ChatGPT解决这个技术问题 Extra ChatGPT

How to get the directory of the currently running file?

go

In nodejs I use __dirname . What is the equivalent of this in Golang?

I have googled and found out this article http://andrewbrookins.com/tech/golang-get-directory-of-the-current-file/ . Where he uses below code

_, filename, _, _ := runtime.Caller(1)
f, err := os.Open(path.Join(path.Dir(filename), "data.csv"))

But is it the right way or idiomatic way to do in Golang?

this is not an answer for your question but you may cache the path to a global var (your file location can not be changed while running :) ) not to run os.open again and again each time your code runs
You should pass 0, not 1, to runtime.Caller().
runtime.Caller(0) will give you the path of the source file, like $GOPATH/src/packagename/main.go. The other answers in this thread are trying to return the path of the executable (like $GOPATH/bin/packagename).
You're assuming the program is running from a file...
Possible duplicate of Go: find the path to the executable

C
Community

EDIT: As of Go 1.8 (Released February 2017) the recommended way of doing this is with os.Executable:

func Executable() (string, error) Executable returns the path name for the executable that started the current process. There is no guarantee that the path is still pointing to the correct executable. If a symlink was used to start the process, depending on the operating system, the result might be the symlink or the path it pointed to. If a stable result is needed, path/filepath.EvalSymlinks might help.

To get just the directory of the executable you can use path/filepath.Dir.

Example:

package main

import (
    "fmt"
    "os"
    "path/filepath"
)

func main() {
    ex, err := os.Executable()
    if err != nil {
        panic(err)
    }
    exPath := filepath.Dir(ex)
    fmt.Println(exPath)
}

OLD ANSWER:

You should be able to use os.Getwd

func Getwd() (pwd string, err error)

Getwd returns a rooted path name corresponding to the current directory. If the current directory can be reached via multiple paths (due to symbolic links), Getwd may return any one of them.

For example:

package main

import (
    "fmt"
    "os"
)

func main() {
    pwd, err := os.Getwd()
    if err != nil {
        fmt.Println(err)
        os.Exit(1)
    }
    fmt.Println(pwd)
}

This is current process working directory. In nodejs it is equivalent to process.cwd() nodejs.org/api/process.html#process_process_cwd
Ok, I see the distinction. Of you're after the location of the binary in the filesytem (rather than the current working directory) I think that runtime.Caller is the closest you'll get to "idiomatic"
'Released February 2017'? It seems time machine has been invented and we have members posting from the future. It is nice to know a future version will have reliable cross platform method, In the meantime we have to stick to currently available solutions.
@ljgww Sorry, I'll take my Delorean and go home :-) I updated my answer in advance because I'd only just seen that upcoming feature and figured I'd forget to update the answer later on.
Edited with path/filepath.Dir because path.Dir only works with forward slashes (Unix style) as directory separators.
G
Gustavo Niemeyer

This should do it:

import (
    "fmt"
    "log"
    "os"
    "path/filepath"
)

func main() {
    dir, err := filepath.Abs(filepath.Dir(os.Args[0]))
    if err != nil {
            log.Fatal(err)
    }
    fmt.Println(dir)
}

Is it possible for there to be an error here? If so, what would the error be, just out of curiosity?
Doesn't work for me play.golang.org/p/c8fe-Zm_bH - os.Args[0] does not necessarily contain the abs path.
It actually works even if os.Args[0] does not contain the abs path. The reason the playground result is not what you expected is because it is inside a sandbox.
This is not a reliable way, see the answer about using osext as this was implementation that worked with all of our clients on various OSs. I had implemented code using this method but it seems to not be very reliable and many users complained of bugs that caused by this method choosing the wrong path for the executable.
Got the same result as emrah using Go 1.6 on Windows (got path of temp folder instead of source file folder). To get the path of your source file's folder without using any external dependency, use a slighly modified version of the OP's code: _, currentFilePath, _, _ := runtime.Caller(0) dirpath := path.Dir(currentFilePath) (note the runtime.Caller(0) instead of runtime.Caller(1))
D
Dobrosław Żybort

Use package osext

It's providing function ExecutableFolder() that returns an absolute path to folder where the currently running program executable reside (useful for cron jobs). It's cross platform.

