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-rw-r--r--cloudinit/monkey_patch.py74
1 files changed, 74 insertions, 0 deletions
diff --git a/cloudinit/monkey_patch.py b/cloudinit/monkey_patch.py
new file mode 100644
index 00000000..24b472ba
--- /dev/null
+++ b/cloudinit/monkey_patch.py
@@ -0,0 +1,74 @@
+# 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 logging
+import sys
+
+FALL_FORMAT = 'FALLBACK: %(asctime)s - %(filename)s[%(levelname)s]: %(message)s'
+
+Handler = logging.Handler
+
+class QuietStreamHandler(Handler):
+ def handleError(self, record):
+ pass
+
+
+class FallbackHandler(Handler):
+ def __init__(self, level=logging.NOTSET, fb_handler=None):
+ super(FallbackHandler, self).__init__(level)
+ if not fb_handler:
+ self.fallback_handler = QuietStreamHandler(sys.stderr)
+ else:
+ self.fallback_handler = fb_handler
+ self.fallback_handler.setFormatter(logging.Formatter(FALL_FORMAT))
+ self.fallback_handler.setLevel(level)
+
+ def flush(self):
+ super(FallbackHandler, self).flush()
+ self.fallback_handler.flush()
+
+ def close(self):
+ super(FallbackHandler, self).close(self)
+ self.fallback_handler.close()
+
+ def setLevel(self, level):
+ super(FallbackHandler, self).setLevel(self, level)
+ self.fallback_logger.setLevel(level)
+
+ def handleError(self, record):
+ try:
+ self.fallback_logger.handle(record)
+ # Always ensure this one is flushed...
+ self.fallback_logger.flush()
+ except:
+ pass
+
+
+def _patch_logging():
+ # Replace handler 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
+ logging.Handler = FallbackHandler
+
+
+def patch():
+ _patch_logging()