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