Enables reading credentials from env vars.

- ServiceAccountCredentials, ServiceAccountJwtHeaderCredentials
and UserRefreshCredentials initializers now take keyword args
via options hash.

- In `credentials_loader.rb`, refactored env var checking into
private methods

- Updated tests & added new tests.

- Fixed existing test for #from_well_known_path 'fails if
the file is invalid', where `from_env` was called instead of
`from_well_known_path`.

- Fixed rubocop errors I introduced, but two existing ones remain.

- Added entry to changelog.

- Fixed rubocop errors from code containing parallel assignments

- Updated rubocop_todo.yml to ignore parallel assignments and
trailing underscore assignments.

.rubocop_todo.yml

@@ -1,5 +1,5 @@
 # This configuration was generated by `rubocop --auto-gen-config`
-# on 2015-04-23 11:18:24 -0700 using RuboCop version 0.30.0.
+# on 2015-05-18 09:38:28 -0700 using RuboCop version 0.31.0.
 # The point is for the user to remove these configuration records
 # one by one as the offenses are removed from the code base.
 # Note that changes in the inspected code, or installation of new
@@ -9,7 +9,17 @@
 Metrics/AbcSize:
   Max: 24
 
-# Offense count: 6
+# Offense count: 10
 # Configuration parameters: CountComments.
 Metrics/MethodLength:
   Max: 13
+
+# Offense count: 1
+# Cop supports --auto-correct.
+Performance/ParallelAssignment:
+  Enabled: false
+
+# Offense count: 1
+# Cop supports --auto-correct.
+Style/TrailingUnderscoreVariable:
+  Enabled: false

CHANGELOG.md

@@ -1,3 +1,8 @@
+### Changes
+
+* Enables passing credentials via environment variables. ([@haabaato][])
+[#27](https://github.com/google/google-auth-library-ruby/issues/27)
+
 ## 0.4.1 (25/04/2015)
 
 ### Changes
@@ -20,3 +25,4 @@
 
 [@tbetbetbe]: https://github.com/tbetbetbe
 [@joneslee85]: https://github.com/joneslee85
+[@haabaato]: https://github.com/haabaato

lib/googleauth.rb

@@ -52,16 +52,38 @@ END
 
       # override CredentialsLoader#make_creds to use the class determined by
       # loading the json.
-      def self.make_creds(json_key_io, scope = nil)
+      def self.make_creds(options = {})
+        json_key_io, scope = options.values_at(:json_key_io, :scope)
+        if json_key_io
           json_key, clz = determine_creds_class(json_key_io)
-        clz.new(StringIO.new(MultiJson.dump(json_key)), scope)
+          clz.new(json_key_io: StringIO.new(MultiJson.dump(json_key)),
+                  scope: scope)
+        else
+          clz = read_creds
+          clz.new(scope: scope)
+        end
+      end
+
+      def self.read_creds
+        env_var = CredentialsLoader::ACCOUNT_TYPE_VAR
+        type = ENV[env_var]
+        fail "#{ACCOUNT_TYPE_VAR} is undefined in env" unless type
+        case type
+        when 'service_account'
+          ServiceAccountCredentials
+        when 'authorized_user'
+          UserRefreshCredentials
+        else
+          fail "credentials type '#{type}' is not supported"
+        end
       end
 
       # Reads the input json and determines which creds class to use.
       def self.determine_creds_class(json_key_io)
         json_key = MultiJson.load(json_key_io.read)
-        fail "the json is missing the #{key} field" unless json_key.key?('type')
+        key = 'type'
-        type = json_key['type']
+        fail "the json is missing the '#{key}' field" unless json_key.key?(key)
+        type = json_key[key]
         case type
         when 'service_account'
           [json_key, ServiceAccountCredentials]

