Add service restart handler

A global var systemd_service_restart_changed is added which toggles
restart on unit file change for all systemd_services.

A systemd_services var 'restart_changed' is added to toggle restarts
on a per-service basis.

systemd daemon is not reloaded in a loop anymore, it is only
reloaded once, in a handler, when unit files change.

Consumer roles of systemd_service can listen to the handler
'systemd service changed' to implement additional orchestration when
service units are modified.

Change-Id: I803bca638c30696004f934ad1e28920786948f38

defaults/main.yml

@@ -17,6 +17,9 @@ systemd_user_name: root
 systemd_group_name: root
 systemd_slice_name: system
 
+# Restart services when a change occurs
+systemd_service_restart_changed: yes
+
 # This is the prefix used for all temp files of a given type.
 systemd_tempd_prefix: tempd
 
@@ -88,6 +91,7 @@ systemd_default_service_type: simple
 #         - '/usr/bin/ServiceY'
 #       execstarts:
 #         - '/usr/bin/stopcmd'
+#       restart_changed: no
 #
 #     - service_name: ServiceZ
 #       config_overrides: {}  # This is used to add in arbitratry unit file options

handlers/main.yml

@@ -0,0 +1,26 @@
+---
+# Copyright 2018, Logan Vig <logan2211@gmail.com>
+#
+# 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 changed services
+  systemd:
+    name: "{{ item.item.service_name | replace(' ', '_') }}"
+    state: restarted
+  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 | changed'

tasks/main.yml

@@ -116,13 +116,21 @@
     config_overrides: "{{ item.config_overrides | default(systemd_service_config_overrides) }}"
     config_type: "ini"
   with_items: "{{ systemd_services }}"
+  notify:
+    - systemd service changed
+  register: systemd_services_result
   tags:
     - systemd-service
 
+- name: Reload systemd on unit change
+  systemd:
+    daemon_reload: yes
+  when:
+    - 'systemd_services_result | changed'
+
 - name: Load service
   systemd:
     name: "{{ item.service_name | replace(' ', '_') }}"
-    daemon_reload: yes
     enabled: "{{ item.enabled | default(systemd_service_enabled) }}"
     state: "{{ item.state | default(omit) }}"
   with_items: "{{ systemd_services }}"

tests/test.yml

@@ -25,7 +25,6 @@
         - service_name: "test simple service0"
           execstarts: "/bin/bash -c 'while true; do sleep 2 && echo test simple service; done'"
           enabled: yes
-          state: started
         - service_name: "test oneshot service0"
           config_overrides:
             Unit: