* .part}. An Object Lifecycle Management rule can be setup on your bucket to automatically
* cleanup objects with the suffix after some period of time. See Object Lifecycle Management for
* full details and a guide on how to setup a Delete rule with a suffix
* match condition.
* - Using parallel composite uploads are not a a one size fits all solution. They have very
* real overhead until uploading a large enough object. The inflection point is dependent upon
* many factors, and there is no one size fits all value. You will need to experiment with
* your deployment and workload to determine if parallel composite uploads are useful to you.
*
*
* In general if you object sizes are smaller than several hundred megabytes it is unlikely
* parallel composite uploads will be beneficial to overall throughput.
*
* @see GrpcStorageOptions.Builder#setBlobWriteSessionConfig(BlobWriteSessionConfig)
* @see BlobWriteSessionConfigs#parallelCompositeUpload()
* @see Storage#blobWriteSession(BlobInfo, BlobWriteOption...)
* @see https://cloud.google.com/storage/docs/parallel-composite-uploads
* @since 2.28.0 This new api is in preview and is subject to breaking changes.
*/
@Immutable
@BetaApi
@TransportCompatibility({Transport.GRPC})
public final class ParallelCompositeUploadBlobWriteSessionConfig extends BlobWriteSessionConfig
implements BlobWriteSessionConfig.GrpcCompatible {
private static final int MAX_PARTS_PER_COMPOSE = 32;
private final int maxPartsPerCompose;
private final ExecutorSupplier executorSupplier;
private final BufferAllocationStrategy bufferAllocationStrategy;
private final PartNamingStrategy partNamingStrategy;
private final PartCleanupStrategy partCleanupStrategy;
private ParallelCompositeUploadBlobWriteSessionConfig(
int maxPartsPerCompose,
ExecutorSupplier executorSupplier,
BufferAllocationStrategy bufferAllocationStrategy,
PartNamingStrategy partNamingStrategy,
PartCleanupStrategy partCleanupStrategy) {
this.maxPartsPerCompose = maxPartsPerCompose;
this.executorSupplier = executorSupplier;
this.bufferAllocationStrategy = bufferAllocationStrategy;
this.partNamingStrategy = partNamingStrategy;
this.partCleanupStrategy = partCleanupStrategy;
}
@InternalApi
ParallelCompositeUploadBlobWriteSessionConfig withMaxPartsPerCompose(int maxPartsPerCompose) {
checkArgument(
2 <= maxPartsPerCompose && maxPartsPerCompose <= 32,
"2 <= maxPartsPerCompose <= 32 (2 <= %s <= 32)",
maxPartsPerCompose);
return new ParallelCompositeUploadBlobWriteSessionConfig(
maxPartsPerCompose,
executorSupplier,
bufferAllocationStrategy,
partNamingStrategy,
partCleanupStrategy);
}
/**
* Specify a specific executor supplier where work will be submitted when performing a parallel
* composite upload.
*
*
Default: {@link ExecutorSupplier#cachedPool()}
*
* @since 2.28.0 This new api is in preview and is subject to breaking changes.
*/
@BetaApi
public ParallelCompositeUploadBlobWriteSessionConfig withExecutorSupplier(
ExecutorSupplier executorSupplier) {
checkNotNull(executorSupplier, "executorSupplier must be non null");
return new ParallelCompositeUploadBlobWriteSessionConfig(
maxPartsPerCompose,
executorSupplier,
bufferAllocationStrategy,
partNamingStrategy,
partCleanupStrategy);
}
/**
* Specify a specific buffering strategy which will dictate how buffers are allocated and used
* when performing a parallel composite upload.
*
*
Default: {@link BufferAllocationStrategy#simple(int)
* BufferAllocationStrategy#simple(16MiB)}
*
* @since 2.28.0 This new api is in preview and is subject to breaking changes.
*/
@BetaApi
public ParallelCompositeUploadBlobWriteSessionConfig withBufferAllocationStrategy(
BufferAllocationStrategy bufferAllocationStrategy) {
checkNotNull(bufferAllocationStrategy, "bufferAllocationStrategy must be non null");
return new ParallelCompositeUploadBlobWriteSessionConfig(
maxPartsPerCompose,
executorSupplier,
bufferAllocationStrategy,
partNamingStrategy,
partCleanupStrategy);
}
/**
* Specify a specific naming strategy which will dictate how individual part and intermediary
* compose objects will be named when performing a parallel composite upload.
