Cloud Storage Tutorial (1st gen)

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Note: This content applies only to Cloud Functions (1st gen). See Cloud Functions version comparison for more information.

For the 2nd gen version of this document, see the Cloud Storage tutorial (2nd gen).

This simple tutorial demonstrates writing, deploying, and triggering an Event-Driven Cloud Function with a Cloud Storage trigger to respond to Cloud Storage events.

Note: Events are delivered using Pub/Sub notifications from Cloud Storage. A bucket can have up to 10 notification configurations set to trigger for a specific event. Setting up too many notifications for the same bucket might exceed the notifications limit for the bucket and make it impossible to create a function, as indicated by the error Cloud Storage bucket ...: Pub/Sub notification limit reached. If you reach the limit, you can't create a function until you take remedial action, such as removing notifications.

If you're looking for code samples for using Cloud Storage itself, visit the Google Cloud sample browser.

Objectives

• Write and deploy an Event-Driven Cloud Function.
• Trigger the function by uploading a file to Cloud Storage.

Costs

In this document, you use the following billable components of Google Cloud:

• Cloud Functions
• Cloud Storage

To generate a cost estimate based on your projected usage, use the pricing calculator. New Google Cloud users might be eligible for a free trial.

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To follow step-by-step guidance for this task directly in the Cloud Shell Editor, click Guide me:

Guide me

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Before you begin

1. Sign in to your Google Cloud account. If you're new to Google Cloud, create an account to evaluate how our products perform in real-world scenarios. New customers also get $300 in free credits to run, test, and deploy workloads.

2. In the Google Cloud console, on the project selector page, select or create a Google Cloud project.

   Note: If you don't plan to keep the resources that you create in this procedure, create a project instead of selecting an existing project. After you finish these steps, you can delete the project, removing all resources associated with the project.

   Go to project selector

3. Make sure that billing is enabled for your Google Cloud project.

4. Enable the Cloud Functions, Cloud Build, Cloud Storage, and Eventarc APIs.

   Enable the APIs

5. Install the Google Cloud CLI.

6. To initialize the gcloud CLI, run the following command:

   gcloud init

7. In the Google Cloud console, on the project selector page, select or create a Google Cloud project.

   Note: If you don't plan to keep the resources that you create in this procedure, create a project instead of selecting an existing project. After you finish these steps, you can delete the project, removing all resources associated with the project.

   Go to project selector

8. Make sure that billing is enabled for your Google Cloud project.

9. Enable the Cloud Functions, Cloud Build, Cloud Storage, and Eventarc APIs.

   Enable the APIs

10. Install the Google Cloud CLI.

11. To initialize the gcloud CLI, run the following command:

    gcloud init

If you already have the gcloud CLI installed, update it by running the following command:

gcloud components update

Note: Make sure the runtime service account key you are using for your Application Default Credentials has either the cloudfunctions.serviceAgent role or the storage.buckets.{get, update} and the resourcemanager.projects.get permissions. For more information on setting these permissions, see Granting, changing, and revoking access to resources.
12. Prepare your development environment:

    Node.js

    Go to the Node.js setup guide

    Python

    Go to the Python setup guide

    Go

    Go to the Go setup guide

    Java

    Go to the Java setup guide

    C#

    Go to the .NET setup guide

    Ruby

    Go to the Ruby setup guide

    PHP

    Go to Using PHP on Google Cloud

Preparing the application

1. Create a Cloud Storage bucket to upload a test file, where YOUR_TRIGGER_BUCKET_NAME is a globally unique bucket name:

   gsutil mb gs://YOUR_TRIGGER_BUCKET_NAME
   

2. Clone the sample app repository to your local machine:

   Node.js

   git clone https://github.com/GoogleCloudPlatform/nodejs-docs-samples.git

   Alternatively, you can download the sample as a zip file and extract it.

   Python

   git clone https://github.com/GoogleCloudPlatform/python-docs-samples.git

   Alternatively, you can download the sample as a zip file and extract it.

   Go

   git clone https://github.com/GoogleCloudPlatform/golang-samples.git

   Alternatively, you can download the sample as a zip file and extract it.

