Implement the 'list-entities' action

This action is the first step needed to implement key rotation
in charmed Ceph.

Change-Id: I59012621a0d9a2a1197fd7f8f0155cf85a37a056

actions.yaml

@@ -443,3 +443,14 @@ pg-repair:
   description: "Repair inconsistent placement groups, if safe to do so."
 reset-osd-count-report:
   description: "Update report of osds present in osd tree. Used for monitoring."
+list-entities:
+  description: "Returns a list of entities recognized by the Ceph cluster."
+  params:
+    format:
+      type: string
+      enum:
+        - json
+        - yaml
+        - text
+      default: text
+      description: "The output format, either json, yaml or text (default)"

src/charm.py

@@ -228,6 +228,8 @@ class CephMonCharm(ops_openstack.core.OSBaseCharm):
                              ops_actions.get_health.get_health_action)
         self._observe_action(self.on.get_erasure_profile_action,
                              ops_actions.get_erasure_profile.erasure_profile)
+        self._observe_action(self.on.list_entities_action,
+                             ops_actions.list_entities.list_entities)
 
         fw.observe(self.on.install, self.on_install)
         fw.observe(self.on.config_changed, self.on_config)

src/ops_actions/__init__.py

@@ -19,4 +19,5 @@ from . import (   # noqa: F401
     create_erasure_profile,
     get_health,
     get_erasure_profile,
+    list_entities,
 )

src/ops_actions/list_entities.py

@@ -0,0 +1,53 @@
+#! /usr/bin/env python3
+#
+# Copyright 2024 Canonical Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#  http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Retrieve a list of entities recognized by the Ceph cluster."""
+
+import json
+import logging
+import subprocess
+import yaml
+
+
+logger = logging.getLogger(__name__)
+
+
+def list_entities(event):
+    try:
+        # NOTE(lmlg): Don't bother passing --format=json or the likes,
+        # since it sometimes contain escaped strings that are incompatible
+        # with python's json module. This method of fetching entities is
+        # simple enough and portable across Ceph versions.
+        out = subprocess.check_call(['sudo', 'ceph', 'auth', 'ls'])
+        ret = []
+
+        for line in out.decode('utf-8').split('\n'):
+            if line and not (line.startswith(' ') or line.startswith('\t') or
+                             line.startswith('\n')):
+                ret.append(line)
+
+        fmt = event.params.get('format', 'text')
+        if fmt == 'json':
+            msg = json.dumps(str(ret))
+        elif fmt == 'yaml':
+            msg = yaml.safe_dump(str(ret))
+        else:
+            msg = '\n'.join(ret)
+
+        event.set_results({'message': msg})
+    except Exception as e:
+        logger.warning(e)
+        event.fail('failed to list entities: {}'.format(str(e)))

unit_tests/test_ceph_actions.py

@@ -17,6 +17,7 @@ import subprocess
 
 import test_utils
 import ops_actions.copy_pool as copy_pool
+import ops_actions.list_entities as list_entities
 
 with mock.patch('charmhelpers.contrib.hardening.harden.harden') as mock_dec:
     mock_dec.side_effect = (lambda *dargs, **dkwargs: lambda f:
@@ -283,3 +284,26 @@ class GetErasureProfile(test_utils.CharmTestCase):
         event.set_results.assert_called_once_with((
             {"message": None}
         ))
+
+
+class ListEntities(test_utils.CharmTestCase):
+    """Run tests for action."""
+
+    def setUp(self):
+        self.harness = Harness(CephMonCharm)
+        self.harness.begin()
+        self.addCleanup(self.harness.cleanup)
+
+    @mock.patch.object(list_entities.subprocess, 'check_call')
+    def test_list_entities(self, check_call):
+        check_call.return_value = b"""
+client.admin
+  key: AQAOwwFmTR3TNxAAIsdYgastd0uKntPtEnoWug==
+mgr.0
+  key: AQAVwwFm/CmaJhAAdacns6DdFe4xZE1iwj8izg==
+"""
+        event = test_utils.MockActionEvent({})
+        self.harness.charm.on_list_entities_action(event)
+        event.set_results.assert_called_once_with(
+            {"message": "client.admin\nmgr.0"}
+        )