Fix most ResourceWarning in the test suite

https://docs.python.org/dev/whatsnew/3.2.html python3 warns about not unclosed files and sockets.

Use context managers with files to close them.

Use context manager to close socket to supervisor on python 3. On python 2 these sockets remain not closed as before.

There are a few warnings left, but output starts to be readable again.

/reviewed-on !78

slapos/grid/SlapObject.py

@@ -568,7 +568,8 @@ class Partition(object):
     shutil.copy(template_location, config_location)
 
     # fill generated buildout with additional information
-    buildout_text = open(config_location).read()
+    with open(config_location) as f:
+      buildout_text = f.read()
     buildout_text += '\n\n' + bytes2str(pkg_resources.resource_string(__name__,
         'templates/buildout-tail.cfg.in')) % {
             'computer_id': self.computer_id,
@@ -580,7 +581,8 @@ class Partition(object):
             'storage_home': self.instance_storage_home,
             'global_ipv4_network_prefix': self.ipv4_global_network,
         }
-    open(config_location, 'w').write(buildout_text)
+    with open(config_location, 'w') as f:
+      f.write(buildout_text)
     os.chmod(config_location, 0o640)
     # Try to find the best possible buildout:
     #  *) if software_root/bin/bootstrap exists use this one to bootstrap
@@ -706,14 +708,16 @@ class Partition(object):
     """Asks supervisord to start the instance. If this instance is not
     installed, we install it.
     """
-    supervisor = self.getSupervisorRPC()
     partition_id = self.computer_partition.getId()
     try:
-      supervisor.startProcessGroup(partition_id, False)
+      with self.getSupervisorRPC() as supervisor:
+        supervisor.startProcessGroup(partition_id, False)
     except xmlrpclib.Fault as exc:
       if exc.faultString.startswith('BAD_NAME:'):
         self.logger.info("Nothing to start on %s..." %
                          self.computer_partition.getId())
+      else:
+        raise
     else:
       self.logger.info("Requested start of %s..." % self.computer_partition.getId())
 
@@ -721,11 +725,13 @@ class Partition(object):
     """Asks supervisord to stop the instance."""
     partition_id = self.computer_partition.getId()
     try:
-      supervisor = self.getSupervisorRPC()
-      supervisor.stopProcessGroup(partition_id, False)
+      with self.getSupervisorRPC() as supervisor:
+        supervisor.stopProcessGroup(partition_id, False)
     except xmlrpclib.Fault as exc:
       if exc.faultString.startswith('BAD_NAME:'):
         self.logger.info('Partition %s not known in supervisord, ignoring' % partition_id)
+      else:
+        raise
     else:
       self.logger.info("Requested stop of %s..." % self.computer_partition.getId())
 
@@ -796,15 +802,18 @@ class Partition(object):
 
   def checkProcessesFromStateList(self, process_list, state_list):
     """Asks supervisord to check if one of the processes are in the state_list."""
-    supervisor = self.getSupervisorRPC()
     for process in process_list:
       try:
-        info = supervisor.getProcessInfo(process)
+        with self.getSupervisorRPC() as supervisor:
+          info = supervisor.getProcessInfo(process)
         if info['statename'] in state_list:
           return True
       except xmlrpclib.Fault as exc:
-        self.logger.debug("BAD process name: %r" % process)
-        continue
+        if exc.faultString.startswith('BAD_NAME:'):
+          self.logger.debug("BAD process name: %r" % process)
+          continue
+        else:
+          raise
     return False
 
