Traçage OpenTelemetry Pub/Sub

Le traçage OpenTelemetry vous permet d'identifier et de suivre la latence de diverses opérations de la bibliothèque cliente Pub/Sub, telles que le traitement par lot, la gestion des baux et le contrôle de flux. La collecte de ces informations peut vous aider à déboguer les problèmes liés à la bibliothèque cliente.

Voici quelques cas d'utilisation potentiels du traçage OpenTelemetry:

• La latence de publication de votre service est plus élevée que d'habitude.
• Vous constatez un nombre élevé de nouvelles diffusions de messages.
• Une modification de la fonction de rappel de votre client abonné entraîne un traitement plus long que d'habitude.

Avant de commencer

Avant de configurer OpenTelemetry, effectuez les tâches suivantes:

• Configurez Pub/Sub à l'aide de l'une des bibliothèques clientes.
• Installez le SDK OpenTelemetry et configurez un exportateur de traces et un fournisseur de traceur.
• Activez l'API Cloud Trace.
• Découvrez comment lire les traces d'observabilité dans le cloud.

Rôles requis

Pour vous assurer que le compte de service dispose des autorisations nécessaires pour exporter des traces vers Cloud Trace, demandez à votre administrateur d'accorder au compte de service les rôles IAM suivants sur votre projet:

• Tout : Agent Cloud Trace (roles/cloudtrace.agent)

Pour en savoir plus sur l'attribution de rôles, consultez la page Gérer l'accès aux projets, aux dossiers et aux organisations.

Ces rôles prédéfinis contiennent les autorisations requises pour exporter des traces vers Cloud Trace. Pour connaître les autorisations exactes requises, développez la section Autorisations requises :

Autorisations requises

Les autorisations suivantes sont requises pour exporter des traces vers Cloud Trace:

• Toutes : cloudtrace.traces.patch

Votre administrateur peut également attribuer au compte de service ces autorisations avec des rôles personnalisés ou d'autres rôles prédéfinis.

Workflow de traçage OpenTelemetry

Pour configurer le traçage OpenTelemetry, vous devez utiliser les bibliothèques clientes Pub/Sub et le SDK OpenTelemetry. Avec le SDK, vous devez configurer un exportateur de trace et un fournisseur de traceur avant de vous connecter aux bibliothèques Pub/Sub. Dans certaines bibliothèques, la configuration d'un fournisseur de traceur est facultative.

• Exportateur de traces Le SDK OpenTelemetry utilise l'exportateur de traces pour déterminer où envoyer les traces.

• Fournisseur de traceur Les bibliothèques clientes Pub/Sub utilisent le fournisseur de traceur pour créer des traces.

Pour configurer le traçage, procédez comme suit:

1. Instancier un exportateur OpenTelemetry Cloud Trace.
2. Si nécessaire, instanciez et enregistrez un fournisseur de traceur à l'aide du SDK OpenTelemetry.
3. Configurez votre client avec l'option d'activation du traçage OpenTelemetry.
4. Utilisez les bibliothèques clientes Pub/Sub pour publier un message.

Fonctionnement du traçage

Pour chaque message publié, la bibliothèque cliente crée une trace. Cette trace représente l'ensemble du cycle de vie du message, du moment où vous le publiez jusqu'à ce qu'il soit accusé réception. Une trace encapsule des informations telles que la durée des opérations, les délais parent et enfant, ainsi que les délais associés.

Une trace se compose d'un délai racine et de ses délais enfants correspondants. Ces plages représentent le travail effectué par la bibliothèque cliente lors du traitement d'un message. Chaque trace de message contient les éléments suivants:

• Pour la publication Contrôle de flux, planification des clés de commande, traitement par lot et longueur de l'RPC de publication.
• Pour les abonnements Contrôle de la simultanéité, planification des clés de commande et gestion des baux.

Pour propager des informations du côté de la publication vers le côté de l'abonnement, les bibliothèques clientes injectent un attribut spécifique au traçage côté publication. Le mécanisme de propagation de contexte n'est activé que lorsque le traçage est activé et est précédé du préfixe googclient_.

Publier des messages avec le traçage

L'exemple de code suivant montre comment activer le traçage à l'aide de la bibliothèque cliente Pub/Sub et du SDK OpenTelemetry. Dans cet exemple, les résultats de traçage sont exportés vers Cloud Trace.

Remarque :Cloud Trace ne fournit des exportateurs que pour Java, Go, Node et Python. Pour exporter avec d'autres langues, utilisez le collecteur OpenTelemetry avec l'exportateurGoogle Cloud. La configuration de ces processus nécessite des étapes supplémentaires qui ne sont pas documentées sur cette page.

