change nhc configuration from replace to lineinfile

Author: sjpb

ansible/roles/nhc/README.md

@@ -63,9 +63,9 @@ to update the autogenerated health checks:
 
 ## Role Variables
 
-- `nhc_replacements`: Optional, default empty list. A list of mappings
-  defining replacements in the autogenerated health checks. Items must have
-  keys `regexp` and `replace` which are as for [ansible.builtin.replace](https://docs.ansible.com/ansible/latest/collections/ansible/builtin/replace_module.html).
+- `nhc_config_changes`: Optional, default empty list. A list of mappings
+  defining replacements in the autogenerated health checks. Mappings may have
+  any keys from [ansible.builtin.lineinfile](https://docs.ansible.com/ansible/latest/collections/ansible/builtin/lineinfile_module.html).
   Note that the NHC [configuration line format](https://github.com/mej/nhc?tab=readme-ov-file#configuration-file-syntax) is:
 
       TARGET || CHECK
@@ -75,20 +75,15 @@ to update the autogenerated health checks:
       '^(\s+\S+\s+)\|\|(\s+.*)$'
 
   captures the `TARGET` and `||` separator as `\1` and the actual check as `\2`.
-  Hence the following item would comment-out checks on a particular interface
-  on all nodes:
-
-      - regexp:  '^(\s+\S+\s+\|\|\s+)(check_hw_eth eth0)$'
-        replace: '#\1\2'
-
-  See documentation for `ansible.builtin.replace` for more information. This is
-  an example only - for this actual case removing the line entirely with
-  `replace: ''` might be better. Using https://regex101.com/ (in Python
-  mode) or similar may be useful during development.
-
-- `nhc_replacements_default`: Optional. As above, but by default includes a
-  mapping to remote the autogenerated timestamp line from the check configuration
-  file for idempotency.
+  Hence - as an example only - the following comments-out checks on a
+  specific interface for all nodes:
+
+  ```yaml
+  nhc_config_changes:
+    - regexp:  '^(\s+\S+\s+\|\|\s+)(check_hw_eth eth0)$'
+      line: '#\1\2'
+      backrefs: yes
+  ```
 
 ## Structure
 

ansible/roles/nhc/defaults/main.yml

@@ -1,6 +1 @@
-nhc_replacements_default:
-  # note this matches a multiline string
-  - regexp: '# This file was automatically generated by nhc-genconf\n#.*'
-    replace: '# This file was automatically generated by nhc-genconf\n# (timestamp removed for idempotency)'
-
-nhc_replacements: []
+nhc_config_changes: []

ansible/roles/nhc/tasks/main.yml

@@ -9,11 +9,18 @@
   failed_when: _nhc_genconf.rc > 1 # https://github.com/mej/nhc/issues/158
 
 - name: Apply modifications to autogenerated NHC configuration
+  ansible.builtin.lineinfile: "{{ item | combine(nhc_lineinfile_defaults) }}"
+  loop: "{{ nhc_config_changes }}"
+  vars:
+    nhc_lineinfile_defaults:
+      path: "{{ nhc_tempfile.path }}"
+
+- name: Remove timestamp from autogenerated NHC configuration
   ansible.builtin.replace:
     path: "{{ nhc_tempfile.path }}"
-    regexp: "{{ item.regexp }}"
-    replace: "{{ item.replace }}"
-  loop: "{{ nhc_replacements_default + nhc_replacements }}"
+    # note this matches a multiline string:
+    regexp: '# This file was automatically generated by nhc-genconf\n#.*'
+    replace: '# This file was automatically generated by nhc-genconf\n# (timestamp removed for idempotency)'
 
 - name: Copy modified NHC configuration to active location
   ansible.builtin.copy:
@@ -23,3 +30,5 @@
     owner: root
     group: root
     mode: u=rw,go= # HealthCheckProgram is run by root
+
+- meta: end_here