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/*
* Copyright 2016 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.pubsub.v1;
import static com.google.common.util.concurrent.MoreExecutors.directExecutor;
import com.google.api.core.ApiFunction;
import com.google.api.core.ApiFuture;
import com.google.api.core.ApiFutureCallback;
import com.google.api.core.ApiFutures;
import com.google.api.core.BetaApi;
import com.google.api.core.SettableApiFuture;
import com.google.api.gax.batching.BatchingSettings;
import com.google.api.gax.batching.FlowControlSettings;
import com.google.api.gax.batching.FlowController;
import com.google.api.gax.batching.FlowController.LimitExceededBehavior;
import com.google.api.gax.core.BackgroundResource;
import com.google.api.gax.core.BackgroundResourceAggregation;
import com.google.api.gax.core.CredentialsProvider;
import com.google.api.gax.core.ExecutorAsBackgroundResource;
import com.google.api.gax.core.ExecutorProvider;
import com.google.api.gax.core.FixedExecutorProvider;
import com.google.api.gax.core.InstantiatingExecutorProvider;
import com.google.api.gax.grpc.GrpcCallContext;
import com.google.api.gax.retrying.RetrySettings;
import com.google.api.gax.rpc.HeaderProvider;
import com.google.api.gax.rpc.NoHeaderProvider;
import com.google.api.gax.rpc.StatusCode;
import com.google.api.gax.rpc.TransportChannelProvider;
import com.google.auth.oauth2.GoogleCredentials;
import com.google.cloud.pubsub.v1.stub.GrpcPublisherStub;
import com.google.cloud.pubsub.v1.stub.PublisherStub;
import com.google.cloud.pubsub.v1.stub.PublisherStubSettings;
import com.google.common.base.Preconditions;
import com.google.pubsub.v1.PublishRequest;
import com.google.pubsub.v1.PublishResponse;
import com.google.pubsub.v1.PubsubMessage;
import com.google.pubsub.v1.TopicName;
import com.google.pubsub.v1.TopicNames;
import io.grpc.CallOptions;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.concurrent.Callable;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.threeten.bp.Duration;
/**
* A Cloud Pub/Sub publisher, that is
* associated with a specific topic at creation.
*
* A {@link Publisher} provides built-in capabilities to automatically handle batching of
* messages, controlling memory utilization, and retrying API calls on transient errors.
*
*
With customizable options that control:
*
*
* - Message batching: such as number of messages or max batch byte size.
*
- Retries: such as the maximum duration of retries for a failing batch of messages.
*
*
* {@link Publisher} will use the credentials set on the channel, which uses application default
* credentials through {@link GoogleCredentials#getApplicationDefault} by default.
*/
public class Publisher implements PublisherInterface {
private static final Logger logger = Logger.getLogger(Publisher.class.getName());
private static final String GZIP_COMPRESSION = "gzip";
private final String topicName;
private final BatchingSettings batchingSettings;
private final boolean enableMessageOrdering;
private final Lock messagesBatchLock;
private final Map messagesBatches;
private final AtomicBoolean activeAlarm;
private final PublisherStub publisherStub;
private final ScheduledExecutorService executor;
private final SequentialExecutorService.CallbackExecutor sequentialExecutor;
private final AtomicBoolean shutdown;
private final BackgroundResource backgroundResources;
private final Waiter messagesWaiter;
private ScheduledFuture currentAlarmFuture;
private final ApiFunction messageTransform;
private MessageFlowController flowController = null;
private final boolean enableCompression;
private final long compressionBytesThreshold;
private final GrpcCallContext publishContext;
private final GrpcCallContext publishContextWithCompression;
/** The maximum number of messages in one request. Defined by the API. */
public static long getApiMaxRequestElementCount() {
return 1000L;
}
/** The maximum size of one request. Defined by the API. */
public static long getApiMaxRequestBytes() {
return 10L * 1000L * 1000L; // 10 megabytes (https://en.wikipedia.org/wiki/Megabyte)
}
private Publisher(Builder builder) throws IOException {
topicName = builder.topicName;
this.batchingSettings = builder.batchingSettings;
FlowControlSettings flowControl = this.batchingSettings.getFlowControlSettings();
if (flowControl != null
&& flowControl.getLimitExceededBehavior() != FlowController.LimitExceededBehavior.Ignore) {
this.flowController =
new MessageFlowController(
flowControl.getMaxOutstandingElementCount(),
flowControl.getMaxOutstandingRequestBytes(),
flowControl.getLimitExceededBehavior());
}
this.enableMessageOrdering = builder.enableMessageOrdering;
this.messageTransform = builder.messageTransform;
this.enableCompression = builder.enableCompression;
this.compressionBytesThreshold = builder.compressionBytesThreshold;
messagesBatches = new HashMap<>();
messagesBatchLock = new ReentrantLock();
activeAlarm = new AtomicBoolean(false);
executor = builder.executorProvider.getExecutor();
sequentialExecutor = new SequentialExecutorService.CallbackExecutor(executor);
List backgroundResourceList = new ArrayList<>();
if (builder.executorProvider.shouldAutoClose()) {
backgroundResourceList.add(new ExecutorAsBackgroundResource(executor));
}
// Publisher used to take maxAttempt == 0 to mean infinity, but to GAX it means don't retry.
