add initial logging support

This logging infrastructure in cloudinit:
- uses python logging
- allows user supplied config of logging.config.fileConfig format to be
  supplied in /etc/cloud/cloud.cfg or in cloud_config by user data.
- by default, tries to use syslog, if that is not available, writes directly to
  /var/log/cloud-init.log (syslog will not be available yet when cloud-init
  runs)
- when using syslog, the doc/21-cloudinit.conf file provides a rsyslogd
  file to be placed in /etc/rsyslog.d/ that will file [CLOUDINIT] messages
  to /var/log/cloud-init.log

1 files changed, 15 insertions, 4 deletions

diff --git a/cloudinit/util.py b/cloudinit/util.py
index 1c838fa8..79115355 100644
--- a/cloudinit/util.py
+++ b/cloudinit/util.py
@@ -20,12 +20,23 @@ import os
 import errno
 import subprocess
 from Cheetah.Template import Template
+import cloudinit
 
 def read_conf(fname):
-	stream = file(fname)
-	conf = yaml.load(stream)
-	stream.close()
-	return conf
+    try:
+	    stream = open(fname,"r")
+	    conf = yaml.load(stream)
+	    stream.close()
+	    return conf
+    except IOError as e:
+        if e.errno == errno.ENOENT:
+            return { }
+        raise
+
+def get_base_cfg(cfgfile=cloudinit.system_config):
+    syscfg = read_conf(cfgfile)
+    builtin = yaml.load(cloudinit.cfg_builtin)
+    return(mergedict(syscfg,builtin))
 
 def get_cfg_option_bool(yobj, key, default=False):
     if not yobj.has_key(key): return default