   def cleanupFolder(self, folder_path):
@@ -830,43 +839,43 @@ class Partition(object):
     #       In future it will not be needed, as update command
     #       is going to be implemented on server side.
     self.logger.debug('Updating supervisord')
-    supervisor = self.getSupervisorRPC()
-    # took from supervisord.supervisorctl.do_update
-    result = supervisor.reloadConfig()
-    added, changed, removed = result[0]
-
-    for gname in removed:
-      results = supervisor.stopProcessGroup(gname)
-      fails = [res for res in results
-               if res['status'] == xmlrpc.Faults.FAILED]
-      if fails:
-        self.logger.warning('Problem while stopping process %r, will try later' % gname)
-      else:
+    with self.getSupervisorRPC() as supervisor:
+      # took from supervisord.supervisorctl.do_update
+      result = supervisor.reloadConfig()
+      added, changed, removed = result[0]
+
+      for gname in removed:
+        results = supervisor.stopProcessGroup(gname)
+        fails = [res for res in results
+                 if res['status'] == xmlrpc.Faults.FAILED]
+        if fails:
+          self.logger.warning('Problem while stopping process %r, will try later' % gname)
+        else:
+          self.logger.info('Stopped %r' % gname)
+        for i in range(0, 10):
+          # Some process may be still running, be nice and wait for them to be stopped.
+          try:
+            supervisor.removeProcessGroup(gname)
+            break
+          except:
+            if i == 9:
+              raise
+            time.sleep(1)
+
+        self.logger.info('Removed %r' % gname)
+
+      for gname in changed:
+        results = supervisor.stopProcessGroup(gname)
         self.logger.info('Stopped %r' % gname)
-      for i in range(0, 10):
-        # Some process may be still running, be nice and wait for them to be stopped.
-        try:
-          supervisor.removeProcessGroup(gname)
-          break
-        except:
-          if i == 9:
-            raise
-          time.sleep(1)
-
-      self.logger.info('Removed %r' % gname)
-
-    for gname in changed:
-      results = supervisor.stopProcessGroup(gname)
-      self.logger.info('Stopped %r' % gname)
-
-      supervisor.removeProcessGroup(gname)
-      supervisor.addProcessGroup(gname)
-      self.logger.info('Updated %r' % gname)
-
-    for gname in added:
-      supervisor.addProcessGroup(gname)
-      self.logger.info('Updated %r' % gname)
-    self.logger.debug('Supervisord updated')
+
+        supervisor.removeProcessGroup(gname)
+        supervisor.addProcessGroup(gname)
+        self.logger.info('Updated %r' % gname)
+
+      for gname in added:
+        supervisor.addProcessGroup(gname)
+        self.logger.info('Updated %r' % gname)
+      self.logger.debug('Supervisord updated')
 
   def _set_ownership(self, path):
     """

slapos/grid/slapgrid.py

@@ -995,7 +995,8 @@ stderr_logfile_backups=1
       periodicity_path = os.path.join(software_path, 'periodicity')
       if os.path.exists(periodicity_path):
         try:
-          periodicity = int(open(periodicity_path).read())
+          with open(periodicity_path) as f:
+            periodicity = int(f.read())
         except ValueError:
           os.remove(periodicity_path)
           self.logger.exception('')
@@ -1031,7 +1032,8 @@ stderr_logfile_backups=1
     # changed).
     if (computer_partition_id not in self.computer_partition_filter_list and
           not self.develop and os.path.exists(timestamp_path)):
-      old_timestamp = open(timestamp_path).read()
+      with open(timestamp_path) as f:
+        old_timestamp = f.read()
       last_runtime = int(os.path.getmtime(timestamp_path))
       if timestamp:
         try:
@@ -1064,9 +1066,7 @@ stderr_logfile_backups=1
     # Include Partition Logging
     log_folder_path = "%s/.slapgrid/log" % instance_path
     mkdir_p(log_folder_path)
-    partition_file_handler = logging.FileHandler(
-                filename="%s/instance.log" % (log_folder_path)
-            )
+
     stat_info = os.stat(instance_path)
     chownDirectory("%s/.slapgrid" % instance_path,
                    uid=stat_info.st_uid,
@@ -1074,9 +1074,13 @@ stderr_logfile_backups=1
 
     formatter = logging.Formatter(
        '[%(asctime)s] %(levelname)-8s %(name)s %(message)s')
+
+    # this partition_file_handler will be cleaned up after this try: block
+    partition_file_handler = logging.FileHandler(
+                filename="%s/instance.log" % (log_folder_path)
+            )
     partition_file_handler.setFormatter(formatter)
     self.logger.addHandler(partition_file_handler)
-
     try:
       self.logger.info('Processing Computer Partition %s.' % computer_partition_id)
       self.logger.info('  Software URL: %s' % software_url)
@@ -1153,8 +1157,9 @@ stderr_logfile_backups=1
             # updating promises state, no need to raise here
             pass
       raise e
-    else:
+    finally:
       self.logger.removeHandler(partition_file_handler)
+      partition_file_handler.close()
 