// We post-process this here to keep backward-compatibility.
// Also, if "message ordering" is enabled, the publisher should retry sending the failed
// message infinitely rather than sending the next one.
RetrySettings.Builder retrySettingsBuilder = builder.retrySettings.toBuilder();
if (retrySettingsBuilder.getMaxAttempts() == 0) {
retrySettingsBuilder.setMaxAttempts(Integer.MAX_VALUE);
}
if (enableMessageOrdering) {
// TODO: is there a way to have the default retry settings for requests without an ordering
// key?
retrySettingsBuilder
.setMaxAttempts(Integer.MAX_VALUE)
.setTotalTimeout(Duration.ofNanos(Long.MAX_VALUE));
}
PublisherStubSettings.Builder stubSettings =
PublisherStubSettings.newBuilder()
.setCredentialsProvider(builder.credentialsProvider)
.setExecutorProvider(FixedExecutorProvider.create(executor))
.setTransportChannelProvider(builder.channelProvider)
.setEndpoint(builder.endpoint)
.setUniverseDomain(builder.universeDomain)
.setHeaderProvider(builder.headerProvider);
stubSettings
.publishSettings()
.setRetryableCodes(
StatusCode.Code.ABORTED,
StatusCode.Code.CANCELLED,
StatusCode.Code.DEADLINE_EXCEEDED,
StatusCode.Code.INTERNAL,
StatusCode.Code.RESOURCE_EXHAUSTED,
StatusCode.Code.UNKNOWN,
StatusCode.Code.UNAVAILABLE)
.setRetrySettings(retrySettingsBuilder.build())
.setBatchingSettings(BatchingSettings.newBuilder().setIsEnabled(false).build());
this.publisherStub = GrpcPublisherStub.create(stubSettings.build());
backgroundResourceList.add(publisherStub);
backgroundResources = new BackgroundResourceAggregation(backgroundResourceList);
shutdown = new AtomicBoolean(false);
messagesWaiter = new Waiter();
this.publishContext = GrpcCallContext.createDefault();
this.publishContextWithCompression =
GrpcCallContext.createDefault()
.withCallOptions(CallOptions.DEFAULT.withCompression(GZIP_COMPRESSION));
}
/** Topic which the publisher publishes to. */
public TopicName getTopicName() {
return TopicNames.parse(topicName);
}
/** Topic which the publisher publishes to. */
public String getTopicNameString() {
return topicName;
}
/**
* Schedules the publishing of a message. The publishing of the message may occur immediately or
* be delayed based on the publisher batching options.
*
* This method blocks in the downcall if using LimitExceededBehavior.Block in the flow control
* settings.
*
*
Example of publishing a message.
*
*
{@code
* String message = "my_message";
* ByteString data = ByteString.copyFromUtf8(message);
* PubsubMessage pubsubMessage = PubsubMessage.newBuilder().setData(data).build();
* ApiFuture messageIdFuture = publisher.publish(pubsubMessage);
* ApiFutures.addCallback(messageIdFuture, new ApiFutureCallback() {
* public void onSuccess(String messageId) {
* System.out.println("published with message id: " + messageId);
* }
*
* public void onFailure(Throwable t) {
* System.out.println("failed to publish: " + t);
* }
* }, MoreExecutors.directExecutor());
* }
*
* @param message the message to publish.
* @return the message ID wrapped in a future.
