os: provide full path to current executable

[gopherbot]

by lost.goblin:

It would be very useful to have a way to find the full path to the current executable.

Not sure if this functionality should go in the os or runtime packages, and what would
be a good name. os.Getpath() or os.Getexecpath() perhaps?

For implementation details for most common platforms here is a good reference:
http://stackoverflow.com/a/1024937/192583

[ianlancetaylor]

Comment 1:

Labels changed: added priority-later, packagechange, removed priority-triage.

[rsc]

Comment 2:

This is not possible in general.
I looked at the stack overflow link. Yuck.

Status changed to LongTerm.

[gopherbot]

Comment 3 by uriel@berlinblue.org:

By "in general" you mean "in a portable way"? Doesn't seem much less portable than
things like os/inotify, and seems to be supported in most platform relatively easily
(just reading a symlink in /proc/ or the like), OS X seems like might be the trickiest.

[minux]

Comment 4:

I've solved the problem on Darwin (without using cgo, of course), a preview CL is at
https://golang.org/cl/6736069/.
before continue, i'd like to solicit opinions about the new API.
package os
func ExecPath() (string, error)
    ExecPath returns the absolute pathname of the current executing file; if
    error occurs, it will return whatever it current gets and the error.
should it be named GetExecPath()? or some other name?
i think implementing it for rest of supported OSes (except Plan 9) is easy.

Owner changed to @minux.

[minux]

Comment 5:

https://golang.org/cl/6736069/

Status changed to Started.

[minux]

Comment 6:

CL 6736069 is rejected mainly because the API whose behavior we can precisely
define (finding the path to re-invoke the current executable) is not what people'd
expect (finding asset files accompanying the executable).
I will extract code from that CL into a separate go-gettable package.

Labels changed: added priority-someday, removed priority-later.

Owner changed to ---.

Status changed to Accepted.

[rsc]

Comment 7:

Labels changed: added repo-main.

[matrixik]

Comment 8:

You could check `osext` package, it's cross platform:
http://godoc.org/bitbucket.org/kardianos/osext
    func Executable() (string, error)
Executable returns an absolute path that can be used to re-invoke the current program.
It may not be valid after the current program exits.
    func ExecutableFolder() (string, error)
Returns same path as Executable, returns just the folder path. Excludes the executable
name.

[minux]

Comment 9:

It seems the consensus is that it's not easy to define the semantics of such
an API without referring to the implementation on each platform.

Status changed to Unfortunate.