Fix nagios module to recognize if file exists and is fifo pipe (#58569)

add felixfontein suggestion to changelogs/fragments/58569-nagios-fifo-fix.yaml

Co-Authored-By: Felix Fontein <felix@fontein.de>
(cherry picked from commit faf50dbace)

changelogs/fragments/58569-nagios-fifo-fix.yaml

@@ -0,0 +1,2 @@
+bugfixes:
+  - nagios module - Fix nagios module to recognize if ``cmdfile`` exists and is fifo pipe.

lib/ansible/modules/monitoring/nagios.py

@@ -196,6 +196,7 @@ EXAMPLES = '''
 import types
 import time
 import os.path
+import stat
 
 from ansible.module_utils.basic import AnsibleModule
 
@@ -389,6 +390,12 @@ class Nagios(object):
         Write the given command to the Nagios command file
         """
 
+        if not os.path.exists(self.cmdfile):
+            self.module.fail_json(msg='nagios command file does not exist',
+                                  cmdfile=self.cmdfile)
+        if not stat.S_ISFIFO(os.stat(self.cmdfile).st_mode):
+            self.module.fail_json(msg='nagios command file is not a fifo file',
+                                  cmdfile=self.cmdfile)
         try:
             fp = open(self.cmdfile, 'w')
             fp.write(cmd)