pkg/relabel/relabel.go
func NewRegexp(s string) (Regexp, error) {
	regex, err := regexp.Compile("^(?:" + s + ")$")
	return Regexp{
		Regexp:   regex,
		original: s,
	}, err
}
func NewRegexp(s string) (Regexp, error) {
	regex, err := regexp.Compile("^(?:" + s + ")$")
	return Regexp{
		Regexp:   regex,
		original: s,
	}, err
}
// NewRegexp creates a new anchored Regexp and returns an error if the
// passed-in regular expression does not compile.