Merge lp:~cjwatson/turku-charms/turku-agent-charm-fix-systemd-harder into lp:turku-charms/turku-agent-charm

[Colin Watson]

Fix installation of systemd units.

We only need to enable those units that have an [Install] section. Trying to enable the others does nothing except producing warnings. We also need to start the units that we've enabled.

[🤖 Canonical IS Merge Bot (canonical-is-mergebot)]

This merge proposal is being monitored by mergebot. Change the status to Approved to merge.

[🤖 Canonical IS Merge Bot (canonical-is-mergebot)]

Change successfully merged at revision 15

=== modified file 'hooks/hooks.py'
--- hooks/hooks.py	2019-07-04 23:42:09 +0000
+++ hooks/hooks.py	2019-07-17 18:07:22 +0000
@@ -28,6 +28,11 @@
     return json.dumps(obj, sort_keys=True, indent=4, separators=(',', ': '))
 
 
+def systemd_is_running():
+    """Is systemd the running init daemon?"""
+    return os.path.isdir('/run/systemd/system')
+
+
 def install():
     subprocess.check_call(['apt-get', 'update'])
     subprocess.check_call(['apt-get', '-y', 'install', 'python3', 'python3-setuptools', 'python3-pkg-resources'])
@@ -53,13 +58,18 @@
                 ):
             shutil.copyfile(os.path.join('files/turku-agent', unit),
                             os.path.join('/etc/systemd/system', unit))
-            # Even if the directory exists, Systemd may not be installed or
-            # enabled.  So don't fail on this systemctl command.
-            try:
-                subprocess.call(['systemctl', 'enable', unit])
-            except OSError as e:
-                if e.errno != 2:
-                    raise
+
+        # Enable and start units.  We only need to operate on those units
+        # that have [Install] sections; the others are activated on demand.
+        if systemd_is_running():
+            installable_units = [
+                'turku-agent-ping.timer',
+                'turku-agent-rsyncd.service',
+                'turku-update-config.timer',
+                ]
+            subprocess.call(['systemctl', 'enable'] + installable_units)
+            subprocess.call(['systemctl', 'daemon-reload'])
+            subprocess.call(['systemctl', 'start'] + installable_units)
 
 
 def configure(juju_stored=None):