Move hostfile line processing to new method.

cdist/config.py

@@ -89,6 +89,25 @@ class Config(object):
         self.local.create_files_dirs()
         self.remote.create_files_dirs()
 
+    @staticmethod
+    def hostfile_process_line(line):
+        """Return host from read line or None if no host present."""
+        if not line:
+            return None
+        # remove comment if present
+        comment_index = line.find('#')
+        if comment_index >= 0:
+            host = line[:comment_index]
+        else:
+            host = line
+        # remove leading and trailing whitespaces
+        host = host.strip()
+        # skip empty lines
+        if host:
+            return host
+        else:
+            return None
+
     @staticmethod
     def hosts(source):
         """Yield hosts from source.
@@ -99,13 +118,7 @@ class Config(object):
             import fileinput
             try:
                 for host in fileinput.input(files=(source)):
-                    # remove comment if present
+                    host = Config.hostfile_process_line(host)
-                    comment_index = host.find('#')
-                    if comment_index >= 0:
-                        host = host[:comment_index]
-                    # remove leading and trailing whitespaces
-                    host = host.strip()
-                    # skip empty lines
                     if host:
                         yield host
             except (IOError, OSError) as e: