Write result stack trace default to file

Question

I use logger in my program defined from pattern as below

var (
    logFile *os.File
    Info    *log.Logger
)

func init() {
    var err error
    logFile, err = os.OpenFile("/my/file/with.log", os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0666)
    if err != nil {
        fmt.Printf("Cannot open log file error:%s. Program was terminated.", err)
        os.Exit(1)
    }
    Info = log.New(logFile,
        "INFO: ", log.Ldate|log.Ltime|log.Lshortfile)
 }

Now I would like write all information from stackTrace if these occured for example from panic() to my log file. Now if some gone was wrong all this information are print to console in my IDE, but if porgram works on server, I lose information if occured some null pointer, wrong pass argument to function, that's why I want write this information to log file. It is possible ?

You should be redirecting stderr and stdout to a file on the server (or into some other logging mechanism). You set `os.Stderr` to another file in your app, but it's going to be more reliable to have that managed externally. — JimB, Oct 19 '16 at 15:19
This is a key. A tried find some function to this in golang doc, but for now nothing. A tried for eg `os.Stderr = os.NewFile(uintptr(syscall.Stderr), "/my/log/file.log")` but dosen't works. I will be trying still something other... unles someone will be faster, and find solution before me — Mbded, Oct 19 '16 at 19:51
`os.NewFile` just returns a new `*os.File` with that file descriptor, so it did nothing except change string returned by `os.Stderr.Name()` — JimB, Oct 19 '16 at 20:09
I found solution http://stackoverflow.com/questions/34772012/capturing-panic-in-golang this I looking for. — Mbded, Oct 21 '16 at 20:47

Marsel Novy · Answer 1 · 2016-10-19T15:45:41.367

0

Use syscall.Dup2 to link the opened file to the standard stream

func main() {
   syscall.Dup2(int(logFile.Fd()), 2)
}

or create panic handler

defer func() {
        err := recover()
        if err != nil {
            //...
        }
    }()

edited Oct 19 '16 at 15:45

answered Oct 19 '16 at 15:39

Marsel Novy

1,777
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You can't create a "global panic handler", because you can only recover within the panicking goroutine. – JimB Oct 19 '16 at 15:41

Write result stack trace default to file

1 Answers1