Module: Google::Cloud::Storage

Defined in:
lib/google/cloud/storage.rb,
lib/google/cloud/storage/file.rb,
lib/google/cloud/storage/bucket.rb,
lib/google/cloud/storage/errors.rb,
lib/google/cloud/storage/project.rb,
lib/google/cloud/storage/service.rb,
lib/google/cloud/storage/version.rb,
lib/google/cloud/storage/file/acl.rb,
lib/google/cloud/storage/file/list.rb,
lib/google/cloud/storage/bucket/acl.rb,
lib/google/cloud/storage/bucket/cors.rb,
lib/google/cloud/storage/bucket/list.rb,
lib/google/cloud/storage/credentials.rb,
lib/google/cloud/storage/file/verifier.rb

Overview

Google Cloud Storage

Google Cloud Storage is an Internet service to store data in Google's cloud. It allows world-wide storage and retrieval of any amount of data and at any time, taking advantage of Google's own reliable and fast networking infrastructure to perform data operations in a cost effective manner.

The goal of google-cloud is to provide a API that is comfortable to Rubyists. Authentication is handled by #storage. You can provide the project and credential information to connect to the Storage service, or if you are running on Google Compute Engine this configuration is taken care of for you.

require "google/cloud/storage"

storage = Google::Cloud::Storage.new(
  project: "my-todo-project",
  keyfile: "/path/to/keyfile.json"
)

bucket = storage.bucket "my-bucket"
file = bucket.file "path/to/my-file.ext"

You can learn more about various options for connection on the Authentication Guide.

To learn more about Cloud Storage, read the Google Cloud Storage Overview .

Retrieving Buckets

A Bucket is the container for your data. There is no limit on the number of buckets that you can create in a project. You can use buckets to organize and control access to your data. Each bucket has a unique name, which is how they are retrieved: (See Project#bucket)

require "google/cloud/storage"

storage = Google::Cloud::Storage.new

bucket = storage.bucket "my-todo-app"

You can also retrieve all buckets on a project: (See Project#buckets)

require "google/cloud/storage"

storage = Google::Cloud::Storage.new

all_buckets = storage.buckets

If you have a significant number of buckets, you may need to paginate through them: (See Bucket::List#token)

require "google/cloud/storage"

storage = Google::Cloud::Storage.new

all_buckets = []
tmp_buckets = storage.buckets
while tmp_buckets.any? do
  tmp_buckets.each do |bucket|
    all_buckets << bucket
  end
  # break loop if no more buckets available
  break if tmp_buckets.token.nil?
  # get the next group of buckets
  tmp_buckets = storage.buckets token: tmp_buckets.token
end

Creating a Bucket

A unique name is all that is needed to create a new bucket: (See Project#create_bucket)

require "google/cloud/storage"

storage = Google::Cloud::Storage.new

bucket = storage.create_bucket "my-todo-app-attachments"

Retrieving Files

A File is an individual pieces of data that you store in Google Cloud Storage. Files contain the data stored as well as metadata describing the data. Files belong to a bucket and cannot be shared among buckets. There is no limit on the number of objects that you can create in a bucket.

Files are retrieved by their name, which is the path of the file in the bucket: (See Bucket#file)

require "google/cloud/storage"

storage = Google::Cloud::Storage.new

bucket = storage.bucket "my-todo-app"
file = bucket.file "avatars/heidi/400x400.png"

You can also retrieve all files in a bucket: (See Bucket#files)

require "google/cloud/storage"

storage = Google::Cloud::Storage.new

bucket = storage.bucket "my-todo-app"
all_files = bucket.files

Or you can retrieve all files in a specified path:

require "google/cloud/storage"

storage = Google::Cloud::Storage.new

bucket = storage.bucket "my-todo-app"
avatar_files = bucket.files prefix: "avatars/"

If you have a significant number of files, you may need to paginate through them: (See File::List#token)

require "google/cloud/storage"

storage = Google::Cloud::Storage.new

bucket = storage.bucket "my-todo-app"

all_files = []
tmp_files = bucket.files
while tmp_files.any? do
  tmp_files.each do |file|
    all_files << file
  end
  # break loop if no more files available
  break if tmp_files.token.nil?
  # get the next group of files
  tmp_files = bucket.files token: tmp_files.token
end

Creating a File

A new File can be uploaded by specifying the location of a file on the local file system, and the name/path that the file should be stored in the bucket. (See Bucket#create_file)

require "google/cloud/storage"

storage = Google::Cloud::Storage.new

bucket = storage.bucket "my-todo-app"
bucket.create_file "/var/todo-app/avatars/heidi/400x400.png",
                   "avatars/heidi/400x400.png"

Customer-supplied encryption keys

By default, Google Cloud Storage manages server-side encryption keys on your behalf. However, a customer-supplied encryption key can be provided with the encryption_key option. If given, the same key must be provided to subsequently download or copy the file. If you use customer-supplied encryption keys, you must securely manage your keys and ensure that they are not lost. Also, please note that file metadata is not encrypted, with the exception of the CRC32C checksum and MD5 hash. The names of files and buckets are also not encrypted, and you can read or update the metadata of an encrypted file without providing the encryption key.

require "google/cloud/storage"
require "digest/sha2"

storage = Google::Cloud::Storage.new
bucket = storage.bucket "my-todo-app"

# Key generation shown for example purposes only. Write your own.
cipher = OpenSSL::Cipher.new "aes-256-cfb"
cipher.encrypt
key = cipher.random_key

bucket.create_file "/var/todo-app/avatars/heidi/400x400.png",
                   "avatars/heidi/400x400.png",
                   encryption_key: key