Remarques

Lorsque vous instanciez le fournisseur de traceur, vous configurez un ratio d'échantillonnage avec le SDK OpenTelemetry. Ce ratio détermine le nombre de traces que le SDK doit échantillonner. Un taux d'échantillonnage plus faible peut vous aider à réduire les coûts de facturation et à éviter que votre service ne dépasse le quota de durée Cloud Trace.

Avertissement :Les traces sont susceptibles d'être modifiées. Le nom et les attributs d'une span peuvent changer sans préavis. N'utilisez les traces d'exécution que de manière interactive. Ne pas utiliser dans l'automatisation. L'exécution de traces non interactives peut entraîner des problèmes si l'architecture de trace sous-jacente change sans préavis.

Go

import (
	"context"
	"fmt"
	"io"

	"cloud.google.com/go/pubsub"
	"go.opentelemetry.io/otel"
	"google.golang.org/api/option"

	texporter "github.com/GoogleCloudPlatform/opentelemetry-operations-go/exporter/trace"
	"go.opentelemetry.io/otel/sdk/resource"
	sdktrace "go.opentelemetry.io/otel/sdk/trace"
	semconv "go.opentelemetry.io/otel/semconv/v1.26.0"
)

// publishOpenTelemetryTracing publishes a single message with OpenTelemetry tracing
// enabled, exporting to Cloud Trace.
func publishOpenTelemetryTracing(w io.Writer, projectID, topicID string, sampling float64) error {
	// projectID := "my-project-id"
	// topicID := "my-topic"
	ctx := context.Background()

	exporter, err := texporter.New(texporter.WithProjectID(projectID),
		// Disable spans created by the exporter.
		texporter.WithTraceClientOptions(
			[]option.ClientOption{option.WithTelemetryDisabled()},
		),
	)
	if err != nil {
		return fmt.Errorf("error instantiating exporter: %w", err)
	}

	resources := resource.NewWithAttributes(
		semconv.SchemaURL,
		semconv.ServiceNameKey.String("publisher"),
	)

	// Instantiate a tracer provider with the following settings
	tp := sdktrace.NewTracerProvider(
		sdktrace.WithBatcher(exporter),
		sdktrace.WithResource(resources),
		sdktrace.WithSampler(
			sdktrace.ParentBased(sdktrace.TraceIDRatioBased(sampling)),
		),
	)

	defer tp.ForceFlush(ctx) // flushes any pending spans
	otel.SetTracerProvider(tp)

	// Create a new client with tracing enabled.
	client, err := pubsub.NewClientWithConfig(ctx, projectID, &pubsub.ClientConfig{
		EnableOpenTelemetryTracing: true,
	})
	if err != nil {
		return fmt.Errorf("pubsub: NewClient: %w", err)
	}
	defer client.Close()

	t := client.Topic(topicID)
	result := t.Publish(ctx, &pubsub.Message{
		Data: []byte("Publishing message with tracing"),
	})
	if _, err := result.Get(ctx); err != nil {
		return fmt.Errorf("pubsub: result.Get: %w", err)
	}
	fmt.Fprintln(w, "Published a traced message")
	return nil
}

C++

// Create a few namespace aliases to make the code easier to read.
namespace gc = ::google::cloud;
namespace otel = gc::otel;
namespace pubsub = gc::pubsub;

// This example uses a simple wrapper to export (upload) OTel tracing data
// to Google Cloud Trace. More complex applications may use different
// authentication, or configure their own OTel exporter.
auto project = gc::Project(project_id);
auto configuration = otel::ConfigureBasicTracing(project);

auto publisher = pubsub::Publisher(pubsub::MakePublisherConnection(
    pubsub::Topic(project_id, topic_id),
    // Configure this publisher to enable OTel tracing. Some applications may
    // chose to disable tracing in some publishers or to dynamically enable
    // this option based on their own configuration.
    gc::Options{}.set<gc::OpenTelemetryTracingOption>(true)));

// After this point, use the Cloud Pub/Sub C++ client library as usual.
// In this example, we will send a few messages and configure a callback
// action for each one.
std::vector<gc::future<void>> ids;
for (int i = 0; i < 5; i++) {
  auto id = publisher.Publish(pubsub::MessageBuilder().SetData("Hi!").Build())
                .then([](gc::future<gc::StatusOr<std::string>> f) {
                  auto id = f.get();
                  if (!id) {
                    std::cout << "Error in publish: " << id.status() << "\n";
                    return;
                  }
                  std::cout << "Sent message with id: (" << *id << ")\n";
                });
  ids.push_back(std::move(id));
}
// Block until the messages are actually sent.
for (auto& id : ids) id.get();

