From 0e6fc9de3aaeec9d82bc6087b2ad1d8ef17d3c67 Mon Sep 17 00:00:00 2001
From: Florian Haas <florian@hastexo.com>
Date: Fri, 13 Nov 2015 15:16:20 +0100
Subject: [PATCH] Add inventory script for LXC containers

Enables an LXC server's configuration as an inventory source for LXC
containers.

In LXC, containers can be defined with an "lxc.group" configuration
option that is normally used with lxc-autostart -g. Here, we are using
the same option to build Ansible inventory groups.

In addition to being grouped according to their lxc.group entry (or
entries, as LXC allows a single container to be in multiple groups),
we also add all containers (including those with no lxc.group entry)
to the "all" group.
---
 contrib/inventory/lxc_inventory.py | 67 ++++++++++++++++++++++++++++++
 1 file changed, 67 insertions(+)
 create mode 100755 contrib/inventory/lxc_inventory.py

diff --git a/contrib/inventory/lxc_inventory.py b/contrib/inventory/lxc_inventory.py
new file mode 100755
index 00000000000..d82bb618b99
--- /dev/null
+++ b/contrib/inventory/lxc_inventory.py
@@ -0,0 +1,67 @@
+#!/usr/bin/env python
+#
+# (c) 2015-16 Florian Haas, hastexo Professional Services GmbH
+# <florian@hastexo.com>
+# Based in part on:
+# libvirt_lxc.py, (c) 2013, Michael Scherer <misc@zarb.org>
+#
+# This file is part of Ansible,
+#
+# Ansible is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Ansible 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 Ansible.  If not, see <http://www.gnu.org/licenses/>.
+"""
+Ansible inventory script for LXC containers. Requires Python
+bindings for LXC API.
+
+In LXC, containers can be grouped by setting the lxc.group option,
+which may be found more than once in a container's
+configuration. So, we enumerate all containers, fetch their list
+of groups, and then build the dictionary in the way Ansible expects
+it.
+"""
+from __future__ import print_function
+
+import sys
+import lxc
+import json
+
+def build_dict():
+    """Returns a dictionary keyed to the defined LXC groups. All
+    containers, including the ones not in any group, are included in the
+    "all" group."""
+    # Enumerate all containers, and list the groups they are in. Also,
+    # implicitly add every container to the 'all' group.
+    containers = dict([(c,
+                        ['all'] +
+                        (lxc.Container(c).get_config_item('lxc.group') or []))
+                       for c in lxc.list_containers()])
+
+    # Extract the groups, flatten the list, and remove duplicates
+    groups = set(sum([g for g in containers.values()], []))
+
+    # Create a dictionary for each group (including the 'all' group
+    return dict([(g, {'hosts': [k for k, v in containers.items() if g in v],
+                      'vars': {'ansible_connection':'lxc'}}) for g in groups])
+
+def main(argv):
+    """Returns a JSON dictionary as expected by Ansible"""
+    result = build_dict()
+    if len(argv) == 2 and argv[1] == '--list':
+        json.dump(result, sys.stdout)
+    elif len(argv) == 3 and argv[1] == '--host':
+        json.dump({'ansible_connection': 'lxc'}, sys.stdout)
+    else:
+        print("Need an argument, either --list or --host <host>", file=sys.stderr)
+
+if __name__ == '__main__':
+    main(sys.argv)