service: Allow templated files to be mounted as full directory

roles/service/meta/argument_specs.yaml

@@ -163,7 +163,9 @@ argument_specs:
               - Mount source.
               - If mount type is volume, name of the volume.
               - If mount type is bind, host path to bind mount inside the container.
-              - If mount type is template, the name of the template file, must end in .j2
+              - >-
+                If mount type is template and template_directory is false, the name of the template file, must end in .j2.
+                If template_directory is true, this is the destination directory
               - If mount type is copy, name of the file or directory to copy. Directory name must end in /.
             type: str
             required: true
@@ -220,9 +222,18 @@ argument_specs:
               Command used to verify templated file validity.
               Will be run in a temporary container using the same container image as the main service.
               File will be available in the same place as in the service container (destination).
-              Only applicable if mount type is template
+              Only applicable if mount type is template.
             type: str
             required: false
+          template_directory:
+            description: >-
+              Whether to create a directory and mount it at the destination file's parent directory.
+              This is required for container to see templated file changes without restart.
+              Only applicable if mount type is template.
+            type: bool
+            required: false
+            default: false
+
       service_container_devices:
         description: List of devices to be added inside the service main container.
         type: list

roles/service/vars/main/mounts.yaml

@@ -25,21 +25,45 @@ _service_container_bind_mounts: >-
     service_container_mounts | selectattr('type', '==', 'bind') +
     ([ _service_container_socket_mount ] if _service_native_socket else [])
   }}
-_service_container_template_mounts: >-
+
+_service_template_mounts_withdefaults: >-
   {{
-    ([{'readonly': true}] * _service_template_mounts | length) |
-    zip(
-      _service_template_mounts |
-        community.general.remove_keys(['mode', 'template_validate_command']),
-      _service_template_mounts |
-        map(attribute='source') |
-        map('regex_replace', '\.j2$', '') |
-        map('regex_replace', '^', _service_host_directory ~ '/mounts/') |
-        map('community.general.dict_kv', 'source'),
+    ([{'readonly': true, 'template_directory': false}] * _service_template_mounts | length)
+    | zip(_service_template_mounts)
+    | map('combine')
+  }}
+_service_template_mounts_plain: "{{ _service_template_mounts_withdefaults | rejectattr('template_directory') }}"
+_service_container_template_mounts_plain: >-
+  {{
+    _service_template_mounts_plain
+    | community.general.remove_keys(['mode', 'template_validate_command', 'template_directory'])
+    | zip(
+      _service_template_mounts_plain
+      | map(attribute='source')
+      | map('regex_replace', '\.j2$', '')
+      | map('regex_replace', '^', _service_host_directory ~ '/mounts/')
+      | map('community.general.dict_kv', 'source'),
       ([{'type': 'bind'}] * _service_template_mounts | length)
     ) |
     map('combine')
   }}
+_service_template_mounts_directory: "{{ _service_template_mounts_withdefaults | selectattr('template_directory') }}"
+_service_container_template_mounts_directory: >-
+  {{
+    _service_template_mounts_directory
+    | community.general.remove_keys(['mode', 'template_validate_command', 'template_directory'])
+    | zip(
+      _service_template_mounts_directory
+      | map(attribute='destination')
+      | map('replace', '/', '_')
+      | map('regex_replace', '^', _service_host_directory ~ '/mounts/')
+      | map('community.general.dict_kv', 'source'),
+      ([{'type': 'bind'}] * _service_template_mounts | length)
+    )
+    | map('combine')
+    | unique
+  }}
+
 _service_container_copy_mounts: >-
   {{
     ([{'readonly': true}] * _service_copy_mounts | length) |
@@ -58,10 +82,11 @@ _service_container_copy_mounts: >-
 
 _service_container_mounts: >-
   {{
-    _service_container_volume_mounts +
-    _service_container_bind_mounts +
-    _service_container_template_mounts +
-    _service_container_copy_mounts
+    _service_container_volume_mounts
+    + _service_container_bind_mounts
+    + _service_container_template_mounts_plain
+    + _service_container_template_mounts_directory
+    + _service_container_copy_mounts
   }}
 
 
@@ -78,20 +103,47 @@ _service_all_template_mounts: >-
       selectattr('type', '==', 'template') |
       unique
   }}
+_service_all_template_mounts_withdefaults: >-
+  {{
+    ([{'readonly': true, 'template_directory': false}] * _service_all_template_mounts | length)
+    | zip(_service_all_template_mounts)
+    | map('combine')
+  }}
+_service_all_template_mounts_plain: "{{ _service_all_template_mounts_withdefaults | rejectattr('template_directory') }}"
+_service_all_template_mounts_directory: "{{ _service_all_template_mounts_withdefaults | selectattr('template_directory') }}"
 _service_all_template_mount_directories: >-
   {{
-    _service_all_template_mounts |
-      map(attribute='source') |
-      map('dirname') |
-      unique |
-      select('!=', '')
+    (
+      _service_all_template_mounts_plain
+      | map(attribute='source')
+      | map('dirname')
+      | unique
+      | select('!=', '')
+    ) + (
+      _service_all_template_mounts_directory
+      | map(attribute='destination')
+      | map('replace', '/', '_')
+    )
   }}
 _service_all_template_mount_host_files: >-
   {{
-    _service_all_template_mounts |
-      map(attribute='source') |
-      map('regex_replace', '\.j2$', '') |
-      map('regex_replace', '^', _service_host_directory ~ '/mounts/')
+    (
+      _service_all_template_mounts_plain
+      | map(attribute='source')
+      | map('regex_replace', '\.j2$', '')
+      | map('regex_replace', '^', _service_host_directory ~ '/mounts/')
+    ) + (
+      _service_all_template_mounts_directory
+      | map(attribute='destination')
+      | map('replace', '/', '_')
+      | map('regex_replace', '^', _service_host_directory ~ '/mounts/')
+      | zip(
+        _service_all_template_mounts_directory
+        | map(attribute='source')
+        | map('regex_replace', '\.j2$', '')
+      ) | map('path_join')
+    )
+
   }}
 
 _service_all_copy_mounts: >-