*/
@Override
public ApiFuture publish(PubsubMessage message) {
Preconditions.checkState(!shutdown.get(), "Cannot publish on a shut-down publisher.");
final String orderingKey = message.getOrderingKey();
Preconditions.checkState(
orderingKey.isEmpty() || enableMessageOrdering,
"Cannot publish a message with an ordering key when message ordering is not enabled in the "
+ "Publisher client. Please create a Publisher client with "
+ "setEnableMessageOrdering(true) in the builder.");
final OutstandingPublish outstandingPublish =
new OutstandingPublish(messageTransform.apply(message));
if (flowController != null) {
try {
flowController.acquire(outstandingPublish.messageSize);
} catch (FlowController.FlowControlException e) {
if (!orderingKey.isEmpty()) {
sequentialExecutor.stopPublish(orderingKey);
}
outstandingPublish.publishResult.setException(e);
return outstandingPublish.publishResult;
}
}
List batchesToSend;
messagesBatchLock.lock();
try {
if (!orderingKey.isEmpty() && sequentialExecutor.keyHasError(orderingKey)) {
outstandingPublish.publishResult.setException(
SequentialExecutorService.CallbackExecutor.CANCELLATION_EXCEPTION);
return outstandingPublish.publishResult;
}
MessagesBatch messagesBatch = messagesBatches.get(orderingKey);
if (messagesBatch == null) {
messagesBatch = new MessagesBatch(batchingSettings, orderingKey);
messagesBatches.put(orderingKey, messagesBatch);
}
batchesToSend = messagesBatch.add(outstandingPublish);
if (!batchesToSend.isEmpty() && messagesBatch.isEmpty()) {
messagesBatches.remove(orderingKey);
}
// Setup the next duration based delivery alarm if there are messages batched.
setupAlarm();
// For messages with an ordering key, we need to publish with messagesBatchLock held in order
// to ensure another publish doesn't slip in and send a batch before these batches we already
// want to send.
if (!batchesToSend.isEmpty() && !orderingKey.isEmpty()) {
for (final OutstandingBatch batch : batchesToSend) {
logger.log(Level.FINER, "Scheduling a batch for immediate sending.");
publishOutstandingBatch(batch);
}
}
} finally {
messagesBatchLock.unlock();
}
messagesWaiter.incrementPendingCount(1);
// For messages without ordering keys, it is okay to send batches without holding
// messagesBatchLock.
if (!batchesToSend.isEmpty() && orderingKey.isEmpty()) {
for (final OutstandingBatch batch : batchesToSend) {
logger.log(Level.FINER, "Scheduling a batch for immediate sending.");
executor.execute(
new Runnable() {
@Override
public void run() {
publishOutstandingBatch(batch);
}
});
}
}
return outstandingPublish.publishResult;
}
/**
* There may be non-recoverable problems with a request for an ordering key. In that case, all
* subsequent requests will fail until this method is called. If the key is not currently paused,
* calling this method will be a no-op.
*
* @param key The key for which to resume publishing.
*/
public void resumePublish(String key) {
Preconditions.checkState(!shutdown.get(), "Cannot publish on a shut-down publisher.");
sequentialExecutor.resumePublish(key);
}
private void setupAlarm() {
if (!messagesBatches.isEmpty()) {
if (!activeAlarm.getAndSet(true)) {
long delayThresholdMs = getBatchingSettings().getDelayThreshold().toMillis();
logger.log(Level.FINER, "Setting up alarm for the next {0} ms.", delayThresholdMs);
currentAlarmFuture =
executor.schedule(
new Runnable() {
@Override
public void run() {
logger.log(Level.FINER, "Sending messages based on schedule.");
activeAlarm.getAndSet(false);
publishAllWithoutInflight();
}
},
delayThresholdMs,
TimeUnit.MILLISECONDS);
}
} else if (currentAlarmFuture != null) {
logger.log(Level.FINER, "Cancelling alarm, no more messages");
if (activeAlarm.getAndSet(false)) {
currentAlarmFuture.cancel(false);
}
}
}
/**
* Publish any outstanding batches if non-empty. This method sends buffered messages, but does not
* wait for the send operations to complete. To wait for messages to send, call {@code get} on the
* futures returned from {@code publish}.
*/
public void publishAllOutstanding() {
OutstandingBatch unorderedOutstandingBatch = null;
messagesBatchLock.lock();
try {
for (MessagesBatch batch : messagesBatches.values()) {
if (!batch.isEmpty()) {
if (!batch.orderingKey.isEmpty()) {
// For messages with an ordering key, we need to publish with messagesBatchLock held in
// order to ensure another publish doesn't slip in and send a batch before these batches
// we already want to send.
publishOutstandingBatch(batch.popOutstandingBatch());
} else {
unorderedOutstandingBatch = batch.popOutstandingBatch();
}
}
}
messagesBatches.clear();
} finally {
messagesBatchLock.unlock();
}
if (unorderedOutstandingBatch != null) {
publishOutstandingBatch(unorderedOutstandingBatch);
}
}
/**
* Publish any outstanding batches if non-empty and there are no other batches in flight. This
* method sends buffered messages, but does not wait for the send operations to complete. To wait
* for messages to send, call {@code get} on the futures returned from {@code publish}.
