Setting Up Google Cloud Storage

You can use a Cloud Storage bucket to store and serve files, such as movies or images or other static content. This document describes how to set up your environment to use the App Engine client library for Cloud Storage.

This API is supported for first-generation runtimes and can be used when upgrading to corresponding second-generation runtimes. If you are updating to the App Engine Go 1.12+ runtime, refer to the migration guide to learn about your migration options for legacy bundled services.

Setting up your project

Create a Google Cloud project, and understand how Go 1.11 apps are structured in App Engine. Write down and save your project ID for use with your application.

Activating a Cloud Storage bucket

To use Cloud Storage, you'll need to activate at least one bucket. You might want to use the default bucket which provides the first 5GB of storage for free. You can activate and use another Cloud Storage bucket. The default bucket includes the first 5GB of storage for free. The default bucket also includes a free quota for Cloud Storage I/O operations. See Pricing, quotas, and limits for more details.

To activate the default Cloud Storage bucket for your app:

1. Click Create under Default Cloud Storage Bucket in the App Engine settings page for your project. Notice the name of this bucket: it is in the form <project-id>.appspot.com.

2. If you need more storage than the 5GB limit, you can increase this by enabling billing for your project, making this a paid bucket. You will be charged for storage over the 5GB limit.

If you want to activate one or more paid buckets, follow the instructions under Creating a bucket to activate them.

Note: When you create a default bucket, you also get a staging bucket with the same name except that staging. is prepended to it. You can use this staging bucket for temporary files used for staging and test purposes; it also has a 5 GB limit, but it is automatically emptied on a weekly basis.

Setting bucket and object permissions

You can find information on allowing your app's service account or other users access the storage bucket and its contents in Setting bucket permissions and Setting object permissions.

Downloading the client library

The App Engine client library for Cloud Storage is available via the go tool. To download the library:

1. Set your GOPATH if needed. If you are using Linux and macOS, you can set your GOPATH as follows:

   mkdir -p $HOME/go
   export GOPATH=$HOME/go

   Note: For Windows instructions, see the Windows section of Getting Started with the Go Programming Language.

2. Download the oauth2, storage, and appengine packages:

   go get -u golang.org/x/oauth2
   go get -u cloud.google.com/go/storage
   go get -u google.golang.org/appengine/...

   Note: These packages will be downloaded to your GOPATH's src directory.

For details about installing the client library, see the Cloud Storage Client Libraries page.

Using the client library with the development app server

You can use the client library with the development server. However because there is no local emulation of Cloud Storage, all requests to read and write files must be sent over the Internet to an actual Cloud Storage bucket.

To use the client library with the development app server:

1. Activate a Cloud Storage bucket.

2. Run dev_appserver.py with the flag --default_gcs_bucket_name [BUCKET_NAME], replacing [BUCKET_NAME] with the name of the Cloud Storage bucket you are using.

   This flag controls the bucket that will be returned when your application calls file.DefaultBucketName(ctx).

Pricing, quotas, and limits

There are no bandwidth charges associated with making calls to Cloud Storage from App Engine's client library. However, there are operations charges. In addition, the calls count against your URL fetch quota as the library uses the URL Fetch service to interact with Cloud Storage.

Notice that Cloud Storage is a pay-to-use service; you will be charged according to the Cloud Storage price sheet.

Alternative ways to access Cloud Storage

Instead of using the client library, you could use the following:

• Cloud Storage Browser in the Google Cloud console, which is useful for uploading objects quickly.
• gsutil, which is a command-line tool for working with files in Cloud Storage.

What's next

• Visit the API Reference documentation.
• Learn how to read and write to Cloud Storage with the App Engine client library for Cloud Storage.
• Review the App Engine and Google Cloud Storage sample.
• View the complete set of Cloud Storage documentation, including additional samples and tutorials.