CLOS-3241: Create Leapp upgrade finish marker file during the last phase

repos/system_upgrade/cloudlinux/actors/createfinishmarker/actor.py

@@ -0,0 +1,25 @@
+from datetime import datetime
+
+from leapp.actors import Actor
+from leapp.tags import FirstBootPhaseTag, IPUWorkflowTag
+from leapp.libraries.common.cllaunch import run_on_cloudlinux
+
+
+class CreateFinishMarker(Actor):
+    """
+    Create a finish marker file to indicate that the upgrade has been completed.
+    Other utilities or tests can check for the existence of this file to determine if the upgrade has been completed.
+    """
+
+    name = 'create_finish_marker'
+    description = 'Create a finish marker file to indicate that the upgrade has been completed.'
+    consumes = ()
+    produces = ()
+    # Place this actor as far as possible in the workflow, after the absolute majority of other actors have run
+    tags = (FirstBootPhaseTag.After, IPUWorkflowTag)
+
+    @run_on_cloudlinux
+    def process(self):
+        # Create a finish marker file to indicate that the upgrade has been completed
+        with open('/var/log/leapp/leapp-upgrade-finished', 'w') as marker_file:
+            marker_file.write('Leapp upgrade completed on: {}\n'.format(datetime.now()))