*/
private void publishAllWithoutInflight() {
OutstandingBatch unorderedOutstandingBatch = null;
messagesBatchLock.lock();
try {
Iterator> it = messagesBatches.entrySet().iterator();
while (it.hasNext()) {
Map.Entry entry = it.next();
MessagesBatch batch = entry.getValue();
String key = entry.getKey();
if (batch.isEmpty()) {
it.remove();
} else if (key.isEmpty()) {
// We will publish the batch with no ordering key outside messagesBatchLock.
unorderedOutstandingBatch = batch.popOutstandingBatch();
it.remove();
} else if (!sequentialExecutor.hasTasksInflight(key)) {
publishOutstandingBatch(batch.popOutstandingBatch());
it.remove();
}
}
} finally {
messagesBatchLock.unlock();
}
if (unorderedOutstandingBatch != null) {
publishOutstandingBatch(unorderedOutstandingBatch);
}
}
/**
* Publish any outstanding batches if non-empty and there are no other batches in flight for
* orderingKey. This method sends buffered messages, but does not wait for the send operations to
* complete. To wait for messages to send, call {@code get} on the futures returned from {@code
* publish}.
*/
private void publishAllWithoutInflightForKey(final String orderingKey) {
messagesBatchLock.lock();
try {
MessagesBatch batch = messagesBatches.get(orderingKey);
if (batch != null && !sequentialExecutor.hasTasksInflight(orderingKey)) {
publishOutstandingBatch(batch.popOutstandingBatch());
messagesBatches.remove(orderingKey);
}
} finally {
messagesBatchLock.unlock();
}
}
private ApiFuture publishCall(OutstandingBatch outstandingBatch) {
GrpcCallContext context = publishContext;
if (enableCompression && outstandingBatch.batchSizeBytes >= compressionBytesThreshold) {
context = publishContextWithCompression;
}
return publisherStub
.publishCallable()
.futureCall(
PublishRequest.newBuilder()
.setTopic(topicName)
.addAllMessages(outstandingBatch.getMessages())
.build(),
context);
}
private void publishOutstandingBatch(final OutstandingBatch outstandingBatch) {
if (outstandingBatch.size() == 0) {
logger.log(Level.WARNING, "Attempted to publish batch with zero messages.");
return;
}
final ApiFutureCallback futureCallback =
new ApiFutureCallback() {
@Override
public void onSuccess(PublishResponse result) {
try {
if (result == null || result.getMessageIdsCount() != outstandingBatch.size()) {
outstandingBatch.onFailure(
new IllegalStateException(
String.format(
"The publish result count %s does not match "
+ "the expected %s results. Please contact Cloud Pub/Sub support "
+ "if this frequently occurs",
result.getMessageIdsCount(), outstandingBatch.size())));
} else {
outstandingBatch.onSuccess(result.getMessageIdsList());
if (!activeAlarm.get()
&& outstandingBatch.orderingKey != null
&& !outstandingBatch.orderingKey.isEmpty()) {
publishAllWithoutInflightForKey(outstandingBatch.orderingKey);
}
}
} finally {
messagesWaiter.incrementPendingCount(-outstandingBatch.size());
}
}
@Override
public void onFailure(Throwable t) {
try {
if (outstandingBatch.orderingKey != null && !outstandingBatch.orderingKey.isEmpty()) {
messagesBatchLock.lock();
try {
MessagesBatch messagesBatch = messagesBatches.get(outstandingBatch.orderingKey);
if (messagesBatch != null) {
for (OutstandingPublish outstanding : messagesBatch.messages) {
outstanding.publishResult.setException(
SequentialExecutorService.CallbackExecutor.CANCELLATION_EXCEPTION);
}
messagesBatches.remove(outstandingBatch.orderingKey);
}
} finally {
messagesBatchLock.unlock();
}
}
outstandingBatch.onFailure(t);
} finally {
messagesWaiter.incrementPendingCount(-outstandingBatch.size());
}
}
};
ApiFuture future;
if (outstandingBatch.orderingKey == null || outstandingBatch.orderingKey.isEmpty()) {
future = publishCall(outstandingBatch);
} else {
// If ordering key is specified, publish the batch using the sequential executor.
