Is it possible to get filename where code is called in Golang?

Question

I was able to get the full path of the current directory, Now I would like to create a function that will read or get the filename where the code is executed. I am able to get the filename but it is return the original filename where the code is written :

func GetFileName() string {
    _, fpath, _, ok := runtime.Caller(0)
    if !ok {
        err := errors.New("failed to get filename")
        panic(err)
    }
    filename := filepath.Base(fpath)
    // remove extension
    filename = removeExtension(filename)
    return filename + ".log"
}

What I want to do is getting the current fileName where the code is executed like :

I created app.go :

package my

function getCurrentFileName() string {
    // some code here that will return the filename where this code is executed.
}

and then when I call getCurrentFileName() in a different file like hello.go in a different location. it will return hello.go.

I have been stuck here for a while and looking for an answer.

icza · Accepted Answer · 2017-11-10T12:49:54.150

Basically this is what you tell / pass to runtime.Caller(): the number of stack entries to skip before returning an entry.

If you pass 0 as in your code, that means return the stack entry where runtime.Caller() is called (where you called runtime.Caller()). Passing 1 will skip your function, and return the function that called your function:

pc, file, line, ok := runtime.Caller(1)
if ok {
    fmt.Printf("Called from %s, line #%d, func: %v\n",
        file, line, runtime.FuncForPC(pc).Name())
}

Example calling a function that contains this (subplay.A() in my example):

 7   func main() {
 8      // Comment line
 9      subplay.A()
10   }

Output:

Called from /home/icza/gows/src/play/play.go, line #9, func: main.main

We see that the code prints that play.go called our function at line #9, from the function main() of the main package.

score 1 · Answer 2 · answered Nov 10 '17 at 09:20

This helper function can give those information:

func Here(skip ...int) (string, string, int, error) {
    sk := 1
    if len(skip) > 0 && skip[0] > 1 {
        sk = skip[0]
    }
    var pc uintptr
    var ok bool
    pc, fileName, fileLine, ok := runtime.Caller(sk)
    if !ok {
        return "", "", 0, fmt.Errorf("N/A")
    }
    fn := runtime.FuncForPC(pc)
    name := fn.Name()
    ix := strings.LastIndex(name, ".")
    if ix > 0 && (ix+1) < len(name) {
        name = name[ix+1:]
    }
    funcName := name
    nd, nf := filepath.Split(fileName)
    fileName = filepath.Join(filepath.Base(nd), nf)
    return funcName, fileName, fileLine, nil
}

The skip parameter is the number of caller frames that we need to go up (the chain of callers).

Is it possible to get filename where code is called in Golang?

2 Answers2

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