     # Run manager tear down
     for manager in self._manager_list:
@@ -1162,7 +1167,8 @@ stderr_logfile_backups=1
 
     # If partition has been successfully processed, write timestamp
     if timestamp:
-      open(timestamp_path, 'w').write(timestamp)
+      with open(timestamp_path, 'w') as f:
+        f.write(timestamp)
 
   def FilterComputerPartitionList(self, computer_partition_list):
     """
@@ -1492,7 +1498,8 @@ stderr_logfile_backups=1
 
             file_path = os.path.join(dir_reports, filename)
             if os.path.exists(file_path):
-              usage = open(file_path, 'r').read()
+              with open(file_path, 'r') as f:
+                usage = f.read()
 
               # We check the validity of xml content of each reports
               if not self.validateXML(usage, partition_consumption_model):
@@ -1538,7 +1545,8 @@ stderr_logfile_backups=1
 
       file_path = os.path.join(computer_report_dir, filename)
       if os.path.exists(file_path):
-        usage = open(file_path, 'r').read()
+        with open(file_path, 'r') as f:
+          usage = f.read()
 
       if self.validateXML(usage, computer_consumption_model):
         self.logger.info('XML file generated by asXML is valid')

slapos/grid/svcbackend.py

@@ -36,6 +36,7 @@ import stat
 import sys
 import time
 from six.moves import xmlrpc_client as xmlrpclib
+import contextlib
 
 from slapos.grid.utils import (createPrivateDirectory, SlapPopen, updateFile)
 from slapos.util import bytes2str
@@ -43,13 +44,25 @@ from slapos.util import bytes2str
 from supervisor import xmlrpc, states
 
 
+@contextlib.contextmanager
 def getSupervisorRPC(socket):
+  """Get a supervisor XML-RPC connection.
+
+  Use in a context manager for proper closing of sockets.
+  """
   supervisor_transport = xmlrpc.SupervisorTransport('', '',
       'unix://' + socket)
   server_proxy = xmlrpclib.ServerProxy('http://127.0.0.1',
       supervisor_transport)
-  return getattr(server_proxy, 'supervisor')
 
+  # python3's xmlrpc is a closing context manager, python2 is not and cannot be
+  # just used as a context manager as it would call __enter__ and __exit__ on
+  # XML-RPC.
+  if sys.version_info.major == 2:
+    yield server_proxy.supervisor
+  else:
+    with server_proxy as s:
+      yield s.supervisor
 
 def _getSupervisordSocketPath(instance_root):
   return os.path.join(instance_root, 'supervisord.socket')
@@ -116,13 +129,13 @@ def _updateWatchdog(socket):
   Then, when running slapgrid, the real watchdog configuration is generated.
   We thus need to reload watchdog configuration if needed and start it.
   """
-  supervisor = getSupervisorRPC(socket)
-  if supervisor.getProcessInfo('watchdog')['state'] not in states.RUNNING_STATES:
-    # XXX workaround for https://github.com/Supervisor/supervisor/issues/339
-    # In theory, only reloadConfig is needed.
-    supervisor.removeProcessGroup('watchdog')
-    supervisor.reloadConfig()
-    supervisor.addProcessGroup('watchdog')
+  with getSupervisorRPC(socket) as supervisor:
+    if supervisor.getProcessInfo('watchdog')['state'] not in states.RUNNING_STATES:
+      # XXX workaround for https://github.com/Supervisor/supervisor/issues/339
+      # In theory, only reloadConfig is needed.
+      supervisor.removeProcessGroup('watchdog')
+      supervisor.reloadConfig()
+      supervisor.addProcessGroup('watchdog')
 