future =
sequentialExecutor.submit(
outstandingBatch.orderingKey,
new Callable>() {
public ApiFuture call() {
return publishCall(outstandingBatch);
}
});
}
ApiFutures.addCallback(future, futureCallback, directExecutor());
}
private final class OutstandingBatch {
final List outstandingPublishes;
final long creationTime;
int attempt;
int batchSizeBytes;
final String orderingKey;
OutstandingBatch(
List outstandingPublishes, int batchSizeBytes, String orderingKey) {
this.outstandingPublishes = outstandingPublishes;
attempt = 1;
creationTime = System.currentTimeMillis();
this.batchSizeBytes = batchSizeBytes;
this.orderingKey = orderingKey;
}
int size() {
return outstandingPublishes.size();
}
private List getMessages() {
List results = new ArrayList<>(outstandingPublishes.size());
for (OutstandingPublish outstandingPublish : outstandingPublishes) {
results.add(outstandingPublish.message);
}
return results;
}
private void onFailure(Throwable t) {
for (OutstandingPublish outstandingPublish : outstandingPublishes) {
if (flowController != null) {
flowController.release(outstandingPublish.messageSize);
}
outstandingPublish.publishResult.setException(t);
}
}
private void onSuccess(Iterable results) {
Iterator messagesResultsIt = outstandingPublishes.iterator();
for (String messageId : results) {
OutstandingPublish nextPublish = messagesResultsIt.next();
if (flowController != null) {
flowController.release(nextPublish.messageSize);
}
nextPublish.publishResult.set(messageId);
}
}
}
private static final class OutstandingPublish {
final SettableApiFuture publishResult;
final PubsubMessage message;
final int messageSize;
OutstandingPublish(PubsubMessage message) {
this.publishResult = SettableApiFuture.create();
this.message = message;
this.messageSize = message.getSerializedSize();
}
}
/** The batching settings configured on this {@code Publisher}. */
public BatchingSettings getBatchingSettings() {
return batchingSettings;
}
/**
* Schedules immediate publishing of any outstanding messages and waits until all are processed.
*
* Sends remaining outstanding messages and prevents future calls to publish. This method
* should be invoked prior to deleting the {@link Publisher} object in order to ensure that no
* pending messages are lost.
*/
public void shutdown() {
Preconditions.checkState(
!shutdown.getAndSet(true), "Cannot shut down a publisher already shut-down.");
if (currentAlarmFuture != null && activeAlarm.getAndSet(false)) {
currentAlarmFuture.cancel(false);
}
publishAllOutstanding();
messagesWaiter.waitComplete();
backgroundResources.shutdown();
}
/**
* Wait for all work has completed execution after a {@link #shutdown()} request, or the timeout
* occurs, or the current thread is interrupted.
*
*
Call this method to make sure all resources are freed properly.
*/
public boolean awaitTermination(long duration, TimeUnit unit) throws InterruptedException {
return backgroundResources.awaitTermination(duration, unit);
}
/**
* Constructs a new {@link Builder} using the given topic.
*
*
Example of creating a {@code Publisher}.
*
*
{@code
* String projectName = "my_project";
* String topicName = "my_topic";
* ProjectTopicName topic = ProjectTopicName.create(projectName, topicName);
* Publisher publisher = Publisher.newBuilder(topic).build();
* try {
* // ...
* } finally {
* // When finished with the publisher, make sure to shutdown to free up resources.
* publisher.shutdown();
* publisher.awaitTermination(1, TimeUnit.MINUTES);
* }
* }
*/
public static Builder newBuilder(TopicName topicName) {
return newBuilder(topicName.toString());
}
/**
* Constructs a new {@link Builder} using the given topic.
*
* Example of creating a {@code Publisher}.
*
*
{@code
* String topic = "projects/my_project/topics/my_topic";
* Publisher publisher = Publisher.newBuilder(topic).build();
* try {
* // ...
* } finally {
* // When finished with the publisher, make sure to shutdown to free up resources.
* publisher.shutdown();
* publisher.awaitTermination(1, TimeUnit.MINUTES);
* }
* }
*/
public static Builder newBuilder(String topicName) {
return new Builder(topicName);
}
/** A builder of {@link Publisher}s. */
public static final class Builder {
static final Duration MIN_TOTAL_TIMEOUT = Duration.ofSeconds(10);
static final Duration MIN_RPC_TIMEOUT = Duration.ofMillis(10);
// Meaningful defaults.
