Add util function for creating/checking dirs

utils/fs.go

@@ -0,0 +1,42 @@
+package utils
+
+import (
+	"fmt"
+	"os"
+	"runtime"
+)
+
+// EnsureDirectory ensures that the given directoy exists and that is has the given permissions set.
+// If path is a file, it is deleted and a directory created.
+// If a directory is created, also all missing directories up to the required one are created with the given permissions.
+func EnsureDirectory(path string, perm os.FileMode) error {
+	// open path
+	f, err := os.Stat(path)
+	if err == nil {
+		// file exists
+		if f.IsDir() {
+			// directory exists, check permissions
+			if runtime.GOOS == "windows" {
+				// TODO: set correct permission on windows
+				// acl.Chmod(path, perm)
+			} else if f.Mode().Perm() != perm {
+				return os.Chmod(path, perm)
+			}
+			return nil
+		}
+		err = os.Remove(path)
+		if err != nil {
+			return fmt.Errorf("could not remove file %s to place dir: %s", path, err)
+		}
+	}
+	// file does not exist (or has been deleted)
+	if err == nil || os.IsNotExist(err) {
+		err = os.MkdirAll(path, perm)
+		if err != nil {
+			return fmt.Errorf("could not create dir %s: %s", path, err)
+		}
+		return nil
+	}
+	// other error opening path
+	return fmt.Errorf("failed to access %s: %s", path, err)
+}