service: Add support for template mounts

Template mounts are templated from jinja2 templates to a service name
-specific directory under /srv and bind mounted inside the container.

roles/service/meta/argument_specs.yaml

@@ -50,11 +50,13 @@ argument_specs:
             choices:
               - volume
               - bind
+              - template
           source:
             description:
               - 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
             type: str
             required: true
           destination:
@@ -62,10 +64,11 @@ argument_specs:
             type: str
             required: true
           readonly:
-            description: If true, volume will be mounted as read only inside the container
+            description:
+              - If true, volume will be mounted as read only inside the container.
+              - Defaults to false for volume and bind, true for template
             type: bool
             required: false
-            default: false
       service_container_secrets:
         description: A list of secrets available to the service container in /run/secrets/<service name>-<secret name>
         type: list
@@ -145,11 +148,13 @@ argument_specs:
                 choices:
                   - volume
                   - bind
+                  - template
               source:
                 description:
                   - 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
                 type: str
                 required: true
               destination:
@@ -157,10 +162,11 @@ argument_specs:
                 type: str
                 required: true
               readonly:
-                description: If true, volume will be mounted as read only inside the container
+                description:
+                  - If true, volume will be mounted as read only inside the container
+                  - Defaults to false for volume and bind, true for template
                 type: bool
                 required: false
-                default: false
           publish_ports:
             description: "A list of published ports in docker format (<host listen address>:<host port>:<container port>)"
             type: list

roles/service/tasks/main.yaml

@@ -25,7 +25,7 @@
   when: service_container_mounts | length > 0
 
 - name: Main container for {{ service_name }}
-  ansible.builtin.include_role:
+  ansible.builtin.import_role:
     name: container
   vars:
     container_name: "{{ service_name }}"

roles/service/tasks/mount.yaml

@@ -0,0 +1,32 @@
+---
+- name: Set container named mounts
+  ansible.builtin.set_fact:
+    _service_container_mounts: >
+      {{ _service_container_mounts +
+      [mount | combine({'source': service_name + '-' + mount.source})] }}
+  when: mount.type == 'volume'
+
+- name: Set container named mounts
+  ansible.builtin.set_fact:
+    _service_container_mounts: "{{ _service_container_mounts + [mount] }}"
+  when: mount.type == 'bind'
+
+- name: Template mounts
+  when: mount.type == 'template'
+  block:
+    - name: Set template host path
+      ansible.builtin.set_fact:
+        _service_template_host_path: "{{ _service_host_directory }}/mounts/{{ (mount.source | split('.'))[0:-1] | join('.') }}" # Strip .j2 extension
+
+    - name: Template files for template mounts
+      ansible.builtin.template:
+        src: "{{ mount.source }}"
+        dest: "{{ _service_template_host_path }}"
+        mode: "0644"
+      notify: "Restart container service {{ service_name }}"
+
+    - name: Set container template mounts
+      ansible.builtin.set_fact:
+        _service_container_mounts: >
+          {{ _service_container_mounts +
+          [{'readonly': true} | combine(mount) | combine({'type': 'bind', 'source': _service_template_host_path})] }}

roles/service/tasks/mounts.yaml

@@ -1,18 +1,21 @@
 ---
-- name: Set container named mounts
-  ansible.builtin.set_fact:
-    _service_container_mounts: >
-      {{ _service_container_mounts +
-      [mount | combine({'source': service_name + '-' + mount.source})] }}
-  when: mount.type == 'volume'
-  loop: "{{ service_container_mounts }}"
-  loop_control:
-    loop_var: mount
+- name: Create template mount directories under /srv
+  when: _service_template_mounts | length > 0
+  block:
+    - name: Create directory {{ _service_host_directory }}
+      ansible.builtin.file:
+        path: "{{ _service_host_directory }}"
+        state: directory
+        mode: "0755"
 
-- name: Set container named mounts
-  ansible.builtin.set_fact:
-    _service_container_mounts: "{{ _service_container_mounts + [mount] }}"
-  when: mount.type == 'bind'
+    - name: Create directory {{ _service_host_directory + '/mounts' }}
+      ansible.builtin.file:
+        path: "{{ _service_host_directory }}/mounts"
+        state: directory
+        mode: "0700"
+
+- name: Set mount definitions for {{ service_name }}
+  ansible.builtin.include_tasks: mount.yaml
   loop: "{{ service_container_mounts }}"
   loop_control:
     loop_var: mount

roles/service/tasks/validation.yaml

@@ -8,3 +8,9 @@
   ansible.builtin.fail:
     msg: "service_postgres_tag needs to be set when database type is postgres"
   when: "service_database_type == 'postgres' and service_postgres_tag is not defined"
+
+- name: Fail if template mount source doesn't end in .j2
+  ansible.builtin.fail:
+    msg: "Template mount source file name needs to end in .j2. The file {{ item.source }} of {{ service_name }} doesn't."
+  when: "item.source | split('.') | last != 'j2'"
+  loop: "{{ _service_template_mounts }}"

roles/service/vars/main.yaml

@@ -0,0 +1,3 @@
+---
+_service_template_mounts: "{{ service_container_mounts | selectattr('type', '==', 'template') | list }}"
+_service_host_directory: "/srv/{{ service_name }}"