ansible-inventory, add --limit option (#79596)

* ansible-inventory, add --limit option

* also graph

* optimize the when not providing limit

* added tests and clog

* avoid empty groups, fix tests

* i swear there as an ignore_errors there already!!?!?!?

* Fix stdout test fallback

Co-authored-by: Sloane Hertel <19572925+s-hertel@users.noreply.github.com>

* simpler approach using subset against inventory directly

* tyupose

* renamed funciton to what it actuall does
got yaml in line with others about removing empty groups

* have graph ignore limts, also note same for --host

* fixed typo long line

* better test

* cause hosvars are not a thing

---------

Co-authored-by: Matt Davis <6775756+nitzmahone@users.noreply.github.com>
Co-authored-by: Sloane Hertel <19572925+s-hertel@users.noreply.github.com>

changelogs/fragments/ainv_limit.yml

@@ -0,0 +1,2 @@
+minor_changes:
+  - ansible-inventory now supports the limit command line options.

lib/ansible/cli/inventory.py

@@ -72,7 +72,6 @@ class InventoryCLI(CLI):
         opt_help.add_runtask_options(self.parser)
 
         # remove unused default options
-        self.parser.add_argument('-l', '--limit', help=argparse.SUPPRESS, action=opt_help.UnrecognizedArgument, nargs='?')
         self.parser.add_argument('--list-hosts', help=argparse.SUPPRESS, action=opt_help.UnrecognizedArgument)
 
         self.parser.add_argument('args', metavar='host|group', nargs='?')
@@ -80,9 +79,10 @@ class InventoryCLI(CLI):
         # Actions
         action_group = self.parser.add_argument_group("Actions", "One of following must be used on invocation, ONLY ONE!")
         action_group.add_argument("--list", action="store_true", default=False, dest='list', help='Output all hosts info, works as inventory script')
-        action_group.add_argument("--host", action="store", default=None, dest='host', help='Output specific host info, works as inventory script')
+        action_group.add_argument("--host", action="store", default=None, dest='host',
+                                  help='Output specific host info, works as inventory script. It will ignore limit')
         action_group.add_argument("--graph", action="store_true", default=False, dest='graph',
-                                  help='create inventory graph, if supplying pattern it must be a valid group name')
+                                  help='create inventory graph, if supplying pattern it must be a valid group name. It will ignore limit')
         self.parser.add_argument_group(action_group)
 
         # graph
@@ -144,7 +144,12 @@ class InventoryCLI(CLI):
             # FIXME: should we template first?
             results = self.dump(myvars)
 
-        elif context.CLIARGS['graph']:
+        else:
+            if context.CLIARGS['subset']:
+                # not doing single host, set limit in general if given
+                self.inventory.subset(context.CLIARGS['subset'])
+
+            if context.CLIARGS['graph']:
                 results = self.inventory_graph()
             elif context.CLIARGS['list']:
                 top = self._get_group('all')
@@ -249,7 +254,7 @@ class InventoryCLI(CLI):
         return dump
 
     @staticmethod
-    def _remove_empty(dump):
+    def _remove_empty_keys(dump):
         # remove empty keys
         for x in ('hosts', 'vars', 'children'):
             if x in dump and not dump[x]:
@@ -302,7 +307,7 @@ class InventoryCLI(CLI):
             results = {}
             results[group.name] = {}
             if group.name != 'all':
-                results[group.name]['hosts'] = [h.name for h in group.hosts]
+                results[group.name]['hosts'] = [h.name for h in self.inventory.get_hosts(group.name)]
             results[group.name]['children'] = []
             for subgroup in group.child_groups:
                 results[group.name]['children'].append(subgroup.name)
@@ -312,7 +317,8 @@ class InventoryCLI(CLI):
             if context.CLIARGS['export']:
                 results[group.name]['vars'] = self._get_group_variables(group)
 
-            self._remove_empty(results[group.name])
+            self._remove_empty_keys(results[group.name])
+            # remove empty groups
             if not results[group.name]:
                 del results[group.name]
 
@@ -349,7 +355,7 @@ class InventoryCLI(CLI):
             # hosts for group
             results[group.name]['hosts'] = {}
             if group.name != 'all':
-                for h in group.hosts:
+                for h in self.inventory.get_hosts(group.name):
                     myvars = {}
                     if h.name not in seen:  # avoid defining host vars more than once
                         seen.append(h.name)
@@ -361,7 +367,10 @@ class InventoryCLI(CLI):
                 if gvars:
                     results[group.name]['vars'] = gvars
 
-            self._remove_empty(results[group.name])
+            self._remove_empty_keys(results[group.name])
+            # remove empty groups
+            if not results[group.name]:
+                del results[group.name]
 
             return results
 
@@ -384,7 +393,7 @@ class InventoryCLI(CLI):
                 results.update(format_group(subgroup))
 
             if group.name != 'all':
-                for host in group.hosts:
+                for host in self.inventory.get_hosts(group.name):
                     if host.name not in seen:
                         seen.add(host.name)
                         host_vars = self._get_host_variables(host=host)
@@ -398,7 +407,8 @@ class InventoryCLI(CLI):
             if context.CLIARGS['export']:
                 results[group.name]['vars'] = self._get_group_variables(group)
 
-            self._remove_empty(results[group.name])
+            self._remove_empty_keys(results[group.name])
+            # remove empty groups
             if not results[group.name]:
                 del results[group.name]
 

test/integration/targets/ansible-inventory/tasks/main.yml

@@ -145,3 +145,25 @@
   loop_control:
     loop_var: toml_package
   when: toml_package is not contains 'tomllib' or (toml_package is contains 'tomllib' and ansible_facts.python.version_info >= [3, 11])
+
+- name: check baseline
+  command: ansible-inventory -i '{{ role_path }}/files/valid_sample.yml' --list
+  register: limited
+
+- name: ensure empty host list
+  assert:
+    that:
+      - "'something' in inv['_meta']['hostvars']"
+  vars:
+    inv: '{{ limited.stdout|from_json}}'
+
+- name: check that limit removes host
+  command: ansible-inventory -i '{{ role_path }}/files/valid_sample.yml'  --limit '!something' --list
+  register: limited
+
+- name: ensure empty host list
+  assert:
+    that:
+      - "'something' not in inv['_meta']['hostvars']"
+  vars:
+    inv: '{{ limited.stdout|from_json}}'