chore: Add tests for ExternalAccount, add methods required to make te…

…st compatible with apply_auth_examples. ExternalAccount was not fully compatible with the other providers, this brings it in line and moves some common methods between the other provides and ExternalAccount into a module which is now included by the AWSClient provider and Signet::Auth::Client

lib/googleauth/base_client.rb

@@ -0,0 +1,76 @@
+# 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 "os"
+
+module Google
+  # Module Auth provides classes that provide Google-specific authorization
+  # used to access Google APIs.
+  module Auth
+    # BaseClient is a class used to contain common methods that are required by any
+    # Credentials Client, including AwsCredentials, ServiceAccountCredentials,
+    # and UserRefreshCredentials.
+    module BaseClient
+      AUTH_METADATA_KEY = :authorization
+
+      # Updates a_hash updated with the authentication token
+      def apply! a_hash, opts = {}
+        # fetch the access token there is currently not one, or if the client
+        # has expired
+        fetch_access_token! opts if needs_access_token?
+        a_hash[AUTH_METADATA_KEY] = "Bearer #{send token_type}"
+      end
+
+      # Returns a clone of a_hash updated with the authentication token
+      def apply a_hash, opts = {}
+        a_copy = a_hash.clone
+        apply! a_copy, opts
+        a_copy
+      end
+
+      # Whether the id_token or access_token is missing or about to expire.
+      def needs_access_token?
+        send(token_type).nil? || expires_within?(60)
+      end
+
+      # Returns a reference to the #apply method, suitable for passing as
+      # a closure
+      def updater_proc
+        proc { |a_hash, opts = {}| apply a_hash, opts }
+      end
+
+      def on_refresh &block
+        @refresh_listeners = [] unless defined? @refresh_listeners
+        @refresh_listeners << block
+      end
+
+      def notify_refresh_listeners
+        listeners = defined?(@refresh_listeners) ? @refresh_listeners : []
+        listeners.each do |block|
+          block.call self
+        end
+      end
+
+      def expires_within?
+        raise "This method must be implemented by a subclass"
+      end
+
+      private
+
+      def token_type
+        raise "This method must be implemented by a subclass"
+      end
+    end
+  end
+end

lib/googleauth/external_account.rb

@@ -13,6 +13,8 @@
 # limitations under the License.
 
 require "time"
+require "googleauth/credentials_loader"
+require "googleauth/base_client"
 require "googleauth/oauth2/sts_client"
 
 module Google
@@ -51,7 +53,7 @@ def self.make_creds options = {}
       def self.read_json_key json_key_io
         json_key = MultiJson.load json_key_io.read
         wanted = [
-          "audience", "subject_token_type", "token_url", "credential_source", "service_account_impersonation_url"
+          "audience", "subject_token_type", "token_url", "credential_source"
         ]
         wanted.each do |key|
           raise "the json is missing the #{key} field" unless json_key.key? key
@@ -64,7 +66,8 @@ def self.read_json_key json_key_io
     # by utilizing the AWS EC2 metadata service and then exchanging the
     # credentials for a short-lived Google Cloud access token.
     class AwsCredentials
-      AUTH_METADATA_KEY = :authorization
+      include BaseClient
+
       STS_GRANT_TYPE = "urn:ietf:params:oauth:grant-type:token-exchange".freeze
       STS_REQUESTED_TOKEN_TYPE = "urn:ietf:params:oauth:token-type:access_token".freeze
       IAM_SCOPE = ["https://www.googleapis.com/auth/iam"].freeze
@@ -85,7 +88,7 @@ def initialize options = {}
         @region = options[:region] || region(options)
         @request_signer = AwsRequestSigner.new @region
 
-        @expiry = nil
+        @expires_at = nil
         @access_token = nil
 
         @sts_client = Google::Auth::OAuth2::STSClient.new token_exchange_endpoint: @token_url
@@ -98,42 +101,64 @@ def fetch_access_token! options = {}
 
         if @service_account_impersonation_url
           impersonated_response = get_impersonated_access_token response["access_token"]
-          @expiry = Time.parse impersonated_response["expireTime"]
-          @access_token = impersonated_response["accessToken"]
+          self.expires_at = impersonated_response["expireTime"]
+          self.access_token = impersonated_response["accessToken"]
         else
           # Extract the expiration time in seconds from the response and calculate the actual expiration time
           # and then save that to the expiry variable.
-          @expiry = Time.now.utc + response["expires_in"].to_i
-          @access_token = response["access_token"]
+          self.expires_at = Time.now.utc + response["expires_in"].to_i
+          self.access_token = response["access_token"]
         end
+
+        notify_refresh_listeners
       end
 
-      # Whether the id_token or access_token is missing or about to expire.
-      def needs_access_token?
-        @access_token.nil? || expires_within?(60)
+      def notify_refresh_listeners
+        listeners = defined?(@refresh_listeners) ? @refresh_listeners : []
+        listeners.each do |block|
+          block.call self
+        end
       end
 
       def expires_within? seconds
-        @expiry && @expiry - Time.now.utc < seconds
+        @expires_at && @expires_at - Time.now.utc < seconds
+      end
+
+      def expires_at
+        @expires_at
+      end
+
+      def expires_at= new_expires_at
+        @expires_at = normalize_timestamp new_expires_at
       end
 
