systemd - do not overwrite unit name when searching (#72985)

* systemd - do not overwrite unit name when searching

PR #72702 introduced a bug that changed the unit name when splitting it up for the purpose
of searching for the unit. This only happens on unit file templates on systems that have a 5.8
or newer kernel and a version of systemd that does not contain a bugfix that causes systmed
to fail to parse dbus.

* Use facts rather than a manual probe to determine if systmed is present

* Remov unnecessary block

* Use vars files instead of set_fact

* Add tests for using a templated unit file

* Update changelog fragment

* Use template to get correct path to sleep binary

changelogs/fragments/systemd-preserve-full-unit-name.yml

@@ -0,0 +1,4 @@
+bugfixes:
+  - >
+    systemd - preserve the full unit name when using a templated service and
+    ``systemd`` failed to parse dbus due to a known bug in ``systemd`` (https://github.com/ansible/ansible/pull/72985)

lib/ansible/modules/systemd.py

@@ -415,10 +415,10 @@ def main():
         elif err and rc == 1 and 'Failed to parse bus message' in err:
             result['status'] = parse_systemctl_show(to_native(out).split('\n'))
 
-            unit, sep, suffix = unit.partition('@')
-            unit_search = '{unit}{sep}*'.format(unit=unit, sep=sep)
-            (rc, out, err) = module.run_command("{systemctl} list-unit-files '{unit_search}'".format(systemctl=systemctl, unit_search=unit_search))
-            is_systemd = unit in out
+            unit_base, sep, suffix = unit.partition('@')
+            unit_search = '{unit_base}{sep}'.format(unit_base=unit_base, sep=sep)
+            (rc, out, err) = module.run_command("{systemctl} list-unit-files '{unit_search}*'".format(systemctl=systemctl, unit_search=unit_search))
+            is_systemd = unit_search in out
 
             (rc, out, err) = module.run_command("{systemctl} is-active '{unit}'".format(systemctl=systemctl, unit=unit))
             result['status']['ActiveState'] = out.rstrip('\n')

test/integration/targets/systemd/handlers/main.yml

@@ -0,0 +1,4 @@
+- name: remove unit file
+  file:
+    path: /etc/systemd/system/sleeper@.service
+    state: absent

test/integration/targets/systemd/tasks/main.yml

@@ -20,18 +20,21 @@
 ## systemctl
 ##
 
-- name: check for systemctl command
-  shell: which systemctl
-  failed_when: False
-  register: systemctl_check
+- name: End if this system does not use systemd
+  meta: end_host
+  when: ansible_facts.service_mgr != 'systemd'
+
+- name: Include distribution specific variables
+  include_vars: "{{ lookup('first_found', params) }}"
+  vars:
+    params:
+      files:
+        - "{{ ansible_facts.distribution }}.yml"
+        - "{{ ansible_facts.os_family }}.yml"
+        - default.yml
+      paths:
+        - vars
 
-- meta: end_host
-  when: systemctl_check.rc != 0
-
-- set_fact:
-    ssh_service: '{{ "ssh" if ansible_os_family == "Debian" else "sshd" }}'
-
-- block:
 - name: get a list of running services
   shell: systemctl | fgrep 'running' | awk '{print $1}' | sed 's/\.service//g' | fgrep -v '.' | egrep ^[a-z]
   register: running_names
@@ -114,3 +117,5 @@
       - systemd_disable_ssh_2 is not changed
       - systemd_enable_ssh_1 is changed
       - systemd_enable_ssh_2 is not changed
+
+- import_tasks: test_unit_template.yml

test/integration/targets/systemd/tasks/test_unit_template.yml

@@ -0,0 +1,50 @@
+- name: Copy service file
+  template:
+    src: sleeper@.service
+    dest: /etc/systemd/system/sleeper@.service
+    owner: root
+    group: root
+    mode: '0644'
+  notify: remove unit file
+
+- name: Reload systemd
+  systemd:
+    daemon_reload: yes
+
+- name: Start and enable service using unit template
+  systemd:
+    name: sleeper@100.service
+    state: started
+    enabled: yes
+  register: template_test_1
+
+- name: Start and enable service using unit template again
+  systemd:
+    name: sleeper@100.service
+    state: started
+    enabled: yes
+  register: template_test_2
+
+- name: Stop and disable service using unit template
+  systemd:
+    name: sleeper@100.service
+    state: stopped
+    enabled: no
+  register: template_test_3
+
+- name: Stop and disable service using unit template again
+  systemd:
+    name: sleeper@100.service
+    state: stopped
+    enabled: no
+  register: template_test_4
+
+- name:
+  assert:
+    that:
+      - template_test_1 is changed
+      - template_test_1 is success
+      - template_test_2 is not changed
+      - template_test_2 is success
+      - template_test_3 is changed
+      - template_test_4 is not changed

test/integration/targets/systemd/templates/sleeper@.service

@@ -0,0 +1,8 @@
+[Unit]
+Description=Basic service to use as a template
+
+[Service]
+ExecStart={{ sleep_bin_path }} %i
+
+[Install]
+WantedBy=multi-user.target

test/integration/targets/systemd/vars/Debian.yml

@@ -0,0 +1,2 @@
+ssh_service: ssh
+sleep_bin_path: /bin/sleep

test/integration/targets/systemd/vars/default.yml

@@ -0,0 +1,2 @@
+ssh_service: sshd
+sleep_bin_path: /usr/bin/sleep