lib/googleauth/credentials_loader.rb

@@ -39,6 +39,14 @@ module Google
     module CredentialsLoader
       extend Memoist
       ENV_VAR = 'GOOGLE_APPLICATION_CREDENTIALS'
+
+      PRIVATE_KEY_VAR = 'GOOGLE_PRIVATE_KEY'
+      CLIENT_EMAIL_VAR = 'GOOGLE_CLIENT_EMAIL'
+      CLIENT_ID_VAR = 'GOOGLE_CLIENT_ID'
+      CLIENT_SECRET_VAR = 'GOOGLE_CLIENT_SECRET'
+      REFRESH_TOKEN_VAR = 'GOOGLE_REFRESH_TOKEN'
+      ACCOUNT_TYPE_VAR = 'GOOGLE_ACCOUNT_TYPE'
+
       NOT_FOUND_ERROR =
         "Unable to read the credential file specified by #{ENV_VAR}"
       WELL_KNOWN_PATH = 'gcloud/application_default_credentials.json'
@@ -63,11 +71,14 @@ module Google
       #
       # @param scope [string|array|nil] the scope(s) to access
       def from_env(scope = nil)
-        return nil unless ENV.key?(ENV_VAR)
+        if ENV.key?(ENV_VAR)
           path = ENV[ENV_VAR]
-        fail 'file #{path} does not exist' unless File.exist?(path)
+          fail "file #{path} does not exist" unless File.exist?(path)
           File.open(path) do |f|
-          return make_creds(f, scope)
+            return make_creds(json_key_io: f, scope: scope)
+          end
+        elsif service_account_env_vars? || authorized_user_env_vars?
+          return make_creds(scope: scope)
         end
       rescue StandardError => e
         raise "#{NOT_FOUND_ERROR}: #{e}"
@@ -83,11 +94,22 @@ module Google
         path = File.join(root, base)
         return nil unless File.exist?(path)
         File.open(path) do |f|
-          return make_creds(f, scope)
+          return make_creds(json_key_io: f, scope: scope)
         end
       rescue StandardError => e
         raise "#{WELL_KNOWN_ERROR}: #{e}"
       end
+
+      private
+
+      def service_account_env_vars?
+        ([PRIVATE_KEY_VAR, CLIENT_EMAIL_VAR] - ENV.keys).empty?
+      end
+
+      def authorized_user_env_vars?
+        ([CLIENT_ID_VAR, CLIENT_SECRET_VAR, REFRESH_TOKEN_VAR] -
+          ENV.keys).empty?
+      end
     end
   end
 end

lib/googleauth/service_account.rb

@@ -62,8 +62,15 @@ module Google
       #
       # @param json_key_io [IO] an IO from which the JSON key can be read
       # @param scope [string|array|nil] the scope(s) to access
-      def initialize(json_key_io, scope = nil)
+      def initialize(options = {})
+        json_key_io, scope = options.values_at(:json_key_io, :scope)
+        if json_key_io
           private_key, client_email = self.class.read_json_key(json_key_io)
+        else
+          private_key = ENV[CredentialsLoader::PRIVATE_KEY_VAR]
+          client_email = ENV[CredentialsLoader::CLIENT_EMAIL_VAR]
+        end
+
         super(token_credential_uri: TOKEN_CRED_URI,
               audience: TOKEN_CRED_URI,
               scope: scope,
@@ -90,7 +97,7 @@ module Google
           client_email: @issuer
         }
         alt_clz = ServiceAccountJwtHeaderCredentials
-        alt = alt_clz.new(StringIO.new(MultiJson.dump(cred_json)))
+        alt = alt_clz.new(json_key_io: StringIO.new(MultiJson.dump(cred_json)))
         alt.apply!(a_hash)
       end
     end
@@ -120,7 +127,7 @@ module Google
       # optional scope. Here's the constructor only has one param, so
       # we modify make_creds to reflect this.
       def self.make_creds(*args)
-        new(args[0])
+        new(json_key_io: args[0][:json_key_io])
       end
 
