Adding HeatEngineVolumes and HeatEngineOptEnvVars support

Change-Id: Icf9b40eed56f69a7ebe4d6c22e6365c2e90a7209
Closes-Bug: #1777852

docker/services/heat-engine.yaml

@@ -41,6 +41,14 @@ parameters:
     default: {}
     description: Parameters specific to the role
     type: json
+  HeatEngineOptVolumes:
+    default: []
+    description: list of optional volumes to be mounted
+    type: comma_delimited_list
+  HeatEngineOptEnvVars:
+    default: []
+    description: list of optional environment variables
+    type: comma_delimited_list
 
 resources:
 
@@ -139,11 +147,15 @@ outputs:
               list_concat:
                 - {get_attr: [ContainersCommon, volumes]}
                 - {get_attr: [HeatEngineLogging, volumes]}
+                - {get_param: HeatEngineOptVolumes}
                 -
                   - /var/lib/kolla/config_files/heat_engine.json:/var/lib/kolla/config_files/config.json:ro
                   - /var/lib/config-data/puppet-generated/heat/:/var/lib/kolla/config_files/src:ro
             environment:
-              - KOLLA_CONFIG_STRATEGY=COPY_ALWAYS
+                  list_concat:
+                    - {get_param: HeatEngineOptEnvVars}
+                    -
+                      - KOLLA_CONFIG_STRATEGY=COPY_ALWAYS
       host_prep_tasks: {get_attr: [HeatEngineLogging, host_prep_tasks]}
       upgrade_tasks:
         - when: step|int == 0