Capability to check for .env file not found error and other possible errors

[LeoBorai]

Description

When running gotdotenv.Load: https://github.com/joho/godotenv/blob/d6ee6871f21dd95e76563a90f522ce9fe75443f8/godotenv.go#L41

Theres no way to check for a "FileNotFound" error. godotenv panics as follows:

➜  server git:(master) ✗ go run main.go
panic: open .env: no such file or directory

goroutine 1 [running]:
main.main()
	.../server/main.go:12 +0xa9
exit status 2

Possible Solution

A possible solution would be to enumerate errors:

var (
        // EnvFileNotFound returns a "env file not found". Happens when godotenv is not able to find a .env file in the cwd
	EnvFileNotFound = errors.New("env file not found")
)

Then provide a ErrorIs like function, for example:

	err := godotenv.Load()

	if err != nil {
		if godotenv.ErrorIs(godotenv.EnvFileNotFound, err) {
                    // Do something
                } else {
		    return nil, err
                }
	}

Thanks in advance!

[cthompson527]

This works for me:

	err := godotenv.Load()
	if os.IsNotExist(err) {
		log.Fatalf(".env does not exist")
	}

[LeoBorai]

I think that does the work, but I'm more focused in something beyond this specific error. And improve error handling by using either an error variable or a handy function to discriminate the error type.

I imagine something like:

package error

// Error returned when GoDotEnv is unable to find the .env file
var EnvFileNotFound error = errors.New(".env file not found")

// Checks if the error is a `EnvFileNotFound` error
func IsEnvFileNotFoundError(err error) bool {
  return err == EnvFileNotFound
}

WDYT?