updates to use tk after for backgrounded tasks, also added background task convenience class for running something in the background and running a callback using tk.after when done

daemon/core/gui/task.py

@@ -0,0 +1,29 @@
+import logging
+import threading
+
+
+class BackgroundTask:
+    def __init__(self, master, task, callback=None, args=()):
+        self.master = master
+        self.args = args
+        self.task = task
+        self.callback = callback
+        self.thread = None
+
+    def start(self):
+        logging.info("starting task")
+        self.thread = threading.Thread(target=self.run, daemon=True)
+        self.thread.start()
+
+    def run(self):
+        result = self.task(*self.args)
+        logging.info("task completed")
+        if self.callback:
+            if result is None:
+                args = ()
+            elif isinstance(result, (list, tuple)):
+                args = result
+            else:
+                args = (result,)
+            logging.info("calling callback: %s", args)
+            self.master.after(0, self.callback, *args)