   Java

   git clone https://github.com/GoogleCloudPlatform/java-docs-samples.git

   Alternatively, you can download the sample as a zip file and extract it.

   C#

   git clone https://github.com/GoogleCloudPlatform/dotnet-docs-samples.git

   Alternatively, you can download the sample as a zip file and extract it.

   Ruby

   git clone https://github.com/GoogleCloudPlatform/ruby-docs-samples.git

   Alternatively, you can download the sample as a zip file and extract it.

   PHP

   git clone https://github.com/GoogleCloudPlatform/php-docs-samples.git

   Alternatively, you can download the sample as a zip file and extract it.

3. Change to the directory that contains the Cloud Functions sample code:

   Node.js

   cd nodejs-docs-samples/functions/helloworld/

   Python

   cd python-docs-samples/functions/helloworld/

   Go

   cd golang-samples/functions/helloworld/

   Java

   cd java-docs-samples/functions/helloworld/hello-gcs/

   C#

   cd dotnet-docs-samples/functions/helloworld/HelloGcs/

   Ruby

   cd ruby-docs-samples/functions/helloworld/storage/

   PHP

   cd php-docs-samples/functions/helloworld_storage/

Deploying and triggering the function

Currently, Cloud Storage functions are based on Pub/Sub notifications from Cloud Storage and support similar event types:

• finalize

• delete

• archive

• metadata update

The following sections describe how to deploy and trigger a function for each of these event types.

Object Finalize

Object finalize events trigger when a "write" of a Cloud Storage Object is successfully finalized. In particular, this means that creating a new object or overwriting an existing object triggers this event. Archive and metadata update operations are ignored by this trigger.

Object Finalize: deploying the function

Take a look at the sample function, which handles Cloud Storage events:

Node.js

/**
 * Generic background Cloud Function to be triggered by Cloud Storage.
 * This sample works for all Cloud Storage CRUD operations.
 *
 * @param {object} file The Cloud Storage file metadata.
 * @param {object} context The event metadata.
 */
exports.helloGCS = (file, context) => {
  console.log(`  Event: ${context.eventId}`);
  console.log(`  Event Type: ${context.eventType}`);
  console.log(`  Bucket: ${file.bucket}`);
  console.log(`  File: ${file.name}`);
  console.log(`  Metageneration: ${file.metageneration}`);
  console.log(`  Created: ${file.timeCreated}`);
  console.log(`  Updated: ${file.updated}`);
};

Python

def hello_gcs(event, context):
    """Background Cloud Function to be triggered by Cloud Storage.
       This generic function logs relevant data when a file is changed,
       and works for all Cloud Storage CRUD operations.
    Args:
        event (dict):  The dictionary with data specific to this type of event.
                       The `data` field contains a description of the event in
                       the Cloud Storage `object` format described here:
                       https://cloud.google.com/storage/docs/json_api/v1/objects#resource
        context (google.cloud.functions.Context): Metadata of triggering event.
    Returns:
        None; the output is written to Cloud Logging
    """

    print(f"Event ID: {context.event_id}")
    print(f"Event type: {context.event_type}")
    print("Bucket: {}".format(event["bucket"]))
    print("File: {}".format(event["name"]))
    print("Metageneration: {}".format(event["metageneration"]))
    print("Created: {}".format(event["timeCreated"]))
    print("Updated: {}".format(event["updated"]))

Go

// Package helloworld provides a set of Cloud Functions samples.
package helloworld