Python

Avant d'essayer cet exemple, suivez les instructions d'installation dans le langage Python qui se trouvent sur la page Démarrage rapide : utiliser des bibliothèques clientes. Pour en savoir plus, consultez la documentation de référence sur l'API Pub/Sub pour Python.

from opentelemetry import trace
from opentelemetry.sdk.trace import TracerProvider
from opentelemetry.sdk.trace.export import (
    BatchSpanProcessor,
)
from opentelemetry.exporter.cloud_trace import CloudTraceSpanExporter
from opentelemetry.sdk.trace.sampling import TraceIdRatioBased, ParentBased

from google.cloud.pubsub_v1 import PublisherClient
from google.cloud.pubsub_v1.types import PublisherOptions

# TODO(developer)
# topic_project_id = "your-topic-project-id"
# trace_project_id = "your-trace-project-id"
# topic_id = "your-topic-id"

# In this sample, we use a Google Cloud Trace to export the OpenTelemetry
# traces: https://cloud.google.com/trace/docs/setup/python-ot
# Choose and configure the exporter for your set up accordingly.

sampler = ParentBased(root=TraceIdRatioBased(1))
trace.set_tracer_provider(TracerProvider(sampler=sampler))

# Export to Google Trace.
cloud_trace_exporter = CloudTraceSpanExporter(
    project_id=trace_project_id,
)
trace.get_tracer_provider().add_span_processor(
    BatchSpanProcessor(cloud_trace_exporter)
)

# Set the `enable_open_telemetry_tracing` option to True when creating
# the publisher client. This in itself is necessary and sufficient for
# the library to export OpenTelemetry traces. However, where the traces
# must be exported to needs to be configured based on your OpenTelemetry
# set up. Refer: https://opentelemetry.io/docs/languages/python/exporters/
publisher = PublisherClient(
    publisher_options=PublisherOptions(
        enable_open_telemetry_tracing=True,
    ),
)

# The `topic_path` method creates a fully qualified identifier
# in the form `projects/{project_id}/topics/{topic_id}`
topic_path = publisher.topic_path(topic_project_id, topic_id)
# Publish messages.
for n in range(1, 10):
    data_str = f"Message number {n}"
    # Data must be a bytestring
    data = data_str.encode("utf-8")
    # When you publish a message, the client returns a future.
    future = publisher.publish(topic_path, data)
    print(future.result())

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

TypeScript

/**
 * TODO(developer): Uncomment these variables before running the sample.
 */
// const topicNameOrId = 'YOUR_TOPIC_OR_ID';
// const data = 'Hello, world!";

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

// Imports the OpenTelemetry API
import {NodeTracerProvider} from '@opentelemetry/sdk-trace-node';
import {diag, DiagConsoleLogger, DiagLogLevel} from '@opentelemetry/api';
import {SimpleSpanProcessor} from '@opentelemetry/sdk-trace-base';

// To output to the console for testing, use the ConsoleSpanExporter.
// import {ConsoleSpanExporter} from '@opentelemetry/sdk-trace-base';

// To output to Cloud Trace, import the OpenTelemetry bridge library.
import {TraceExporter} from '@google-cloud/opentelemetry-cloud-trace-exporter';

import {Resource} from '@opentelemetry/resources';
import {SEMRESATTRS_SERVICE_NAME} from '@opentelemetry/semantic-conventions';

// Enable the diagnostic logger for OpenTelemetry
diag.setLogger(new DiagConsoleLogger(), DiagLogLevel.DEBUG);

// Log spans out to the console, for testing.
// const exporter = new ConsoleSpanExporter();

// Log spans out to Cloud Trace, for production.
const exporter = new TraceExporter();

// Build a tracer provider and a span processor to do
// something with the spans we're generating.
const provider = new NodeTracerProvider({
  resource: new Resource({
    [SEMRESATTRS_SERVICE_NAME]: 'otel publisher example',
  }),
});
const processor = new SimpleSpanProcessor(exporter);
provider.addSpanProcessor(processor);
provider.register();

// Creates a client; cache this for further use.
const pubSubClient = new PubSub({enableOpenTelemetryTracing: true});

async function publishMessage(topicNameOrId: string, data: string) {
  // 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 publisher = pubSubClient.topic(topicNameOrId);

  const messageId = await publisher.publishMessage({data: dataBuffer});
  console.log(`Message ${messageId} published.`);

  // The rest of the sample is in service to making sure that any
  // buffered Pub/Sub messages and/or OpenTelemetry spans are properly
  // flushed to the server side. In normal usage, you'd only need to do
  // something like this on process shutdown.
  await publisher.flush();
  await processor.forceFlush();
  await new Promise(r => setTimeout(r, OTEL_TIMEOUT * 1000));
}

Node.js

/**
 * TODO(developer): Uncomment these variables before running the sample.
 */
// const topicNameOrId = 'YOUR_TOPIC_OR_ID';
// const data = 'Hello, world!";

