slapos node prune: write software pid file

slapos node prune already detected the case where software was running
and refused to run while software was runnning, to prevent a case where
software writes files and prune removes them because they are not yet
referenced, but nothing prevented the other way around: slapos node
software should not start while slapos node prune is deleting files. To
prevent this, make slapos node prune actually use software pid file,
then software will refuse to start while prune is running.

slapos/cli/prune.py

@@ -34,6 +34,7 @@ import six.moves.configparser as configparser
 
 from slapos.cli.config import ConfigCommand
 from slapos.grid.slapgrid import merged_options
+from slapos.grid.utils import setRunning, setFinished
 from slapos.util import rmtree
 
 
@@ -66,7 +67,13 @@ class PruneCommand(ConfigCommand):
       self.app.log.error('Cannot prune while software is running')
       sys.exit(-1)
 
-    sys.exit(do_prune(self.app.log, options, args.dry_run))
+    if pidfile_software:
+      setRunning(logger=self.app.log, pidfile=pidfile_software)
+    try:
+      do_prune(self.app.log, options, args.dry_run)
+    finally:
+      if pidfile_software:
+        setFinished(pidfile_software)
 
 
 def _prune(

slapos/tests/test_cli.py

@@ -399,6 +399,25 @@ class TestCliNode(CliMixin):
           pidfile='/opt/slapos/slapgrid-cp.pid')
       processComputerPartitionList.assert_called_once()
 
+  def test_node_prune(self):
+    """slapos node prune command
+    """
+    app = slapos.cli.entry.SlapOSApp()
+
+    with patch('slapos.cli.prune.setRunning') as write_pid_file, \
+         patch('slapos.cli.prune.merged_options', return_value={
+            'shared_part_list': 'something',
+            'pidfile_software': 'pidfile_software.pid',
+         }), \
+         patch('slapos.cli.prune.do_prune') as do_prune:
+
+      app.run(('node', 'prune'))
+
+      write_pid_file.assert_called_once_with(
+          logger=mock.ANY,
+          pidfile='pidfile_software.pid')
+      do_prune.assert_called_once()
+
 
 class TestCliList(CliMixin):
   def test_list(self):