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

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

// GCSEvent is the payload of a GCS event.
type GCSEvent struct {
	Kind                    string                 `json:"kind"`
	ID                      string                 `json:"id"`
	SelfLink                string                 `json:"selfLink"`
	Name                    string                 `json:"name"`
	Bucket                  string                 `json:"bucket"`
	Generation              string                 `json:"generation"`
	Metageneration          string                 `json:"metageneration"`
	ContentType             string                 `json:"contentType"`
	TimeCreated             time.Time              `json:"timeCreated"`
	Updated                 time.Time              `json:"updated"`
	TemporaryHold           bool                   `json:"temporaryHold"`
	EventBasedHold          bool                   `json:"eventBasedHold"`
	RetentionExpirationTime time.Time              `json:"retentionExpirationTime"`
	StorageClass            string                 `json:"storageClass"`
	TimeStorageClassUpdated time.Time              `json:"timeStorageClassUpdated"`
	Size                    string                 `json:"size"`
	MD5Hash                 string                 `json:"md5Hash"`
	MediaLink               string                 `json:"mediaLink"`
	ContentEncoding         string                 `json:"contentEncoding"`
	ContentDisposition      string                 `json:"contentDisposition"`
	CacheControl            string                 `json:"cacheControl"`
	Metadata                map[string]interface{} `json:"metadata"`
	CRC32C                  string                 `json:"crc32c"`
	ComponentCount          int                    `json:"componentCount"`
	Etag                    string                 `json:"etag"`
	CustomerEncryption      struct {
		EncryptionAlgorithm string `json:"encryptionAlgorithm"`
		KeySha256           string `json:"keySha256"`
	}
	KMSKeyName    string `json:"kmsKeyName"`
	ResourceState string `json:"resourceState"`
}

// HelloGCS consumes a(ny) GCS event.
func HelloGCS(ctx context.Context, e GCSEvent) error {
	meta, err := metadata.FromContext(ctx)
	if err != nil {
		return fmt.Errorf("metadata.FromContext: %w", err)
	}
	log.Printf("Event ID: %v\n", meta.EventID)
	log.Printf("Event type: %v\n", meta.EventType)
	log.Printf("Bucket: %v\n", e.Bucket)
	log.Printf("File: %v\n", e.Name)
	log.Printf("Metageneration: %v\n", e.Metageneration)
	log.Printf("Created: %v\n", e.TimeCreated)
	log.Printf("Updated: %v\n", e.Updated)
	return nil
}

Java

import com.google.cloud.functions.BackgroundFunction;
import com.google.cloud.functions.Context;
import functions.eventpojos.GcsEvent;
import java.util.logging.Logger;

/**
 * Example Cloud Storage-triggered function.
 * This function can process any event from Cloud Storage.
 */
public class HelloGcs implements BackgroundFunction<GcsEvent> {
  private static final Logger logger = Logger.getLogger(HelloGcs.class.getName());

  @Override
  public void accept(GcsEvent event, Context context) {
    logger.info("Event: " + context.eventId());
    logger.info("Event Type: " + context.eventType());
    logger.info("Bucket: " + event.getBucket());
    logger.info("File: " + event.getName());
    logger.info("Metageneration: " + event.getMetageneration());
    logger.info("Created: " + event.getTimeCreated());
    logger.info("Updated: " + event.getUpdated());
  }
}

C#

using CloudNative.CloudEvents;
using Google.Cloud.Functions.Framework;
using Google.Events.Protobuf.Cloud.Storage.V1;
using Microsoft.Extensions.Logging;
using System.Threading;
using System.Threading.Tasks;

namespace HelloGcs;

 /// <summary>
 /// Example Cloud Storage-triggered function.
 /// This function can process any event from Cloud Storage.
 /// </summary>
public class Function : ICloudEventFunction<StorageObjectData>
{
    private readonly ILogger _logger;

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

    public Task HandleAsync(CloudEvent cloudEvent, StorageObjectData data, CancellationToken cancellationToken)
    {
        _logger.LogInformation("Event: {event}", cloudEvent.Id);
        _logger.LogInformation("Event Type: {type}", cloudEvent.Type);
        _logger.LogInformation("Bucket: {bucket}", data.Bucket);
        _logger.LogInformation("File: {file}", data.Name);
        _logger.LogInformation("Metageneration: {metageneration}", data.Metageneration);
        _logger.LogInformation("Created: {created:s}", data.TimeCreated?.ToDateTimeOffset());
        _logger.LogInformation("Updated: {updated:s}", data.Updated?.ToDateTimeOffset());
        return Task.CompletedTask;
    }
}

