Add append option to tripleo_derive_hci_parameters module

The module already has the parameter new_heat_environment_path,
which is a path to a file that gets overwritten each time the
module is called. Add append_new_heat_environment_path, which
is a new bool parameter that defaults to false to perserve the
existing behavior. If the new parameter is true, then merge the
new derived paramters into the file without loosing the existing
derived paramters already in the file.

To close bug 1926627, use new_heat_environment_path with the new
option in the existing role loop. Also, remove the unnecessary
task to write out the derived_parameter_result variable because
we now write it in the previous task.

Closes-Bug: #1926627
Change-Id: Iabb0cbda57fabf27d0e5d8b1cc75706785ecd967

tripleo_ansible/ansible_plugins/modules/tripleo_derive_hci_parameters.py

@@ -15,6 +15,7 @@
 # under the License.
 """Derive paramters for HCI (hyper-converged) deployments"""
 
+import os
 import re
 import yaml
 
@@ -64,6 +65,10 @@ options:
         description: Path to file new where resultant derived parameters will be written; result will be valid input to TripleO client, e.g. /home/stack/derived_paramaters.yaml
         required: False
         type: str
+    append_new_heat_environment_path:
+        description: If new_heat_environment_path already exists and append_new_heat_environment_path is true, then append new content to the existing new_heat_environment_path instead of overwriting a new version of that file.
+        required: False
+        type: bool
     report_path:
         description: Path to file new where a report on how HCI paramters were derived be written, e.g. /home/stack/hci_derived_paramaters.txt
         required: False
@@ -446,6 +451,7 @@ def main():
         average_guest_memory_size_in_mb=dict(type=int, required=False, default=0),
         derived_parameters=dict(type=dict, required=False),
         new_heat_environment_path=dict(type=str, required=False),
+        append_new_heat_environment_path=dict(type=bool, required=False),
         report_path=dict(type=str, required=False),
     )
     module = AnsibleModule(
@@ -491,8 +497,29 @@ def main():
         existing_params[role_name_parameters] = role_derivation
         # write out to file if requested
         if module.params['new_heat_environment_path'] and not module.check_mode:
-            output = {}
-            output['parameter_defaults'] = existing_params
+            if module.params['append_new_heat_environment_path'] and \
+               os.path.exists(module.params['new_heat_environment_path']):
+                with open(module.params['new_heat_environment_path'], 'r') as stream:
+                    try:
+                        output = yaml.safe_load(stream)
+                        if 'parameter_defaults' in output:
+                            output['parameter_defaults'][role_name_parameters] = \
+                                role_derivation
+                        else:
+                            result['failed'] = True
+                            result['message'] = ("tripleo_derive_hci_parameters module "
+                                                 "cannot append to environment file %s. "
+                                                 "It is missing the 'parameter_defaults' "
+                                                 "key. Try again with the parameter "
+                                                 "append_new_heat_environment_path set "
+                                                 "False") \
+                            % module.params['new_heat_environment_path']
+                    except yaml.YAMLError as exc:
+                        result['failed'] = True
+                        result['message'] = exec
+            else:
+                output = {}
+                output['parameter_defaults'] = existing_params
             with open(module.params['new_heat_environment_path'], 'w') as outfile:
                 yaml.safe_dump(output, outfile, default_flow_style=False)
             # because we wrote a file we're making a change on the target system

tripleo_ansible/playbooks/cli-derive-parameters.yaml

@@ -54,19 +54,8 @@
         tripleo_role_name: "{{ outer_item }}"
         tripleo_environment_parameters: "{{ tripleo_get_flatten_params.stack_data.environment_parameters }}"
         tripleo_heat_resource_tree: "{{ tripleo_get_flatten_params.stack_data.heat_resource_tree }}"
+        new_heat_environment_path: "{{ derived_environment_path }}"
+        append_new_heat_environment_path: True
       loop: "{{ tripleo_role_list.roles }}"
       loop_control:
         loop_var: outer_item
-
-    - name: Write environment to {{ derived_environment_path }}
-      block:
-        - name: create derived params dictionary
-          set_fact:
-            derived_params_env: "{{ {'parameter_defaults': derived_parameters_result['derived_parameters'] | default({})} }}"
-        - name: Write environment
-          copy:
-            dest: "{{ derived_environment_path }}"
-            content: "{{ derived_params_env | to_nice_yaml(indent=2) }}"
-      when:
-        - derived_environment_path is defined
-        - derived_parameters_result is defined

tripleo_ansible/roles/tripleo_derived_parameters/defaults/main.yml

@@ -23,3 +23,5 @@ tripleo_plan_name: Overcloud
 tripleo_role_name: undefined
 tripleo_environment_parameters: {}
 tripleo_heat_resource_tree: {}
+new_heat_environment_path: ""
+append_new_heat_environment_path: false

tripleo_ansible/roles/tripleo_derived_parameters/molecule/default/converge.yml

@@ -36,6 +36,8 @@
         tripleo_environment_parameters: "{{ tripleo_get_flatten_params.stack_data.environment_parameters }}"
         tripleo_heat_resource_tree: "{{ tripleo_get_flatten_params.stack_data.heat_resource_tree }}"
         baremetal_data: "{{ lookup('file', '../mock_baremetal_{{ outer_item }}') | from_yaml }}"
+        new_heat_environment_path: ""
+        append_new_heat_environment_path: false
       loop: "{{ tripleo_role_list.roles }}"
       loop_control:
         loop_var: outer_item

tripleo_ansible/roles/tripleo_derived_parameters/tasks/main.yml

@@ -206,6 +206,8 @@
         average_guest_cpu_utilization_percentage: "{{ average_guest_cpu_utilization_percentage }}"
         average_guest_memory_size_in_mb: "{{ average_guest_memory_size_in_mb }}"
         derived_parameters: "{{ derived_parameters }}"
+        new_heat_environment_path: "{{ new_heat_environment_path }}"
+        append_new_heat_environment_path: "{{ append_new_heat_environment_path }}"
       register: derived_parameters_result
 
     - name: Show HCI derived paramters results