Fix Secret check_mode (#343)

When adding a Secret and using stringData, check_mode will always show
changes. An existing resource fetched from Kubernetes will have the
stringData already base64 encoded and merged into the data attribute.
This change performs the base64 encoding and merging with the provided
definition to more accurately represent the current state of the
cluster.

This change only affects check_mode. When making any changes to the
cluster the stringData is passed along as provided in the definition.

Closes #282.

changelogs/fragments/343-secret-check-mode.yaml

@@ -0,0 +1,2 @@
+bugfixes:
+  - k8s - fix check_mode always showing changes when using stringData on Secrets (https://github.com/ansible-collections/community.kubernetes/issues/282).

molecule/default/tasks/apply.yml

@@ -761,6 +761,81 @@
         that:
           - deploy_after_serviceaccount_removal is failed
 
+    - name: Add a secret
+      k8s:
+        definition:
+          apiVersion: v1
+          kind: Secret
+          metadata:
+            name: apply-secret
+            namespace: "{{ apply_namespace }}"
+          type: Opaque
+          stringData:
+            foo: bar
+      register: k8s_secret
+
+    - name: Check secret was created
+      assert:
+        that:
+          - k8s_secret is changed
+          - k8s_secret.result.data.foo
+
+    - name: Add same secret
+      k8s:
+        definition:
+          apiVersion: v1
+          kind: Secret
+          metadata:
+            name: apply-secret
+            namespace: "{{ apply_namespace }}"
+          type: Opaque
+          stringData:
+            foo: bar
+      register: k8s_secret
+
+    - name: Check nothing changed
+      assert:
+        that:
+          - k8s_secret is not changed
+
+    - name: Add same secret with check mode on
+      k8s:
+        definition:
+          apiVersion: v1
+          kind: Secret
+          metadata:
+            name: apply-secret
+            namespace: "{{ apply_namespace }}"
+          type: Opaque
+          stringData:
+            foo: bar
+      check_mode: yes
+      register: k8s_secret
+
+    - name: Check nothing changed
+      assert:
+        that:
+          - k8s_secret is not changed
+
+    - name: Add same secret with check mode on using data
+      k8s:
+        definition:
+          apiVersion: v1
+          kind: Secret
+          metadata:
+            name: apply-secret
+            namespace: "{{ apply_namespace }}"
+          type: Opaque
+          data:
+            foo: YmFy
+      check_mode: yes
+      register: k8s_secret
+
+    - name: Check nothing changed
+      assert:
+        that:
+          - k8s_secret is not changed
+
   always:
     - name: Remove namespace
       k8s:

plugins/module_utils/common.py

@@ -18,6 +18,7 @@
 from __future__ import absolute_import, division, print_function
 __metaclass__ = type
 
+import base64
 import time
 import os
 import traceback
@@ -28,7 +29,7 @@ from distutils.version import LooseVersion
 
 from ansible.module_utils.basic import AnsibleModule, missing_required_lib
 from ansible.module_utils.six import iteritems, string_types
-from ansible.module_utils._text import to_native
+from ansible.module_utils._text import to_native, to_bytes, to_text
 from ansible.module_utils.common.dict_transformations import dict_merge
 from ansible.module_utils.parsing.convert_bool import boolean
 
@@ -690,7 +691,7 @@ class K8sAnsibleMixin(object):
         else:
             if self.apply:
                 if self.check_mode:
-                    ignored, patch = apply_object(resource, definition)
+                    ignored, patch = apply_object(resource, _encode_stringdata(definition))
                     if existing:
                         k8s_obj = dict_merge(existing.to_dict(), patch)
                     else:
@@ -721,7 +722,7 @@ class K8sAnsibleMixin(object):
 
             if not existing:
                 if self.check_mode:
-                    k8s_obj = definition
+                    k8s_obj = _encode_stringdata(definition)
                 else:
                     try:
                         k8s_obj = resource.create(definition, namespace=namespace).to_dict()
@@ -757,7 +758,7 @@ class K8sAnsibleMixin(object):
 
             if existing and force:
                 if self.check_mode:
-                    k8s_obj = definition
+                    k8s_obj = _encode_stringdata(definition)
                 else:
                     try:
                         k8s_obj = resource.replace(definition, name=name, namespace=namespace, append_hash=self.append_hash).to_dict()
@@ -781,7 +782,7 @@ class K8sAnsibleMixin(object):
 
             # Differences exist between the existing obj and requested params
             if self.check_mode:
-                k8s_obj = dict_merge(existing.to_dict(), definition)
+                k8s_obj = dict_merge(existing.to_dict(), _encode_stringdata(definition))
             else:
                 if LooseVersion(self.openshift_version) < LooseVersion("0.6.2"):
                     k8s_obj, error = self.patch_resource(resource, definition, existing, name,
@@ -858,3 +859,12 @@ class KubernetesAnsibleModule(AnsibleModule, K8sAnsibleMixin):
 
         self.warn("class KubernetesAnsibleModule is deprecated"
                   " and will be removed in 2.0.0. Please use K8sAnsibleMixin instead.")
+
+
+def _encode_stringdata(definition):
+    if definition['kind'] == 'Secret' and 'stringData' in definition:
+        for k, v in definition['stringData'].items():
+            encoded = base64.b64encode(to_bytes(v))
+            definition.setdefault('data', {})[k] = to_text(encoded)
+        del definition['stringData']
+    return definition

tests/unit/module_utils/test_common.py

@@ -0,0 +1,39 @@
+# -*- coding: utf-8 -*-
+# Copyright: (c) 2021, Ansible Project
+# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
+
+from __future__ import absolute_import, division, print_function
+
+__metaclass__ = type
+
+
+from ansible_collections.community.kubernetes.plugins.module_utils.common import (
+    _encode_stringdata,
+)
+
+
+def test_encode_stringdata_modifies_definition():
+    definition = {
+        "apiVersion": "v1",
+        "kind": "Secret",
+        "type": "Opaque",
+        "stringData": {
+            "mydata": "ansiβle"
+        }
+    }
+    res = _encode_stringdata(definition)
+    assert "stringData" not in res
+    assert res["data"]["mydata"] == "YW5zac6ybGU="
+
+
+def test_encode_stringdata_does_not_modify_data():
+    definition = {
+        "apiVersion": "v1",
+        "kind": "Secret",
+        "type": "Opaque",
+        "data": {
+            "mydata": "Zm9vYmFy"
+        }
+    }
+    res = _encode_stringdata(definition)
+    assert res["data"]["mydata"] == "Zm9vYmFy"