       # Reads the private key and client email fields from the service account
@@ -135,8 +142,14 @@ module Google
       # Initializes a ServiceAccountJwtHeaderCredentials.
       #
       # @param json_key_io [IO] an IO from which the JSON key can be read
-      def initialize(json_key_io)
+      def initialize(options = {})
+        json_key_io = options[:json_key_io]
+        if json_key_io
           private_key, client_email = self.class.read_json_key(json_key_io)
+        else
+          private_key = ENV[CredentialsLoader::PRIVATE_KEY_VAR]
+          client_email = ENV[CredentialsLoader::CLIENT_EMAIL_VAR]
+        end
         @private_key = private_key
         @issuer = client_email
         @signing_key = OpenSSL::PKey::RSA.new(private_key)

lib/googleauth/user_refresh.rb

@@ -63,8 +63,15 @@ module Google
       #
       # @param json_key_io [IO] an IO from which the JSON key can be read
       # @param scope [string|array|nil] the scope(s) to access
-      def initialize(json_key_io, scope = nil)
+      def initialize(options = {})
-        user_creds = self.class.read_json_key(json_key_io)
+        json_key_io, scope = options.values_at(:json_key_io, :scope)
+        user_creds = self.class.read_json_key(json_key_io) if json_key_io
+        user_creds ||= {
+          client_id: ENV[CredentialsLoader::CLIENT_ID_VAR],
+          client_secret: ENV[CredentialsLoader::CLIENT_SECRET_VAR],
+          refresh_token: ENV[CredentialsLoader::REFRESH_TOKEN_VAR]
+        }
+
         super(token_credential_uri: TOKEN_CRED_URI,
               client_id: user_creds['client_id'],
               client_secret: user_creds['client_secret'],

spec/googleauth/get_application_default_spec.rb

@@ -38,14 +38,18 @@ require 'spec_helper'
 describe '#get_application_default' do
   before(:example) do
     @key = OpenSSL::PKey::RSA.new(2048)
-    @var_name = CredentialsLoader::ENV_VAR
+    @var_name = ENV_VAR
-    @orig = ENV[@var_name]
+    @credential_vars = [
+      ENV_VAR, PRIVATE_KEY_VAR, CLIENT_EMAIL_VAR, CLIENT_ID_VAR,
+      CLIENT_SECRET_VAR, REFRESH_TOKEN_VAR, ACCOUNT_TYPE_VAR]
+    @original_env_vals = {}
+    @credential_vars.each { |var| @original_env_vals[var] = ENV[var] }
     @home = ENV['HOME']
     @scope = 'https://www.googleapis.com/auth/userinfo.profile'
   end
 
   after(:example) do
-    ENV[@var_name] = @orig unless @orig.nil?
+    @credential_vars.each { |var| ENV[var] = @original_env_vals[var] }
     ENV['HOME'] = @home unless @home == ENV['HOME']
   end
 
@@ -95,8 +99,7 @@ describe '#get_application_default' do
     it 'succeeds with default file without GOOGLE_APPLICATION_CREDENTIALS' do
       ENV.delete(@var_name) unless ENV[@var_name].nil?
       Dir.mktmpdir do |dir|
-        key_path = File.join(dir, '.config',
+        key_path = File.join(dir, '.config', WELL_KNOWN_PATH)
-                             CredentialsLoader::WELL_KNOWN_PATH)
         FileUtils.mkdir_p(File.dirname(key_path))
         File.write(key_path, cred_json_text)
         ENV['HOME'] = dir
@@ -107,8 +110,7 @@ describe '#get_application_default' do
     it 'succeeds with default file without a scope' do
       ENV.delete(@var_name) unless ENV[@var_name].nil?
       Dir.mktmpdir do |dir|
-        key_path = File.join(dir, '.config',
+        key_path = File.join(dir, '.config', WELL_KNOWN_PATH)
-                             CredentialsLoader::WELL_KNOWN_PATH)
         FileUtils.mkdir_p(File.dirname(key_path))
         File.write(key_path, cred_json_text)
         ENV['HOME'] = dir
@@ -137,17 +139,31 @@ describe '#get_application_default' do
       end
       stubs.verify_stubbed_calls
     end
+
+    it 'succeeds if environment vars are valid' do
+      ENV.delete(@var_name) unless ENV[@var_name].nil? # no env var
+      ENV[PRIVATE_KEY_VAR] = cred_json[:private_key]
+      ENV[CLIENT_EMAIL_VAR] = cred_json[:client_email]
+      ENV[CLIENT_ID_VAR] = cred_json[:client_id]
+      ENV[CLIENT_SECRET_VAR] = cred_json[:client_secret]
+      ENV[REFRESH_TOKEN_VAR] = cred_json[:refresh_token]
+      ENV[ACCOUNT_TYPE_VAR] = cred_json[:type]
+      expect(Google::Auth.get_application_default(@scope)).to_not be_nil
+    end
   end
 
