1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
|
# Copyright 2015 Google, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
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
NO_METADATA_SERVER_ERROR = <<~ERROR.freeze
Error code 404 trying to get security access token
from Compute Engine metadata for the default service account. This
may be because the virtual machine instance does not have permission
scopes specified.
ERROR
UNEXPECTED_ERROR_SUFFIX = <<~ERROR.freeze
trying to get security access token from Compute Engine metadata for
the default service account
ERROR
# 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.
DEFAULT_METADATA_HOST = "169.254.169.254".freeze
# @private Unused and deprecated
COMPUTE_AUTH_TOKEN_URI =
"http://169.254.169.254/computeMetadata/v1/instance/service-accounts/default/token".freeze
# @private Unused and deprecated
COMPUTE_ID_TOKEN_URI =
"http://169.254.169.254/computeMetadata/v1/instance/service-accounts/default/identity".freeze
# @private Unused and deprecated
COMPUTE_CHECK_URI = "http://169.254.169.254".freeze
class << self
extend Memoist
def metadata_host
ENV.fetch "GCE_METADATA_HOST", DEFAULT_METADATA_HOST
end
def compute_check_uri
"http://#{metadata_host}".freeze
end
def compute_auth_token_uri
"#{compute_check_uri}/computeMetadata/v1/instance/service-accounts/default/token".freeze
end
def compute_id_token_uri
"#{compute_check_uri}/computeMetadata/v1/instance/service-accounts/default/identity".freeze
end
# Detect if this appear to be a GCE instance, by checking if metadata
# is available.
def on_gce? options = {}
# TODO: This should use google-cloud-env instead.
c = options[:connection] || Faraday.default_connection
headers = { "Metadata-Flavor" => "Google" }
resp = c.get compute_check_uri, nil, headers do |req|
req.options.timeout = 1.0
req.options.open_timeout = 0.1
end
return false unless resp.status == 200
resp.headers["Metadata-Flavor"] == "Google"
rescue Faraday::TimeoutError, Faraday::ConnectionFailed
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
retry_with_error do
uri = target_audience ? GCECredentials.compute_id_token_uri : GCECredentials.compute_auth_token_uri
query = target_audience ? { "audience" => target_audience, "format" => "full" } : {}
query[:scopes] = Array(scope).join "," if scope
resp = c.get uri, query, "Metadata-Flavor" => "Google"
case resp.status
when 200
content_type = resp.headers["content-type"]
if ["text/html", "application/text"].include? content_type
{ (target_audience ? "id_token" : "access_token") => resp.body }
else
Signet::OAuth2.parse_credentials resp.body, content_type
end
when 403, 500
msg = "Unexpected error code #{resp.status} #{UNEXPECTED_ERROR_SUFFIX}"
raise Signet::UnexpectedStatusError, msg
when 404
raise Signet::AuthorizationError, NO_METADATA_SERVER_ERROR
else
msg = "Unexpected error code #{resp.status} #{UNEXPECTED_ERROR_SUFFIX}"
raise Signet::AuthorizationError, msg
end
end
end
end
end
end
|