*
*
Default: {@link PartNamingStrategy#noPrefix()}
*
* @since 2.28.0 This new api is in preview and is subject to breaking changes.
*/
@BetaApi
public ParallelCompositeUploadBlobWriteSessionConfig withPartNamingStrategy(
PartNamingStrategy partNamingStrategy) {
checkNotNull(partNamingStrategy, "partNamingStrategy must be non null");
return new ParallelCompositeUploadBlobWriteSessionConfig(
maxPartsPerCompose,
executorSupplier,
bufferAllocationStrategy,
partNamingStrategy,
partCleanupStrategy);
}
/**
* Specify a specific cleanup strategy which will dictate what cleanup operations are performed
* automatically when performing a parallel composite upload.
*
*
Default: {@link PartCleanupStrategy#always()}
*
* @since 2.28.0 This new api is in preview and is subject to breaking changes.
*/
@BetaApi
public ParallelCompositeUploadBlobWriteSessionConfig withPartCleanupStrategy(
PartCleanupStrategy partCleanupStrategy) {
checkNotNull(partCleanupStrategy, "partCleanupStrategy must be non null");
return new ParallelCompositeUploadBlobWriteSessionConfig(
maxPartsPerCompose,
executorSupplier,
bufferAllocationStrategy,
partNamingStrategy,
partCleanupStrategy);
}
@BetaApi
static ParallelCompositeUploadBlobWriteSessionConfig withDefaults() {
return new ParallelCompositeUploadBlobWriteSessionConfig(
MAX_PARTS_PER_COMPOSE,
ExecutorSupplier.cachedPool(),
BufferAllocationStrategy.simple(ByteSizeConstants._16MiB),
PartNamingStrategy.noPrefix(),
PartCleanupStrategy.always());
}
@InternalApi
@Override
WriterFactory createFactory(Clock clock) throws IOException {
Executor executor = executorSupplier.get();
BufferHandlePool bufferHandlePool = bufferAllocationStrategy.get();
return new ParallelCompositeUploadWriterFactory(clock, executor, bufferHandlePool);
}
/**
* A strategy which dictates how buffers are to be used for individual parts. The chosen strategy
* will apply to all instances of {@link BlobWriteSession} created from a single instance of
* {@link Storage}.
*
* @see #withBufferAllocationStrategy(BufferAllocationStrategy)
* @since 2.28.0 This new api is in preview and is subject to breaking changes.
*/
@BetaApi
@Immutable
public abstract static class BufferAllocationStrategy extends Factory
implements Serializable {
private BufferAllocationStrategy() {}
/**
* Create a buffer strategy which will rely upon standard garbage collection. Each buffer will
* be used once and then garbage collected.
*
* @param capacity the number of bytes each buffer should be
* @see #withBufferAllocationStrategy(BufferAllocationStrategy)
* @since 2.28.0 This new api is in preview and is subject to breaking changes.
*/
@BetaApi
public static BufferAllocationStrategy simple(int capacity) {
return new SimpleBufferAllocationStrategy(capacity);
}
/**
* Create a buffer strategy which will have a fixed size pool of buffers. Each buffer will be
* lazily allocated.
*
* @param bufferCount the number of buffers the pool will be
* @param bufferCapacity the number of bytes each buffer should be
* @see #withBufferAllocationStrategy(BufferAllocationStrategy)
* @since 2.28.0 This new api is in preview and is subject to breaking changes.
*/
@BetaApi
public static BufferAllocationStrategy fixedPool(int bufferCount, int bufferCapacity) {
return new FixedPoolBufferAllocationStrategy(bufferCount, bufferCapacity);
}
private static class SimpleBufferAllocationStrategy extends BufferAllocationStrategy {
private static final long serialVersionUID = 8884826090481043434L;
private final int capacity;
private SimpleBufferAllocationStrategy(int capacity) {
this.capacity = capacity;
}
@Override
BufferHandlePool get() {
return BufferHandlePool.simple(capacity);
}
}
private static class FixedPoolBufferAllocationStrategy extends BufferAllocationStrategy {
private static final long serialVersionUID = 3288902741819257066L;
private final int bufferCount;
private final int bufferCapacity;
private FixedPoolBufferAllocationStrategy(int bufferCount, int bufferCapacity) {
this.bufferCount = bufferCount;
this.bufferCapacity = bufferCapacity;
}
@Override
BufferHandlePool get() {
return BufferHandlePool.fixedPool(bufferCount, bufferCapacity);
}
}
}
/**
* Class which will be used to supply an Executor where work will be submitted when performing a
* parallel composite upload.