static final long DEFAULT_ELEMENT_COUNT_THRESHOLD = 100L;
static final long DEFAULT_REQUEST_BYTES_THRESHOLD = 1000L; // 1 kB
static final Duration DEFAULT_DELAY_THRESHOLD = Duration.ofMillis(1);
private static final Duration DEFAULT_INITIAL_RPC_TIMEOUT = Duration.ofSeconds(5);
private static final Duration DEFAULT_MAX_RPC_TIMEOUT = Duration.ofSeconds(60);
private static final Duration DEFAULT_TOTAL_TIMEOUT = Duration.ofSeconds(600);
private static final Duration DEFAULT_INITIAL_RETRY_DELAY = Duration.ofMillis(100);
private static final Duration DEFAULT_MAX_RETRY_DELAY = Duration.ofSeconds(60);
private static final double DEFAULT_MULTIPLIER = 4;
static final BatchingSettings DEFAULT_BATCHING_SETTINGS =
BatchingSettings.newBuilder()
.setDelayThreshold(DEFAULT_DELAY_THRESHOLD)
.setRequestByteThreshold(DEFAULT_REQUEST_BYTES_THRESHOLD)
.setElementCountThreshold(DEFAULT_ELEMENT_COUNT_THRESHOLD)
.setFlowControlSettings(
FlowControlSettings.newBuilder()
.setLimitExceededBehavior(FlowController.LimitExceededBehavior.Ignore)
.build())
.build();
static final RetrySettings DEFAULT_RETRY_SETTINGS =
RetrySettings.newBuilder()
.setTotalTimeout(DEFAULT_TOTAL_TIMEOUT)
.setInitialRetryDelay(DEFAULT_INITIAL_RETRY_DELAY)
.setRetryDelayMultiplier(DEFAULT_MULTIPLIER)
.setMaxRetryDelay(DEFAULT_MAX_RETRY_DELAY)
.setInitialRpcTimeout(DEFAULT_INITIAL_RPC_TIMEOUT)
.setRpcTimeoutMultiplier(DEFAULT_MULTIPLIER)
.setMaxRpcTimeout(DEFAULT_MAX_RPC_TIMEOUT)
.build();
static final boolean DEFAULT_ENABLE_MESSAGE_ORDERING = false;
private static final int THREADS_PER_CPU = 5;
static final ExecutorProvider DEFAULT_EXECUTOR_PROVIDER =
InstantiatingExecutorProvider.newBuilder()
.setExecutorThreadCount(THREADS_PER_CPU * Runtime.getRuntime().availableProcessors())
.build();
static final boolean DEFAULT_ENABLE_COMPRESSION = false;
static final long DEFAULT_COMPRESSION_BYTES_THRESHOLD = 240L;
String topicName;
private String endpoint = null;
private String universeDomain = null;
// Batching options
BatchingSettings batchingSettings = DEFAULT_BATCHING_SETTINGS;
RetrySettings retrySettings = DEFAULT_RETRY_SETTINGS;
private boolean enableMessageOrdering = DEFAULT_ENABLE_MESSAGE_ORDERING;
private TransportChannelProvider channelProvider =
TopicAdminSettings.defaultGrpcTransportProviderBuilder().setChannelsPerCpu(1).build();
private HeaderProvider headerProvider = new NoHeaderProvider();
private HeaderProvider internalHeaderProvider =
TopicAdminSettings.defaultApiClientHeaderProviderBuilder().build();
ExecutorProvider executorProvider = DEFAULT_EXECUTOR_PROVIDER;
private CredentialsProvider credentialsProvider =
TopicAdminSettings.defaultCredentialsProviderBuilder().build();
private ApiFunction messageTransform =
new ApiFunction() {
@Override
public PubsubMessage apply(PubsubMessage input) {
return input;
}
};
private boolean enableCompression = DEFAULT_ENABLE_COMPRESSION;
private long compressionBytesThreshold = DEFAULT_COMPRESSION_BYTES_THRESHOLD;
private Builder(String topic) {
this.topicName = Preconditions.checkNotNull(topic);
}
/**
* {@code ChannelProvider} to use to create Channels, which must point at Cloud Pub/Sub
* endpoint.
*
* For performance, this client benefits from having multiple underlying connections. See
* {@link com.google.api.gax.grpc.InstantiatingGrpcChannelProvider.Builder#setPoolSize(int)}.
*/
public Builder setChannelProvider(TransportChannelProvider channelProvider) {
this.channelProvider = Preconditions.checkNotNull(channelProvider);
return this;
}
/**
* Sets the static header provider. The header provider will be called during client
* construction only once. The headers returned by the provider will be cached and supplied as
* is for each request issued by the constructed client. Some reserved headers can be overridden
* (e.g. Content-Type) or merged with the default value (e.g. User-Agent) by the underlying
* transport layer.
*
* @param headerProvider the header provider
* @return the builder
*/
@BetaApi
public Builder setHeaderProvider(HeaderProvider headerProvider) {
this.headerProvider = Preconditions.checkNotNull(headerProvider);
return this;
}
/**
* Sets the static header provider for getting internal (library-defined) headers. The header
* provider will be called during client construction only once. The headers returned by the
* provider will be cached and supplied as is for each request issued by the constructed client.
* Some reserved headers can be overridden (e.g. Content-Type) or merged with the default value
* (e.g. User-Agent) by the underlying transport layer.
