adds timeout check when network_cli run without persistence (#20299)

* checks if signal hander is set and sets it if not (will be set if coming
  from ansible-connection)
* will now timeout long running commands based on DEFAULT_TIMEOUT setting

lib/ansible/plugins/connection/network_cli.py

@@ -24,6 +24,7 @@ import json
 import signal
 import datetime
 
+from ansible import constants as C
 from ansible.errors import AnsibleConnectionFailure
 from ansible.module_utils.six.moves import StringIO
 from ansible.plugins import terminal_loader
@@ -203,6 +204,7 @@ class Connection(_Connection):
 
     def alarm_handler(self, signum, frame):
         """Alarm handler raised in case of command timeout """
+        display.debug('alarm_handler fired!')
         self.close_shell()
 
     def exec_command(self, cmd):
@@ -242,7 +244,12 @@ class Connection(_Connection):
             return (1, '', str(exc))
 
         try:
+            if not signal.getsignal(signal.SIGALRM):
+                display.debug('setting alarm handler in network_cli')
+                signal.signal(signal.SIGALRM, self.alarm_handler)
+            signal.alarm(C.DEFAULT_TIMEOUT)
             out = self.send(obj)
+            signal.alarm(0)
             return (0, out, '')
         except (AnsibleConnectionFailure, ValueError) as exc:
             return (1, '', str(exc))