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, 28 insertions, 0 deletions

diff --git a/cloudinit/distros/__init__.py b/cloudinit/distros/__init__.py
index 426a2cf4..fe0015c6 100755
--- a/cloudinit/distros/__init__.py
+++ b/cloudinit/distros/__init__.py
@@ -798,6 +798,34 @@ class Distro(persistence.CloudInitPickleMixin, metaclass=abc.ABCMeta):
             args.append(message)
         return args
 
+    def manage_service(self, action, service):
+        """
+        Perform the requested action on a service. This handles the common
+        'systemctl' and 'service' cases and may be overridden in subclasses
+        as necessary.
+        May raise ProcessExecutionError
+        """
+        init_cmd = self.init_cmd
+        if self.uses_systemd() or 'systemctl' in init_cmd:
+            init_cmd = ['systemctl']
+            cmds = {'stop': ['stop', service],
+                    'start': ['start', service],
+                    'enable': ['enable', service],
+                    'restart': ['restart', service],
+                    'reload': ['reload-or-restart', service],
+                    'try-reload': ['reload-or-try-restart', service],
+                    }
+        else:
+            cmds = {'stop': [service, 'stop'],
+                    'start': [service, 'start'],
+                    'enable': [service, 'start'],
+                    'restart': [service, 'restart'],
+                    'reload': [service, 'restart'],
+                    'try-reload': [service, 'restart'],
+                    }
+        cmd = list(init_cmd) + list(cmds[action])
+        return subp.subp(cmd, capture=True)
+
 
 def _apply_hostname_transformations_to_url(url: str, transformations: list):
     """