Add ability for charms to delete crm resources

Change-Id: I407b40fe154a30de6e607849126d71fbc99fd158

common.py

@@ -286,7 +286,9 @@ class CRM(dict):
         self['groups'][name] = specs
 
     def delete_resource(self, *resources):
-        """Deletes one or more objects/resources within Pacemaker.
+        """Specify objects/resources to be deleted from within Pacemaker. This
+           is not additive, the list of resources is set to exaclty what was
+           passed in.
 
         Parameters
         ----------
@@ -303,6 +305,26 @@ class CRM(dict):
         """
         self['delete_resources'] = resources
 
+    def add_delete_resource(self, resource):
+        """Specify an object/resource to delete from within Pacemaker. It can
+           be called multiple times to add additional resources to the deletion
+           list.
+
+        Parameters
+        ----------
+        resources: str
+            the name or id of the specific resource to delete.
+
+        Returns
+        -------
+        None
+
+        See Also
+        --------
+        http://crmsh.github.io/man/#cmdhelp_configure_delete
+        """
+        self['delete_resources'] = (*self['delete_resources'], resource)
+
     def init_services(self, *resources):
         """Specifies that the service(s) is an init or upstart service.
 

requires.py

@@ -114,6 +114,15 @@ class HAClusterRequires(RelationBase):
         self.bind_on(iface=iface, mcastport=mcastport)
         self.manage_resources(resources)
 
+    def delete_resource(self, resource_name):
+        resource_dict = self.get_local('resources')
+        if resource_dict:
+            resources = relations.hacluster.common.CRM(**resource_dict)
+        else:
+            resources = relations.hacluster.common.CRM()
+        resources.add_delete_resource(resource_name)
+        self.set_local(resources=resources)
+
     def add_vip(self, name, vip, iface=None, netmask=None):
         """Add a VirtualIP object for each user specified vip to self.resources
 

unit_tests/test_common.py

@@ -192,6 +192,27 @@ class TestHAClusterCommonCRM(unittest.TestCase):
             crm['delete_resources'],
             ('res_mysql_vip', 'grp_mysql'))
 
+    def test_add_delete_resource(self):
+        crm = common.CRM()
+        crm.add_delete_resource('res_mysql_vip')
+        self.assertEqual(crm['delete_resources'], ('res_mysql_vip',))
+
+    def test_add_delete_resource_multi(self):
+        crm = common.CRM()
+        crm.add_delete_resource('res_mysql_vip')
+        crm.add_delete_resource('grp_mysql')
+        self.assertEqual(
+            crm['delete_resources'],
+            ('res_mysql_vip', 'grp_mysql'))
+
+    def test_add_delete_resource_mix(self):
+        crm = common.CRM()
+        crm.delete_resource('grp_mysql')
+        crm.add_delete_resource('res_mysql_vip')
+        self.assertEqual(
+            crm['delete_resources'],
+            ('grp_mysql', 'res_mysql_vip'))
+
     def test_init_services(self):
         crm = common.CRM()
         crm.init_services('haproxy')

unit_tests/test_requires.py

@@ -11,6 +11,7 @@
 # limitations under the License.
 
 
+import copy
 import json
 import mock
 import unittest
@@ -212,6 +213,48 @@ class TestHAClusterRequires(unittest.TestCase):
         self.bind_on.assert_called_once_with(iface='tr34', mcastport=111)
         self.manage_resources.assert_called_once_with('resources')
 
+    def test_delete_resource(self):
+        expected = {
+            'resources': {},
+            'resource_params': {},
+            'delete_resources': ('doomed_res',),
+            'groups': {},
+            'ms': {},
+            'orders': {},
+            'colocations': {},
+            'clones': {},
+            'locations': {},
+            'init_services': []}
+        self.patch_kr('get_local', None)
+        self.patch_kr('set_local')
+        self.cr.delete_resource('doomed_res')
+        self.set_local.assert_called_once_with(resources=expected)
+
+    def test_delete_resource_multi(self):
+        base = {
+            'resources': {},
+            'resource_params': {},
+            'groups': {},
+            'ms': {},
+            'orders': {},
+            'colocations': {},
+            'clones': {},
+            'locations': {},
+            'init_services': []}
+        res_with_res1 = copy.deepcopy(base)
+        res_with_res1_res2 = copy.deepcopy(base)
+        res_with_res1['delete_resources'] = ('doomed_res1',)
+        res_with_res1_res2['delete_resources'] = ('doomed_res1', 'doomed_res2')
+        get_local_results = [res_with_res1, base]
+        self.patch_kr('get_local')
+        self.get_local.side_effect = lambda x: get_local_results.pop()
+        self.patch_kr('set_local')
+        self.cr.delete_resource('doomed_res1')
+        self.cr.delete_resource('doomed_res2')
+        self.set_local.assert_has_calls([
+            mock.call(resources=res_with_res1),
+            mock.call(resources=res_with_res1_res2)])
+
     def test_add_vip(self):
         expected = {
             'resources': {