Add max-stacks-per-tenant config option

This configuration option allows operators to change the default of
how many stacks a project can have in parallel.

This key has been available since Mitaka:
https://docs.openstack.org/mitaka/config-reference/orchestration.html

Closes-Bug: #1871772
Change-Id: I4dc0008c1098a969d62ee4a8afe76de4bfb5c235

config.yaml

@@ -262,3 +262,8 @@ options:
       override YAML files in the service's policy.d directory.  The resource
       file should be a ZIP file containing at least one yaml file with a .yaml
       or .yml extension.  If False then remove the overrides.
+  max-stacks-per-tenant:
+    type: int
+    default:
+    description: |
+      Maximum number of stacks any one tenant may have active at one time.

hooks/heat_context.py

@@ -146,3 +146,9 @@ class InstanceUserContext(context.OSContextGenerator):
             instance_user = config('instance-user')
         ctxt['instance_user'] = instance_user
         return ctxt
+
+
+class QuotaConfigurationContext(context.OSContextGenerator):
+    def __call__(self):
+        ctxt = {"max_stacks_per_tenant": config('max-stacks-per-tenant')}
+        return ctxt

hooks/heat_utils.py

@@ -70,6 +70,7 @@ from heat_context import (
     HeatApacheSSLContext,
     HeatHAProxyContext,
     HeatPluginContext,
+    QuotaConfigurationContext,
 )
 
 TEMPLATES = 'templates/'
@@ -133,6 +134,7 @@ CONFIG_FILES = OrderedDict([
                      HeatSecurityContext(),
                      InstanceUserContext(),
                      HeatPluginContext(),
+                     QuotaConfigurationContext(),
                      context.SyslogContext(),
                      context.LogLevelContext(),
                      context.WorkerConfigContext(),

templates/mitaka/heat.conf

@@ -18,6 +18,9 @@ stack_domain_admin = heat_domain_admin
 stack_domain_admin_password = {{ heat_domain_admin_passwd }}
 stack_user_domain_name = heat
 num_engine_workers = {{ workers }}
+{%- if max_stacks_per_tenant %}
+max_stacks_per_tenant = {{ max_stacks_per_tenant }}
+{%- endif %}
 {% if sections and 'DEFAULT' in sections -%}
 {% for key, value in sections['DEFAULT'] -%}
 {{ key }} = {{ value }}

templates/ocata/heat.conf

@@ -18,6 +18,9 @@ stack_domain_admin = heat_domain_admin
 stack_domain_admin_password = {{ heat_domain_admin_passwd }}
 stack_user_domain_name = heat
 num_engine_workers = {{ workers }}
+{%- if max_stacks_per_tenant %}
+max_stacks_per_tenant = {{ max_stacks_per_tenant }}
+{%- endif %}
 {% if sections and 'DEFAULT' in sections -%}
 {% for key, value in sections['DEFAULT'] -%}
 {{ key }} = {{ value }}

unit_tests/test_heat_context.py

@@ -72,6 +72,12 @@ class TestHeatContext(CharmTestCase):
         self.assertEqual(
             heat_context.HeatIdentityServiceContext()(), final_result)
 
+    def test_quota_configuration_context(self):
+        expected = {'max_stacks_per_tenant': '999'}
+        self.config.side_effect = self.test_config.get
+        self.test_config.set('max-stacks-per-tenant', '999')
+        self.assertEqual(heat_context.QuotaConfigurationContext()(), expected)
+
 
 class HeatPluginContextTest(CharmTestCase):