Add a more generic API for notebook logging.

python/lsst/log/utils.py

@@ -100,3 +100,21 @@ def finish(self):
         os.dup2(self._filehandle, self._fd)
         os.close(self._filehandle)
         self._thread.join()
+
+
+_redirect = None
+
+
+def enable_notebook_logging(dest=sys.stderr):
+    """Enable notebook output for log4cxx messages."""
+    global _redirect
+    if _redirect is None:
+        _redirect = LogRedirect(dest=dest)
+
+
+def disable_notebook_logging():
+    """Stop notebook output for log4cxx messages."""
+    global _redirect
+    if _redirect is not None:
+        _redirect.finish()
+        _redirect = None