 def launchSupervisord(instance_root, logger,
                       supervisord_additional_argument_list=None):
@@ -132,13 +145,15 @@ def launchSupervisord(instance_root, logger,
     trynum = 1
     while trynum < 6:
       try:
-        supervisor = getSupervisorRPC(socket)
-        status = supervisor.getState()
+        with getSupervisorRPC(socket) as supervisor:
+          status = supervisor.getState()
       except xmlrpclib.Fault as e:
         if e.faultCode == 6 and e.faultString == 'SHUTDOWN_STATE':
           logger.info('Supervisor in shutdown procedure, will check again later.')
           trynum += 1
           time.sleep(2 * trynum)
+        else:
+          raise
       except Exception:
         # In case if there is problem with connection, assume that supervisord
         # is not running and try to run it
@@ -187,8 +202,8 @@ def launchSupervisord(instance_root, logger,
     while trynum < 6:
       try:
         socketlib.setdefaulttimeout(current_timeout)
-        supervisor = getSupervisorRPC(socket)
-        status = supervisor.getState()
+        with getSupervisorRPC(socket) as supervisor:
+          status = supervisor.getState()
         if status['statename'] == 'RUNNING' and status['statecode'] == 1:
           return
         logger.warning('Wrong status name %(statename)r and code '

slapos/grid/utils.py

@@ -312,7 +312,9 @@ def launchBuildout(path, buildout_binary, logger,
   uid = stat_info.st_uid
   gid = stat_info.st_gid
   # Extract python binary to prevent shebang size limit
-  line = open(buildout_binary, 'r').readline()
+  with open(buildout_binary, 'r') as f:
+    line = f.readline()
+
   invocation_list = []
   if line.startswith('#!'):
     line = line[2:]

slapos/grid/watchdog.py

@@ -143,8 +143,10 @@ class Watchdog(object):
       # Partition never managed to deploy successfully, ignore bang
       return True
 
-    last_bang_timestamp = int(open(slapos_last_bang_timestamp_file_path, 'r').read())
-    deployment_timestamp = int(open(partition_timestamp_file_path, 'r').read())
+    with open(slapos_last_bang_timestamp_file_path, 'r') as f:
+      last_bang_timestamp = int(f.read())
+    with open(partition_timestamp_file_path, 'r') as f:
+      deployment_timestamp = int(f.read())
     if deployment_timestamp > last_bang_timestamp:
       # It previously banged BEFORE latest successful deployment
       # i.e it haven't banged since last successful deployment
@@ -175,10 +177,12 @@ class Watchdog(object):
         COMPUTER_PARTITION_LATEST_BANG_TIMESTAMP_FILENAME
     )
     if os.path.exists(partition_timestamp_file_path):
-      timestamp = open(partition_timestamp_file_path, 'r').read()
+      with open(partition_timestamp_file_path, 'r') as f:
+        timestamp = f.read()
     else:
       timestamp = '0'
-    open(slapos_last_bang_timestamp_file_path, 'w').write(timestamp)
+    with open(slapos_last_bang_timestamp_file_path, 'w') as f:
+      f.write(timestamp)
 
   def handle_process_state_change_event(self, headers, payload_dict):
     partition_id = payload_dict['groupname']

slapos/manager/portredir.py

@@ -167,13 +167,13 @@ class Manager(object):
     partition.writeSupervisorConfigurationFile()
 
     # Start processes
-    supervisord = partition.getSupervisorRPC()
-    for program in socat_programs:
-      process_name = '{}:{}'.format(group_id, program['name'])
-      status = supervisord.getProcessInfo(process_name)
+    with partition.getSupervisorRPC() as supervisor:
+      for program in socat_programs:
+        process_name = '{}:{}'.format(group_id, program['name'])
+        status = supervisor.getProcessInfo(process_name)
 
-      if status['start'] == 0:
-        supervisord.startProcess(process_name, False)
+        if status['start'] == 0:
+          supervisor.startProcess(process_name, False)
 
   def report(self, partition):
     """Method called at `slapos node report` phase.

slapos/manager/prerm.py

@@ -80,16 +80,16 @@ class Manager(object):
       partition.writeSupervisorConfigurationFile()
 
