Add ability to create templated services

This functionality is pretty neat and used widely if you need to pass
specific argument to the unit service, but rest of the parameters can
be left intact.

Change-Id: I6eb80ac0f9f0257402697a255518bb2c66d0dfd5

defaults/main.yml

@@ -114,6 +114,10 @@ systemd_environment: {}
 #  `environment` -- (optional) set additional environment settings, this option is a hash of strings.
 #  `environment_file` -- (optional) set additional environment settings through a given file. this option is a string.
 #  `dynamic_user` -- (optional) Dynamically set a UNIX user and group when the unit is started; only works if systemd >= 235.
+#  `template_arguments` -- (optional) List of arguments that would be enabled/started in case service is a template.
+#                          For that to work properly, service_name should end with `@`, ie `dhcpcd@`
+#                          Systemd service template documentation can be found by the link:
+#                          https://www.freedesktop.org/software/systemd/man/systemd.service.html#Service%20Templates
 #  `state_directory` -- (optional) Relative path the state directory; only works if systemd >= 235.
 #  `systemd_overrides` -- (optional) Dictionary that may contain custom structure in config_overrides format that
 #                         will be used to generate systemd overrides in /etc/systemd/system/service_name.service.d/overrides.conf
@@ -238,4 +242,12 @@ systemd_environment: {}
 #             - ServiceZ
 #             - ServiceY
 #       restart_changed: no
+#
+# Example below will result in creating 2 templated services: Templated@arg1 and Templated@arg2
+#     - service_name: Templated@
+#       execstarts:
+#         - /tmp/script %i
+#       template_arguments:
+#         - arg1
+#         - arg2
 systemd_services: []

handlers/main.yml

@@ -14,15 +14,15 @@
 # limitations under the License.
 
 - name: Restart changed services
-  systemd:
-    name: "{{ item.item.service_name | replace(' ', '_') }}.{{ (item.item.timer is defined) | ternary('timer', 'service') }}"
-    state: restarted
+  include_tasks: handlers/systemd_restart.yml
   listen: systemd service changed
-  with_items: "{{ systemd_services_result.results }}"
   when:
-    - 'item.item.restart_changed | default(systemd_service_restart_changed) | bool'
-    - 'item.item.state is not defined'
-    - 'item.item.enabled | default(systemd_service_enabled) | bool'
-    - 'item is changed'
+    - 'services_results.item.restart_changed | default(systemd_service_restart_changed) | bool'
+    - 'services_results.item.state is not defined'
+    - 'services_results.item.enabled | default(systemd_service_enabled) | bool'
+    - 'services_results is changed'
+  loop: "{{ systemd_services_result.results }}"
+  loop_control:
+    loop_var: services_results
   tags:
    - systemd-service

handlers/systemd_restart.yml

@@ -0,0 +1,22 @@
+---
+# Copyright 2021, City Network International AB.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+- name: "Restart service {{ services_results.item.service_name | replace(' ', '_') }}"
+  systemd:
+    name: "{{ services_results.item.service_name | replace(' ', '_') }}{{ template_argument }}.{{ (services_results.item.timer is defined) | ternary('timer', 'service') }}"
+    state: restarted
+  loop: "{{ services_results.item.template_arguments | default(['']) }}"
+  loop_control:
+    loop_var: template_argument

releasenotes/notes/templated_service-f31e4515c2fd75ab.yaml

@@ -0,0 +1,7 @@
+---
+features:
+  - |
+    Allow to create `templated services <https://www.freedesktop.org/software/systemd/man/systemd.service.html#Service%20Templates>`_
+    Now for systemd_services you are allowed to provide template_arguments,
+    which can contain a list of arguments with which templated services
+    would be created.

tasks/main.yml

@@ -140,25 +140,10 @@
   when:
     - (systemd_services_result is changed) or (systemd_timer_result is changed) or ('true' in systemd_socket.results | map(attribute='changed') | list )
 
-- name: Load service
-  systemd:
-    name: "{{ item.service_name | replace(' ', '_') }}.service"
-    enabled: "{{ item.enabled | default(systemd_service_enabled) }}"
-    state: "{{ (item.timer is defined) | ternary(omit, (item.state | default(omit))) }}"
-  with_items: "{{ systemd_services }}"
-  when:
-    - item.load | default(True)
-  tags:
-    - systemd-service
-
-- name: Load timer
-  systemd:
-    name: "{{ item.service_name | replace(' ', '_') }}.timer"
-    enabled: "{{ item.enabled | default(systemd_service_enabled) }}"
-    state: "{{ item.timer.state | default(omit) }}"
-  when:
-    - item.timer is defined
-  with_items: "{{ systemd_services }}"
+- include_tasks: systemd_load.yml
+  loop: "{{ systemd_services }}"
+  loop_control:
+    loop_var: service
   tags:
     - systemd-service
 

tasks/systemd_load.yml

@@ -0,0 +1,39 @@
+---
+# Copyright 2021, City Network International AB.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# NOTE(noonedeadpunk): If we don't have template_arguments set, we just iterate over list with
+#                      empty string as element. This won't have any effect on the results, but
+#                      we reduce code duplication
+- name: "Load service {{ service.service_name | replace(' ', '_') }}"
+  systemd:
+    name: "{{ service.service_name | replace(' ', '_') }}{{ template_argument }}.service"
+    enabled: "{{ service.enabled | default(systemd_service_enabled) }}"
+    state: "{{ (service.timer is defined) | ternary(omit, (service.state | default(omit))) }}"
+  when:
+    - service.load | default(True)
+  loop: "{{ service.template_arguments | default(['']) }}"
+  loop_control:
+    loop_var: template_argument
+
+- name: "Load timer {{ service.service_name | replace(' ', '_') }}"
+  systemd:
+    name: "{{ service.service_name | replace(' ', '_') }}{{ template_argument }}.timer"
+    enabled: "{{ service.enabled | default(systemd_service_enabled) }}"
+    state: "{{ service.timer.state | default(omit) }}"
+  when:
+    - service.timer is defined
+  with_items: "{{ service.template_arguments | default(['']) }}"
+  loop_control:
+    loop_var: template_argument

tests/test.yml

@@ -64,6 +64,15 @@
             state: "started"
             cron_minute: 30
             cron_hour: 1
+        - service_name: "test_templated_service@"
+          service_type: oneshot
+          execstarts:
+            - "/bin/bash -c 'echo %i'"
+          template_arguments:
+            - 1
+            - 2
+          enabled: yes
+          state: started
 
   post_tasks:
     - name: Check Services