logging - Golang: How to capture panic and log this error to original log file? -

i tried capture panic , log error:

func (s *server) sayhello(ctx context.context, in *pb.hellorequest) (*pb.helloreply, error) {     defer func() {         if err := recover(); err != nil {             glog.errorf("recovered err: %v", err)         }     }()     panic("tish panic")     return &pb.helloreply{message: "hello " + in.name}, nil } 

but surprise, "recovered err: " never occurs in log file, instead, occurs in /var/log/messages.

how can log error in original log file?

[updated]

if there no panic, glog.errorf log correctly log dir; when there panic, can't:

// glog log correctly, unless uncomment panic below glog.errorf("this normal log: %v", err)   // panic("tish panic") 

maybe impossible, since that's crash means?

you need call glog.flush() in deferred function. documentation of glog:

log output buffered , written periodically using flush. programs should call flush before exiting guarantee log output written.

https://godoc.org/github.com/golang/glog