       # check the state of all process, if the process is not started yes, start it
-      supervisord = partition.getSupervisorRPC()
-      process_list_string = ""
-      for name in wrapper_list:
-        process_name = '-'.join([partition_id, group_suffix]) + ':' + name
-        process_list_string += '%s\n' % process_name
-        status = supervisord.getProcessInfo(process_name)
-        if status['start'] == 0:
-          # process is not started yet
-          logger.info("Starting pre-delete process %r..." % name)
-          supervisord.startProcess(process_name, False)
+      with partition.getSupervisorRPC() as supervisor:
+        process_list_string = ""
+        for name in wrapper_list:
+          process_name = '-'.join([partition_id, group_suffix]) + ':' + name
+          process_list_string += '%s\n' % process_name
+          status = supervisor.getProcessInfo(process_name)
+          if status['start'] == 0:
+            # process is not started yet
+            logger.info("Starting pre-delete process %r..." % name)
+            supervisor.startProcess(process_name, False)
 
       # ask to slapgrid to check theses scripts before destroy partition
       with open(wait_filepath, 'w') as f:

slapos/tests/cli.py

@@ -185,7 +185,8 @@ class TestCliProxyShow(CliMixin):
     self.assertEqual('', stdout.getvalue())
     self.assertEqual('', stderr.getvalue())
     # our pager was set to output to this temporary file
-    self.assertIn('287375f0cba269902ba1bc50242839d7', open(tmp.name, 'r').read())
+    with open(tmp.name, 'r') as f:
+      self.assertIn('287375f0cba269902ba1bc50242839d7', f.read())
 
 
 class TestCliNode(CliMixin):

slapos/tests/promise.py

@@ -646,8 +646,10 @@ class RunPromise(GenericPromise):
 
     self.assertTrue(os.path.exists(first_state_file))
     self.assertTrue(os.path.exists(second_state_file))
-    first_result = json.load(open(first_state_file))
-    second_result = json.load(open(second_state_file))
+    with open(first_state_file) as f:
+      first_result = json.load(f)
+    with open(second_state_file) as f:
+      second_result = json.load(f)
     self.assertEqual(first_result['name'], first_promise)
     self.assertEqual(second_result['name'], second_promise)
     first_date = first_result['result']['date']
@@ -659,8 +661,10 @@ class RunPromise(GenericPromise):
       self.launcher.run() # only my_first_promise will run but second_promise still failing
     self.assertEqual(str(exc.exception), 'Promise %r failed.' % second_promise)
 
-    first_result = json.load(open(first_state_file))
-    second_result = json.load(open(second_state_file))
+    with open(first_state_file) as f:
+      first_result = json.load(f)
+    with open(second_state_file) as f:
+      second_result = json.load(f)
     self.assertNotEqual(first_result['result']['date'], first_date)
     self.assertEqual(second_result['result']['date'], second_date)
     first_date = first_result['result']['date']
@@ -671,8 +675,10 @@ class RunPromise(GenericPromise):
       self.launcher.run()
     self.assertEqual(str(exc.exception), 'Promise %r failed.' % second_promise)
 
-    first_result = json.load(open(first_state_file))
-    second_result = json.load(open(second_state_file))
+    with open(first_state_file) as f:
+      first_result = json.load(f)
+    with open(second_state_file) as f:
+      second_result = json.load(f)
     self.assertNotEqual(first_result['result']['date'], first_date)
     self.assertNotEqual(second_result['result']['date'], second_date)
 
@@ -696,8 +702,10 @@ class RunPromise(GenericPromise):
 
     self.assertTrue(os.path.exists(first_state_file))
     self.assertTrue(os.path.exists(second_state_file))
-    first_result = json.load(open(first_state_file))
-    second_result = json.load(open(second_state_file))
+    with open(first_state_file) as f:
+      first_result = json.load(f)
+    with open(second_state_file) as f:
+      second_result = json.load(f)
     self.assertEqual(first_result['name'], first_promise)
     self.assertEqual(second_result['name'], second_promise)
     first_date = first_result['result']['date']
@@ -709,8 +717,10 @@ class RunPromise(GenericPromise):
       self.launcher.run() # only my_first_promise will run but second_promise still failing
     self.assertEqual(str(exc.exception), 'Promise %r failed.' % second_promise)
 
