Leave the details of service management to the distro (#1074)

Various modules restart services and they all have logic to try and
detect if they are running on a system that needs 'systemctl' or
'service', and then have code to decide which order the arguments
need to be etc. On top of that, not all modules do this in the same way.

The duplication and different approaches are not ideal but this also
makes it hard to add support for a new distribution that does not use
either 'systemctl' or 'service'.

This change adds a new manage_service() method to the distro class
and updates several modules to use it.

1 files changed, 17 insertions, 25 deletions

diff --git a/cloudinit/config/cc_fan.py b/cloudinit/config/cc_fan.py
index 77984bca..91f50e22 100644
--- a/cloudinit/config/cc_fan.py
+++ b/cloudinit/config/cc_fan.py
@@ -52,35 +52,26 @@ BUILTIN_CFG = {
 }
 
 
-def stop_update_start(service, config_file, content, systemd=False):
-    if systemd:
-        cmds = {'stop': ['systemctl', 'stop', service],
-                'start': ['systemctl', 'start', service],
-                'enable': ['systemctl', 'enable', service]}
-    else:
-        cmds = {'stop': ['service', 'stop'],
-                'start': ['service', 'start']}
-
-    def run(cmd, msg):
-        try:
-            return subp.subp(cmd, capture=True)
-        except subp.ProcessExecutionError as e:
-            LOG.warning("failed: %s (%s): %s", service, cmd, e)
-            return False
-
-    stop_failed = not run(cmds['stop'], msg='stop %s' % service)
+def stop_update_start(distro, service, config_file, content):
+    try:
+        distro.manage_service('stop', service)
+        stop_failed = False
+    except subp.ProcessExecutionError as e:
+        stop_failed = True
+        LOG.warning("failed to stop %s: %s", service, e)
+
     if not content.endswith('\n'):
         content += '\n'
     util.write_file(config_file, content, omode="w")
 
-    ret = run(cmds['start'], msg='start %s' % service)
-    if ret and stop_failed:
-        LOG.warning("success: %s started", service)
-
-    if 'enable' in cmds:
-        ret = run(cmds['enable'], msg='enable %s' % service)
+    try:
+        distro.manage_service('start', service)
+        if stop_failed:
+            LOG.warning("success: %s started", service)
+    except subp.ProcessExecutionError as e:
+        LOG.warning("failed to start %s: %s", service, e)
 
-    return ret
+    distro.manage_service('enable', service)
 
 
 def handle(name, cfg, cloud, log, args):
@@ -99,7 +90,8 @@ def handle(name, cfg, cloud, log, args):
         distro.install_packages(['ubuntu-fan'])
 
     stop_update_start(
+        distro,
         service='ubuntu-fan', config_file=mycfg.get('config_path'),
-        content=mycfg.get('config'), systemd=distro.uses_systemd())
+        content=mycfg.get('config'))
 
 # vi: ts=4 expandtab