Add local and NetBox server notes and improve reliability

internal/storage/file.go

@@ -0,0 +1,32 @@
+// Package storage provides atomic file replacement in the destination directory.
+package storage
+
+import (
+	"os"
+	"path/filepath"
+)
+
+func WriteFile(path string, data []byte, mode os.FileMode) error {
+	if err := os.MkdirAll(filepath.Dir(path), 0o700); err != nil {
+		return err
+	}
+	f, err := os.CreateTemp(filepath.Dir(path), ".netssh-*")
+	if err != nil {
+		return err
+	}
+	defer os.Remove(f.Name())
+	defer f.Close()
+	if err := f.Chmod(mode); err != nil {
+		return err
+	}
+	if _, err := f.Write(data); err != nil {
+		return err
+	}
+	if err := f.Sync(); err != nil {
+		return err
+	}
+	if err := f.Close(); err != nil {
+		return err
+	}
+	return os.Rename(f.Name(), path)
+}