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

// Imports the OpenTelemetry API
const {NodeTracerProvider} = require('@opentelemetry/sdk-trace-node');
const {diag, DiagConsoleLogger, DiagLogLevel} = require('@opentelemetry/api');
const {SimpleSpanProcessor} = require('@opentelemetry/sdk-trace-base');

// To output to the console for testing, use the ConsoleSpanExporter.
// import {ConsoleSpanExporter} from '@opentelemetry/sdk-trace-base';

// To output to Cloud Trace, import the OpenTelemetry bridge library.
const {
  TraceExporter,
} = require('@google-cloud/opentelemetry-cloud-trace-exporter');

const {Resource} = require('@opentelemetry/resources');
const {
  SEMRESATTRS_SERVICE_NAME,
} = require('@opentelemetry/semantic-conventions');

// Enable the diagnostic logger for OpenTelemetry
diag.setLogger(new DiagConsoleLogger(), DiagLogLevel.DEBUG);

// Log spans out to the console, for testing.
// const exporter = new ConsoleSpanExporter();

// Log spans out to Cloud Trace, for production.
const exporter = new TraceExporter();

// Build a tracer provider and a span processor to do
// something with the spans we're generating.
const provider = new NodeTracerProvider({
  resource: new Resource({
    [SEMRESATTRS_SERVICE_NAME]: 'otel publisher example',
  }),
});
const processor = new SimpleSpanProcessor(exporter);
provider.addSpanProcessor(processor);
provider.register();

// Creates a client; cache this for further use.
const pubSubClient = new PubSub({enableOpenTelemetryTracing: true});

async function publishMessage(topicNameOrId, data) {
  // 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 publisher = pubSubClient.topic(topicNameOrId);

  const messageId = await publisher.publishMessage({data: dataBuffer});
  console.log(`Message ${messageId} published.`);

  // The rest of the sample is in service to making sure that any
  // buffered Pub/Sub messages and/or OpenTelemetry spans are properly
  // flushed to the server side. In normal usage, you'd only need to do
  // something like this on process shutdown.
  await publisher.flush();
  await processor.forceFlush();
  await new Promise(r => setTimeout(r, OTEL_TIMEOUT * 1000));
}

Java

import com.google.api.core.ApiFuture;
import com.google.cloud.opentelemetry.trace.TraceConfiguration;
import com.google.cloud.opentelemetry.trace.TraceExporter;
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 io.opentelemetry.api.OpenTelemetry;
import io.opentelemetry.sdk.OpenTelemetrySdk;
import io.opentelemetry.sdk.resources.Resource;
import io.opentelemetry.sdk.trace.SdkTracerProvider;
import io.opentelemetry.sdk.trace.export.SimpleSpanProcessor;
import io.opentelemetry.sdk.trace.export.SpanExporter;
import io.opentelemetry.sdk.trace.samplers.Sampler;
import io.opentelemetry.semconv.ResourceAttributes;
import java.io.IOException;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;

public class OpenTelemetryPublisherExample {
  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";

    openTelemetryPublisherExample(projectId, topicId);
  }

  public static void openTelemetryPublisherExample(String projectId, String topicId)
      throws IOException, ExecutionException, InterruptedException {
    Resource resource =
        Resource.getDefault()
            .toBuilder()
            .put(ResourceAttributes.SERVICE_NAME, "publisher-example")
            .build();

    // Creates a Cloud Trace exporter.
    SpanExporter traceExporter =
        TraceExporter.createWithConfiguration(
            TraceConfiguration.builder().setProjectId(projectId).build());

    SdkTracerProvider sdkTracerProvider =
        SdkTracerProvider.builder()
            .setResource(resource)
            .addSpanProcessor(SimpleSpanProcessor.create(traceExporter))
            .setSampler(Sampler.alwaysOn())
            .build();

    OpenTelemetry openTelemetry =
        OpenTelemetrySdk.builder().setTracerProvider(sdkTracerProvider).buildAndRegisterGlobal();

    TopicName topicName = TopicName.of(projectId, topicId);

    Publisher publisher = null;
    try {
      // Create a publisher instance with the created OpenTelemetry object and enabling tracing.
      publisher =
          Publisher.newBuilder(topicName)
              .setOpenTelemetry(openTelemetry)
              .setEnableOpenTelemetryTracing(true)
              .build();

      String message = "Hello World!";
      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);
      String messageId = messageIdFuture.get();
      System.out.println("Published message ID: " + messageId);
    } finally {
      if (publisher != null) {
        // When finished with the publisher, shutdown to free up resources.
        publisher.shutdown();
        publisher.awaitTermination(1, TimeUnit.MINUTES);
      }
    }
  }
}

