1 files changed, 40 insertions, 1 deletions
diff --git a/lib/common/filepath.go b/lib/common/filepath.go
index 603c2a2..42ef82f 100644
--- a/lib/common/filepath.go
+++ b/lib/common/filepath.go
@@ -1,6 +1,13 @@
 package common
 
-import "os"
+import (
+	"fmt"
+	"os"
+	"os/user"
+	"path"
+	"path/filepath"
+	"regexp"
+)
 
 // Exists returns whether the given file or directory exists or not
 func Exists(path string) bool {
@@ -13,3 +20,35 @@ func Exists(path string) bool {
 	}
 	return true
 }
+
+// ResolveEnvVar Resolved environment variable regarding the syntax ${MYVAR}
+// or $MYVAR following by a slash or a backslash
+func ResolveEnvVar(s string) (string, error) {
+
+	// Resolved tilde : ~/
+	if s[:2] == "~/" {
+		if usr, err := user.Current(); err == nil {
+			s = filepath.Join(usr.HomeDir, s[2:])
+		}
+	}
+
+	// Resolved ${MYVAR}
+	re := regexp.MustCompile("\\${([^}]+)}")
+	vars := re.FindAllStringSubmatch(s, -1)
+	res := s
+	for _, v := range vars {
+		val := os.Getenv(v[1])
+		if val == "" {
+			return res, fmt.Errorf("ERROR: %s env variable not defined", v[1])
+		}
+
+		rer := regexp.MustCompile("\\${" + v[1] + "}")
+		res = rer.ReplaceAllString(res, val)
+	}
+
+	// Resolved $MYVAR following by a slash (or a backslash for Windows)
+	// TODO
+	//re := regexp.MustCompile("\\$([^\\/])+/")
+
+	return path.Clean(res), nil
+}