Provide a mechanism to hide fields from output (#629)

Provide a mechanism to hide fields from output

SUMMARY
The k8s and k8s_info modules can be a little noisy in verbose mode, and most of that is due to managedFields.
If we can provide a mechanism to hide managedFields, the output is a lot more useful.
ISSUE TYPE

Feature Pull Request

COMPONENT NAME
k8s, k8s_info
ADDITIONAL INFORMATION
Before
ANSIBLE_COLLECTIONS_PATH=../../.. ansible -m k8s_info -a 'kind=ConfigMap name=hide-fields-cm namespace=hide-fields' localhost 
[WARNING]: No inventory was parsed, only implicit localhost is available
localhost | SUCCESS => {
    "api_found": true,
    "changed": false,
    "resources": [
        {
            "apiVersion": "v1",
            "data": {
                "another": "value",
                "hello": "world"
            },
            "kind": "ConfigMap",
            "metadata": {
                "annotations": {
                    "kubectl.kubernetes.io/last-applied-configuration": "{\"apiVersion\":\"v1\",\"data\":{\"another\":\"value\",\"hello\":\"world\"},\"kind\":\"ConfigMap\",\"metadata\":{\"annotations\":{},\"name\":\"hide-fields-cm\",\"namespace\":\"hide-fields\"}}\n"
                },
                "creationTimestamp": "2023-06-13T01:47:47Z",
                "managedFields": [
                    {
                        "apiVersion": "v1",
                        "fieldsType": "FieldsV1",
                        "fieldsV1": {
                            "f:data": {
                                ".": {},
                                "f:another": {},
                                "f:hello": {}
                            },
                            "f:metadata": {
                                "f:annotations": {
                                    ".": {},
                                    "f:kubectl.kubernetes.io/last-applied-configuration": {}
                                }
                            }
                        },
                        "manager": "kubectl-client-side-apply",
                        "operation": "Update",
                        "time": "2023-06-13T01:47:47Z"
                    }
                ],
                "name": "hide-fields-cm",
                "namespace": "hide-fields",
                "resourceVersion": "2557394",
                "uid": "f233da63-6374-4079-9825-3562c0ed123c"
            }
        }
    ]
}

After
ANSIBLE_COLLECTIONS_PATH=../../.. ansible -m k8s_info -a 'kind=ConfigMap name=hide-fields-cm namespace=hide-fields hidden_fields=metadata.managedFields' localhost
[WARNING]: No inventory was parsed, only implicit localhost is available
localhost | SUCCESS => {
    "api_found": true,
    "changed": false,
    "resources": [
        {
            "apiVersion": "v1",
            "data": {
                "another": "value",
                "hello": "world"
            },
            "kind": "ConfigMap",
            "metadata": {
                "annotations": {
                    "kubectl.kubernetes.io/last-applied-configuration": "{\"apiVersion\":\"v1\",\"data\":{\"another\":\"value\",\"hello\":\"world\"},\"kind\":\"ConfigMap\",\"metadata\":{\"annotations\":{},\"name\":\"hide-fields-cm\",\"namespace\":\"hide-fields\"}}\n"
                },
                "creationTimestamp": "2023-06-13T01:47:47Z",
                "name": "hide-fields-cm",
                "namespace": "hide-fields",
                "resourceVersion": "2557394",
                "uid": "f233da63-6374-4079-9825-3562c0ed123c"
            }
        }
    ]
}

Reviewed-by: Mike Graves <mgraves@redhat.com>
Reviewed-by: Will Thames

plugins/module_utils/k8s/runner.py

@@ -17,6 +17,7 @@ from ansible_collections.kubernetes.core.plugins.module_utils.k8s.resource impor
 from ansible_collections.kubernetes.core.plugins.module_utils.k8s.service import (
     K8sService,
     diff_objects,
+    hide_fields,
 )
 from ansible_collections.kubernetes.core.plugins.module_utils.k8s.exceptions import (
     ResourceTimeout,
@@ -137,6 +138,7 @@ def perform_action(svc, definition: Dict, params: Dict) -> Dict:
     state = params.get("state", None)
     kind = definition.get("kind")
     api_version = definition.get("apiVersion")
+    hidden_fields = params.get("hidden_fields")
 