# Store your key and hash securely for later use.
file = bucket.file "avatars/heidi/400x400.png",
                   encryption_key: key

Downloading a File

Files can be downloaded to the local file system. (See File#download)

require "google/cloud/storage"

storage = Google::Cloud::Storage.new

bucket = storage.bucket "my-todo-app"
file = bucket.file "avatars/heidi/400x400.png"
file.download "/var/todo-app/avatars/heidi/400x400.png"

Using Signed URLs

Access without authentication can be granted to a File for a specified period of time. This URL uses a cryptographic signature of your credentials to access the file. (See File#signed_url)

require "google/cloud/storage"

storage = Google::Cloud::Storage.new

bucket = storage.bucket "my-todo-app"
file = bucket.file "avatars/heidi/400x400.png"
shared_url = file.signed_url method: "GET",
                             expires: 300 # 5 minutes from now

Controlling Access to a Bucket

Access to a bucket is controlled with Bucket#acl. A bucket has owners, writers, and readers. Permissions can be granted to an individual user's email address, a group's email address, as well as many predefined lists. See the Access Control guide for more.

Access to a bucket can be granted to a user by appending "user-" to the email address:

require "google/cloud/storage"

storage = Google::Cloud::Storage.new

bucket = storage.bucket "my-todo-app"

email = "heidi@example.net"
bucket.acl.add_reader "user-#{email}"

Access to a bucket can be granted to a group by appending "group-" to the email address:

require "google/cloud/storage"

storage = Google::Cloud::Storage.new

bucket = storage.bucket "my-todo-app"

email = "authors@example.net"
bucket.acl.add_reader "group-#{email}"

Access to a bucket can also be granted to a predefined list of permissions:

require "google/cloud/storage"

storage = Google::Cloud::Storage.new

bucket = storage.bucket "my-todo-app"

bucket.acl.public!

Controlling Access to a File

Access to a file is controlled in two ways, either by the setting the default permissions to all files in a bucket with Bucket#default_acl, or by setting permissions to an individual file with File#acl.

Access to a file can be granted to a user by appending "user-" to the email address:

require "google/cloud/storage"

storage = Google::Cloud::Storage.new

bucket = storage.bucket "my-todo-app"
file = bucket.file "avatars/heidi/400x400.png"

email = "heidi@example.net"
file.acl.add_reader "user-#{email}"

Access to a file can be granted to a group by appending "group-" to the email address:

require "google/cloud/storage"

storage = Google::Cloud::Storage.new

bucket = storage.bucket "my-todo-app"
file = bucket.file "avatars/heidi/400x400.png"

email = "authors@example.net"
file.acl.add_reader "group-#{email}"

Access to a file can also be granted to a predefined list of permissions:

require "google/cloud/storage"

storage = Google::Cloud::Storage.new

bucket = storage.bucket "my-todo-app"
file = bucket.file "avatars/heidi/400x400.png"

file.acl.public!

Configuring retries and timeout

You can configure how many times API requests may be automatically retried. When an API request fails, the response will be inspected to see if the request meets criteria indicating that it may succeed on retry, such as 500 and 503 status codes or a specific internal error code such as rateLimitExceeded. If it meets the criteria, the request will be retried after a delay. If another error occurs, the delay will be increased before a subsequent attempt, until the retries limit is reached.

You can also set the request timeout value in seconds.

require "google/cloud/storage"

storage = Google::Cloud::Storage.new retries: 10, timeout: 120

See the Storage status and error codes for a list of error conditions.

Defined Under Namespace

Classes: Bucket, File, FileVerificationError, Project, SignedUrlUnavailable

Constant Summary collapse

VERSION = 
"0.23.0"

Class Method Summary collapse

Class Method Details

.new(project: nil, keyfile: nil, scope: nil, retries: nil, timeout: nil) ⇒ Google::Cloud::Storage::Project

Creates a new object for connecting to the Storage service. Each call creates a new connection.

For more information on connecting to Google Cloud see the Authentication Guide.

Examples:

require "google/cloud/storage"

storage = Google::Cloud::Storage.new(
  project: "my-todo-project",
  keyfile: "/path/to/keyfile.json"
)

bucket = storage.bucket "my-bucket"
file = bucket.file "path/to/my-file.ext"

Parameters:

  • project (String) —

    Project identifier for the Storage service you are connecting to.

  • keyfile (String, Hash) —

    Keyfile downloaded from Google Cloud. If file path the file must be readable.

  • scope (String, Array<String>) —

    The OAuth 2.0 scopes controlling the set of resources and operations that the connection can access. See Using OAuth 2.0 to Access Google APIs.

    The default scope is:

    • https://www.googleapis.com/auth/devstorage.full_control
  • retries (Integer) —

    Number of times to retry requests on server error. The default value is 3. Optional.

  • timeout (Integer) —

    Default timeout to use in requests. Optional.

Returns:



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# File 'lib/google/cloud/storage.rb', line 426

def self.new project: nil, keyfile: nil, scope: nil, retries: nil,
             timeout: nil
  project ||= Google::Cloud::Storage::Project.default_project
  project = project.to_s # Always cast to a string
  fail ArgumentError, "project is missing" if project.empty?

  if keyfile.nil?
    credentials = Google::Cloud::Storage::Credentials.default scope: scope
  else
    credentials = Google::Cloud::Storage::Credentials.new(
      keyfile, scope: scope)
  end

  Google::Cloud::Storage::Project.new(
    Google::Cloud::Storage::Service.new(
      project, credentials, retries: retries, timeout: timeout))
end