   describe 'when credential type is service account' do
-    def cred_json_text
+    let(:cred_json) do
-      cred_json = {
+      {
         private_key_id: 'a_private_key_id',
         private_key: @key.to_pem,
         client_email: 'app@developer.gserviceaccount.com',
         client_id: 'app.apps.googleusercontent.com',
         type: 'service_account'
       }
+    end
+
+    def cred_json_text
       MultiJson.dump(cred_json)
     end
 
@@ -156,13 +172,16 @@ describe '#get_application_default' do
   end
 
   describe 'when credential type is authorized_user' do
-    def cred_json_text
+    let(:cred_json) do
-      cred_json = {
+      {
         client_secret: 'privatekey',
         refresh_token: 'refreshtoken',
         client_id: 'app.apps.googleusercontent.com',
         type: 'authorized_user'
       }
+    end
+
+    def cred_json_text
       MultiJson.dump(cred_json)
     end
 
@@ -171,13 +190,16 @@ describe '#get_application_default' do
   end
 
   describe 'when credential type is unknown' do
-    def cred_json_text
+    let(:cred_json) do
-      cred_json = {
+      {
         client_secret: 'privatekey',
         refresh_token: 'refreshtoken',
         client_id: 'app.apps.googleusercontent.com',
         type: 'not_known_type'
       }
+    end
+
+    def cred_json_text
       MultiJson.dump(cred_json)
     end
 
@@ -197,8 +219,7 @@ describe '#get_application_default' do
     it 'fails if the well known file contains the creds' do
       ENV.delete(@var_name) unless ENV[@var_name].nil?
       Dir.mktmpdir do |dir|
-        key_path = File.join(dir, '.config',
+        key_path = File.join(dir, '.config', WELL_KNOWN_PATH)
-                             CredentialsLoader::WELL_KNOWN_PATH)
         FileUtils.mkdir_p(File.dirname(key_path))
         File.write(key_path, cred_json_text)
         ENV['HOME'] = dir
@@ -208,5 +229,14 @@ describe '#get_application_default' do
         expect(&blk).to raise_error RuntimeError
       end
     end
+
+    it 'fails if env vars are set' do
+      ENV[PRIVATE_KEY_VAR] = cred_json[:private_key]
+      ENV[CLIENT_EMAIL_VAR] = cred_json[:client_email]
+      blk = proc do
+        Google::Auth.get_application_default(@scope)
+      end
+      expect(&blk).to raise_error RuntimeError
+    end
   end
 end

spec/googleauth/service_account_spec.rb

@@ -108,12 +108,22 @@ end
 describe Google::Auth::ServiceAccountCredentials do
   ServiceAccountCredentials = Google::Auth::ServiceAccountCredentials
   let(:client_email) { 'app@developer.gserviceaccount.com' }
+  let(:cred_json) do
+    {
+      private_key_id: 'a_private_key_id',
+      private_key: @key.to_pem,
+      client_email: client_email,
+      client_id: 'app.apps.googleusercontent.com',
+      type: 'service_account'
+    }
+  end
 
   before(:example) do
     @key = OpenSSL::PKey::RSA.new(2048)
     @client = ServiceAccountCredentials.new(
-      StringIO.new(cred_json_text),
+      json_key_io: StringIO.new(cred_json_text),
-      'https://www.googleapis.com/auth/userinfo.profile')
+      scope: 'https://www.googleapis.com/auth/userinfo.profile'
+    )
   end
 
   def make_auth_stubs(opts = {})
@@ -131,13 +141,6 @@ describe Google::Auth::ServiceAccountCredentials do
   end
 
   def cred_json_text
-    cred_json = {
-      private_key_id: 'a_private_key_id',
-      private_key: @key.to_pem,
-      client_email: client_email,
-      client_id: 'app.apps.googleusercontent.com',
-      type: 'service_account'
-    }
     MultiJson.dump(cred_json)
   end
 
