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

87 lines
3.7 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 'faraday'
require 'googleauth/signet'
require 'memoist'
module Google
# Module Auth provides classes that provide Google-specific authorization
# used to access Google APIs.
module Auth
# Extends Signet::OAuth2::Client so that the auth token is obtained from
# the GCE metadata server.
class GCECredentials < Signet::OAuth2::Client
# The IP Address is used in the URIs to speed up failures on non-GCE
# systems.
COMPUTE_AUTH_TOKEN_URI = 'http://169.254.169.254/computeMetadata/v1/'\
'instance/service-accounts/default/token'
COMPUTE_CHECK_URI = 'http://169.254.169.254'
class << self
extend Memoist
# Detect if this appear to be a GCE instance, by checking if metadata
# is available
def on_gce?(options = {})
c = options[:connection] || Faraday.default_connection
resp = c.get(COMPUTE_CHECK_URI) do |req|
# Comment from: oauth2client/client.py
#
# Note: the explicit `timeout` below is a workaround. The underlying
# issue is that resolving an unknown host on some networks will take
# 20-30 seconds; making this timeout short fixes the issue, but
# could lead to false negatives in the event that we are on GCE, but
# the metadata resolution was particularly slow. The latter case is
# "unlikely".
req.options.timeout = 0.1
end
return false unless resp.status == 200
return false unless resp.headers.key?('Metadata-Flavor')
return resp.headers['Metadata-Flavor'] == 'Google'
rescue Faraday::TimeoutError, Faraday::ConnectionFailed
return false
end
memoize :on_gce?
end
# Overrides the super class method to change how access tokens are
# fetched.
def fetch_access_token(options = {})
c = options[:connection] || Faraday.default_connection
c.headers = { 'Metadata-Flavor' => 'Google' }
resp = c.get(COMPUTE_AUTH_TOKEN_URI)
Signet::OAuth2.parse_credentials(resp.body,
resp.headers['content-type'])
end
end
end
end