*
* @param internalHeaderProvider the internal header provider
* @return the builder
*/
Builder setInternalHeaderProvider(HeaderProvider internalHeaderProvider) {
this.internalHeaderProvider = Preconditions.checkNotNull(internalHeaderProvider);
return this;
}
/** {@code CredentialsProvider} to use to create Credentials to authenticate calls. */
public Builder setCredentialsProvider(CredentialsProvider credentialsProvider) {
this.credentialsProvider = Preconditions.checkNotNull(credentialsProvider);
return this;
}
// Batching options
public Builder setBatchingSettings(BatchingSettings batchingSettings) {
Preconditions.checkNotNull(batchingSettings);
Preconditions.checkNotNull(batchingSettings.getElementCountThreshold());
Preconditions.checkArgument(batchingSettings.getElementCountThreshold() > 0);
Preconditions.checkNotNull(batchingSettings.getRequestByteThreshold());
Preconditions.checkArgument(batchingSettings.getRequestByteThreshold() > 0);
Preconditions.checkNotNull(batchingSettings.getDelayThreshold());
Preconditions.checkArgument(batchingSettings.getDelayThreshold().toMillis() > 0);
FlowControlSettings flowControlSettings = batchingSettings.getFlowControlSettings();
if (flowControlSettings.getLimitExceededBehavior() != LimitExceededBehavior.Ignore) {
Preconditions.checkArgument(flowControlSettings.getMaxOutstandingElementCount() > 0);
Preconditions.checkArgument(flowControlSettings.getMaxOutstandingRequestBytes() > 0);
}
this.batchingSettings = batchingSettings;
return this;
}
/** Configures the Publisher's retry parameters. */
public Builder setRetrySettings(RetrySettings retrySettings) {
Preconditions.checkArgument(
retrySettings.getTotalTimeout().compareTo(MIN_TOTAL_TIMEOUT) >= 0);
Preconditions.checkArgument(
retrySettings.getInitialRpcTimeout().compareTo(MIN_RPC_TIMEOUT) >= 0);
this.retrySettings = retrySettings;
return this;
}
/** Sets the message ordering option. */
public Builder setEnableMessageOrdering(boolean enableMessageOrdering) {
this.enableMessageOrdering = enableMessageOrdering;
return this;
}
/** Gives the ability to set a custom executor to be used by the library. */
public Builder setExecutorProvider(ExecutorProvider executorProvider) {
this.executorProvider = Preconditions.checkNotNull(executorProvider);
return this;
}
/**
* Gives the ability to set an {@link ApiFunction} that will transform the {@link PubsubMessage}
* before it is sent
*/
@BetaApi
public Builder setTransform(ApiFunction messageTransform) {
this.messageTransform =
Preconditions.checkNotNull(messageTransform, "The messageTransform cannnot be null.");
return this;
}
/** Gives the ability to override the gRPC endpoint. */
public Builder setEndpoint(String endpoint) {
this.endpoint = endpoint;
return this;
}
/** Gives the ability to override the universe domain. */
public Builder setUniverseDomain(String universeDomain) {
this.universeDomain = universeDomain;
return this;
}
/** Gives the ability to enable transport compression. */
public Builder setEnableCompression(boolean enableCompression) {
this.enableCompression = enableCompression;
return this;
}
/**
* Sets the threshold (in bytes) above which messages are compressed for transport. Only takes
* effect if setEnableCompression(true) is also called."
*/
public Builder setCompressionBytesThreshold(long compressionBytesThreshold) {
this.compressionBytesThreshold = compressionBytesThreshold;
return this;
}
/** Returns the default BatchingSettings used by the client if settings are not provided. */
public static BatchingSettings getDefaultBatchingSettings() {
return DEFAULT_BATCHING_SETTINGS;
}
public Publisher build() throws IOException {
return new Publisher(this);
}
}
private static class MessageFlowController {
private final Lock lock;
private final Long messageLimit;
private final Long byteLimit;
private final FlowController.LimitExceededBehavior limitBehavior;
private Long outstandingMessages;
private Long outstandingBytes;
private LinkedList awaitingMessageAcquires;
private LinkedList awaitingBytesAcquires;
MessageFlowController(
Long messageLimit, Long byteLimit, FlowController.LimitExceededBehavior limitBehavior) {
this.messageLimit = messageLimit;
this.byteLimit = byteLimit;
this.limitBehavior = limitBehavior;
this.lock = new ReentrantLock();
this.outstandingMessages = 0L;
this.outstandingBytes = 0L;
this.awaitingMessageAcquires = new LinkedList();
this.awaitingBytesAcquires = new LinkedList();
}
void acquire(long messageSize) throws FlowController.FlowControlException {
if (messageSize > byteLimit) {
logger.log(
Level.WARNING,
"Attempted to publish message with byte size > request byte flow control limit.");
throw new FlowController.MaxOutstandingRequestBytesReachedException(byteLimit);
}
lock.lock();
try {
if (outstandingMessages >= messageLimit
&& limitBehavior == FlowController.LimitExceededBehavior.ThrowException) {
throw new FlowController.MaxOutstandingElementCountReachedException(messageLimit);
}
if (outstandingBytes + messageSize >= byteLimit
&& limitBehavior == FlowController.LimitExceededBehavior.ThrowException) {
throw new FlowController.MaxOutstandingRequestBytesReachedException(byteLimit);
}
// We can acquire or we should wait until we can acquire.
