Do domain resolution for portal (#461)

* Do domain resolution for portal

iscsiadm support domain resolution (ex: iscsiadm -m discovery -t sendtargets -p iscsi.chiehmin.com).
However, open_iscsi module will try to match the portal with discovered results which will never
matched cause the discovered results use IP to represent node.

This patch do portal DNS resolution first to solve this situation.

Signed-off-by: Chieh-Min Wang <chiehminw@synology.com>

* Update changelogs/fragments/461-resolve-domain-for-iscsi-portal.yml

Co-authored-by: Andrew Klychkov <aaklychkov@mail.ru>

Co-authored-by: Andrew Klychkov <aaklychkov@mail.ru>

changelogs/fragments/461-resolve-domain-for-iscsi-portal.yml

@@ -0,0 +1,2 @@
+minor_changes:
+- open_iscsi - allow ``portal`` parameter to be a domain name by resolving the portal ip address beforehand (https://github.com/ansible-collections/community.general/pull/461).

plugins/modules/system/open_iscsi.py

@@ -21,7 +21,7 @@ requirements:
 options:
     portal:
         description:
-        - The IP address of the iSCSI target.
+        - The domain name or IP address of the iSCSI target.
         type: str
         aliases: [ ip ]
     port:
@@ -72,11 +72,17 @@ options:
 '''
 
 EXAMPLES = r'''
+- name: Perform a discovery on sun.com and show available target nodes
+  open_iscsi:
+    show_nodes: yes
+    discover: yes
+    portal: sun.com
+
 - name: Perform a discovery on 10.1.2.3 and show available target nodes
   open_iscsi:
     show_nodes: yes
     discover: yes
-    portal: 10.1.2.3
+    ip: 10.1.2.3
 
 # NOTE: Only works if exactly one target is exported to the initiator
 - name: Discover targets on portal and login to the one available
@@ -98,6 +104,7 @@ EXAMPLES = r'''
 
 import glob
 import os
+import socket
 import time
 
 from ansible.module_utils.basic import AnsibleModule
@@ -270,6 +277,12 @@ def main():
 
     # parameters
     portal = module.params['portal']
+    if portal:
+        try:
+            portal = socket.getaddrinfo(portal, None)[0][4][0]
+        except socket.gaierror:
+            module.fail_json(msg="Portal address is incorrect")
+
     target = module.params['target']
     port = module.params['port']
     login = module.params['login']