From 067b63ccbc6942a0399eb43d7fdf314b5c9b417f Mon Sep 17 00:00:00 2001
From: Michele Bologna <michele.bologna@suse.com>
Date: Thu, 14 Dec 2017 18:20:02 +0100
Subject: [PATCH] Feat: add grain for all FQDNs

This PR adds a grain named fqdns to the grains.
fqdns represents all the FQDNs known for the system on all available interfaces (excluding lo).

Note: hostname != FQDN

hostname is the UNIX name of the machine. A machine can have one and only one hostname.
FQDN is host.domain that resolves to an IP address that the machines is answering to.
A machine can have 1+ FQDNs.

Upstream PR:
https://github.com/saltstack/salt/pull/45060
---
 salt/grains/core.py                      | 27 +++++++++++++++++++++++++++
 tests/integration/modules/test_grains.py |  1 +
 tests/unit/grains/test_core.py           |  1 +
 3 files changed, 29 insertions(+)

diff --git a/salt/grains/core.py b/salt/grains/core.py
index 9352987abd..f8e36a895e 100644
--- a/salt/grains/core.py
+++ b/salt/grains/core.py
@@ -1890,6 +1890,33 @@ def append_domain():
     return grain
 
 
+def fqdns():
+    '''
+    Return all known FQDNs for the system by enumerating all interfaces and
+    then trying to reverse resolve them (excluding 'lo' interface).
+    '''
+    # Provides:
+    # fqdns
+
+    grains = {}
+    fqdns = set()
+
+    addresses = salt.utils.network.ip_addrs(include_loopback=False,
+        interface_data=_INTERFACES)
+    addresses.extend(salt.utils.network.ip_addrs6(include_loopback=False,
+        interface_data=_INTERFACES))
+
+    for ip in addresses:
+        try:
+            fqdns.add(socket.gethostbyaddr(ip)[0])
+        except (socket.error, socket.herror,
+            socket.gaierror, socket.timeout) as e:
+            log.error("Exception during resolving address: " + str(e))
+
+    grains['fqdns'] = list(fqdns)
+    return grains
+
+
 def ip_fqdn():
     '''
     Return ip address and FQDN grains
diff --git a/tests/integration/modules/test_grains.py b/tests/integration/modules/test_grains.py
index 709f882b45..aa7bd44202 100644
--- a/tests/integration/modules/test_grains.py
+++ b/tests/integration/modules/test_grains.py
@@ -51,6 +51,7 @@ class TestModulesGrains(ModuleCase):
             'cpuarch',
             'domain',
             'fqdn',
+            'fqdns',
             'gid',
             'groupname',
             'host',
diff --git a/tests/unit/grains/test_core.py b/tests/unit/grains/test_core.py
index e781fadefe..dba8d082c5 100644
--- a/tests/unit/grains/test_core.py
+++ b/tests/unit/grains/test_core.py
@@ -7,6 +7,7 @@
 from __future__ import absolute_import, print_function, unicode_literals
 import logging
 import os
+import socket
 
 # Import Salt Testing Libs
 try:
-- 
2.16.2