Ruby

require "functions_framework"

FunctionsFramework.cloud_event "hello_gcs" do |event|
  # This function supports all Cloud Storage events.
  # 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 "Event: #{event.id}"
  logger.info "Event Type: #{event.type}"
  logger.info "Bucket: #{payload['bucket']}"
  logger.info "File: #{payload['name']}"
  logger.info "Metageneration: #{payload['metageneration']}"
  logger.info "Created: #{payload['timeCreated']}"
  logger.info "Updated: #{payload['updated']}"
end

PHP

use CloudEvents\V1\CloudEventInterface;
use Google\CloudFunctions\FunctionsFramework;

// Register the function with Functions Framework.
// This enables omitting the `FUNCTIONS_SIGNATURE_TYPE=cloudevent` environment
// variable when deploying. The `FUNCTION_TARGET` environment variable should
// match the first parameter.
FunctionsFramework::cloudEvent('helloGCS', 'helloGCS');

function helloGCS(CloudEventInterface $cloudevent)
{
    // This function supports all Cloud Storage event types.
    $log = fopen(getenv('LOGGER_OUTPUT') ?: 'php://stderr', 'wb');
    $data = $cloudevent->getData();
    fwrite($log, 'Event: ' . $cloudevent->getId() . PHP_EOL);
    fwrite($log, 'Event Type: ' . $cloudevent->getType() . PHP_EOL);
    fwrite($log, 'Bucket: ' . $data['bucket'] . PHP_EOL);
    fwrite($log, 'File: ' . $data['name'] . PHP_EOL);
    fwrite($log, 'Metageneration: ' . $data['metageneration'] . PHP_EOL);
    fwrite($log, 'Created: ' . $data['timeCreated'] . PHP_EOL);
    fwrite($log, 'Updated: ' . $data['updated'] . PHP_EOL);
}

To deploy the function, run the following command in the directory where the sample code is located:

Node.js

gcloud functions deploy helloGCS \
--runtime nodejs20 \
--trigger-resource YOUR_TRIGGER_BUCKET_NAME \
--trigger-event google.storage.object.finalize

Use the --runtime flag to specify the runtime ID of a supported Node.js version to run your function.

Python

gcloud functions deploy hello_gcs \
--runtime python312 \
--trigger-resource YOUR_TRIGGER_BUCKET_NAME \
--trigger-event google.storage.object.finalize

Use the --runtime flag to specify the runtime ID of a supported Python version to run your function.

Go

gcloud functions deploy HelloGCS \
--runtime go121 \
--trigger-resource YOUR_TRIGGER_BUCKET_NAME \
--trigger-event google.storage.object.finalize

Use the --runtime flag to specify the runtime ID of a supported Go version to run your function.

Java

gcloud functions deploy java-gcs-function \
--entry-point functions.HelloGcs \
--runtime java17 \
--memory 512MB \
--trigger-resource YOUR_TRIGGER_BUCKET_NAME \
--trigger-event google.storage.object.finalize

Use the --runtime flag to specify the runtime ID of a supported Java version to run your function.

C#

gcloud functions deploy csharp-gcs-function \
--entry-point HelloGcs.Function \
--runtime dotnet6 \
--trigger-resource YOUR_TRIGGER_BUCKET_NAME \
--trigger-event google.storage.object.finalize

Use the --runtime flag to specify the runtime ID of a supported .NET version to run your function.

Ruby

gcloud functions deploy hello_gcs --runtime ruby32 \
--trigger-resource YOUR_TRIGGER_BUCKET_NAME \
--trigger-event google.storage.object.finalize

Use the --runtime flag to specify the runtime ID of a supported Ruby version to run your function.

PHP

 gcloud functions deploy helloGCS --runtime php82 \
--trigger-resource YOUR_TRIGGER_BUCKET_NAME \
--trigger-event google.storage.object.finalize

Use the --runtime flag to specify the runtime ID of a supported PHP version to run your function.

where YOUR_TRIGGER_BUCKET_NAME is the name of the Cloud Storage bucket that triggers the function.

