google-auth-library-ruby/lib/googleauth/service_account.rb

116 lines
4.6 KiB
Ruby

# Copyright 2015, Google Inc.
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
# * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# * Redistributions in binary form must reproduce the above
# copyright notice, this list of conditions and the following disclaimer
# in the documentation and/or other materials provided with the
# distribution.
# * Neither the name of Google Inc. nor the names of its
# contributors may be used to endorse or promote products derived from
# this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
require 'googleauth/signet'
require 'memoist'
require 'multi_json'
require 'openssl'
require 'rbconfig'
# Reads the private key and client email fields from service account JSON key.
def read_json_key(json_key_io)
json_key = MultiJson.load(json_key_io.read)
fail 'missing client_email' unless json_key.key?('client_email')
fail 'missing private_key' unless json_key.key?('private_key')
[json_key['private_key'], json_key['client_email']]
end
module Google
# Module Auth provides classes that provide Google-specific authorization
# used to access Google APIs.
module Auth
# Authenticates requests using Google's Service Account credentials.
#
# This class allows authorizing requests for service accounts directly
# from credentials from a json key file downloaded from the developer
# console (via 'Generate new Json Key').
#
# cf [Application Default Credentials](http://goo.gl/mkAHpZ)
class ServiceAccountCredentials < Signet::OAuth2::Client
ENV_VAR = 'GOOGLE_APPLICATION_CREDENTIALS'
NOT_FOUND_PREFIX =
"Unable to read the credential file specified by #{ENV_VAR}"
TOKEN_CRED_URI = 'https://www.googleapis.com/oauth2/v3/token'
WELL_KNOWN_PATH = 'gcloud/application_default_credentials.json'
WELL_KNOWN_PREFIX = 'Unable to read the default credential file'
class << self
extend Memoist
# determines if the current OS is windows
def windows?
RbConfig::CONFIG['host_os'] =~ /Windows|mswin/
end
memoize :windows?
# Creates an instance from the path specified in an environment
# variable.
#
# @param scope [string|array] the scope(s) to access
def from_env(scope)
return nil unless ENV.key?(ENV_VAR)
path = ENV[ENV_VAR]
fail 'file #{path} does not exist' unless File.exist?(path)
return new(scope, File.open(path))
rescue StandardError => e
raise "#{NOT_FOUND_PREFIX}: #{e}"
end
# Creates an instance from a well known path.
#
# @param scope [string|array] the scope(s) to access
def from_well_known_path(scope)
home_var = windows? ? 'APPDATA' : 'HOME'
root = ENV[home_var].nil? ? '' : ENV[home_var]
base = WELL_KNOWN_PATH
base = File.join('.config', base) unless windows?
path = File.join(root, base)
return nil unless File.exist?(path)
return new(scope, File.open(path))
rescue StandardError => e
raise "#{WELL_KNOWN_PREFIX}: #{e}"
end
end
# Initializes a ServiceAccountCredentials.
#
# @param scope [string|array] the scope(s) to access
# @param json_key_io [IO] an IO from which the JSON key can be read
def initialize(scope, json_key_io)
private_key, client_email = read_json_key(json_key_io)
super(token_credential_uri: TOKEN_CRED_URI,
audience: TOKEN_CRED_URI, # TODO: confirm this
scope: scope,
issuer: client_email,
signing_key: OpenSSL::PKey::RSA.new(private_key))
end
end
end
end