fix(connector/google): make admin email optional for default creds

Signed-off-by: Mark Sagi-Kazar <mark.sagikazar@gmail.com>

connector/google/google.go

@@ -283,7 +283,9 @@ func (c *googleConnector) getGroups(email string, fetchTransitiveGroupMembership
 // the google admin api. If no serviceAccountFilePath is defined, the application default credential
 // is used.
 func createDirectoryService(serviceAccountFilePath, email string, logger log.Logger) (*admin.Service, error) {
-	if email == "" {
+	// We know impersonation is required when using a service account credential
+	// TODO: or is it?
+	if email == "" && serviceAccountFilePath != "" {
 		return nil, fmt.Errorf("directory service requires adminEmail")
 	}
 
@@ -308,7 +310,12 @@ func createDirectoryService(serviceAccountFilePath, email string, logger log.Log
 	if err != nil {
 		return nil, fmt.Errorf("unable to parse credentials to config: %v", err)
 	}
-	config.Subject = email
+
+	// Only attempt impersonation when there is a user configured
+	if email != "" {
+		config.Subject = email
+	}
+
 	return admin.NewService(ctx, option.WithHTTPClient(config.Client(ctx)))
 }
 

connector/google/google_test.go

@@ -74,10 +74,11 @@ func TestOpen(t *testing.T) {
 	for name, reference := range map[string]testCase{
 		"missing_admin_email": {
 			config: &Config{
-				ClientID:     "testClient",
-				ClientSecret: "testSecret",
-				RedirectURI:  ts.URL + "/callback",
-				Scopes:       []string{"openid", "groups"},
+				ClientID:               "testClient",
+				ClientSecret:           "testSecret",
+				RedirectURI:            ts.URL + "/callback",
+				Scopes:                 []string{"openid", "groups"},
+				ServiceAccountFilePath: serviceAccountFilePath,
 			},
 			expectedErr: "requires adminEmail",
 		},