-    first_result = json.load(open(first_state_file))
-    second_result = json.load(open(second_state_file))
+    with open(first_state_file) as f:
+      first_result = json.load(f)
+    with open(second_state_file) as f:
+      second_result = json.load(f)
     self.assertNotEqual(first_result['result']['date'], first_date)
     self.assertEqual(second_result['result']['date'], second_date)
     first_date = first_result['result']['date']
@@ -725,8 +735,10 @@ class RunPromise(GenericPromise):
     self.configureLauncher()
     self.launcher.run() # now all succeed
 
-    first_result = json.load(open(first_state_file))
-    second_result = json.load(open(second_state_file))
+    with open(first_state_file) as f:
+      first_result = json.load(f)
+    with open(second_state_file) as f:
+      second_result = json.load(f)
     self.assertNotEqual(first_result['result']['date'], first_date)
     self.assertNotEqual(second_result['result']['date'], second_date)
 

slapos/tests/slapgrid.py

@@ -176,8 +176,9 @@ class BasicMixin(object):
 
   def assertLogContent(self, log_path, expected, tries=600):
     for i in range(tries):
-      if expected in open(log_path).read():
-        return
+      with open(log_path) as f:
+        if expected in f.read():
+          return
       time.sleep(0.1)
     self.fail('%r not found in %s' % (expected, log_path))
 
@@ -205,7 +206,8 @@ class BasicMixin(object):
     svc = os.path.join(self.instance_root, 'var', 'run', 'supervisord.pid')
     if os.path.exists(svc):
       try:
-        pid = int(open(svc).read().strip())
+        with open(svc) as f:
+          pid = int(f.read().strip())
       except ValueError:
         pass
       else:
@@ -483,7 +485,8 @@ class InstanceForTest(object):
     if not os.path.isdir(promise_path):
       os.makedirs(promise_path)
     promise = os.path.join(promise_path, promise_name)
-    open(promise, 'w').write(promise_content)
+    with open(promise, 'w') as f:
+      f.write(promise_content)
     os.chmod(promise, 0o777)
 
   def setCertificate(self, certificate_repository_path):
@@ -492,11 +495,13 @@ class InstanceForTest(object):
     self.cert_file = os.path.join(certificate_repository_path,
                                   "%s.crt" % self.name)
     self.certificate = str(random.random())
-    open(self.cert_file, 'w').write(self.certificate)
+    with open(self.cert_file, 'w') as f:
+      f.write(self.certificate)
     self.key_file = os.path.join(certificate_repository_path,
                                  '%s.key' % self.name)
     self.key = str(random.random())
-    open(self.key_file, 'w').write(self.key)
+    with open(self.key_file, 'w') as f:
+      f.write(self.key)
 
 
 class SoftwareForTest(object):
@@ -532,22 +537,24 @@ class SoftwareForTest(object):
     """
     Set template.cfg
     """
-    open(os.path.join(self.srdir, 'template.cfg'), 'w').write(template)
+    with open(os.path.join(self.srdir, 'template.cfg'), 'w') as f:
+      f.write(template)
 
   def setBuildout(self, buildout="""#!/bin/sh
 touch worked"""):
     """
     Set a buildout exec in bin
     """
-    open(os.path.join(self.srbindir, 'buildout'), 'w').write(buildout)
+    with open(os.path.join(self.srbindir, 'buildout'), 'w') as f:
+      f.write(buildout)
     os.chmod(os.path.join(self.srbindir, 'buildout'), 0o755)
 
   def setPeriodicity(self, periodicity):
     """
     Set a periodicity file
     """
-    with open(os.path.join(self.srdir, 'periodicity'), 'w') as fout:
-      fout.write(str(periodicity))
+    with open(os.path.join(self.srdir, 'periodicity'), 'w') as f:
+      f.write(str(periodicity))
 
