Um die Suche zu vereinfachen und die Dokumentation zu verbessern, teilen wir die Dokumentation der 1. Generation und der 2. Generation in separate Gruppen ein.

Unendliche Wiederholungsversuche in Cloud Functions vermeiden

In diesem Beispiel wird gezeigt, wie Sie unendliche Wiederholungsversuche in Cloud Functions vermeiden, indem die Funktion nur innerhalb eines bestimmten Zeitraums nach dem Auslöseereignis ausgeführt wird.

Weitere Informationen

Eine ausführliche Dokumentation, die dieses Codebeispiel enthält, finden Sie hier:

Ereignisgesteuerte Funktionswiederholungen aktivieren

Codebeispiel

Go

Richten Sie die Standardanmeldedaten für Anwendungen ein, um sich bei Cloud Run Functions zu authentifizieren. Weitere Informationen finden Sie unter Authentifizierung für eine lokale Entwicklungsumgebung einrichten.


// Package tips contains tips for writing Cloud Functions in Go.
package tips

import (
	"context"
	"fmt"
	"log"
	"time"

	"github.com/GoogleCloudPlatform/functions-framework-go/functions"
	"github.com/cloudevents/sdk-go/v2/event"
)

func init() {
	functions.CloudEvent("FiniteRetryPubSub", FiniteRetryPubSub)
}

// MessagePublishedData contains the full Pub/Sub message
// See the documentation for more details:
// https://cloud.google.com/eventarc/docs/cloudevents#pubsub
type MessagePublishedData struct {
	Message PubSubMessage
}

// PubSubMessage is the payload of a Pub/Sub event.
// See the documentation for more details:
// https://cloud.google.com/pubsub/docs/reference/rest/v1/PubsubMessage
type PubSubMessage struct {
	Data []byte `json:"data"`
}

// FiniteRetryPubSub demonstrates how to avoid inifinite retries.
func FiniteRetryPubSub(ctx context.Context, e event.Event) error {
	var msg MessagePublishedData
	if err := e.DataAs(&msg); err != nil {
		return fmt.Errorf("event.DataAs: %w", err)
	}

	// Ignore events that are too old.
	expiration := e.Time().Add(10 * time.Second)
	if time.Now().After(expiration) {
		log.Printf("event timeout: halting retries for expired event '%q'", e.ID())
		return nil
	}

	// Add your message processing logic.
	return processTheMessage(msg)
}

Java


import com.google.cloud.functions.CloudEventsFunction;
import io.cloudevents.CloudEvent;
import java.time.Duration;
import java.time.ZoneOffset;
import java.time.ZonedDateTime;
import java.util.logging.Logger;

public class RetryTimeout implements CloudEventsFunction {
  private static final Logger logger = Logger.getLogger(RetryTimeout.class.getName());
  private static final long MAX_EVENT_AGE = 10_000;

  /**
   * Cloud Event Function that only executes within
   * a certain time period after the triggering event
   */
  @Override
  public void accept(CloudEvent event) throws Exception {
    ZonedDateTime utcNow = ZonedDateTime.now(ZoneOffset.UTC);
    ZonedDateTime timestamp = event.getTime().atZoneSameInstant(ZoneOffset.UTC);

    long eventAge = Duration.between(timestamp, utcNow).toMillis();

    // Ignore events that are too old
    if (eventAge > MAX_EVENT_AGE) {
      logger.info(String.format("Dropping event with timestamp %s.", timestamp));
      return;
    }

    // Process events that are recent enough
    // To retry this invocation, throw an exception here
    logger.info(String.format("Processing event with timestamp %s.", timestamp));
  }
}

Node.js

const functions = require('@google-cloud/functions-framework');

/**
 * Cloud Event Function that only executes within
 * a certain time period after the triggering event
 *
 * @param {object} event The Cloud Functions event.
 * @param {function} callback The callback function.
 */
functions.cloudEvent('avoidInfiniteRetries', (event, callback) => {
  const eventAge = Date.now() - Date.parse(event.time);
  const eventMaxAge = 10000;

  // Ignore events that are too old
  if (eventAge > eventMaxAge) {
    console.log(`Dropping event ${event} with age ${eventAge} ms.`);
    callback();
    return;
  }

  // Do what the function is supposed to do
  console.log(`Processing event ${event} with age ${eventAge} ms.`);

  // Retry failed function executions
  const failed = false;
  if (failed) {
    callback('some error');
  } else {
    callback();
  }
});

Python

from datetime import datetime, timezone

# The 'python-dateutil' package must be included in requirements.txt.
from dateutil import parser

import functions_framework


@functions_framework.cloud_event
def avoid_infinite_retries(cloud_event):
    """Cloud Event Function that only executes within a certain
    time period after the triggering event.

    Args:
        cloud_event: The cloud event associated with the current trigger
    Returns:
        None; output is written to Stackdriver Logging
    """
    timestamp = cloud_event["time"]

    event_time = parser.parse(timestamp)
    event_age = (datetime.now(timezone.utc) - event_time).total_seconds()
    event_age_ms = event_age * 1000

    # Ignore events that are too old
    max_age_ms = 10000
    if event_age_ms > max_age_ms:
        print("Dropped {} (age {}ms)".format(cloud_event["id"], event_age_ms))
        return "Timeout"

    # Do what the function is supposed to do
    print("Processed {} (age {}ms)".format(cloud_event["id"], event_age_ms))
    return  # To retry the execution, raise an exception here

Nächste Schritte

Informationen zum Suchen und Filtern von Codebeispielen für andere Google Cloud-Produkte finden Sie im Google Cloud-Beispielbrowser.