Pesan batch

Pesan batch membuat klien penayang dengan setelan pengelompokan kustom dan menggunakannya untuk memublikasikan beberapa pesan.

Dokumen ini memberikan informasi tentang penggunaan pesan batch dengan pesan yang dipublikasikan ke topik.

Sebelum memulai

Sebelum mengonfigurasi alur kerja publikasi, pastikan Anda telah menyelesaikan tugas-tugas berikut:

• Pelajari topik dan alur kerja publikasi.
• Buat topik.

Peran yang diperlukan

Untuk mendapatkan izin yang diperlukan guna memublikasikan pesan ke topik, minta administrator untuk memberi Anda peran IAM Pub/Sub Publisher (roles/pubsub.publisher) pada topik. Untuk mengetahui informasi selengkapnya tentang cara memberikan peran, lihat Mengelola akses ke project, folder, dan organisasi.

Anda mungkin juga bisa mendapatkan izin yang diperlukan melalui peran khusus atau peran bawaan lainnya.

Anda memerlukan izin tambahan untuk membuat atau memperbarui topik dan langganan.

Menggunakan pesan batch

Lihat contoh kode berikut untuk mempelajari cara mengonfigurasi setelan pesan batch untuk penayang Anda.

C++

Sebelum mencoba contoh ini, ikuti petunjuk penyiapan C++ di Panduan Memulai: Menggunakan Library Klien. Untuk mengetahui informasi selengkapnya, lihat dokumentasi referensi Pub/Sub C++ API.

namespace pubsub = ::google::cloud::pubsub;
using ::google::cloud::future;
using ::google::cloud::Options;
using ::google::cloud::StatusOr;
[](std::string project_id, std::string topic_id) {
  auto topic = pubsub::Topic(std::move(project_id), std::move(topic_id));
  // By default, the publisher will flush a batch after 10ms, after it
  // contains more than 100 message, or after it contains more than 1MiB of
  // data, whichever comes first. This changes those defaults.
  auto publisher = pubsub::Publisher(pubsub::MakePublisherConnection(
      std::move(topic),
      Options{}
          .set<pubsub::MaxHoldTimeOption>(std::chrono::milliseconds(20))
          .set<pubsub::MaxBatchBytesOption>(4 * 1024 * 1024L)
          .set<pubsub::MaxBatchMessagesOption>(200)));

  std::vector<future<void>> ids;
  for (char const* data : {"1", "2", "3", "go!"}) {
    ids.push_back(
        publisher.Publish(pubsub::MessageBuilder().SetData(data).Build())
            .then([data](future<StatusOr<std::string>> f) {
              auto s = f.get();
              if (!s) return;
              std::cout << "Sent '" << data << "' (" << *s << ")\n";
            }));
  }
  publisher.Flush();
  // Block until they are actually sent.
  for (auto& id : ids) id.get();
}

C#

Sebelum mencoba contoh ini, ikuti petunjuk penyiapan C# di Panduan Memulai: Menggunakan Library Klien. Untuk mengetahui informasi selengkapnya, lihat dokumentasi referensi Pub/Sub C# API.

using Google.Api.Gax;
using Google.Cloud.PubSub.V1;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;

public class PublishBatchedMessagesAsyncSample
{
    public async Task<int> PublishBatchMessagesAsync(string projectId, string topicId, IEnumerable<string> messageTexts)
    {
        TopicName topicName = TopicName.FromProjectTopic(projectId, topicId);

        // Default Settings:
        // byteCountThreshold: 1000000
        // elementCountThreshold: 100
        // delayThreshold: 10 milliseconds
        var customSettings = new PublisherClient.Settings
        {
            BatchingSettings = new BatchingSettings(
                elementCountThreshold: 50,
                byteCountThreshold: 10240,
                delayThreshold: TimeSpan.FromMilliseconds(500))
        };

        PublisherClient publisher = await new PublisherClientBuilder
        {
            TopicName = topicName,
            Settings = customSettings
        }.BuildAsync();

        int publishedMessageCount = 0;
        var publishTasks = messageTexts.Select(async text =>
        {
            try
            {
                string message = await publisher.PublishAsync(text);
                Console.WriteLine($"Published message {message}");
                Interlocked.Increment(ref publishedMessageCount);
            }
            catch (Exception exception)
            {
                Console.WriteLine($"An error occurred when publishing message {text}: {exception.Message}");
            }
        });
        await Task.WhenAll(publishTasks);
        return publishedMessageCount;
    }
}