@@ -154,13 +157,18 @@ describe Google::Auth::ServiceAccountCredentials do
   describe '#from_env' do
     before(:example) do
       @var_name = ENV_VAR
-      @orig = ENV[@var_name]
+      @credential_vars = [
+        ENV_VAR, PRIVATE_KEY_VAR, CLIENT_EMAIL_VAR, ACCOUNT_TYPE_VAR]
+      @original_env_vals = {}
+      @credential_vars.each { |var| @original_env_vals[var] = ENV[var] }
+      ENV[ACCOUNT_TYPE_VAR] = cred_json[:type]
+
       @scope = 'https://www.googleapis.com/auth/userinfo.profile'
       @clz = ServiceAccountCredentials
     end
 
     after(:example) do
-      ENV[@var_name] = @orig unless @orig.nil?
+      @credential_vars.each { |var| ENV[var] = @original_env_vals[var] }
     end
 
     it 'returns nil if the GOOGLE_APPLICATION_CREDENTIALS is unset' do
@@ -187,6 +195,13 @@ describe Google::Auth::ServiceAccountCredentials do
         expect(@clz.from_env(@scope)).to_not be_nil
       end
     end
+
+    it 'succeeds when GOOGLE_PRIVATE_KEY and GOOGLE_CLIENT_EMAIL env vars are'\
+      ' valid' do
+      ENV[PRIVATE_KEY_VAR] = cred_json[:private_key]
+      ENV[CLIENT_EMAIL_VAR] = cred_json[:client_email]
+      expect(@clz.from_env(@scope)).to_not be_nil
+    end
   end
 
   describe '#from_well_known_path' do
@@ -224,20 +239,22 @@ describe Google::Auth::ServiceAccountJwtHeaderCredentials do
 
   let(:client_email) { 'app@developer.gserviceaccount.com' }
   let(:clz) { Google::Auth::ServiceAccountJwtHeaderCredentials }
-
+  let(:cred_json) do
-  before(:example) do
+    {
-    @key = OpenSSL::PKey::RSA.new(2048)
-    @client = clz.new(StringIO.new(cred_json_text))
-  end
-
-  def cred_json_text
-    cred_json = {
       private_key_id: 'a_private_key_id',
       private_key: @key.to_pem,
       client_email: client_email,
       client_id: 'app.apps.googleusercontent.com',
       type: 'service_account'
     }
+  end
+
+  before(:example) do
+    @key = OpenSSL::PKey::RSA.new(2048)
+    @client = clz.new(json_key_io: StringIO.new(cred_json_text))
+  end
+
+  def cred_json_text
     MultiJson.dump(cred_json)
   end
 
@@ -246,11 +263,15 @@ describe Google::Auth::ServiceAccountJwtHeaderCredentials do
   describe '#from_env' do
     before(:example) do
       @var_name = ENV_VAR
-      @orig = ENV[@var_name]
+      @credential_vars = [
+        ENV_VAR, PRIVATE_KEY_VAR, CLIENT_EMAIL_VAR, ACCOUNT_TYPE_VAR]
+      @original_env_vals = {}
+      @credential_vars.each { |var| @original_env_vals[var] = ENV[var] }
+      ENV[ACCOUNT_TYPE_VAR] = cred_json[:type]
     end
 
     after(:example) do
-      ENV[@var_name] = @orig unless @orig.nil?
+      @credential_vars.each { |var| ENV[var] = @original_env_vals[var] }
     end
 
     it 'returns nil if the GOOGLE_APPLICATION_CREDENTIALS is unset' do
@@ -277,6 +298,13 @@ describe Google::Auth::ServiceAccountJwtHeaderCredentials do
         expect(clz.from_env).to_not be_nil
       end
     end
+
+    it 'succeeds when GOOGLE_PRIVATE_KEY and GOOGLE_CLIENT_EMAIL env vars are'\
+      ' valid' do
+      ENV[PRIVATE_KEY_VAR] = cred_json[:private_key]
+      ENV[CLIENT_EMAIL_VAR] = cred_json[:client_email]
+      expect(clz.from_env(@scope)).to_not be_nil
+    end
   end
 
   describe '#from_well_known_path' do

spec/googleauth/user_refresh_spec.rb

@@ -40,15 +40,26 @@ require 'openssl'
 require 'spec_helper'
 require 'tmpdir'
 