 
 @implementer(IManager)
@@ -873,11 +880,12 @@ class TestSlapgridCPWithMasterWatchdog(MasterMixin, unittest.TestCase):
     # Prepare watchdog
     self.watchdog_banged = os.path.join(self._tempdir, 'watchdog_banged')
     watchdog_path = os.path.join(self._tempdir, 'watchdog')
-    open(watchdog_path, 'w').write(WATCHDOG_TEMPLATE.format(
-        python_path=sys.executable,
-        sys_path=sys.path,
-        watchdog_banged=self.watchdog_banged
-    ))
+    with open(watchdog_path, 'w') as f:
+      f.write(WATCHDOG_TEMPLATE.format(
+          python_path=sys.executable,
+          sys_path=sys.path,
+          watchdog_banged=self.watchdog_banged
+      ))
     os.chmod(watchdog_path, 0o755)
     self.grid.watchdog_path = watchdog_path
     slapos.grid.slapgrid.WATCHDOG_PATH = watchdog_path
@@ -908,7 +916,8 @@ class TestSlapgridCPWithMasterWatchdog(MasterMixin, unittest.TestCase):
       daemon_log = os.path.join(partition.partition_path, '.0_daemon.log')
       self.assertLogContent(daemon_log, 'Failing')
       self.assertIsCreated(self.watchdog_banged)
-      self.assertIn('daemon', open(self.watchdog_banged).read())
+      with open(self.watchdog_banged) as f:
+        self.assertIn('daemon', f.read())
 
   def test_one_failing_daemon_in_run_will_not_bang_with_watchdog(self):
     """
@@ -1059,8 +1068,10 @@ class TestSlapgridCPWithMasterWatchdog(MasterMixin, unittest.TestCase):
       watchdog.handle_event(headers, payload)
       self.assertEqual(instance.sequence, ['/softwareInstanceBang'])
 
-      self.assertEqual(open(os.path.join(partition, slapos.grid.slapgrid.COMPUTER_PARTITION_LATEST_BANG_TIMESTAMP_FILENAME)).read(), timestamp_content)
-
+      with open(os.path.join(
+          partition,
+          slapos.grid.slapgrid.COMPUTER_PARTITION_LATEST_BANG_TIMESTAMP_FILENAME)) as f:
+        self.assertEqual(f.read(), timestamp_content)
 
   def test_watchdog_ignore_bang_if_partition_not_deployed(self):
     """
@@ -1092,8 +1103,10 @@ class TestSlapgridCPWithMasterWatchdog(MasterMixin, unittest.TestCase):
       watchdog.handle_event(headers, payload)
       self.assertEqual(instance.sequence, ['/softwareInstanceBang'])
 
-      self.assertNotEqual(open(os.path.join(partition, slapos.grid.slapgrid.COMPUTER_PARTITION_LATEST_BANG_TIMESTAMP_FILENAME)).read(), timestamp_content)
-
+      with open(os.path.join(
+          partition,
+          slapos.grid.slapgrid.COMPUTER_PARTITION_LATEST_BANG_TIMESTAMP_FILENAME)) as f:
+        self.assertNotEqual(f.read(), timestamp_content)
 
   def test_watchdog_bang_only_once_if_partition_never_deployed(self):
     """
@@ -1179,7 +1192,10 @@ class TestSlapgridCPWithMasterWatchdog(MasterMixin, unittest.TestCase):
       watchdog.handle_event(headers, payload)
       self.assertEqual(instance.sequence, ['/softwareInstanceBang'])
 
-      self.assertEqual(open(os.path.join(partition, slapos.grid.slapgrid.COMPUTER_PARTITION_LATEST_BANG_TIMESTAMP_FILENAME)).read(), timestamp_content)
+      with open(os.path.join(
+          partition,
+          slapos.grid.slapgrid.COMPUTER_PARTITION_LATEST_BANG_TIMESTAMP_FILENAME)) as f:
+        self.assertEqual(f.read(), timestamp_content)
 
       # Second bang
       event = watchdog.process_state_events[0]
@@ -1207,7 +1223,10 @@ class TestSlapgridCPWithMasterWatchdog(MasterMixin, unittest.TestCase):
       watchdog.handle_event(headers, payload)
       self.assertEqual(instance.sequence, ['/softwareInstanceBang'])
 
-      self.assertEqual(open(os.path.join(partition, slapos.grid.slapgrid.COMPUTER_PARTITION_LATEST_BANG_TIMESTAMP_FILENAME)).read(), timestamp_content)
+      with open(os.path.join(
+          partition,
+          slapos.grid.slapgrid.COMPUTER_PARTITION_LATEST_BANG_TIMESTAMP_FILENAME)) as f:
+        self.assertEqual(f.read(), timestamp_content)
 
