release: 0.2.1

fix "rename invalid cross-device link"

Makefile

@@ -1,5 +1,5 @@
 NAME=multini
-VERSION=0.2
+VERSION=0.2.1
 GOCMD=go
 LDFLAGS:="$(LDFLAGS) -X 'main.Version=$(VERSION)'"
 GOBUILD=$(GOCMD) build -ldflags=$(LDFLAGS)

writer.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"bufio"
+	"io"
 	"io/ioutil"
 	"os"
 	"path/filepath"
@@ -9,6 +10,47 @@ import (
 	"multini/types"
 )
 
+// Source: https://gist.github.com/var23rav/23ae5d0d4d830aff886c3c970b8f6c6b
+/*
+   GoLang: os.Rename() give error "invalid cross-device link" for Docker container with Volumes.
+   MoveFile(source, destination) will work moving file between folders
+*/
+func tryMoveFile(sourcePath, destPath string) error {
+	inputFile, err := os.Open(sourcePath)
+	if err != nil {
+		return err
+	}
+	outputFile, err := os.Create(destPath)
+	if err != nil {
+		inputFile.Close()
+		return err
+	}
+	defer outputFile.Close()
+	_, err = io.Copy(outputFile, inputFile)
+	inputFile.Close()
+	if err != nil {
+		return err
+	}
+	// The copy was successful, so now delete the original file
+	err = os.Remove(sourcePath)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func tryRemoveRenameFile(sourcePath, destPath string) bool {
+	err := os.Remove(destPath)
+	if err != nil {
+		return false
+	}
+	err = os.Rename(sourcePath, destPath)
+	if err != nil {
+		return false
+	}
+	return true
+}
+
 func replaceOriginal(oldFile, newFile string) error {
 	realOldFile, err := filepath.EvalSymlinks(oldFile)
 	if err != nil {
@@ -23,14 +65,11 @@ func replaceOriginal(oldFile, newFile string) error {
 
 	var uid, gid int = GetUidGid(infoOldFile)
 
-	err = os.Remove(realOldFile)
+	if !tryRemoveRenameFile(newFile, realOldFile) {
+		err = tryMoveFile(newFile, realOldFile)
 		if err != nil {
 			return err
 		}
-
-	err = os.Rename(newFile, realOldFile)
-	if err != nil {
-		return err
 	}
 
 	err = os.Chmod(realOldFile, mode)