1 files changed, 48 insertions, 0 deletions
diff --git a/klippy/queuelogger.py b/klippy/queuelogger.py
new file mode 100644
index 00000000..8494c6a8
--- /dev/null
+++ b/klippy/queuelogger.py
@@ -0,0 +1,48 @@
+# Code to implement asynchronous logging from a background thread
+#
+# Copyright (C) 2016  Kevin O'Connor <kevin@koconnor.net>
+#
+# This file may be distributed under the terms of the GNU GPLv3 license.
+import logging, threading, Queue
+
+# Class to forward all messages through a queue to a background thread
+class QueueHandler(logging.Handler):
+    def __init__(self, queue):
+        logging.Handler.__init__(self)
+        self.queue = queue
+    def emit(self, record):
+        try:
+            self.format(record)
+            record.msg = record.message
+            record.args = None
+            record.exc_info = None
+            self.queue.put_nowait(record)
+        except Exception:
+            self.handleError(record)
+
+# Class to poll a queue in a background thread and log each message
+class QueueListener(object):
+    def __init__(self, handler):
+        self.handler = handler
+        self.queue = Queue.Queue()
+        self.thread = threading.Thread(target=self._bg_thread)
+        self.thread.start()
+    def _bg_thread(self):
+        while 1:
+            record = self.queue.get(True)
+            if record is None:
+                break
+            self.handler.handle(record)
+    def stop(self):
+        self.queue.put_nowait(None)
+        self.thread.join()
+
+def setup_bg_logging(filename, debuglevel):
+    logoutput = open(filename, 'wb')
+    handler = logging.StreamHandler(logoutput)
+    ql = QueueListener(handler)
+    qh = QueueHandler(ql.queue)
+    root = logging.getLogger()
+    root.addHandler(qh)
+    root.setLevel(debuglevel)
+    return ql