Online documentation

package main

import (
    "github.com/kardianos/osext"
    "fmt"
    "log"
)

func main() {
    folderPath, err := osext.ExecutableFolder()
    if err != nil {
        log.Fatal(err)
    }
    fmt.Println(folderPath)
}

This is the only answer that produced the expected results for me both on Windows and on Linux.
This works fine until you'd like to use it with go run main.go for local development. Not sure how best to get around that without building an executable beforehand each time.
Sorry I don't know how to make it work with go run. This binaries are put in temporary folder each time.
@DerekDowling a way would be first doing a go install, then running go build -v *.go && ./main. The -v would tell you which files are being built. Generally, I've found that the time different between go run and go build is tolerable if I've already run go install. For windows users on powershell, the command will be go build -v {*}.go && ./main.exe
Since this will return $GOPATH/bin/, why not use $GOPATH/bin/?
A
Ari Seyhun
filepath.Abs("./")

Abs returns an absolute representation of path. If the path is not absolute it will be joined with the current working directory to turn it into an absolute path.

As stated in the comment, this returns the directory which is currently active.


This returns the current directory, not the directory of the current file. For instance, this would be different if the executable was called from a different path.
v
vikyd

os.Executable: https://tip.golang.org/pkg/os/#Executable

filepath.EvalSymlinks: https://golang.org/pkg/path/filepath/#EvalSymlinks

Full Demo:

package main

import (
    "fmt"
    "os"
    "path/filepath"
)

func main() {
    var dirAbsPath string
    ex, err := os.Executable()
    if err == nil {
        dirAbsPath = filepath.Dir(ex)
        fmt.Println(dirAbsPath)
        return
    }

    exReal, err := filepath.EvalSymlinks(ex)
    if err != nil {
        panic(err)
    }
    dirAbsPath = filepath.Dir(exReal)
    fmt.Println(dirAbsPath)
}

I'm pretty sure this would be the current answer.
On windows this gave me a \Local\Temp directory.
M
Matt

I came from Node.js to Go. The Node.js equivalent to __dirname in Go is:

_, filename, _, ok := runtime.Caller(0)
if !ok {
    return nil, errors.New("unable to get the current filename")
}
dirname := filepath.Dir(file)

Some other mentions in this thread and why they're wrong:

os.Executable() will give you the filepath of the currently running executable. This is equivalent to process.argv[0] in Node. This is not true if you want to take the __dirname of a sub-package.

os.Getwd() will give you the current working directory. This is the equivalent to process.cwd() in Node. This will be wrong when you run your program from another directory.

Lastly, I'd recommend against pulling in a third-party package for this use case. Here's a package you can use:

package current

// Filename is the __filename equivalent
func Filename() (string, error) {
    _, filename, _, ok := runtime.Caller(1)
    if !ok {
        return "", errors.New("unable to get the current filename")
    }
    return filename, nil
}


// Dirname is the __dirname equivalent
func Dirname() (string, error) {
    filename, err := Filename()
    if err != nil {
        return "", err
    }
    return filepath.Dir(filename), nil
}

Note that I've adjusted runtime.Caller(1) to 1 because we want to get the directory of the package that called current.Dirname(), not the directory containing the current package.


THANK YOU. This is the best answer I found after digging through multiple answers and different sites.
b
benyamin

if you use this way :

dir, err := filepath.Abs(filepath.Dir(os.Args[0]))
if err != nil {
    log.Fatal(err)
}
fmt.Println(dir)

you will get the /tmp path when you are running program using some IDE like GoLand because the executable will save and run from /tmp

i think the best way for getting the currentWorking Directory or '.' is :

import(
  "os" 
  "fmt"
  "log"
)

func main() {
  dir, err := os.Getwd()
    if err != nil {
        log.Fatal(err)
    }
  fmt.Println(dir)
}

the os.Getwd() function will return the current working directory. and its all without using of any external library :D


This is not correct. This returns the working directory of the user executing the process and not the directory of the file. Use filepath.abs.
it returns the working Directory of the running executable file. then if you are using an IDE like goland and there is no config for working directory in the build options then it will run from /tmp , then what usage /tmp have for you!??but if you use os.Getwd() it returns the .exe or elf executable file path. not /tmp.
@Bit Using base template of debugging in such an IDE, yes give you that, then just hit 'Edit Configuration' and fill 'Output Directory', so you will see 'os.Args[0]' path is what you want
@ϻαϻɾΣɀО-MaMrEzO yes,right. but if you handle it in my way , if you run code in another computer , you aren't have to config that in any new system.
A
Another Prog

If you use package osext by kardianos and you need to test locally, like Derek Dowling commented:

This works fine until you'd like to use it with go run main.go for local development. Not sure how best to get around that without building an executable beforehand each time.