+include Google::Auth::CredentialsLoader
+
 describe Google::Auth::UserRefreshCredentials do
   UserRefreshCredentials = Google::Auth::UserRefreshCredentials
-  CredentialsLoader = Google::Auth::CredentialsLoader
+
+  let(:cred_json) do
+    {
+      client_secret: 'privatekey',
+      client_id: 'client123',
+      refresh_token: 'refreshtoken',
+      type: 'authorized_user'
+    }
+  end
 
   before(:example) do
     @key = OpenSSL::PKey::RSA.new(2048)
     @client = UserRefreshCredentials.new(
-      StringIO.new(cred_json_text),
+      json_key_io: StringIO.new(cred_json_text),
-      'https://www.googleapis.com/auth/userinfo.profile')
+      scope: 'https://www.googleapis.com/auth/userinfo.profile'
+    )
   end
 
   def make_auth_stubs(opts = {})
@@ -64,12 +75,6 @@ describe Google::Auth::UserRefreshCredentials do
   end
 
   def cred_json_text(missing = nil)
-    cred_json = {
-      client_secret: 'privatekey',
-      client_id: 'client123',
-      refresh_token: 'refreshtoken',
-      type: 'authorized_user'
-    }
     cred_json.delete(missing.to_sym) unless missing.nil?
     MultiJson.dump(cred_json)
   end
@@ -78,14 +83,18 @@ describe Google::Auth::UserRefreshCredentials do
 
   describe '#from_env' do
     before(:example) do
-      @var_name = CredentialsLoader::ENV_VAR
+      @var_name = ENV_VAR
-      @orig = ENV[@var_name]
+      @credential_vars = [
+        ENV_VAR, CLIENT_ID_VAR, CLIENT_SECRET_VAR, REFRESH_TOKEN_VAR,
+        ACCOUNT_TYPE_VAR]
+      @original_env_vals = {}
+      @credential_vars.each { |var| @original_env_vals[var] = ENV[var] }
       @scope = 'https://www.googleapis.com/auth/userinfo.profile'
       @clz = UserRefreshCredentials
     end
 
     after(:example) do
-      ENV[@var_name] = @orig unless @orig.nil?
+      @credential_vars.each { |var| ENV[var] = @original_env_vals[var] }
     end
 
     it 'returns nil if the GOOGLE_APPLICATION_CREDENTIALS is unset' do
@@ -125,13 +134,22 @@ describe Google::Auth::UserRefreshCredentials do
         expect(@clz.from_env(@scope)).to_not be_nil
       end
     end
+
+    it 'succeeds when GOOGLE_CLIENT_ID, GOOGLE_CLIENT_SECRET, and '\
+      'GOOGLE_REFRESH_TOKEN env vars are valid' do
+      ENV[CLIENT_ID_VAR] = cred_json[:client_id]
+      ENV[CLIENT_SECRET_VAR] = cred_json[:client_secret]
+      ENV[REFRESH_TOKEN_VAR] = cred_json[:refresh_token]
+      ENV[ACCOUNT_TYPE_VAR] = cred_json[:type]
+      expect(@clz.from_env(@scope)).to_not be_nil
+    end
   end
 
   describe '#from_well_known_path' do
     before(:example) do
       @home = ENV['HOME']
       @scope = 'https://www.googleapis.com/auth/userinfo.profile'
-      @known_path = CredentialsLoader::WELL_KNOWN_PATH
+      @known_path = WELL_KNOWN_PATH
       @clz = UserRefreshCredentials
     end
 
@@ -152,7 +170,7 @@ describe Google::Auth::UserRefreshCredentials do
           FileUtils.mkdir_p(File.dirname(key_path))
           File.write(key_path, cred_json_text(missing))
           ENV['HOME'] = dir
-          expect { @clz.from_env(@scope) }.to raise_error
+          expect { @clz.from_well_known_path(@scope) }.to raise_error
         end
       end
     end