go-multierror

go-multierror is a package for Go that provides a mechanism for representing a list of error values as a single error.

This allows a function in Go to return an error that might actually be a list of errors. If the caller knows this, they can unwrap the list and access the errors. If the caller doesn’t know, the error formats to a nice human-readable format.

go-multierror is fully compatible with the Go standard library errors package, including the functions As, Is, and Unwrap. This provides a standardized approach for introspecting on error values.

Install using go get github.com/hashicorp/go-multierror.

Usage

var result error

if err := step1(); err != nil {
	result = multierror.Append(result, err)
}
if err := step2(); err != nil {
	result = multierror.Append(result, err)
}

return result

Returning a multierror only if there are errors

var result *multierror.Error

// ... accumulate errors here

// Return the `error` only if errors were added to the multierror, otherwise
// return nil since there are no errors.
return result.ErrorOrNil()