// Start by acquiring a slot for a message.
CountDownLatch messageWaiter = null;
while (outstandingMessages >= messageLimit) {
if (messageWaiter == null) {
// This message gets added to the back of the line.
messageWaiter = new CountDownLatch(1);
awaitingMessageAcquires.addLast(messageWaiter);
} else {
// This message already in line stays at the head of the line.
messageWaiter = new CountDownLatch(1);
awaitingMessageAcquires.set(0, messageWaiter);
}
lock.unlock();
try {
messageWaiter.await();
} catch (InterruptedException e) {
logger.log(Level.WARNING, "Interrupted while waiting to acquire flow control tokens");
}
lock.lock();
}
++outstandingMessages;
if (messageWaiter != null) {
awaitingMessageAcquires.removeFirst();
}
// There may be some surplus messages left; let the next message waiting for a token have
// one.
if (!awaitingMessageAcquires.isEmpty() && outstandingMessages < messageLimit) {
awaitingMessageAcquires.getFirst().countDown();
}
// Now acquire space for bytes.
CountDownLatch bytesWaiter = null;
Long bytesRemaining = messageSize;
while (outstandingBytes + bytesRemaining >= byteLimit) {
// Take what is available.
Long available = byteLimit - outstandingBytes;
bytesRemaining -= available;
outstandingBytes = byteLimit;
if (bytesWaiter == null) {
// This message gets added to the back of the line.
bytesWaiter = new CountDownLatch(1);
awaitingBytesAcquires.addLast(bytesWaiter);
} else {
// This message already in line stays at the head of the line.
bytesWaiter = new CountDownLatch(1);
awaitingBytesAcquires.set(0, bytesWaiter);
}
lock.unlock();
try {
bytesWaiter.await();
} catch (InterruptedException e) {
logger.log(Level.WARNING, "Interrupted while waiting to acquire flow control tokens");
}
lock.lock();
}
outstandingBytes += bytesRemaining;
if (bytesWaiter != null) {
awaitingBytesAcquires.removeFirst();
}
// There may be some surplus bytes left; let the next message waiting for bytes have some.
if (!awaitingBytesAcquires.isEmpty() && outstandingBytes < byteLimit) {
awaitingBytesAcquires.getFirst().countDown();
}
} finally {
lock.unlock();
}
}
private void notifyNextAcquires() {
if (!awaitingMessageAcquires.isEmpty()) {
CountDownLatch awaitingAcquire = awaitingMessageAcquires.getFirst();
awaitingAcquire.countDown();
}
if (!awaitingBytesAcquires.isEmpty()) {
CountDownLatch awaitingAcquire = awaitingBytesAcquires.getFirst();
awaitingAcquire.countDown();
}
}
void release(long messageSize) {
lock.lock();
--outstandingMessages;
outstandingBytes -= messageSize;
notifyNextAcquires();
lock.unlock();
}
}
private class MessagesBatch {
private List messages;
private int batchedBytes;
private String orderingKey;
private final BatchingSettings batchingSettings;
private MessagesBatch(BatchingSettings batchingSettings, String orderingKey) {
this.batchingSettings = batchingSettings;
this.orderingKey = orderingKey;
reset();
}
private OutstandingBatch popOutstandingBatch() {
OutstandingBatch batch = new OutstandingBatch(messages, batchedBytes, orderingKey);
reset();
return batch;
}
private void reset() {
messages = new LinkedList<>();
batchedBytes = 0;
}
private boolean isEmpty() {
return messages.isEmpty();
}
private int getBatchedBytes() {
return batchedBytes;
}
private int getMessagesCount() {
return messages.size();
}
private boolean hasBatchingBytes() {
return getMaxBatchBytes() > 0;
}
private long getMaxBatchBytes() {
return batchingSettings.getRequestByteThreshold();
}
private List add(OutstandingPublish outstandingPublish) {
List batchesToSend = new ArrayList<>();
// Check if the next message makes the current batch exceed the max batch byte size.
if (!isEmpty()
&& hasBatchingBytes()
&& getBatchedBytes() + outstandingPublish.messageSize >= getMaxBatchBytes()) {
batchesToSend.add(popOutstandingBatch());
}
messages.add(outstandingPublish);
batchedBytes += outstandingPublish.messageSize;
// Border case: If the message to send is greater or equals to the max batch size then send it
// immediately.
// Alternatively if after adding the message we have reached the batch max messages then we
// have a batch to send.
if ((hasBatchingBytes() && outstandingPublish.messageSize >= getMaxBatchBytes())
|| getMessagesCount() == batchingSettings.getElementCountThreshold()) {
batchesToSend.add(popOutstandingBatch());
}
return batchesToSend;
}
}
}