Allow for creating yum repo based on metalink only (#30736)

lib/ansible/modules/packaging/os/yum_repository.py

@@ -49,7 +49,7 @@ options:
       - URL to the directory where the yum repository's 'repodata' directory
         lives.
       - It can also be a list of multiple URLs.
-      - This or the I(mirrorlist) parameter is required if I(state) is set to
+      - This, the I(metalink) or I(mirrorlist) parameters are required if I(state) is set to
         C(present).
   cost:
     required: false
@@ -219,12 +219,14 @@ options:
       - Specifies a URL to a metalink file for the repomd.xml, a list of
         mirrors for the entire repository are generated by converting the
         mirrors for the repomd.xml file to a I(baseurl).
+      - This, the I(baseurl) or I(mirrorlist) parameters are required if I(state) is set to
+        C(present).
   mirrorlist:
     required: false
     default: null
     description:
       - Specifies a URL to a file containing a list of baseurls.
-      - This or the I(baseurl) parameter is required if I(state) is set to
+      - This, the I(baseurl) or I(metalink) parameters are required if I(state) is set to
         C(present).
   mirrorlist_expire:
     required: false
@@ -563,10 +565,11 @@ class YumRepo(object):
         # Baseurl/mirrorlist is not required because for removal we need only
         # the repo name. This is why we check if the baseurl/mirrorlist is
         # defined.
-        if (self.params['baseurl'], self.params['mirrorlist']) == (None, None):
+        req_params = (self.params['baseurl'], self.params['metalink'], self.params['mirrorlist'])
+        if req_params == (None, None, None):
             self.module.fail_json(
-                msg='Parameter "baseurl" or "mirrorlist" is required for '
-                'adding a new repo.')
+                msg="Parameter 'baseurl', 'metalink' or 'mirrorlist' is required for "
+                    "adding a new repo.")
 
         # Set options
         for key, value in sorted(self.params.items()):
@@ -709,9 +712,10 @@ def main():
     if state == 'present':
         if (
                 module.params['baseurl'] is None and
+                module.params['metalink'] is None and
                 module.params['mirrorlist'] is None):
             module.fail_json(
-                msg="Parameter 'baseurl' or 'mirrorlist' is required.")
+                msg="Parameter 'baseurl', 'metalink' or 'mirrorlist' is required.")
         if module.params['description'] is None:
             module.fail_json(
                 msg="Parameter 'description' is required.")