Object Finalize: triggering the function

To trigger the function:

1. Create an empty gcf-test.txt file in the directory where the sample code is located.

2. Upload the file to Cloud Storage in order to trigger the function:

   gsutil cp gcf-test.txt gs://YOUR_TRIGGER_BUCKET_NAME
   

   where YOUR_TRIGGER_BUCKET_NAME is the name of your Cloud Storage bucket where you will upload a test file.

3. Check the logs to make sure the executions have completed:

   gcloud functions logs read --limit 50
   

Object Delete

Object delete events are most useful for non-versioning buckets. They are triggered when an old version of an object is deleted. In addition, they are triggered when an object is overwritten. Object delete triggers can also be used with versioning buckets, triggering when a version of an object is permanently deleted.

Object Delete: deploying the function

Using the same sample code as in the finalize example, deploy the function with object delete as the trigger event. Run the following command in the directory where the sample code is located:

Node.js

gcloud functions deploy helloGCS \
--runtime nodejs20 \
--trigger-resource YOUR_TRIGGER_BUCKET_NAME \
--trigger-event google.storage.object.delete

Use the --runtime flag to specify the runtime ID of a supported Node.js version to run your function.

Python

gcloud functions deploy hello_gcs \
--runtime python312 \
--trigger-resource YOUR_TRIGGER_BUCKET_NAME \
--trigger-event google.storage.object.delete

Use the --runtime flag to specify the runtime ID of a supported Python version to run your function.

Go

gcloud functions deploy HelloGCS \
--runtime go121 \
--trigger-resource YOUR_TRIGGER_BUCKET_NAME \
--trigger-event google.storage.object.delete

Use the --runtime flag to specify the runtime ID of a supported Go version to run your function.

Java

gcloud functions deploy java-gcs-function \
--entry-point functions.HelloGcs \
--runtime java17 \
--memory 512MB \
--trigger-resource YOUR_TRIGGER_BUCKET_NAME \
--trigger-event google.storage.object.delete

Use the --runtime flag to specify the runtime ID of a supported Java version to run your function.

C#

gcloud functions deploy csharp-gcs-function \
--entry-point HelloGcs.Function \
--runtime dotnet6 \
--trigger-resource YOUR_TRIGGER_BUCKET_NAME \
--trigger-event google.storage.object.delete

Use the --runtime flag to specify the runtime ID of a supported .NET version to run your function.

Ruby

gcloud functions deploy hello_gcs --runtime ruby32 \
--trigger-resource YOUR_TRIGGER_BUCKET_NAME \
--trigger-event google.storage.object.delete

Use the --runtime flag to specify the runtime ID of a supported Ruby version to run your function.

PHP

 gcloud functions deploy helloGCS --runtime php82 \
--trigger-resource YOUR_TRIGGER_BUCKET_NAME \
--trigger-event google.storage.object.delete

Use the --runtime flag to specify the runtime ID of a supported PHP version to run your function.

where YOUR_TRIGGER_BUCKET_NAME is the name of the Cloud Storage bucket that triggers the function.

Object Delete: triggering the function

To trigger the function:

1. Create an empty gcf-test.txt file in the directory where the sample code is located.

2. Make sure that your bucket is non-versioning:

   gsutil versioning set off gs://YOUR_TRIGGER_BUCKET_NAME
   

3. Upload the file to Cloud Storage:

   gsutil cp gcf-test.txt gs://YOUR_TRIGGER_BUCKET_NAME
   

   where YOUR_TRIGGER_BUCKET_NAME is the name of your Cloud Storage bucket where you will upload a test file. At this point the function should not execute yet.

4. Delete the file to trigger the function:

   gsutil rm gs://YOUR_TRIGGER_BUCKET_NAME/gcf-test.txt
   

5. Check the logs to make sure the executions have completed:

   gcloud functions logs read --limit 50
   

Note that the function may take some time to finish executing.

Object Archive

Object archive events can be used only with versioning buckets. They are triggered when an old version of an object is archived. In particular, this means that when an object is overwritten or deleted, an archive event is triggered.

