wip - write in place

pkg/yqlib/file_utils.go

@@ -0,0 +1,50 @@
+package yqlib
+
+import (
+	"io"
+	"os"
+)
+
+func safelyRenameFile(from string, to string) {
+	if renameError := os.Rename(from, to); renameError != nil {
+		log.Debugf("Error renaming from %v to %v, attempting to copy contents", from, to)
+		log.Debug(renameError.Error())
+		// can't do this rename when running in docker to a file targeted in a mounted volume,
+		// so gracefully degrade to copying the entire contents.
+		if copyError := copyFileContents(from, to); copyError != nil {
+			log.Errorf("Failed copying from %v to %v", from, to)
+			log.Error(copyError.Error())
+		} else {
+			removeErr := os.Remove(from)
+			if removeErr != nil {
+				log.Errorf("failed removing original file: %s", from)
+			}
+		}
+	}
+}
+
+// thanks https://stackoverflow.com/questions/21060945/simple-way-to-copy-a-file-in-golang
+func copyFileContents(src, dst string) (err error) {
+	in, err := os.Open(src) // nolint gosec
+	if err != nil {
+		return err
+	}
+	defer safelyCloseFile(in)
+	out, err := os.Create(dst)
+	if err != nil {
+		return err
+	}
+	defer safelyCloseFile(out)
+	if _, err = io.Copy(out, in); err != nil {
+		return err
+	}
+	return out.Sync()
+}
+
+func safelyCloseFile(file *os.File) {
+	err := file.Close()
+	if err != nil {
+		log.Error("Error closing file!")
+		log.Error(err.Error())
+	}
+}