Cloud Functions cambió de nombre a Cloud Run Functions. Para obtener más información, consulta la entrada de blog sobre Cloud Run Functions.

Activador de Firestore

Activa una función en respuesta a una actualización de la base de datos de Firestore.

Explora más

Para obtener documentación en la que se incluye esta muestra de código, consulta lo siguiente:

Activadores de Google Cloud Firestore (1st gen)

Muestra de código

C#

Para autenticarte en funciones de Cloud Run, configura las credenciales predeterminadas de la aplicación. Si deseas obtener más información, consulta Configura la autenticación para un entorno de desarrollo local.

using CloudNative.CloudEvents;
using Google.Cloud.Functions.Framework;
using Google.Events.Protobuf.Cloud.Firestore.V1;
using Microsoft.Extensions.Logging;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;

namespace FirebaseFirestore;

public class Function : ICloudEventFunction<DocumentEventData>
{
    private readonly ILogger _logger;

    public Function(ILogger<Function> logger) =>
        _logger = logger;

    public Task HandleAsync(CloudEvent cloudEvent, DocumentEventData data, CancellationToken cancellationToken)
    {
        _logger.LogInformation("Function triggered by event on {subject}", cloudEvent.Subject);
        _logger.LogInformation("Event type: {type}", cloudEvent.Type);
        MaybeLogDocument("Old value", data.OldValue);
        MaybeLogDocument("New value", data.Value);

        // In this example, we don't need to perform any asynchronous operations, so the
        // method doesn't need to be declared async.
        return Task.CompletedTask;
    }

    /// <summary>
    /// Logs the names and values of the fields in a document in a very simplistic way.
    /// </summary>
    private void MaybeLogDocument(string message, Document document)
    {
        if (document is null)
        {
            return;
        }

        // ConvertFields converts the Firestore representation into a .NET-friendly
        // representation.
        IReadOnlyDictionary<string, object> fields = document.ConvertFields();
        var fieldNamesAndTypes = fields
            .OrderBy(pair => pair.Key)
            .Select(pair => $"{pair.Key}: {pair.Value}");
        _logger.LogInformation(message + ": {fields}", string.Join(", ", fieldNamesAndTypes));
    }
}

Go


// Package hello contains a Cloud Function triggered by a Firestore event.
package hello

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

	"cloud.google.com/go/functions/metadata"
)

// FirestoreEvent is the payload of a Firestore event.
type FirestoreEvent struct {
	OldValue   FirestoreValue `json:"oldValue"`
	Value      FirestoreValue `json:"value"`
	UpdateMask struct {
		FieldPaths []string `json:"fieldPaths"`
	} `json:"updateMask"`
}

// FirestoreValue holds Firestore fields.
type FirestoreValue struct {
	CreateTime time.Time `json:"createTime"`
	// Fields is the data for this value. The type depends on the format of your
	// database. Log the interface{} value and inspect the result to see a JSON
	// representation of your database fields.
	Fields     interface{} `json:"fields"`
	Name       string      `json:"name"`
	UpdateTime time.Time   `json:"updateTime"`
}

// HelloFirestore is triggered by a change to a Firestore document.
func HelloFirestore(ctx context.Context, e FirestoreEvent) error {
	meta, err := metadata.FromContext(ctx)
	if err != nil {
		return fmt.Errorf("metadata.FromContext: %w", err)
	}
	log.Printf("Function triggered by change to: %v", meta.Resource)
	log.Printf("Old value: %+v", e.OldValue)
	log.Printf("New value: %+v", e.Value)
	return nil
}

Java

import com.google.cloud.functions.Context;
import com.google.cloud.functions.RawBackgroundFunction;
import com.google.gson.Gson;
import com.google.gson.JsonObject;
import java.util.logging.Logger;

public class FirebaseFirestore implements RawBackgroundFunction {
  private static final Logger logger = Logger.getLogger(FirebaseFirestore.class.getName());

  // Use GSON (https://github.com/google/gson) to parse JSON content.
  private static final Gson gson = new Gson();

  @Override
  public void accept(String json, Context context) {
    JsonObject body = gson.fromJson(json, JsonObject.class);
    logger.info("Function triggered by event on: " + context.resource());
    logger.info("Event type: " + context.eventType());

    if (body != null && body.has("oldValue")) {
      logger.info("Old value:");
      logger.info(body.get("oldValue").getAsString());
    }

    if (body != null && body.has("value")) {
      logger.info("New value:");
      logger.info(body.get("value").getAsString());
    }
  }
}

Node.js

/**
 * Background Function triggered by a change to a Firestore document.
 *
 * @param {!Object} event The Cloud Functions event.
 * @param {!Object} context Cloud Functions event metadata.
 */
exports.helloFirestore = (event, context) => {
  const triggerResource = context.resource;

  console.log(`Function triggered by event on: ${triggerResource}`);
  console.log(`Event type: ${context.eventType}`);

  if (event.oldValue && Object.keys(event.oldValue).length) {
    console.log('\nOld value:');
    console.log(JSON.stringify(event.oldValue, null, 2));
  }

  if (event.value && Object.keys(event.value).length) {
    console.log('\nNew value:');
    console.log(JSON.stringify(event.value, null, 2));
  }
};

PHP


use Google\CloudFunctions\CloudEvent;

function firebaseFirestore(CloudEvent $cloudevent)
{
    $log = fopen(getenv('LOGGER_OUTPUT') ?: 'php://stderr', 'wb');

    fwrite($log, 'Event: ' . $cloudevent->getId() . PHP_EOL);
    fwrite($log, 'Event Type: ' . $cloudevent->getType() . PHP_EOL);

    $data = $cloudevent->getData();

    $resource = $data['resource'];
    fwrite($log, 'Function triggered by event on: ' . $resource . PHP_EOL);

    if (isset($data['oldValue'])) {
        fwrite($log, 'Old value: ' . json_encode($data['oldValue']) . PHP_EOL);
    }

    if (isset($data['value'])) {
        fwrite($log, 'New value: ' . json_encode($data['value']) . PHP_EOL);
    }
}

Python

import json

def hello_firestore(data, context):
    """Triggered by a change to a Firestore document.
    Args:
        data (dict): The event payload.
        context (google.cloud.functions.Context): Metadata for the event.
    """
    trigger_resource = context.resource

    print("Function triggered by change to: %s" % trigger_resource)

    print("\nOld value:")
    print(json.dumps(data["oldValue"]))

    print("\nNew value:")
    print(json.dumps(data["value"]))

Ruby

require "functions_framework"

# Triggered by a change to a Firestore document.
FunctionsFramework.cloud_event "hello_firestore" do |event|
  # The event parameter is a CloudEvents::Event::V1 object.
  # See https://cloudevents.github.io/sdk-ruby/latest/CloudEvents/Event/V1.html
  payload = event.data

  logger.info "Function triggered by change to: #{event.source}"
  logger.info "Old value: #{payload['oldValue']}"
  logger.info "New value: #{payload['value']}"
end

¿Qué sigue?

Para buscar y filtrar muestras de código para otros productos de Google Cloud, consulta el navegador de muestra de Google Cloud.