Package errors is simple error handler for Go language.
It's reference pkg/errors and privides similar functionality.
This package can be installed with the go get command:
go get github.com/ebiy0rom0/errors
This package obtains stack traces for all functions.
If want to issue your own errors(e.g. validation checks) use errors.New or errors.Errorf.
// Cases requiring 0 or more for param
if param <= 0 {
return errors.New("param is less than 0.")
// or new format error is:
// return errors.Errorf("param is %d but required 0 or more.", param)
}If using an existing error or an error returned by a function, use errors.Wrap or errors.Wrapf.
Both can wrap variables that satisfy the error interface.
// Cases failed file open and returned os.ErrNotExist
name := "example.log"
fp, err := os.Open(name)
if err != nil {
return errors.Wrap(err, "no log output distination.")
// or wrap format error is:
// return errors.Wrapf(err, "no log file %s", name)
}If you don't want to add a message to the error to wrap, you can use errors.WithStack.
This is useful when the wrap message to be wrapped is equivalent to an error message.
// Cases failed check to file exists and returned os.ErrNotExist
name := "example.txt"
info, err := os.Stat(name)
if err != nil {
// The wrap message notifies that the file does not exist,
// but it's satisfied by os.ErrNotExist.
return errors.WithStack(err)
}errors.Wrap and errors.Wrapf implements Unwrap and can be checked with standard errors.Is and errors.As.
Equivalent functions are provided by this package and can be used.
// fileopen() returns os.ErrNotExist wrapped by errors.Wrap
err := fileopen(name)
if errors.Is(err, os.ErrNotExist) {
fmt.Printf("error is %v", os.ErrNotExist)
}This package implement fmt.Formatter and supports %s and %v by the fmt package.
%s print the error. If for wrapped error,
print at chained recursively.
%v simultaneously printed stack trace obtained at oldest.
MIT License