From 45ffbcd9a45e2164c8d42771cb6df7080da70faf Mon Sep 17 00:00:00 2001
From: Liam Young <liam.young@canonical.com>
Date: Sat, 26 Jan 2019 15:30:21 +0000
Subject: [PATCH] Allow charms to specify mandatory_config.

Allow a charm to specify config options that must be set. The charm
can do this by creating a list of config options called
mandatory_config. The check is run everytime assess_status is called.

Change-Id: I2bb9d2d873e1916624a26c08b036a16e91195b86
---
 charms_openstack/charm/core.py                | 23 +++++++++++++++++++
 .../charms_openstack/charm/test_core.py       | 23 +++++++++++++++++++
 unit_tests/charms_openstack/charm/utils.py    |  9 +++++++-
 3 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/charms_openstack/charm/core.py b/charms_openstack/charm/core.py
index 4328ce2..1edbf54 100644
--- a/charms_openstack/charm/core.py
+++ b/charms_openstack/charm/core.py
@@ -1088,6 +1088,7 @@ class BaseOpenStackCharmAssessStatus(object):
         for f in [self.check_if_paused,
                   self.custom_assess_status_check,
                   self.check_interfaces,
+                  self.check_mandatory_config,
                   self.check_services_running]:
             state, message = f()
             if state is not None:
@@ -1199,6 +1200,28 @@ class BaseOpenStackCharmAssessStatus(object):
         # Everything is fine.
         return None, None
 
+    def check_mandatory_config(self):
+        """Check that all mandatory config has been set.
+
+        Returns (None, None) if the interfaces are okay, or a status, message
+        if any of the config is missing.
+
+        :returns status & message info
+        :rtype: (status, message) or (None, None)
+        """
+        missing_config = []
+        status = None
+        message = None
+        if getattr(self, 'mandatory_config', None):
+            for c in self.mandatory_config:
+                if hookenv.config(c) is None:
+                    missing_config.append(c)
+        if missing_config:
+            status = 'blocked'
+            message = 'The following mandatory config is unset: {}'.format(
+                ','.join(missing_config))
+        return status, message
+
     def states_to_check(self, required_relations=None):
         """Construct a default set of connected and available states for each
         of the relations passed, along with error messages and new status
diff --git a/unit_tests/charms_openstack/charm/test_core.py b/unit_tests/charms_openstack/charm/test_core.py
index 23e4fe3..544e050 100644
--- a/unit_tests/charms_openstack/charm/test_core.py
+++ b/unit_tests/charms_openstack/charm/test_core.py
@@ -15,6 +15,9 @@ from unit_tests.charms_openstack.charm.common import (
 import unit_tests.utils as utils
 
 TEST_CONFIG = {'config': True,
+               'mandconfig1': 'Iamset',
+               'mandconfig2': 'Iamalsoset',
+               'mandconfig3': None,
                'openstack-origin': None}
 SNAP_MAP = {
     'mysnap': {
@@ -197,6 +200,7 @@ class TestBaseOpenStackCharmAssessStatus(BaseOpenStackCharmTest):
         # disable all of the check functions
         self.patch_target('check_if_paused', return_value=(None, None))
         self.patch_target('check_interfaces', return_value=(None, None))
+        self.patch_target('check_mandatory_config', return_value=(None, None))
         self.patch_target('custom_assess_status_check',
                           return_value=(None, None))
         self.patch_target('check_services_running', return_value=(None, None))
@@ -210,6 +214,7 @@ class TestBaseOpenStackCharmAssessStatus(BaseOpenStackCharmTest):
         # check all the check functions got called
         self.check_if_paused.assert_called_once_with()
         self.check_interfaces.assert_called_once_with()
+        self.check_mandatory_config.assert_called_once_with()
         self.custom_assess_status_check.assert_called_once_with()
         self.check_services_running.assert_called_once_with()
 
@@ -289,6 +294,24 @@ class TestBaseOpenStackCharmAssessStatus(BaseOpenStackCharmTest):
         }
         self.assertEqual(self.target.check_interfaces(), (None, None))
 
+    def test_check_mandatory_config_no_mandatory_config(self):
+        self.assertEqual(
+            self.target.check_mandatory_config(),
+            (None, None))
+
+    def test_check_mandatory_config_config_set(self):
+        self.target.mandatory_config = ['mandconfig1', 'mandconfig2']
+        self.assertEqual(
+            self.target.check_mandatory_config(),
+            (None, None))
+
+    def test_check_mandatory_config_config_unset(self):
+        self.target.mandatory_config = ['mandconfig1', 'mandconfig3']
+        self.assertEqual(
+            self.target.check_mandatory_config(),
+            ('blocked',
+             'The following mandatory config is unset: mandconfig3'))
+
     def test_check_assess_status_check_services_running(self):
         # verify that the function calls _ows_check_services_running() with the
         # valid information
diff --git a/unit_tests/charms_openstack/charm/utils.py b/unit_tests/charms_openstack/charm/utils.py
index 348f7b8..0d9561b 100644
--- a/unit_tests/charms_openstack/charm/utils.py
+++ b/unit_tests/charms_openstack/charm/utils.py
@@ -18,11 +18,18 @@ class BaseOpenStackCharmTest(unit_tests.utils.BaseTestCase):
         cls.patched_config_started = None
         cls.patched_config = None
 
+    def _get_config(self, x=None):
+        if x:
+            return self._test_config.get(x, None)
+        else:
+            return self._test_config
+
     def setUp(self, target_cls, test_config):
         super().setUp()
         # set up the return value on the mock before instantiating the class to
         # get the config into the class.config.
-        chm_core.hookenv.config.return_value = test_config
+        self._test_config = test_config
+        chm_core.hookenv.config.side_effect = self._get_config
         self.target = target_cls()
 
     def tearDown(self):