Sync log.py from oslo

This change syncs log.py from oslo-incubator with commit
79e8a9a08daf563aa8a8d9280c9a6a27dcafc8f2

To honor RFC5424 add use_syslog_rfc_format config option
(default False, would be deprecated in J after existing
syslog format deprecation) which adds APP-NAME to syslog message
before MSG part to reflect application or service name.
Usable only with use_syslog, otherwise ignored.

During J, the default logging format for syslog should be changed
to always provide APP-NAME, thus use_syslog_rfc_format could be
deprecated in J as well.

Since the rootwrap code was graduating to a separate library,
so the rootwrap related change should just go into oslo.rootwrap
and when oslo.rootwrap is released, nova will pull in the library.

Change-Id: I6018c7322314a4b57052be1ec0fc5fa437069f44
Closes-bug: 904307

etc/nova/nova.conf.sample

@@ -1651,9 +1651,17 @@
 # Deprecated group/name - [DEFAULT]/logdir
 #log_dir=<None>
 
-# Use syslog for logging. (boolean value)
+# Use syslog for logging. Existing syslog format is DEPRECATED
+# during I, and then will be changed in J to honor RFC5424
+# (boolean value)
 #use_syslog=false
 
+# (Optional) Use syslog rfc5424 format for logging. If
+# enabled, will add APP-NAME (RFC5424) before the MSG part of
+# the syslog message.  The old format without APP-NAME is
+# deprecated in I, and will be removed in J. (boolean value)
+#use_syslog_rfc_format=false
+
 # syslog facility to receive log lines (string value)
 #syslog_log_facility=LOG_USER
 

nova/openstack/common/log.py

@@ -115,7 +115,18 @@ logging_cli_opts = [
                     '--log-file paths'),
     cfg.BoolOpt('use-syslog',
                 default=False,
-                help='Use syslog for logging.'),
+                help='Use syslog for logging. '
+                     'Existing syslog format is DEPRECATED during I, '
+                     'and then will be changed in J to honor RFC5424'),
+    cfg.BoolOpt('use-syslog-rfc-format',
+                # TODO(bogdando) remove or use True after existing
+                #    syslog format deprecation in J
+                default=False,
+                help='(Optional) Use syslog rfc5424 format for logging. '
+                     'If enabled, will add APP-NAME (RFC5424) before the '
+                     'MSG part of the syslog message.  The old format '
+                     'without APP-NAME is deprecated in I, '
+                     'and will be removed in J.'),
     cfg.StrOpt('syslog-log-facility',
                default='LOG_USER',
                help='syslog facility to receive log lines')
@@ -457,6 +468,17 @@ def _find_facility_from_conf():
     return facility
 
 
+class RFCSysLogHandler(logging.handlers.SysLogHandler):
+    def __init__(self, *args, **kwargs):
+        self.binary_name = _get_binary_name()
+        super(RFCSysLogHandler, self).__init__(*args, **kwargs)
+
+    def format(self, record):
+        msg = super(RFCSysLogHandler, self).format(record)
+        msg = self.binary_name + ' ' + msg
+        return msg
+
+
 def _setup_logging_from_conf():
     log_root = getLogger(None).logger
     for handler in log_root.handlers:
@@ -464,8 +486,14 @@ def _setup_logging_from_conf():
 
     if CONF.use_syslog:
         facility = _find_facility_from_conf()
-        syslog = logging.handlers.SysLogHandler(address='/dev/log',
-                                                facility=facility)
+        # TODO(bogdando) use the format provided by RFCSysLogHandler
+        #   after existing syslog format deprecation in J
+        if CONF.use_syslog_rfc_format:
+            syslog = RFCSysLogHandler(address='/dev/log',
+                                      facility=facility)
+        else:
+            syslog = logging.handlers.SysLogHandler(address='/dev/log',
+                                                    facility=facility)
         log_root.addHandler(syslog)
 
     logpath = _get_log_file_path()