Recevoir des messages avec le traçage

Go

import (
	"context"
	"fmt"
	"io"
	"sync/atomic"
	"time"

	"cloud.google.com/go/pubsub"
	texporter "github.com/GoogleCloudPlatform/opentelemetry-operations-go/exporter/trace"
	"go.opentelemetry.io/otel"
	"go.opentelemetry.io/otel/sdk/resource"
	sdktrace "go.opentelemetry.io/otel/sdk/trace"
	semconv "go.opentelemetry.io/otel/semconv/v1.24.0"
	"google.golang.org/api/option"
)

func subscribeOpenTelemetryTracing(w io.Writer, projectID, subID string, sampleRate float64) error {
	// projectID := "my-project-id"
	// subID := "my-sub"
	// sampleRate := "1.0"
	ctx := context.Background()

	exporter, err := texporter.New(texporter.WithProjectID(projectID),
		// Disable spans created by the exporter.
		texporter.WithTraceClientOptions(
			[]option.ClientOption{option.WithTelemetryDisabled()},
		),
	)
	if err != nil {
		return fmt.Errorf("error instantiating exporter: %w", err)
	}

	resources := resource.NewWithAttributes(
		semconv.SchemaURL,
		semconv.ServiceNameKey.String("subscriber"),
	)

	// Instantiate a tracer provider with the following settings
	tp := sdktrace.NewTracerProvider(
		sdktrace.WithBatcher(exporter),
		sdktrace.WithResource(resources),
		sdktrace.WithSampler(
			sdktrace.ParentBased(sdktrace.TraceIDRatioBased(sampleRate)),
		),
	)

	defer tp.ForceFlush(ctx) // flushes any pending spans
	otel.SetTracerProvider(tp)

	// Create a new client with tracing enabled.
	client, err := pubsub.NewClientWithConfig(ctx, projectID, &pubsub.ClientConfig{
		EnableOpenTelemetryTracing: true,
	})
	if err != nil {
		return fmt.Errorf("pubsub.NewClient: %w", err)
	}
	defer client.Close()

	sub := client.Subscription(subID)

	// Receive messages for 10 seconds, which simplifies testing.
	// Comment this out in production, since `Receive` should
	// be used as a long running operation.
	ctx, cancel := context.WithTimeout(ctx, 10*time.Second)
	defer cancel()

	var received int32
	err = sub.Receive(ctx, func(_ context.Context, msg *pubsub.Message) {
		fmt.Fprintf(w, "Got message: %q\n", string(msg.Data))
		atomic.AddInt32(&received, 1)
		msg.Ack()
	})
	if err != nil {
		return fmt.Errorf("sub.Receive: %w", err)
	}
	fmt.Fprintf(w, "Received %d messages\n", received)

	return nil
}

C++

#include "google/cloud/opentelemetry/configure_basic_tracing.h"
#include "google/cloud/opentelemetry_options.h"
#include "google/cloud/pubsub/message.h"
#include "google/cloud/pubsub/publisher.h"
#include "google/cloud/pubsub/subscriber.h"
#include "google/cloud/pubsub/subscription.h"
#include <iostream>

int main(int argc, char* argv[]) try {
  if (argc != 4) {
    std::cerr << "Usage: " << argv[0]
              << " <project-id> <topic-id> <subscription-id>\n";
    return 1;
  }

  std::string const project_id = argv[1];
  std::string const topic_id = argv[2];
  std::string const subscription_id = argv[3];

  // Create a few namespace aliases to make the code easier to read.
  namespace gc = ::google::cloud;
  namespace otel = gc::otel;
  namespace pubsub = gc::pubsub;

  auto constexpr kWaitTimeout = std::chrono::seconds(30);

  auto project = gc::Project(project_id);
  auto configuration = otel::ConfigureBasicTracing(project);

  // Publish a message with tracing enabled.
  auto publisher = pubsub::Publisher(pubsub::MakePublisherConnection(
      pubsub::Topic(project_id, topic_id),
      gc::Options{}.set<gc::OpenTelemetryTracingOption>(true)));
  // Block until the message is actually sent and throw on error.
  auto id = publisher.Publish(pubsub::MessageBuilder().SetData("Hi!").Build())
                .get()
                .value();
  std::cout << "Sent message with id: (" << id << ")\n";

  // Receive a message using streaming pull with tracing enabled.
  auto subscriber = pubsub::Subscriber(pubsub::MakeSubscriberConnection(
      pubsub::Subscription(project_id, subscription_id),
      gc::Options{}.set<gc::OpenTelemetryTracingOption>(true)));

  auto session =
      subscriber.Subscribe([&](pubsub::Message const& m, pubsub::AckHandler h) {
        std::cout << "Received message " << m << "\n";
        std::move(h).ack();
      });

  std::cout << "Waiting for messages on " + subscription_id + "...\n";