       # Fourth bang
       event = watchdog.process_state_events[0]
@@ -1237,7 +1256,8 @@ class TestSlapgridCPPartitionProcessing(MasterMixin, unittest.TestCase):
       timestamp_path = os.path.join(instance.partition_path, '.timestamp')
       self.setSlapgrid()
       self.assertEqual(self.grid.processComputerPartitionList(), slapgrid.SLAPGRID_SUCCESS)
-      self.assertIn(timestamp, open(timestamp_path).read())
+      with open(timestamp_path) as f:
+        self.assertIn(timestamp, f.read())
       self.assertEqual(instance.sequence,
                        ['/stoppedComputerPartition'])
 

slapos/tests/slapobject.py

@@ -459,14 +459,16 @@ class TestPartitionDestructionLock(MasterMixin, unittest.TestCase):
     software = self.createSoftware()
     partition = self.createPartition(software.url, retention_delay=delay)
     partition.install()
-    deployed_delay = int(open(partition.retention_lock_delay_file_path).read())
+    with open(partition.retention_lock_delay_file_path) as f:
+      deployed_delay = int(f.read())
     self.assertEqual(delay, deployed_delay)
 
   def test_no_retention_lock_delay(self):
     software = self.createSoftware()
     partition = self.createPartition(software.url)
     partition.install()
-    delay = open(partition.retention_lock_delay_file_path).read()
+    with open(partition.retention_lock_delay_file_path) as f:
+      delay = f.read()
     self.assertTrue(delay, '0')
 
     self.assertTrue(partition.destroy())
@@ -485,7 +487,8 @@ class TestPartitionDestructionLock(MasterMixin, unittest.TestCase):
     partition.install()
     partition.destroy()
 
-    deployed_delay = int(open(partition.retention_lock_delay_file_path).read())
+    with open(partition.retention_lock_delay_file_path) as f:
+      deployed_delay = int(f.read())
     self.assertEqual(delay, deployed_delay)
 
   def test_retention_lock_delay_is_respected(self):
@@ -494,7 +497,8 @@ class TestPartitionDestructionLock(MasterMixin, unittest.TestCase):
     partition = self.createPartition(software.url, retention_delay=delay)
     partition.install()
 
-    deployed_delay = float(open(partition.retention_lock_delay_file_path).read())
+    with open(partition.retention_lock_delay_file_path) as f:
+      deployed_delay = float(f.read())
     self.assertEqual(int(delay), int(deployed_delay))
 
     self.assertFalse(partition.destroy())
@@ -510,7 +514,8 @@ class TestPartitionDestructionLock(MasterMixin, unittest.TestCase):
     partition.install()
     self.assertFalse(os.path.exists(partition.retention_lock_date_file_path))
     partition.destroy()
-    deployed_date = float(open(partition.retention_lock_date_file_path).read())
+    with open(partition.retention_lock_date_file_path) as f:
+      deployed_date = float(f.read())
     self.assertEqual(delay * 3600 * 24 + int(time.time()), int(deployed_date))
 
   def test_retention_lock_date_does_not_change(self):
@@ -529,5 +534,6 @@ class TestPartitionDestructionLock(MasterMixin, unittest.TestCase):
     partition.install()
     partition.destroy()
 
-    deployed_date = float(open(partition.retention_lock_date_file_path).read())
+    with open(partition.retention_lock_date_file_path) as f:
+      deployed_date = float(f.read())
     self.assertEqual(delay * 3600 * 24 + int(now), int(deployed_date))

slapos/tests/slapproxy/__init__.py

@@ -1142,7 +1142,8 @@ database_uri = %(tempdir)s/lib/external_proxy.db
         'external_proxy_host': self.external_proxy_host,
         'external_proxy_port': self.external_proxy_port
     }
-    open(self.slapos_cfg, 'w').write(configuration)
+    with open(self.slapos_cfg, 'w') as f:
+      f.write(configuration)
 
   def external_proxy_add_free_partition(self, partition_amount, computer_id=None):
     """