*
* @see #withExecutorSupplier(ExecutorSupplier)
* @since 2.28.0 This new api is in preview and is subject to breaking changes.
*/
@BetaApi
@Immutable
public abstract static class ExecutorSupplier extends Factory implements Serializable {
private static final AtomicInteger INSTANCE_COUNTER = new AtomicInteger(1);
private ExecutorSupplier() {}
/**
* Create a cached thread pool for submitting work
*
* @see #withExecutorSupplier(ExecutorSupplier)
* @since 2.28.0 This new api is in preview and is subject to breaking changes.
*/
@BetaApi
public static ExecutorSupplier cachedPool() {
return new CachedSupplier();
}
/**
* Create a fixed size thread pool for submitting work
*
* @param poolSize the number of threads in the pool
* @see #withExecutorSupplier(ExecutorSupplier)
* @since 2.28.0 This new api is in preview and is subject to breaking changes.
*/
@BetaApi
public static ExecutorSupplier fixedPool(int poolSize) {
return new FixedSupplier(poolSize);
}
/**
* Wrap an existing executor instance which will be used for submitting work
*
* Choosing to use this supplier type will make your instance of {@link StorageOptions}
* unable to be serialized.
*
* @param executor the executor to use
* @see #withExecutorSupplier(ExecutorSupplier)
* @since 2.28.0 This new api is in preview and is subject to breaking changes.
*/
@BetaApi
public static ExecutorSupplier useExecutor(Executor executor) {
requireNonNull(executor, "executor must be non null");
return new SuppliedExecutorSupplier(executor);
}
@NonNull
private static ThreadFactory newThreadFactory() {
return new ThreadFactoryBuilder()
.setDaemon(true)
.setNameFormat("c.g.c:g-c-s:pcu-" + INSTANCE_COUNTER.getAndIncrement() + "-%d")
.build();
}
private static class SuppliedExecutorSupplier extends ExecutorSupplier {
private final Executor executor;
public SuppliedExecutorSupplier(Executor executor) {
this.executor = executor;
}
@Override
Executor get() {
return executor;
}
private void writeObject(ObjectOutputStream out) throws IOException {
throw new java.io.InvalidClassException(this.getClass().getName() + "; Not serializable");
}
}
private static class CachedSupplier extends ExecutorSupplier implements Serializable {
private static final long serialVersionUID = 7768210719775319260L;
@Override
Executor get() {
ThreadFactory threadFactory = newThreadFactory();
return Executors.newCachedThreadPool(threadFactory);
}
}
private static class FixedSupplier extends ExecutorSupplier implements Serializable {
private static final long serialVersionUID = 7771825977551614347L;
private final int poolSize;
public FixedSupplier(int poolSize) {
this.poolSize = poolSize;
}
@Override
Executor get() {
ThreadFactory threadFactory = newThreadFactory();
return Executors.newFixedThreadPool(poolSize, threadFactory);
}
}
}
/**
* A naming strategy which will be used to generate a name for a part or intermediary compose
* object.
*
* @see #withPartNamingStrategy(PartNamingStrategy)
* @since 2.28.0 This new api is in preview and is subject to breaking changes.
*/
@BetaApi
@Immutable
public abstract static class PartNamingStrategy implements Serializable {
private static final long serialVersionUID = 8343436026774231869L;
private static final String FIELD_SEPARATOR = ";";
private static final Encoder B64 = Base64.getUrlEncoder().withoutPadding();
private static final HashFunction OBJECT_NAME_HASH_FUNCTION = Hashing.goodFastHash(128);
private final SecureRandom rand;
@VisibleForTesting
@InternalApi
PartNamingStrategy(SecureRandom rand) {
this.rand = rand;
}
String fmtName(String ultimateObjectName, PartRange partRange) {
// generate 128 bits of random data
byte[] bytes = new byte[16];
rand.nextBytes(bytes);
// encode it to base 64, yielding 22 characters
String randomKey = B64.encodeToString(bytes);
return fmtFields(randomKey, ultimateObjectName, partRange.encode());
}
abstract String fmtFields(String randomKey, String nameDigest, String partRange);
/**
* Default strategy in which no stable prefix is defined.
*
*
General format is
*
*
* {randomKeyDigest};{objectInfoDigest};{partIndex}.part
*
*
* {@code {objectInfoDigest}} will be fixed for an individual {@link BlobWriteSession}.