  // Blocks until the timeout is reached.
  auto result = session.wait_for(kWaitTimeout);
  if (result == std::future_status::timeout) {
    std::cout << "timeout reached, ending session\n";
    session.cancel();
  }

  return 0;
} catch (google::cloud::Status const& status) {
  std::cerr << "google::cloud::Status thrown: " << status << "\n";
  return 1;
}

Python

from opentelemetry import trace
from opentelemetry.sdk.trace import TracerProvider
from opentelemetry.sdk.trace.export import (
    BatchSpanProcessor,
)
from opentelemetry.exporter.cloud_trace import CloudTraceSpanExporter
from opentelemetry.sdk.trace.sampling import TraceIdRatioBased, ParentBased

from google.cloud import pubsub_v1
from google.cloud.pubsub_v1 import SubscriberClient
from google.cloud.pubsub_v1.types import SubscriberOptions

# TODO(developer)
# subscription_project_id = "your-subscription-project-id"
# subscription_id = "your-subscription-id"
# cloud_trace_project_id = "your-cloud-trace-project-id"
# timeout = 300.0

# In this sample, we use a Google Cloud Trace to export the OpenTelemetry
# traces: https://cloud.google.com/trace/docs/setup/python-ot
# Choose and configure the exporter for your set up accordingly.

sampler = ParentBased(root=TraceIdRatioBased(1))
trace.set_tracer_provider(TracerProvider(sampler=sampler))

# Export to Google Trace
cloud_trace_exporter = CloudTraceSpanExporter(
    project_id=cloud_trace_project_id,
)
trace.get_tracer_provider().add_span_processor(
    BatchSpanProcessor(cloud_trace_exporter)
)
# Set the `enable_open_telemetry_tracing` option to True when creating
# the subscriber client. This in itself is necessary and sufficient for
# the library to export OpenTelemetry traces. However, where the traces
# must be exported to needs to be configured based on your OpenTelemetry
# set up. Refer: https://opentelemetry.io/docs/languages/python/exporters/
subscriber = SubscriberClient(
    subscriber_options=SubscriberOptions(enable_open_telemetry_tracing=True)
)

# The `subscription_path` method creates a fully qualified identifier
# in the form `projects/{project_id}/subscriptions/{subscription_id}`
subscription_path = subscriber.subscription_path(
    subscription_project_id, subscription_id
)

# Define callback to be called when a message is received.
def callback(message: pubsub_v1.subscriber.message.Message) -> None:
    # Ack message after processing it.
    print(message.data)
    message.ack()

# Wrap subscriber in a 'with' block to automatically call close() when done.
with subscriber:
    try:
        # Optimistically subscribe to messages on the subscription.
        streaming_pull_future = subscriber.subscribe(
            subscription_path, callback=callback
        )
        streaming_pull_future.result(timeout=timeout)
    except TimeoutError:
        print("Successfully subscribed until the timeout passed.")
        streaming_pull_future.cancel()  # Trigger the shutdown.
        streaming_pull_future.result()  # Block until the shutdown is complete.

TypeScript

/**
 * TODO(developer): Uncomment these variables before running the sample.
 */
// const subscriptionNameOrId = 'YOUR_SUBSCRIPTION_OR_ID';

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

// Imports the OpenTelemetry API
import {NodeTracerProvider} from '@opentelemetry/sdk-trace-node';
import {diag, DiagConsoleLogger, DiagLogLevel} from '@opentelemetry/api';
import {SimpleSpanProcessor} from '@opentelemetry/sdk-trace-base';

// To output to the console for testing, use the ConsoleSpanExporter.
// import {ConsoleSpanExporter} from '@opentelemetry/sdk-trace-base';

// To output to Cloud Trace, import the OpenTelemetry bridge library.
import {TraceExporter} from '@google-cloud/opentelemetry-cloud-trace-exporter';

import {Resource} from '@opentelemetry/resources';
import {SEMRESATTRS_SERVICE_NAME} from '@opentelemetry/semantic-conventions';

// Enable the diagnostic logger for OpenTelemetry
diag.setLogger(new DiagConsoleLogger(), DiagLogLevel.DEBUG);

// Log spans out to the console, for testing.
// const exporter = new ConsoleSpanExporter();

// Log spans out to Cloud Trace, for production.
const exporter = new TraceExporter();

// Build a tracer provider and a span processor to do
// something with the spans we're generating.
const provider = new NodeTracerProvider({
  resource: new Resource({
    [SEMRESATTRS_SERVICE_NAME]: 'otel subscriber example',
  }),
});
const processor = new SimpleSpanProcessor(exporter);
provider.addSpanProcessor(processor);
provider.register();

