Error out if LDAP CA cert is not valid

If the configured LDAP CA cert can not be successfully loaded to the
Pool let the creation of the Graph Service fail.

extensions/graph/pkg/server/http/server.go

@@ -59,6 +59,10 @@ func Server(opts ...Option) (http.Service, error) {
 		svc.EventsPublisher(publisher),
 	)
 
+	if handle == nil {
+		return http.Service{}, errors.New("could not initialize graph service")
+	}
+
 	{
 		handle = svc.NewInstrument(handle, options.Metrics)
 		handle = svc.NewLogging(handle, options.Logger)

extensions/graph/pkg/service/v0/service.go

@@ -106,10 +106,13 @@ func NewService(opts ...Option) Service {
 				certs := x509.NewCertPool()
 				pemData, err := ioutil.ReadFile(options.Config.Identity.LDAP.CACert)
 				if err != nil {
-					options.Logger.Error().Msgf("Error initializing LDAP Backend: '%s'", err)
+					options.Logger.Error().Err(err).Msgf("Error initializing LDAP Backend")
+					return nil
+				}
+				if !certs.AppendCertsFromPEM(pemData) {
+					options.Logger.Error().Msgf("Error initializing LDAP Backend. Adding CA cert failed")
 					return nil
 				}
-				certs.AppendCertsFromPEM(pemData)
 				tlsConf.RootCAs = certs
 			}