*
*
NOTE:The way in which both {@code randomKeyDigest} and {@code
* objectInfoDigest} are generated is undefined and subject to change at any time.
*
* @see #withPartNamingStrategy(PartNamingStrategy)
* @since 2.28.0 This new api is in preview and is subject to breaking changes.
*/
@BetaApi
public static PartNamingStrategy noPrefix() {
SecureRandom rand = new SecureRandom();
return new NoPrefix(rand);
}
/**
* Strategy in which an explicit stable prefix is present on each part and intermediary compose
* object.
*
*
General format is
*
*
* {prefixPattern}/{randomKeyDigest};{objectInfoDigest};{partIndex}.part
*
*
* {@code {objectInfoDigest}} will be fixed for an individual {@link BlobWriteSession}.
*
*
NOTE:The way in which both {@code randomKeyDigest} and {@code
* objectInfoDigest} are generated is undefined and subject to change at any time.
*
*
Care must be taken when choosing to specify a stable prefix as this can create hotspots in
* the keyspace for object names. See Object Naming
* Convention Guidelines for more details.
*
* @see #withPartNamingStrategy(PartNamingStrategy)
* @since 2.28.0 This new api is in preview and is subject to breaking changes.
*/
@BetaApi
public static PartNamingStrategy prefix(String prefixPattern) {
checkNotNull(prefixPattern, "prefixPattern must be non null");
SecureRandom rand = new SecureRandom();
return new WithPrefix(rand, prefixPattern);
}
/**
* Strategy in which the end object name is the prefix included and is present on each part and
* intermediary compose object.
*
*
General format is
*
*
* {objectName}-{randomKeyDigest};{objectInfoDigest};{partIndex}.part
*
*
* {@code {objectInfoDigest}} will be fixed for an individual {@link BlobWriteSession}.
*
*
NOTE:The way in which both {@code randomKeyDigest} and {@code
* objectInfoDigest} are generated is undefined and subject to change at any time.
*
* @see #withPartNamingStrategy(PartNamingStrategy)
* @since 2.30.2 This new api is in preview and is subject to breaking changes.
*/
@BetaApi
public static PartNamingStrategy useObjectNameAsPrefix() {
return useObjectNameAsPrefix("");
}
private static PartNamingStrategy useObjectNameAsPrefix(String prefixPattern) {
checkNotNull(prefixPattern, "prefixPattern must be non null");
SecureRandom rand = new SecureRandom();
return new WithObjectLevelPrefix(rand, prefixPattern);
}
static final class WithPrefix extends PartNamingStrategy {
private static final long serialVersionUID = 5709330763161570411L;
private final String prefix;
private WithPrefix(SecureRandom rand, String prefix) {
super(rand);
this.prefix = prefix;
}
@Override
protected String fmtFields(String randomKey, String ultimateObjectName, String partRange) {
HashCode hashCode =
OBJECT_NAME_HASH_FUNCTION.hashString(ultimateObjectName, StandardCharsets.UTF_8);
String nameDigest = B64.encodeToString(hashCode.asBytes());
return prefix
+ "/"
+ randomKey
+ FIELD_SEPARATOR
+ nameDigest
+ FIELD_SEPARATOR
+ partRange
+ ".part";
}
}
static final class WithObjectLevelPrefix extends PartNamingStrategy {
private static final long serialVersionUID = 5157942020618764450L;
private final String prefix;
private WithObjectLevelPrefix(SecureRandom rand, String prefix) {
super(rand);
// If no prefix is specified we will create the part files under the same directory as the
// ultimate object.
this.prefix = prefix.isEmpty() ? prefix : prefix + "/";
}
@Override
protected String fmtFields(String randomKey, String ultimateObjectName, String partRange) {
HashCode hashCode =
OBJECT_NAME_HASH_FUNCTION.hashString(ultimateObjectName, StandardCharsets.UTF_8);
String nameDigest = B64.encodeToString(hashCode.asBytes());
return prefix
+ ultimateObjectName
+ "-"
+ randomKey
+ FIELD_SEPARATOR
+ nameDigest
+ FIELD_SEPARATOR
+ partRange
+ ".part";
}
}
static final class NoPrefix extends PartNamingStrategy {
private static final long serialVersionUID = 5202415556658566017L;
public NoPrefix(SecureRandom rand) {
super(rand);
}
@Override
protected String fmtFields(String randomKey, String nameDigest, String partRange) {
return randomKey
+ FIELD_SEPARATOR
// todo: do we want to
// include a hint where the object came from, similar to gcloud
// https://cloud.google.com/storage/docs/parallel-composite-uploads#gcloud-pcu
// + "com.google.cloud:google-cloud-storage"
// + FIELD_SEPARATOR
+ nameDigest
+ FIELD_SEPARATOR
+ partRange
+ ".part";
}
}
}
/**
* A cleanup strategy which will dictate what cleanup operations are performed automatically when
* performing a parallel composite upload.