// Creates a client; cache this for further use.
const pubSubClient = new PubSub({enableOpenTelemetryTracing: true});

async function subscriptionListen(subscriptionNameOrId: string) {
  const subscriber = pubSubClient.subscription(subscriptionNameOrId);

  // Message handler for subscriber
  const messageHandler = async (message: Message) => {
    console.log(`Message ${message.id} received.`);
    message.ack();
  };

  // Error handler for subscriber
  const errorHandler = async (error: Error) => {
    console.log('Received error:', error);
  };

  // Listens for new messages from the topic
  subscriber.on('message', messageHandler);
  subscriber.on('error', errorHandler);

  // Ensures that all spans got flushed by the exporter. This function
  // is in service to making sure that any buffered Pub/Sub messages
  // and/or OpenTelemetry spans are properly flushed to the server
  // side. In normal usage, you'd only need to do something like this
  // on process shutdown.
  async function shutdown() {
    await subscriber.close();
    await processor.forceFlush();
    await new Promise(r => setTimeout(r, OTEL_TIMEOUT * 1000));
  }

  // Wait a bit for the subscription to receive messages, then shut down
  // gracefully. This is for the sample only; normally you would not need
  // this delay.
  await new Promise<void>(r =>
    setTimeout(async () => {
      subscriber.removeAllListeners();
      await shutdown();
      r();
    }, SUBSCRIBER_TIMEOUT * 1000)
  );
}

Node.js

/**
 * TODO(developer): Uncomment these variables before running the sample.
 */
// const subscriptionNameOrId = 'YOUR_SUBSCRIPTION_OR_ID';

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

// Imports the OpenTelemetry API
const {NodeTracerProvider} = require('@opentelemetry/sdk-trace-node');
const {diag, DiagConsoleLogger, DiagLogLevel} = require('@opentelemetry/api');
const {SimpleSpanProcessor} = require('@opentelemetry/sdk-trace-base');

// To output to the console for testing, use the ConsoleSpanExporter.
// import {ConsoleSpanExporter} from '@opentelemetry/sdk-trace-base';

// To output to Cloud Trace, import the OpenTelemetry bridge library.
const {
  TraceExporter,
} = require('@google-cloud/opentelemetry-cloud-trace-exporter');

const {Resource} = require('@opentelemetry/resources');
const {
  SEMRESATTRS_SERVICE_NAME,
} = require('@opentelemetry/semantic-conventions');

// Enable the diagnostic logger for OpenTelemetry
diag.setLogger(new DiagConsoleLogger(), DiagLogLevel.DEBUG);

// Log spans out to the console, for testing.
// const exporter = new ConsoleSpanExporter();

// Log spans out to Cloud Trace, for production.
const exporter = new TraceExporter();

// Build a tracer provider and a span processor to do
// something with the spans we're generating.
const provider = new NodeTracerProvider({
  resource: new Resource({
    [SEMRESATTRS_SERVICE_NAME]: 'otel subscriber example',
  }),
});
const processor = new SimpleSpanProcessor(exporter);
provider.addSpanProcessor(processor);
provider.register();

// Creates a client; cache this for further use.
const pubSubClient = new PubSub({enableOpenTelemetryTracing: true});

async function subscriptionListen(subscriptionNameOrId) {
  const subscriber = pubSubClient.subscription(subscriptionNameOrId);

  // Message handler for subscriber
  const messageHandler = async message => {
    console.log(`Message ${message.id} received.`);
    message.ack();
  };

  // Error handler for subscriber
  const errorHandler = async error => {
    console.log('Received error:', error);
  };

  // Listens for new messages from the topic
  subscriber.on('message', messageHandler);
  subscriber.on('error', errorHandler);

  // Ensures that all spans got flushed by the exporter. This function
  // is in service to making sure that any buffered Pub/Sub messages
  // and/or OpenTelemetry spans are properly flushed to the server
  // side. In normal usage, you'd only need to do something like this
  // on process shutdown.
  async function shutdown() {
    await subscriber.close();
    await processor.forceFlush();
    await new Promise(r => setTimeout(r, OTEL_TIMEOUT * 1000));
  }

  // Wait a bit for the subscription to receive messages, then shut down
  // gracefully. This is for the sample only; normally you would not need
  // this delay.
  await new Promise(r =>
    setTimeout(async () => {
      subscriber.removeAllListeners();
      await shutdown();
      r();
    }, SUBSCRIBER_TIMEOUT * 1000)
  );
}

