From 80eb53deb9f80694c5fd0e0190197de1ff496716 Mon Sep 17 00:00:00 2001
From: Joshua Harlow <harlowja@yahoo-inc.com>
Date: Wed, 10 Oct 2012 16:21:22 -0700
Subject: System config niceness!

1. Move out the old helpers that provided oop access/reading/writing
   to various standard conf files and place those in parsers instead.
2. Unify the 'update_hostname' which varied very little	between	distros
   and make it generic so that subclasses can only provide a couple of
   functions to	obtain the hostname updating functionality
3. Implement that new set of functions in rhel/debian
4. Use the new parsers chop_comment function for similar use
   cases as well as add a new utils make header	function that
   can be used for configuration files that are	newly generated
   to use (less	duplication here of this same thing being done
   in multiple places.
5. Add in a distro '_apply_hostname' which calls out to	the 'hostname'
   program to set the system hostname (more duplication	elimination).
6. Make the 'constant' filenames being written to for configuration
   by the various distros be instance members instead of string
   constants 'sprinkled' throughout the code
---
 cloudinit/distros/parsers/hosts.py | 92 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 92 insertions(+)
 create mode 100644 cloudinit/distros/parsers/hosts.py

(limited to 'cloudinit/distros/parsers/hosts.py')

diff --git a/cloudinit/distros/parsers/hosts.py b/cloudinit/distros/parsers/hosts.py
new file mode 100644
index 00000000..5374ab0b
--- /dev/null
+++ b/cloudinit/distros/parsers/hosts.py
@@ -0,0 +1,92 @@
+# vi: ts=4 expandtab
+#
+#    Copyright (C) 2012 Yahoo! Inc.
+#
+#    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/>.
+
+from StringIO import StringIO
+
+from cloudinit.distros.parsers import chop_comment
+
+
+# See: man hosts
+# or http://unixhelp.ed.ac.uk/CGI/man-cgi?hosts
+class HostsConf(object):
+    def __init__(self, text):
+        self._text = text
+        self._contents = None
+
+    def parse(self):
+        if self._contents is None:
+            self._contents = self._parse(self._text)
+
+    def get_entry(self, ip):
+        self.parse()
+        options = []
+        for (line_type, components) in self._contents:
+            if line_type == 'option':
+                (pieces, _tail) = components
+                if len(pieces) and pieces[0] == ip:
+                    options.append(pieces[1:])
+        return options
+
+    def del_entries(self, ip):
+        self.parse()
+        n_entries = []
+        for (line_type, components) in self._contents:
+            if line_type != 'option':
+                n_entries.append((line_type, components))
+                continue
+            else:
+                (pieces, _tail) = components
+                if len(pieces) and pieces[0] == ip:
+                    pass
+                elif len(pieces):
+                    n_entries.append((line_type, list(components)))
+        self._contents = n_entries
+
+    def add_entry(self, ip, canonical_hostname, *aliases):
+        self.parse()
+        self._contents.append(('option',
+                              ([ip, canonical_hostname] + list(aliases), '')))
+
+    def _parse(self, contents):
+        entries = []
+        for line in contents.splitlines():
+            if not len(line.strip()):
+                entries.append(('blank', [line]))
+                continue
+            (head, tail) = chop_comment(line.strip(), '#')
+            if not len(head):
+                entries.append(('all_comment', [line]))
+                continue
+            entries.append(('option', [head.split(None), tail]))
+        return entries
+
+    def __str__(self):
+        self.parse()
+        contents = StringIO()
+        for (line_type, components) in self._contents:
+            if line_type == 'blank':
+                contents.write("%s\n")
+            elif line_type == 'all_comment':
+                contents.write("%s\n" % (components[0]))
+            elif line_type == 'option':
+                (pieces, tail) = components
+                pieces = [str(p) for p in pieces]
+                pieces = "\t".join(pieces)
+                contents.write("%s%s\n" % (pieces, tail))
+        return contents.getvalue()
+
-- 
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