1 files changed, 53 insertions, 14 deletions

diff --git a/cloudinit/util.py b/cloudinit/util.py
index 5bf8e8b2..ba9becda 100644
--- a/cloudinit/util.py
+++ b/cloudinit/util.py
@@ -18,6 +18,7 @@
 import yaml
 import os
 import os.path
+import shutil
 import errno
 import subprocess
 from Cheetah.Template import Template
@@ -86,10 +87,24 @@ def get_cfg_option_str(yobj, key, default=None):
     return yobj[key]
 
 def get_cfg_option_list_or_str(yobj, key, default=None):
-    if not yobj.has_key(key): return default
-    if yobj[key] is None: return []
-    if isinstance(yobj[key],list): return yobj[key]
-    return([yobj[key]])
+    """
+    Gets the C{key} config option from C{yobj} as a list of strings. If the
+    key is present as a single string it will be returned as a list with one
+    string arg.
+
+    @param yobj: The configuration object.
+    @param key: The configuration key to get.
+    @param default: The default to return if key is not found.
+    @return: The configuration option as a list of strings or default if key
+        is not found.
+    """
+    if not key in yobj:
+        return default
+    if yobj[key] is None:
+        return []
+    if isinstance(yobj[key], list):
+        return yobj[key]
+    return [yobj[key]]
 
 # get a cfg entry by its path array
 # for f['a']['b']: get_cfg_by_path(mycfg,('a','b'))
@@ -100,27 +115,51 @@ def get_cfg_by_path(yobj,keyp,default=None):
         cur = cur[tok]
     return(cur)
 
-# merge values from cand into source
-# if src has a key, cand will not override
-def mergedict(src,cand):
-    if isinstance(src,dict) and isinstance(cand,dict):
-        for k,v in cand.iteritems():
+def mergedict(src, cand):
+    """
+    Merge values from C{cand} into C{src}. If C{src} has a key C{cand} will
+    not override. Nested dictionaries are merged recursively.
+    """
+    if isinstance(src, dict) and isinstance(cand, dict):
+        for k, v in cand.iteritems():
             if k not in src:
                 src[k] = v
             else:
-                src[k] = mergedict(src[k],v)
+                src[k] = mergedict(src[k], v)
     return src
 
-def write_file(filename,content,mode=0644,omode="wb"):
+def delete_dir_contents(dirname):
+    """
+    Deletes all contents of a directory without deleting the directory itself.
+
+    @param dirname: The directory whose contents should be deleted.
+    """
+    for node in os.listdir(dirname):
+        node_fullpath = os.path.join(dirname, node)
+        if os.path.isdir(node_fullpath):
+            shutil.rmtree(node_fullpath)
+        else:
+            os.unlink(node_fullpath)
+
+def write_file(filename, content, mode=0644, omode="wb"):
+    """
+    Writes a file with the given content and sets the file mode as specified.
+    Resotres the SELinux context if possible.
+
+    @param filename: The full path of the file to write.
+    @param content: The content to write to the file.
+    @param mode: The filesystem mode to set on the file.
+    @param omode: The open mode used when opening the file (r, rb, a, etc.)
+    """
     try:
         os.makedirs(os.path.dirname(filename))
     except OSError as e:
         if e.errno != errno.EEXIST:
             raise e
 
-    f=open(filename,omode)
-    if mode != None:
-        os.chmod(filename,mode)
+    f = open(filename, omode)
+    if mode is not None:
+        os.chmod(filename, mode)
     f.write(content)
     f.close()
     restorecon_if_possible(filename)