Add get-admin-password action with unit test

Implemented a new action to provide users the possibility of
retrieving Keystone service's admin password via juju action.
The result of this action is equivalent to running
“juju run --unit {keystone unit} leader-get admin_passwd”.

Closes-Bug: #1858657
Change-Id: I231c4b73016f7e7b4ba7f06219dd8e212402a339

actions.yaml

@@ -14,4 +14,8 @@ openstack-upgrade:
     Perform openstack upgrades. Config option action-managed-upgrade must be
     set to True.
 security-checklist:
-  description: Validate the running configuration against the OpenStack security guides checklist
+  description: |
+    Validate the running configuration against the OpenStack security guides
+    checklist.
+get-admin-password:
+  description: Retrieve the admin password for the Keystone service.

actions/admin_password.py

@@ -0,0 +1,53 @@
+#!/usr/bin/env python3
+#
+# Copyright 2022 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.
+
+import os
+import sys
+
+sys.path.append('.')
+
+from charmhelpers.core.hookenv import (
+    function_set,
+    function_fail,
+    leader_get,
+)
+
+
+def get_admin_password(arg):
+    """Implementation of 'get-admin-password' action."""
+    function_set({'admin-password': leader_get("admin_passwd")})
+
+
+ACTIONS = {
+    "get-admin-password": get_admin_password
+}
+
+
+def main(args):
+    action_name = os.path.basename(args[0])
+    try:
+        action = ACTIONS[action_name]
+    except KeyError:
+        return "Action {} undefined".format(action_name)
+    else:
+        try:
+            action(args)
+        except Exception as e:
+            function_fail("Action {} failed: {}".format(action_name, str(e)))
+
+
+if __name__ == "__main__":
+    sys.exit(main(sys.argv))

actions/get-admin-password

@@ -0,0 +1 @@
+admin_password.py

unit_tests/test_admin_password.py

@@ -0,0 +1,72 @@
+# Copyright 2022 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.
+
+from unittest import mock
+from test_utils import CharmTestCase
+
+from actions import admin_password
+
+
+TO_PATCH = [
+    'leader_get',
+    'function_set',
+]
+
+
+class GetAdminPasswordTestCase(CharmTestCase):
+    def setUp(self):
+        super(GetAdminPasswordTestCase, self).setUp(
+            admin_password, TO_PATCH)
+
+    def test_get_admin_password(self):
+        admin_password.get_admin_password([])
+        self.function_set.assert_called_with({'admin-password':
+                                             self.leader_get("admin_passwd")})
+
+
+class MainTestCase(CharmTestCase):
+
+    def setUp(self):
+        super(MainTestCase, self).setUp(admin_password, ["function_fail"])
+
+    def test_invokes_action(self):
+        dummy_calls = []
+
+        def dummy_action(arg):
+            dummy_calls.append(True)
+
+        with mock.patch.dict(admin_password.ACTIONS, {"foo": dummy_action}):
+            admin_password.main(["foo"])
+        self.assertEqual(dummy_calls, [True])
+
+    def test_unknown_action(self):
+        """Unknown actions aren't a traceback."""
+        exit_string = admin_password.main(["foo"])
+        self.assertEqual("Action foo undefined", exit_string)
+
+    def assert_function_fail_msg(self, action_name, msg):
+        """Shortcut for asserting error with default structure"""
+        admin_password.function_fail.assert_called_with("Action {} "
+                                                        "failed: {}"
+                                                        .format(action_name,
+                                                                msg))
+
+    def test_failing_action(self):
+        """Actions which traceback trigger function_fail() calls."""
+        def dummy_action(arg):
+            raise ValueError("uh oh")
+
+        with mock.patch.dict(admin_password.ACTIONS, {"foo": dummy_action}):
+            admin_password.main(["foo"])
+        self.assert_function_fail_msg("foo", "uh oh")