The solution to this is to make a gorun.exe utility instead of using go run. The gorun.exe utility would compile the project using "go build", then run it right after, in the normal directory of your project.

I had this issue with other compilers and found myself making these utilities since they are not shipped with the compiler... it is especially arcane with tools like C where you have to compile and link and then run it (too much work).

If anyone likes my idea of gorun.exe (or elf) I will likely upload it to github soon..

Sorry, this answer is meant as a comment, but I cannot comment due to me not having a reputation big enough yet.

Alternatively, "go run" could be modified (if it does not have this feature already) to have a parameter such as "go run -notemp" to not run the program in a temporary directory (or something similar). But I would prefer just typing out gorun or "gor" as it is shorter than a convoluted parameter. Gorun.exe or gor.exe would need to be installed in the same directory as your go compiler

Implementing gorun.exe (or gor.exe) would be trivial, as I have done it with other compilers in only a few lines of code... (famous last words ;-)


If you want it to both work with "go run" and built executable then simply use _, callerFile, _, _ := runtime.Caller(0) executablePath := filepath.Dir(callerFile) instead
@Jocelyn, your comment is so great that you should make that into a full answer! This certainly did the trick for me — on my own setup, I have a local copy of the environment in macOS, which I mostly use to catch syntax errors (and a few semantic ones); then I sync the code to the deployment server, which runs under Ubuntu Linux, and of course the environment is completely different... so there is a real need to figure out where the file paths are to properly load templates, configuration files, static files, etc...
I
Isaac Weingarten

Sometimes this is enough, the first argument will always be the file path

package main

import (
    "fmt"
    "os"
)


func main() {
    fmt.Println(os.Args[0])

    // or
    dir, _ := os.Getwd()
    fmt.Println(dir)
}

g
gaurav arora
dir, err := os.Getwd()
    if err != nil {
        fmt.Println(err)
    }

this is for golang version: go version go1.13.7 linux/amd64

works for me, for go run main.go. If I run go build -o fileName, and put the final executable in some other folder, then that path is given while running the executable.


V
VonC

Do not use the "Answer recommended by Go Language" with runtime.Caller(0).

That works when you go build or go install a program, because you are re-compiling it.

But when you go build a program and then distribute it (copy) on your colleagues' workstations (who don't have Go, and just need the executable), the result of runtime.Caller(0) would still be the path of where you built it (from your computer).
Ie a path which would likely not exist on their own computer.

os.Args[0] or, better, os.Executable() (mentioned here) and kardianos/osext (mentioned here and here), are more reliable.


Likewise any answer that uses getwd will also be wrong especially when the exe is placed in the path and executed from another location.
1
1mike12

None of the answers here worked for me, at least on go version go1.16.2 darwin/amd64. This is the only thing close to the __dirname functionality in node

This was posted by goland engineer Daniil Maslov in the jetbrains forums

pasted below for easier reading:

The trick is actually very simple and is to get the current executing and add .. to the project root.

Create a new directory and file like testing_init.go with the following content:

package testing_init

import (
  "os"
  "path"
  "runtime"
)

func init() {
  _, filename, _, _ := runtime.Caller(0)
  dir := path.Join(path.Dir(filename), "..")
  err := os.Chdir(dir)
  if err != nil {
    panic(err)
  }
}

After that, just import the package into any of the test files:


package main_test

import (
  _ "project/testing_init"
)

Now you can specify paths from the project root


Z
Zubair Hassan

If your file is not in the main package then the above answers won't work I tried different approaches to find find the directory of the currently running file but failed.

The best possible answer is in the question itself this is how I find the current working directory of the file which is not in the main package.

_, filename, _, _ := runtime.Caller(1)
pwd := path.Dir(filename)

z
zld126126
// GetCurrentDir
func GetCurrentDir() string {
    p, _ := os.Getwd()
    return p
}
// GetParentDir
func GetParentDir(dirctory string) string {
    return substr(dirctory, 0, strings.LastIndex(dirctory, "/"))
}
func substr(s string, pos, length int) string {
    runes := []rune(s)
    l := pos + length
    if l > len(runes) {
        l = len(runes)
    }
    return string(runes[pos:l])
}

Your answer could be improved with additional supporting information. Please edit to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers in the help center.
Ṃųỻịgǻňạcểơửṩ

Gustavo Niemeyer's answer is great. But in Windows, runtime proc is mostly in another dir, like this:

"C:\Users\XXX\AppData\Local\Temp"

If you use relative file path, like "/config/api.yaml", this will use your project path where your code exists.


This is not an answer. It's just a comment on someone else's answer.

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