-      # Updates a_hash updated with the authentication token
-      def apply! a_hash, opts = {}
-        # fetch the access token there is currently not one, or if the client
-        # has expired
-        fetch_access_token! opts if needs_access_token?
-        a_hash[AUTH_METADATA_KEY] = "Bearer #{@access_token}"
+      def access_token
+        @access_token
       end
 
-      # Returns a clone of a_hash updated with the authentication token
-      def apply a_hash, opts = {}
-        a_copy = a_hash.clone
-        apply! a_copy, opts
-        a_copy
+      def access_token= new_access_token
+        @access_token = new_access_token
       end
 
       private
 
+      def token_type
+        :access_token
+      end
+
+      def normalize_timestamp time
+        case time
+        when NilClass
+          nil
+        when Time
+          time
+        when String
+          Time.parse time
+        else
+          raise "Invalid time value #{time}"
+        end
+      end
+
       def exchange_token credentials
         request_options = @request_signer.generate_signed_request(
           credentials,
@@ -170,9 +195,7 @@ def get_impersonated_access_token token, options = {}
         response = c.post @service_account_impersonation_url do |req|
           req.headers["Authorization"] = "Bearer #{token}"
           req.headers["Content-Type"] = "application/json"
-          req.body = MultiJson.dump({
-                                      scope: @scope
-                                    })
+          req.body = MultiJson.dump({ scope: @scope })
         end
 
         if response.status != 200

lib/googleauth/oauth2/sts_client.rb

@@ -74,7 +74,7 @@ def exchange_token options = {}
           request_body = {
             grant_type: options[:grant_type],
             audience: options[:audience],
-            scope: options[:scopes]&.join(" ") || [],
+            scope: Array(options[:scopes])&.join(" ") || [],
             requested_token_type: options[:requested_token_type],
             subject_token: options[:subject_token],
             subject_token_type: options[:subject_token_type]

lib/googleauth/service_account.rb

@@ -130,7 +130,7 @@ def apply_self_signed_jwt! a_hash
     # cf [Application Default Credentials](https://cloud.google.com/docs/authentication/production)
     class ServiceAccountJwtHeaderCredentials
       JWT_AUD_URI_KEY = :jwt_aud_uri
-      AUTH_METADATA_KEY = Signet::OAuth2::AUTH_METADATA_KEY
+      AUTH_METADATA_KEY = Signet::OAuth2::Client::AUTH_METADATA_KEY
       TOKEN_CRED_URI = "https://www.googleapis.com/oauth2/v4/token".freeze
       SIGNING_ALGORITHM = "RS256".freeze
       EXPIRY = 60

lib/googleauth/signet.rb

@@ -13,16 +13,18 @@
 # limitations under the License.
 
 require "signet/oauth_2/client"
+require "googleauth/base_client"
 
 module Signet
   # OAuth2 supports OAuth2 authentication.
   module OAuth2
-    AUTH_METADATA_KEY = :authorization
     # Signet::OAuth2::Client creates an OAuth2 client
     #
     # This reopens Client to add #apply and #apply! methods which update a
     # hash with the fetched authentication token.
     class Client
+      include Google::Auth::BaseClient
+
       def configure_connection options
         @connection_info =
           options[:connection_builder] || options[:default_connection]
@@ -34,37 +36,6 @@ def token_type
         target_audience ? :id_token : :access_token
       end
 
-      # Whether the id_token or access_token is missing or about to expire.
-      def needs_access_token?
-        send(token_type).nil? || expires_within?(60)
-      end
-
-      # Updates a_hash updated with the authentication token
-      def apply! a_hash, opts = {}
-        # fetch the access token there is currently not one, or if the client
-        # has expired
-        fetch_access_token! opts if needs_access_token?
-        a_hash[AUTH_METADATA_KEY] = "Bearer #{send token_type}"
-      end
-
-      # Returns a clone of a_hash updated with the authentication token
-      def apply a_hash, opts = {}
-        a_copy = a_hash.clone
-        apply! a_copy, opts
-        a_copy
-      end
-
-      # Returns a reference to the #apply method, suitable for passing as
-      # a closure
-      def updater_proc
-        proc { |a_hash, opts = {}| apply a_hash, opts }
-      end
-
-      def on_refresh &block
-        @refresh_listeners = [] unless defined? @refresh_listeners
-        @refresh_listeners << block
-      end
-
       alias orig_fetch_access_token! fetch_access_token!
       def fetch_access_token! options = {}
         unless options[:connection]
@@ -78,13 +49,6 @@ def fetch_access_token! options = {}
         info
       end
 
-      def notify_refresh_listeners
-        listeners = defined?(@refresh_listeners) ? @refresh_listeners : []
-        listeners.each do |block|
-          block.call self
-        end
-      end
-
       def build_default_connection
         if !defined?(@connection_info)
           nil