     result = {"changed": False, "result": {}}
     instance = {}
@@ -212,7 +214,7 @@ def perform_action(svc, definition: Dict, params: Dict) -> Dict:
             existing = existing.to_dict()
         else:
             existing = {}
-        match, diffs = diff_objects(existing, instance)
+        match, diffs = diff_objects(existing, instance, hidden_fields)
         if match and diffs:
             result.setdefault("warnings", []).append(
                 "No meaningful diff was generated, but the API may not be idempotent "
@@ -222,7 +224,7 @@ def perform_action(svc, definition: Dict, params: Dict) -> Dict:
         if svc.module._diff:
             result["diff"] = diffs
 
-    result["result"] = instance
+    result["result"] = hide_fields(instance, hidden_fields)
     if not success:
         raise ResourceTimeout(
             '"{0}" "{1}": Timed out waiting on resource'.format(

plugins/module_utils/k8s/service.py

@@ -1,6 +1,7 @@
 # Copyright: (c) 2021, Red Hat | Ansible
 # GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
 
+import copy
 from typing import Any, Dict, List, Optional, Tuple
 
 from ansible_collections.kubernetes.core.plugins.module_utils.hashes import (
@@ -248,6 +249,7 @@ class K8sService:
         wait_timeout: Optional[int] = 120,
         state: Optional[str] = "present",
         condition: Optional[Dict] = None,
+        hidden_fields: Optional[List] = None,
     ) -> Dict:
         resource = self.find_resource(kind, api_version)
         api_found = bool(resource)
@@ -310,7 +312,9 @@ class K8sService:
         instances = resources.get("items") or [resources]
 
         if not wait:
-            result["resources"] = instances
+            result["resources"] = [
+                hide_fields(instance, hidden_fields) for instance in instances
+            ]
             return result
 
         # Now wait for the specified state of any resource instances we have found.
@@ -329,7 +333,7 @@ class K8sService:
                     "Failed to gather information about %s(s) even"
                     " after waiting for %s seconds" % (res.get("kind"), duration)
                 )
-            result["resources"].append(res)
+            result["resources"].append(hide_fields(res, hidden_fields))
         return result
 
     def create(self, resource: Resource, definition: Dict) -> Dict:
@@ -495,7 +499,9 @@ class K8sService:
         return k8s_obj
 
 
-def diff_objects(existing: Dict, new: Dict) -> Tuple[bool, Dict]:
+def diff_objects(
+    existing: Dict, new: Dict, hidden_fields: Optional[list] = None
+) -> Tuple[bool, Dict]:
     result = {}
     diff = recursive_diff(existing, new)
     if not diff:
@@ -517,4 +523,29 @@ def diff_objects(existing: Dict, new: Dict) -> Tuple[bool, Dict]:
     if not set(result["before"]["metadata"].keys()).issubset(ignored_keys):
         return False, result
 
+    result["before"] = hide_fields(result["before"], hidden_fields)
+    result["after"] = hide_fields(result["after"], hidden_fields)
+
     return True, result
+
+
+def hide_fields(definition: dict, hidden_fields: Optional[list]) -> dict:
+    if not hidden_fields:
+        return definition
+    result = copy.deepcopy(definition)
+    for hidden_field in hidden_fields:
+        result = hide_field(result, hidden_field)
+    return result
+
+
+# hide_field is not hugely sophisticated and designed to cope
+# with e.g. status or metadata.managedFields rather than e.g.
+# spec.template.spec.containers[0].env[3].value
+def hide_field(definition: dict, hidden_field: str) -> dict:
+    split = hidden_field.split(".", 1)
+    if split[0] in definition:
+        if len(split) == 2:
+            definition[split[0]] = hide_field(definition[split[0]], split[1])
+        else:
+            del definition[split[0]]
+    return definition