Refactor satellite_upgrade_services to use SystemdServicesTasks

We used to just delete the symlinks in /etc/systemd, but with the new
systemd actors this doesn't work anymore as they will restore the
pre-delete state because they by default aim at having source and
target systems match in terms of services. By using SystemdServicesTasks
we can explicitly turn those services off and inform all interested
parties about this.

repos/system_upgrade/common/actors/satellite_upgrade_services/actor.py

@@ -2,8 +2,8 @@
 import os
 
 from leapp.actors import Actor
-from leapp.models import SatelliteFacts
-from leapp.tags import ApplicationsPhaseTag, IPUWorkflowTag
+from leapp.models import SatelliteFacts, SystemdServicesTasks
+from leapp.tags import FactsPhaseTag, IPUWorkflowTag
 
 SYSTEMD_WANTS_BASE = '/etc/systemd/system/multi-user.target.wants/'
 SERVICES_TO_DISABLE = ['dynflow-sidekiq@*', 'foreman', 'foreman-proxy',
@@ -18,18 +18,17 @@ class SatelliteUpgradeServices(Actor):
 
     name = 'satellite_upgrade_services'
     consumes = (SatelliteFacts,)
-    produces = ()
-    tags = (IPUWorkflowTag, ApplicationsPhaseTag)
+    produces = (SystemdServicesTasks,)
+    tags = (IPUWorkflowTag, FactsPhaseTag)
 
     def process(self):
         facts = next(self.consume(SatelliteFacts), None)
         if not facts or not facts.has_foreman:
             return
 
         # disable services, will be re-enabled by the installer
+        services_to_disable = []
         for service_name in SERVICES_TO_DISABLE:
             for service in glob.glob(os.path.join(SYSTEMD_WANTS_BASE, '{}.service'.format(service_name))):
-                try:
-                    os.unlink(service)
-                except OSError as e:
-                    self.log.warning('Failed disabling service {}: {}'.format(service, e))
+                services_to_disable.append(os.path.basename(service))
+        self.produce(SystemdServicesTasks(to_disable=services_to_disable))

repos/system_upgrade/common/actors/satellite_upgrade_services/tests/unit_test_satellite_upgrade_services.py

@@ -0,0 +1,24 @@
+import glob
+
+from leapp.models import SatelliteFacts, SatellitePostgresqlFacts, SystemdServicesTasks
+
+
+def test_disable_httpd(monkeypatch, current_actor_context):
+    def mock_glob():
+        orig_glob = glob.glob
+
+        def mocked_glob(pathname):
+            if pathname == '/etc/systemd/system/multi-user.target.wants/httpd.service':
+                return [pathname]
+            return orig_glob(pathname)
+
+        return mocked_glob
+
+    monkeypatch.setattr('glob.glob', mock_glob())
+
+    current_actor_context.feed(SatelliteFacts(has_foreman=True,
+                                              postgresql=SatellitePostgresqlFacts(local_postgresql=False)))
+    current_actor_context.run()
+
+    message = current_actor_context.consume(SystemdServicesTasks)[0]
+    assert 'httpd.service' in message.to_disable