save_variables: Use threaded io

Signed-off-by: Timofey Titovets <nefelim4ag@gmail.com>

klippy/extras/save_variables.py

@@ -11,6 +11,8 @@ class SaveVariables:
         self.printer = config.get_printer()
         self.filename = os.path.expanduser(config.get('filename'))
         self.allVariables = {}
+        aio = self.printer.load_object(config, 'aio_executor')
+        self.executor = aio.allocate_executor("save_variables")
         try:
             if not os.path.exists(self.filename):
                 open(self.filename, "w").close()
@@ -24,7 +26,7 @@ class SaveVariables:
         allvars = {}
         varfile = configparser.ConfigParser()
         try:
-            varfile.read(self.filename)
+            self.executor.submit(varfile.read, self.filename)
             if varfile.has_section('Variables'):
                 for name, val in varfile.items('Variables'):
                     allvars[name] = ast.literal_eval(val)
@@ -51,9 +53,10 @@ class SaveVariables:
         for name, val in sorted(newvars.items()):
             varfile.set('Variables', name, repr(val))
         try:
-            f = open(self.filename, "w")
-            varfile.write(f)
-            f.close()
+            def write_out():
+                with open(self.filename, "w") as f:
+                    varfile.write(f)
+            self.executor.submit(write_out)
         except:
             msg = "Unable to save variable"
             logging.exception(msg)