Go

Sebelum mencoba contoh ini, ikuti petunjuk penyiapan Go di Panduan Memulai: Menggunakan Library Klien. Untuk mengetahui informasi selengkapnya, lihat dokumentasi referensi Pub/Sub Go API.

import (
	"context"
	"fmt"
	"io"
	"strconv"
	"time"

	"cloud.google.com/go/pubsub"
)

func publishWithSettings(w io.Writer, projectID, topicID string) error {
	// projectID := "my-project-id"
	// topicID := "my-topic"
	ctx := context.Background()
	client, err := pubsub.NewClient(ctx, projectID)
	if err != nil {
		return fmt.Errorf("pubsub.NewClient: %w", err)
	}
	defer client.Close()
	var results []*pubsub.PublishResult
	var resultErrors []error
	t := client.Topic(topicID)
	t.PublishSettings.ByteThreshold = 5000
	t.PublishSettings.CountThreshold = 10
	t.PublishSettings.DelayThreshold = 100 * time.Millisecond

	for i := 0; i < 10; i++ {
		result := t.Publish(ctx, &pubsub.Message{
			Data: []byte("Message " + strconv.Itoa(i)),
		})
		results = append(results, result)
	}
	// The Get method blocks until a server-generated ID or
	// an error is returned for the published message.
	for i, res := range results {
		id, err := res.Get(ctx)
		if err != nil {
			resultErrors = append(resultErrors, err)
			fmt.Fprintf(w, "Failed to publish: %v", err)
			continue
		}
		fmt.Fprintf(w, "Published message %d; msg ID: %v\n", i, id)
	}
	if len(resultErrors) != 0 {
		return fmt.Errorf("Get: %v", resultErrors[len(resultErrors)-1])
	}
	fmt.Fprintf(w, "Published messages with batch settings.")
	return nil
}

Java

Sebelum mencoba contoh ini, ikuti petunjuk penyiapan Java di Panduan Memulai: Menggunakan Library Klien. Untuk mengetahui informasi selengkapnya, lihat dokumentasi referensi Java API Pub/Sub.

import com.google.api.core.ApiFuture;
import com.google.api.core.ApiFutures;
import com.google.api.gax.batching.BatchingSettings;
import com.google.cloud.pubsub.v1.Publisher;
import com.google.protobuf.ByteString;
import com.google.pubsub.v1.PubsubMessage;
import com.google.pubsub.v1.TopicName;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;
import org.threeten.bp.Duration;

public class PublishWithBatchSettingsExample {
  public static void main(String... args) throws Exception {
    // TODO(developer): Replace these variables before running the sample.
    String projectId = "your-project-id";
    String topicId = "your-topic-id";

    publishWithBatchSettingsExample(projectId, topicId);
  }

  public static void publishWithBatchSettingsExample(String projectId, String topicId)
      throws IOException, ExecutionException, InterruptedException {
    TopicName topicName = TopicName.of(projectId, topicId);
    Publisher publisher = null;
    List<ApiFuture<String>> messageIdFutures = new ArrayList<>();

    try {
      // Batch settings control how the publisher batches messages
      long requestBytesThreshold = 5000L; // default : 1000 bytes
      long messageCountBatchSize = 100L; // default : 100 message

      Duration publishDelayThreshold = Duration.ofMillis(100); // default : 1 ms

      // Publish request get triggered based on request size, messages count & time since last
      // publish, whichever condition is met first.
      BatchingSettings batchingSettings =
          BatchingSettings.newBuilder()
              .setElementCountThreshold(messageCountBatchSize)
              .setRequestByteThreshold(requestBytesThreshold)
              .setDelayThreshold(publishDelayThreshold)
              .build();

      // Create a publisher instance with default settings bound to the topic
      publisher = Publisher.newBuilder(topicName).setBatchingSettings(batchingSettings).build();

      // schedule publishing one message at a time : messages get automatically batched
      for (int i = 0; i < 100; i++) {
        String message = "message " + i;
        ByteString data = ByteString.copyFromUtf8(message);
        PubsubMessage pubsubMessage = PubsubMessage.newBuilder().setData(data).build();

        // Once published, returns a server-assigned message id (unique within the topic)
        ApiFuture<String> messageIdFuture = publisher.publish(pubsubMessage);
        messageIdFutures.add(messageIdFuture);
      }
    } finally {
      // Wait on any pending publish requests.
      List<String> messageIds = ApiFutures.allAsList(messageIdFutures).get();

      System.out.println("Published " + messageIds.size() + " messages with batch settings.");

      if (publisher != null) {
        // When finished with the publisher, shutdown to free up resources.
        publisher.shutdown();
        publisher.awaitTermination(1, TimeUnit.MINUTES);
      }
    }
  }
}

Node.js

Sebelum mencoba contoh ini, ikuti petunjuk penyiapan Node.js di Panduan Memulai: Menggunakan Library Klien. Untuk mengetahui informasi selengkapnya, lihat dokumentasi referensi API Node.js Pub/Sub.

