Merged trunk lp:cloud-init

1 files changed, 58 insertions, 0 deletions

diff --git a/cloudinit/patcher.py b/cloudinit/patcher.py
new file mode 100644
index 00000000..0f3c034e
--- /dev/null
+++ b/cloudinit/patcher.py
@@ -0,0 +1,58 @@
+# vi: ts=4 expandtab
+#
+#    Copyright (C) 2012 Canonical Ltd.
+#    Copyright (C) 2012 Yahoo! Inc.
+#
+#    Author: Scott Moser <scott.moser@canonical.com>
+#    Author: Joshua Harlow <harlowja@yahoo-inc.com>
+#
+#    This program is free software: you can redistribute it and/or modify
+#    it under the terms of the GNU General Public License version 3, as
+#    published by the Free Software Foundation.
+#
+#    This program is distributed in the hope that it will be useful,
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#    GNU General Public License for more details.
+#
+#    You should have received a copy of the GNU General Public License
+#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+import imp
+import logging
+import sys
+
+# Default fallback format
+FALL_FORMAT = ('FALLBACK: %(asctime)s - %(filename)s[%(levelname)s]: ' +
+               '%(message)s')
+
+
+class QuietStreamHandler(logging.StreamHandler):
+    def handleError(self, record):
+        pass
+
+
+def _patch_logging():
+    # Replace 'handleError' with one that will be more
+    # tolerant of errors in that it can avoid
+    # re-notifying on exceptions and when errors
+    # do occur, it can at least try to write to
+    # sys.stderr using a fallback logger
+    fallback_handler = QuietStreamHandler(sys.stderr)
+    fallback_handler.setFormatter(logging.Formatter(FALL_FORMAT))
+
+    def handleError(self, record):  # pylint: disable=W0613
+        try:
+            fallback_handler.handle(record)
+            fallback_handler.flush()
+        except IOError:
+            pass
+    setattr(logging.Handler, 'handleError', handleError)
+
+
+def patch():
+    imp.acquire_lock()
+    try:
+        _patch_logging()
+    finally:
+        imp.release_lock()