Java

import com.google.cloud.opentelemetry.trace.TraceConfiguration;
import com.google.cloud.opentelemetry.trace.TraceExporter;
import com.google.cloud.pubsub.v1.AckReplyConsumer;
import com.google.cloud.pubsub.v1.MessageReceiver;
import com.google.cloud.pubsub.v1.Subscriber;
import com.google.pubsub.v1.ProjectSubscriptionName;
import com.google.pubsub.v1.PubsubMessage;
import io.opentelemetry.api.OpenTelemetry;
import io.opentelemetry.sdk.OpenTelemetrySdk;
import io.opentelemetry.sdk.resources.Resource;
import io.opentelemetry.sdk.trace.SdkTracerProvider;
import io.opentelemetry.sdk.trace.export.SimpleSpanProcessor;
import io.opentelemetry.sdk.trace.export.SpanExporter;
import io.opentelemetry.sdk.trace.samplers.Sampler;
import io.opentelemetry.semconv.ResourceAttributes;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;

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

    openTelemetrySubscriberExample(projectId, subscriptionId);
  }

  public static void openTelemetrySubscriberExample(String projectId, String subscriptionId) {
    Resource resource =
        Resource.getDefault()
            .toBuilder()
            .put(ResourceAttributes.SERVICE_NAME, "subscriber-example")
            .build();

    // Creates a Cloud Trace exporter.
    SpanExporter traceExporter =
        TraceExporter.createWithConfiguration(
            TraceConfiguration.builder().setProjectId(projectId).build());

    SdkTracerProvider sdkTracerProvider =
        SdkTracerProvider.builder()
            .setResource(resource)
            .addSpanProcessor(SimpleSpanProcessor.create(traceExporter))
            .setSampler(Sampler.alwaysOn())
            .build();

    OpenTelemetry openTelemetry =
        OpenTelemetrySdk.builder().setTracerProvider(sdkTracerProvider).buildAndRegisterGlobal();

    ProjectSubscriptionName subscriptionName =
        ProjectSubscriptionName.of(projectId, subscriptionId);

    // Instantiate an asynchronous message receiver.
    MessageReceiver receiver =
        (PubsubMessage message, AckReplyConsumer consumer) -> {
          // Handle incoming message, then ack the received message.
          System.out.println("Id: " + message.getMessageId());
          System.out.println("Data: " + message.getData().toStringUtf8());
          consumer.ack();
        };

    Subscriber subscriber = null;
    try {
      subscriber =
          Subscriber.newBuilder(subscriptionName, receiver)
              .setOpenTelemetry(openTelemetry)
              .setEnableOpenTelemetryTracing(true)
              .build();

      // Start the subscriber.
      subscriber.startAsync().awaitRunning();
      System.out.printf("Listening for messages on %s:\n", subscriptionName.toString());
      // Allow the subscriber to run for 30s unless an unrecoverable error occurs.
      subscriber.awaitTerminated(30, TimeUnit.SECONDS);
    } catch (TimeoutException timeoutException) {
      // Shut down the subscriber after 30s. Stop receiving messages.
      subscriber.stopAsync();
    }
  }
}

Analyser une trace

Les sections suivantes contiennent des informations détaillées sur la façon de suivre et d'analyser une trace dans la console Google Cloud .

Remarques

• Lors de la publication d'un lot de messages, la période RPC de publication est capturée dans une trace distincte.
• Un RPC de publication comporte plusieurs plages d'origine, car plusieurs appels de création peuvent entraîner un RPC de publication lorsqu'ils sont regroupés.

• Les segments d'OpenTelemetry peuvent avoir zéro ou un segment parent.

  Les délais représentant des opérations groupées, comme un lot de publication (qui devrait logiquement avoir plusieurs parents) ne peuvent pas être représentés à l'aide de zéro ou d'un seul délai parent.

Intervalles de suivi créés pendant le cycle de vie du message

L'image suivante montre un exemple de segments créés dans une seule trace pour un seul message.

Chaque intervalle peut comporter des attributs supplémentaires qui fournissent des informations supplémentaires, telles que la taille en octets du message et les informations sur la clé de tri.

Les attributs de span transmettent des métadonnées supplémentaires, telles que la clé de tri du message, l'ID du message et la taille du message.

Les plages de publication et d'abonnement principales sont complétées par des événements de plage, qui correspondent au moment où un appel réseau est émis et terminé.

Résoudre les problèmes courants

Les problèmes suivants peuvent entraîner des problèmes de traçage:

• Le compte de service que vous utilisez pour exporter des traces ne dispose pas du rôle roles/cloudtrace.agent requis.
• Le quota du nombre maximal de segments ingérés dans Cloud Trace a été atteint.
• Votre application est arrêtée sans appeler la fonction de vidage appropriée.

Étape suivante

• Bonnes pratiques concernant les abonnements
• Bonnes pratiques pour la publication