/**
 * TODO(developer): Uncomment these variables before running the sample.
 */
// const topicName = 'YOUR_TOPIC_NAME';
// const data = JSON.stringify({foo: 'bar'});
// const maxMessages = 10;
// const maxWaitTime = 10;

// Imports the Google Cloud client library
const {PubSub} = require('@google-cloud/pubsub');

// Creates a client; cache this for further use
const pubSubClient = new PubSub();

async function publishBatchedMessages(
  topicNameOrId,
  data,
  maxMessages,
  maxWaitTime
) {
  // Publishes the message as a string, e.g. "Hello, world!" or JSON.stringify(someObject)
  const dataBuffer = Buffer.from(data);

  // Cache topic objects (publishers) and reuse them.
  const publishOptions = {
    batching: {
      maxMessages: maxMessages,
      maxMilliseconds: maxWaitTime * 1000,
    },
  };
  const batchPublisher = pubSubClient.topic(topicNameOrId, publishOptions);

  const promises = [];
  for (let i = 0; i < 10; i++) {
    promises.push(
      (async () => {
        const messageId = await batchPublisher.publishMessage({
          data: dataBuffer,
        });
        console.log(`Message ${messageId} published.`);
      })()
    );
  }
  await Promise.all(promises);
}

Node.js

Sebelum mencoba contoh ini, ikuti petunjuk penyiapan Node.js di Panduan Memulai: Menggunakan Library Klien. Untuk mengetahui informasi selengkapnya, lihat dokumentasi referensi API Node.js Pub/Sub.

/**
 * TODO(developer): Uncomment these variables before running the sample.
 */
// const topicName = 'YOUR_TOPIC_NAME';
// const data = JSON.stringify({foo: 'bar'});
// const maxMessages = 10;
// const maxWaitTime = 10;

// Imports the Google Cloud client library
import {PublishOptions, PubSub} from '@google-cloud/pubsub';

// Creates a client; cache this for further use
const pubSubClient = new PubSub();

async function publishBatchedMessages(
  topicNameOrId: string,
  data: string,
  maxMessages: number,
  maxWaitTime: number
) {
  // Publishes the message as a string, e.g. "Hello, world!" or JSON.stringify(someObject)
  const dataBuffer = Buffer.from(data);

  // Cache topic objects (publishers) and reuse them.
  const publishOptions: PublishOptions = {
    batching: {
      maxMessages: maxMessages,
      maxMilliseconds: maxWaitTime * 1000,
    },
  };
  const batchPublisher = pubSubClient.topic(topicNameOrId, publishOptions);

  const promises: Promise<void>[] = [];
  for (let i = 0; i < 10; i++) {
    promises.push(
      (async () => {
        const messageId = await batchPublisher.publishMessage({
          data: dataBuffer,
        });
        console.log(`Message ${messageId} published.`);
      })()
    );
  }
  await Promise.all(promises);
}

PHP

Sebelum mencoba contoh ini, ikuti petunjuk penyiapan PHP di Panduan Memulai: Menggunakan Library Klien. Untuk mengetahui informasi selengkapnya, lihat dokumentasi referensi API PHP Pub/Sub.

use Google\Cloud\PubSub\PubSubClient;

/**
 * Publishes a message for a Pub/Sub topic.
 *
 * The publisher should be used in conjunction with the `google-cloud-batch`
 * daemon, which should be running in the background.
 *
 * To start the daemon, from your project root call `vendor/bin/google-cloud-batch daemon`.
 *
 * @param string $projectId  The Google project ID.
 * @param string $topicName  The Pub/Sub topic name.
 * @param string $message    The message to publish.
 */
function publish_message_batch($projectId, $topicName, $message)
{
    // Check if the batch daemon is running.
    if (getenv('IS_BATCH_DAEMON_RUNNING') !== 'true') {
        trigger_error(
            'The batch daemon is not running. Call ' .
            '`vendor/bin/google-cloud-batch daemon` from ' .
            'your project root to start the daemon.',
            E_USER_NOTICE
        );
    }

