OAuth-core/config/reader/preprocessor.go

package reader

import (
	"os"
	"regexp"
)

func ReplaceEnvVars(raw []byte) ([]byte, error) {
	re := regexp.MustCompile(`\$\{([A-Za-z0-9_]+)\}`)
	if re.Match(raw) {
		dataS := string(raw)
		res := re.ReplaceAllStringFunc(dataS, replaceEnvVars)
		return []byte(res), nil
	} else {
		return raw, nil
	}
}

func replaceEnvVars(element string) string {
	v := element[2 : len(element)-1]
	el := os.Getenv(v)
	return el
}