Object Archive: deploying the function

Using the same sample code as in the finalize example, deploy the function with object archive as the trigger event. Run the following command in the directory where the sample code is located:

Node.js

gcloud functions deploy helloGCS \
--runtime nodejs20 \
--trigger-resource YOUR_TRIGGER_BUCKET_NAME \
--trigger-event google.storage.object.archive

Use the --runtime flag to specify the runtime ID of a supported Node.js version to run your function.

Python

gcloud functions deploy hello_gcs \
--runtime python312 \
--trigger-resource YOUR_TRIGGER_BUCKET_NAME \
--trigger-event google.storage.object.archive

Use the --runtime flag to specify the runtime ID of a supported Python version to run your function.

Go

gcloud functions deploy HelloGCS \
--runtime go121 \
--trigger-resource YOUR_TRIGGER_BUCKET_NAME \
--trigger-event google.storage.object.archive

Use the --runtime flag to specify the runtime ID of a supported Go version to run your function.

Java

gcloud functions deploy java-gcs-function \
--entry-point functions.HelloGcs \
--runtime java17 \
--memory 512MB \
--trigger-resource YOUR_TRIGGER_BUCKET_NAME \
--trigger-event google.storage.object.archive

Use the --runtime flag to specify the runtime ID of a supported Java version to run your function.

C#

gcloud functions deploy csharp-gcs-function \
--entry-point HelloGcs.Function \
--runtime dotnet6 \
--trigger-resource YOUR_TRIGGER_BUCKET_NAME \
--trigger-event google.storage.object.archive

Use the --runtime flag to specify the runtime ID of a supported .NET version to run your function.

Ruby

gcloud functions deploy hello_gcs --runtime ruby32 \
--trigger-resource YOUR_TRIGGER_BUCKET_NAME \
--trigger-event google.storage.object.archive

Use the --runtime flag to specify the runtime ID of a supported Ruby version to run your function.

PHP

 gcloud functions deploy helloGCS --runtime php82 \
--trigger-resource YOUR_TRIGGER_BUCKET_NAME \
--trigger-event google.storage.object.archive

Use the --runtime flag to specify the runtime ID of a supported PHP version to run your function.

where YOUR_TRIGGER_BUCKET_NAME is the name of the Cloud Storage bucket that triggers the function.

Object Archive: triggering the function

To trigger the function:

1. Create an empty gcf-test.txt file in the directory where the sample code is located.

2. Make sure that your bucket has versioning enabled:

   gsutil versioning set on gs://YOUR_TRIGGER_BUCKET_NAME
   

3. Upload the file to Cloud Storage:

   gsutil cp gcf-test.txt gs://YOUR_TRIGGER_BUCKET_NAME
   

   where YOUR_TRIGGER_BUCKET_NAME is the name of your Cloud Storage bucket where you will upload a test file. At this point the function should not execute yet.

4. Archive the file to trigger the function:

   gsutil rm gs://YOUR_TRIGGER_BUCKET_NAME/gcf-test.txt
   

5. Watch the logs to make sure the executions have completed:

   gcloud functions logs read --limit 50
   

Object Metadata Update

Metadata update events are triggered when the metadata of existing object is updated.

Object Metadata Update: deploying the function

Using the same sample code as in the finalize example, deploy the function with metadata update as the trigger event. Run the following command in the directory where the sample code is located:

Node.js

gcloud functions deploy helloGCS \
--runtime nodejs20 \
--trigger-resource YOUR_TRIGGER_BUCKET_NAME \
--trigger-event google.storage.object.metadataUpdate

Use the --runtime flag to specify the runtime ID of a supported Node.js version to run your function.

Python

gcloud functions deploy hello_gcs \
--runtime python312 \
--trigger-resource YOUR_TRIGGER_BUCKET_NAME \
--trigger-event google.storage.object.metadataUpdate

Use the --runtime flag to specify the runtime ID of a supported Python version to run your function.