    $batchOptions = [
        'batchSize' => 100, // Max messages for each batch.
        'callPeriod' => 0.01, // Max time in seconds between each batch publish.
    ];

    $pubsub = new PubSubClient([
        'projectId' => $projectId,
    ]);
    $topic = $pubsub->topic($topicName);
    $publisher = $topic->batchPublisher([
        'batchOptions' => $batchOptions
    ]);

    for ($i = 0; $i < 10; $i++) {
        $publisher->publish(['data' => $message]);
    }

    print('Messages enqueued for publication.' . PHP_EOL);
}

Python

Sebelum mencoba contoh ini, ikuti petunjuk penyiapan Python di Panduan Memulai: Menggunakan Library Klien. Untuk mengetahui informasi selengkapnya, lihat dokumentasi referensi Pub/Sub Python API.

from concurrent import futures
from google.cloud import pubsub_v1

# TODO(developer)
# project_id = "your-project-id"
# topic_id = "your-topic-id"

# Configure the batch to publish as soon as there are 10 messages
# or 1 KiB of data, or 1 second has passed.
batch_settings = pubsub_v1.types.BatchSettings(
    max_messages=10,  # default 100
    max_bytes=1024,  # default 1 MB
    max_latency=1,  # default 10 ms
)
publisher = pubsub_v1.PublisherClient(batch_settings)
topic_path = publisher.topic_path(project_id, topic_id)
publish_futures = []

# Resolve the publish future in a separate thread.
def callback(future: pubsub_v1.publisher.futures.Future) -> None:
    message_id = future.result()
    print(message_id)

for n in range(1, 10):
    data_str = f"Message number {n}"
    # Data must be a bytestring
    data = data_str.encode("utf-8")
    publish_future = publisher.publish(topic_path, data)
    # Non-blocking. Allow the publisher client to batch multiple messages.
    publish_future.add_done_callback(callback)
    publish_futures.append(publish_future)

futures.wait(publish_futures, return_when=futures.ALL_COMPLETED)

print(f"Published messages with batch settings to {topic_path}.")

Ruby

Sebelum mencoba contoh ini, ikuti petunjuk penyiapan Ruby di Panduan Memulai: Menggunakan Library Klien. Untuk mengetahui informasi selengkapnya, lihat dokumentasi referensi Pub/Sub Ruby API.

# topic_id = "your-topic-id"

pubsub = Google::Cloud::Pubsub.new

# Start sending messages in one request once the size of all queued messages
# reaches 1 MB or the number of queued messages reaches 20
topic = pubsub.topic topic_id, async: {
  max_bytes:    1_000_000,
  max_messages: 20
}
10.times do |i|
  topic.publish_async "This is message ##{i}."
end

# Stop the async_publisher to send all queued messages immediately.
topic.async_publisher.stop.wait!
puts "Messages published asynchronously in batch."

Menonaktifkan pesan batch

Untuk menonaktifkan pengelompokan di library klien, tetapkan nilai max_messages ke 1.

Pesan batch dan pengiriman sesuai urutan

Dengan pengiriman yang diurutkan, kegagalan untuk mengonfirmasi pesan apa pun dalam batch berarti semua pesan dalam batch, termasuk pesan yang dikirim sebelum pesan yang tidak dikonfirmasi, akan dikirim ulang.

Kuota dan batas pada pesan batch

Sebelum mengonfigurasi pesan batch, pertimbangkan pengaruh faktor seperti kuota throughput publikasi dan ukuran maksimum batch. Library klien tingkat tinggi memastikan bahwa permintaan batch tetap dalam batas yang ditentukan.

• 1.000 byte adalah ukuran permintaan minimum yang dipertimbangkan untuk tujuan biaya, meskipun ukuran pesan sebenarnya mungkin lebih kecil dari 1.000 byte.
• Pub/Sub memiliki batas ukuran 10 MB atau jumlah pesan 1.000 untuk satu permintaan publikasi batch.

Untuk mengetahui informasi selengkapnya, lihat Kuota dan batas Pub/Sub.

Langkah selanjutnya

Untuk mempelajari cara mengonfigurasi opsi publikasi lanjutan, lihat hal berikut:

• Mengompresi pesan

• Mencoba kembali permintaan

• Kontrol alur

• Kontrol konkurensi