Parse multiple values for single key in cmdline facts (#49591)

* Facts parsing for cmdline can now handle multiple values for a single key.
* Unit tests for cmdline fact parsing
* Review comments

Fixes: #22766

Signed-off-by: Abhijeet Kasurde <akasurde@redhat.com>

changelogs/fragments/22766-fact-cmdline-return_multiple_lvm_values.yaml

@@ -0,0 +1,2 @@
+minor_changes:
+- cmdline fact parsing can return multiple values of a single key. Deprecate cmdline fact in favor of proc_cmdline.

docs/docsite/rst/porting_guides/porting_guide_2.8.rst

@@ -55,6 +55,12 @@ In Ansible 2.7 and older::
     
     {{ foo.bar.baz if (foo is defined and foo.bar is defined and foo.bar.baz is defined) else 'DEFAULT' }}
 
+Command line facts
+------------------
+
+``cmdline`` facts returned in system will be deprecated in favor of ``proc_cmdline``. This change handles special case where Kernel command line parameter
+contains multiple values with the same key.
+
 Command Line
 ============
 

lib/ansible/module_utils/facts/system/cmdline.py

@@ -44,6 +44,27 @@ class CmdLineFactCollector(BaseFactCollector):
 
         return cmdline_dict
 
+    def _parse_proc_cmdline_facts(self, data):
+        cmdline_dict = {}
+        try:
+            for piece in shlex.split(data, posix=False):
+                item = piece.split('=', 1)
+                if len(item) == 1:
+                    cmdline_dict[item[0]] = True
+                else:
+                    if item[0] in cmdline_dict:
+                        if isinstance(cmdline_dict[item[0]], list):
+                            cmdline_dict[item[0]].append(item[1])
+                        else:
+                            new_list = [cmdline_dict[item[0]], item[1]]
+                            cmdline_dict[item[0]] = new_list
+                    else:
+                        cmdline_dict[item[0]] = item[1]
+        except ValueError:
+            pass
+
+        return cmdline_dict
+
     def collect(self, module=None, collected_facts=None):
         cmdline_facts = {}
 
@@ -53,4 +74,6 @@ class CmdLineFactCollector(BaseFactCollector):
             return cmdline_facts
 
         cmdline_facts['cmdline'] = self._parse_proc_cmdline(data)
+        cmdline_facts['proc_cmdline'] = self._parse_proc_cmdline_facts(data)
+
         return cmdline_facts

test/units/module_utils/facts/system/test_cmdline.py

@@ -0,0 +1,67 @@
+# unit tests for ansible system cmdline fact collectors
+# -*- coding: utf-8 -*-
+# Copyright: (c) 2018, Ansible Project
+# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
+
+from __future__ import absolute_import, division, print_function
+__metaclass__ = type
+
+import pytest
+from ansible.module_utils.facts.system.cmdline import CmdLineFactCollector
+
+test_data = [
+    (
+        "crashkernel=auto rd.lvm.lv=fedora_test-elementary-os/root rd.lvm.lv=fedora_test-elementary-os/swap rhgb quiet",
+        {
+            'crashkernel': 'auto',
+            'quiet': True,
+            'rd.lvm.lv': [
+                'fedora_test-elementary-os/root',
+                'fedora_test-elementary-os/swap',
+            ],
+            'rhgb': True
+        }
+    ),
+    (
+        "root=/dev/mapper/vg_ssd-root ro rd.lvm.lv=fedora_xenon/root rd.lvm.lv=fedora_xenon/swap rhgb quiet "
+        "resume=/dev/mapper/fedora_xenon-swap crashkernel=128M zswap.enabled=1",
+        {
+            'crashkernel': '128M',
+            'quiet': True,
+            'rd.lvm.lv': [
+                'fedora_xenon/root',
+                'fedora_xenon/swap'
+            ],
+            'resume': '/dev/mapper/fedora_xenon-swap',
+            'rhgb': True,
+            'ro': True,
+            'root': '/dev/mapper/vg_ssd-root',
+            'zswap.enabled': '1'
+        }
+    ),
+    (
+        "rhgb",
+        {
+            "rhgb": True
+        }
+    ),
+    (
+        "root=/dev/mapper/vg_ssd-root",
+        {
+            'root': '/dev/mapper/vg_ssd-root',
+        }
+    ),
+    (
+        "",
+        {},
+    )
+]
+
+test_ids = ['lvm_1', 'lvm_2', 'single_without_equal_sign', 'single_with_equal_sign', 'blank_cmdline']
+
+
+@pytest.mark.parametrize("cmdline, cmdline_dict", test_data, ids=test_ids)
+def test_cmd_line_factor(cmdline, cmdline_dict):
+    cmdline_facter = CmdLineFactCollector()
+    parsed_cmdline = cmdline_facter._parse_proc_cmdline_facts(data=cmdline)
+    assert parsed_cmdline == cmdline_dict