*
* @see #withPartCleanupStrategy(PartCleanupStrategy)
* @since 2.28.0 This new api is in preview and is subject to breaking changes.
*/
@BetaApi
@Immutable
public static class PartCleanupStrategy implements Serializable {
private static final long serialVersionUID = -1434253614347199051L;
private final boolean deletePartsOnSuccess;
private final boolean deleteAllOnError;
private PartCleanupStrategy(boolean deletePartsOnSuccess, boolean deleteAllOnError) {
this.deletePartsOnSuccess = deletePartsOnSuccess;
this.deleteAllOnError = deleteAllOnError;
}
boolean isDeletePartsOnSuccess() {
return deletePartsOnSuccess;
}
boolean isDeleteAllOnError() {
return deleteAllOnError;
}
/**
* If an unrecoverable error is encountered, define whether to attempt to delete any objects
* already uploaded.
*
*
Default: {@code true}
*
* @since 2.28.0 This new api is in preview and is subject to breaking changes.
*/
@BetaApi
PartCleanupStrategy withDeleteAllOnError(boolean deleteAllOnError) {
return new PartCleanupStrategy(deletePartsOnSuccess, deleteAllOnError);
}
/**
* Cleanup strategy which will always attempt to clean up part and intermediary compose objects
* either on success or on error.
*
* @see #withPartCleanupStrategy(PartCleanupStrategy)
* @since 2.28.0 This new api is in preview and is subject to breaking changes.
*/
@BetaApi
public static PartCleanupStrategy always() {
return new PartCleanupStrategy(true, true);
}
/**
* Cleanup strategy which will only attempt to clean up parts and intermediary compose objects
* either on success.
*
* @see #withPartCleanupStrategy(PartCleanupStrategy)
* @since 2.28.0 This new api is in preview and is subject to breaking changes.
*/
@BetaApi
public static PartCleanupStrategy onlyOnSuccess() {
return new PartCleanupStrategy(true, false);
}
/**
* Cleanup strategy which will never attempt to clean up parts or intermediary compose objects
* either on success or on error.
*
* @see #withPartCleanupStrategy(PartCleanupStrategy)
* @since 2.28.0 This new api is in preview and is subject to breaking changes.
*/
@BetaApi
public static PartCleanupStrategy never() {
return new PartCleanupStrategy(false, false);
}
}
private abstract static class Factory implements Serializable {
private static final long serialVersionUID = 271806144227661056L;
private Factory() {}
abstract T get();
}
private class ParallelCompositeUploadWriterFactory implements WriterFactory {
private final Clock clock;
private final Executor executor;
private final BufferHandlePool bufferHandlePool;
private ParallelCompositeUploadWriterFactory(
Clock clock, Executor executor, BufferHandlePool bufferHandlePool) {
this.clock = clock;
this.executor = executor;
this.bufferHandlePool = bufferHandlePool;
}
@Override
public WritableByteChannelSession writeSession(
StorageInternal s, BlobInfo info, Opts opts) {
return new PCUSession(s, info, opts);
}
private final class PCUSession
implements WritableByteChannelSession {
private final SettableApiFuture result;
private final StorageInternal storageInternal;
private final BlobInfo info;
private final Opts opts;
private PCUSession(
StorageInternal storageInternal, BlobInfo info, Opts opts) {
this.storageInternal = storageInternal;
this.info = info;
this.opts = opts;
result = SettableApiFuture.create();
}
@Override
public ApiFuture openAsync() {
ParallelCompositeUploadWritableByteChannel channel =
new ParallelCompositeUploadWritableByteChannel(
bufferHandlePool,
executor,
partNamingStrategy,
partCleanupStrategy,
maxPartsPerCompose,
result,
storageInternal,
info,
opts);
return ApiFutures.immediateFuture(channel);
}
@Override
public ApiFuture getResult() {
return result;
}
}
}
}