Go

gcloud functions deploy HelloGCS \
--runtime go121 \
--trigger-resource YOUR_TRIGGER_BUCKET_NAME \
--trigger-event google.storage.object.metadataUpdate

Use the --runtime flag to specify the runtime ID of a supported Go version to run your function.

Java

gcloud functions deploy java-gcs-function \
--entry-point functions.HelloGcs \
--runtime java17 \
--memory 512MB \
--trigger-resource YOUR_TRIGGER_BUCKET_NAME \
--trigger-event google.storage.object.metadataUpdate

Use the --runtime flag to specify the runtime ID of a supported Java version to run your function.

C#

gcloud functions deploy csharp-gcs-function \
--entry-point HelloGcs.Function \
--runtime dotnet6 \
--trigger-resource YOUR_TRIGGER_BUCKET_NAME \
--trigger-event google.storage.object.metadataUpdate

Use the --runtime flag to specify the runtime ID of a supported .NET version to run your function.

Ruby

gcloud functions deploy hello_gcs --runtime ruby32 \
--trigger-resource YOUR_TRIGGER_BUCKET_NAME \
--trigger-event google.storage.object.metadataUpdate

Use the --runtime flag to specify the runtime ID of a supported Ruby version to run your function.

PHP

 gcloud functions deploy helloGCS --runtime php82 \
--trigger-resource YOUR_TRIGGER_BUCKET_NAME \
--trigger-event google.storage.object.metadataUpdate

Use the --runtime flag to specify the runtime ID of a supported PHP version to run your function.

where YOUR_TRIGGER_BUCKET_NAME is the name of the Cloud Storage bucket that triggers the function.

Object Metadata Update: triggering the function

To trigger the function:

1. Create an empty gcf-test.txt file in the directory where the sample code is located.

2. Make sure that your bucket is non-versioning:

   gsutil versioning set off gs://YOUR_TRIGGER_BUCKET_NAME
   

3. Upload the file to Cloud Storage:

   gsutil cp gcf-test.txt gs://YOUR_TRIGGER_BUCKET_NAME
   

   where YOUR_TRIGGER_BUCKET_NAME is the name of your Cloud Storage bucket where you will upload a test file. At this point the function should not execute yet.

4. Update the metadata of the file:

   gsutil -m setmeta -h "Content-Type:text/plain" gs://YOUR_TRIGGER_BUCKET_NAME/gcf-test.txt
   

5. Watch the logs to make sure the executions have completed:

   gcloud functions logs read --limit 50
   

Clean up

To avoid incurring charges to your Google Cloud account for the resources used in this tutorial, either delete the project that contains the resources, or keep the project and delete the individual resources.

Deleting the project

The easiest way to eliminate billing is to delete the project that you created for the tutorial.

To delete the project:

Caution: Deleting a project has the following effects:

• Everything in the project is deleted. If you used an existing project for the tasks in this document, when you delete it, you also delete any other work you've done in the project.
• Custom project IDs are lost. When you created this project, you might have created a custom project ID that you want to use in the future. To preserve the URLs that use the project ID, such as an appspot.com URL, delete selected resources inside the project instead of deleting the whole project.

If you plan to explore multiple architectures, tutorials, or quickstarts, reusing projects can help you avoid exceeding project quota limits.

1. In the Google Cloud console, go to the Manage resources page.

   Go to Manage resources

2. In the project list, select the project that you want to delete, and then click Delete.
3. In the dialog, type the project ID, and then click Shut down to delete the project.

Deleting the Cloud Function

Deleting Cloud Functions does not remove any resources stored in Cloud Storage.

To delete the Cloud Function you created in this tutorial, run the following command:

Node.js

gcloud functions delete helloGCS 

Python

gcloud functions delete hello_gcs 

Go

gcloud functions delete HelloGCS 

Java

gcloud functions delete java-gcs-function 

C#

gcloud functions delete csharp-gcs-function 

Ruby

gcloud functions delete hello_gcs 

PHP

gcloud functions delete helloGCS 

You can also delete Cloud Functions from the Google Cloud console.

What's next

• Learn how to perform OCR on images uploaded to a bucket.
• Learn how to translate text files using Cloud Functions.