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.
Setting up your project
Follow the instructions in Creating a Guestbook Application to set up your environment, create a 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 always activate and use another Cloud Storage bucket if you want, but only 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:
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
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.
Setting bucket and object permissions
Downloading the client library
The App Engine client library for Cloud Storage is available via the
To download the library:
GOPATHif needed. If you are using Linux and macOS, you can set your
mkdir -p $HOME/go export GOPATH=$HOME/go
go get -u golang.org/x/oauth2 go get -u cloud.google.com/go/storage go get -u google.golang.org/appengine/...
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:
dev_appserver.pywith 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
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 Google 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.
- 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.