diff --git a/storlets/gateway/common/logger.py b/storlets/gateway/common/logger.py
index 5b7ae7a4..bd4f57e1 100644
--- a/storlets/gateway/common/logger.py
+++ b/storlets/gateway/common/logger.py
@@ -28,20 +28,16 @@ class StorletLogger(object):
         if self._file is not None:
             raise StorletLoggerError('StorletLogger is already open')
 
-        try:
-            log_dir_path = os.path.dirname(self.log_path)
-            if not os.path.exists(log_dir_path):
-                os.makedirs(log_dir_path, 0o700)
+        log_dir_path = os.path.dirname(self.log_path)
+        if not os.path.exists(log_dir_path):
+            os.makedirs(log_dir_path, 0o700)
 
-            self._file = open(self.log_path, 'a')
-            os.chmod(self.log_path, 0o600)
-        except Exception:
-            raise
+        self._file = open(self.log_path, 'a')
+        os.chmod(self.log_path, 0o600)
 
     def getfd(self):
         if self._file is None:
-            # TODO(kota_): Is it safe to return None?
-            return None
+            raise StorletLoggerError('StorletLogger is not open')
         return self._file.fileno()
 
     def getsize(self):
@@ -52,12 +48,8 @@ class StorletLogger(object):
         if self._file is None:
             raise StorletLoggerError('StorletLogger is not open')
 
-        try:
-            self._file.close()
-        except Exception:
-            raise
-        else:
-            self._file = None
+        self._file.close()
+        self._file = None
 
     @contextmanager
     def activate(self):
diff --git a/tests/unit/gateway/common/test_logger.py b/tests/unit/gateway/common/test_logger.py
index aaf92bfc..9b472313 100644
--- a/tests/unit/gateway/common/test_logger.py
+++ b/tests/unit/gateway/common/test_logger.py
@@ -64,7 +64,9 @@ class TestStorletLogger(unittest.TestCase):
             self.logger.close()
 
     def test_getfd(self):
-        self.assertIsNone(self.logger.getfd())
+        with self.assertRaises(StorletLoggerError):
+            self.logger.getfd()
+
         self.logger.open()
         self.assertIsNotNone(self.logger.getfd())
         self.logger.close()
diff --git a/tests/unit/gateway/gateways/docker/test_runtime.py b/tests/unit/gateway/gateways/docker/test_runtime.py
index f21bc4a5..fd423ab7 100644
--- a/tests/unit/gateway/gateways/docker/test_runtime.py
+++ b/tests/unit/gateway/gateways/docker/test_runtime.py
@@ -513,26 +513,30 @@ class TestStorletInvocationProtocol(unittest.TestCase):
         with mock.patch('storlets.gateway.gateways.docker.runtime.SBusClient.'
                         'execute') as execute:
             execute.return_value = SBusResponse(True, 'OK', 'someid')
-            self.protocol._send_execute_command()
+            with self.protocol.storlet_logger.activate():
+                self.protocol._send_execute_command()
             self.assertEqual('someid', self.protocol.task_id)
 
         with mock.patch('storlets.gateway.gateways.docker.runtime.SBusClient.'
                         'execute') as execute:
             execute.return_value = SBusResponse(True, 'OK')
             with self.assertRaises(StorletRuntimeException):
-                self.protocol._send_execute_command()
+                with self.protocol.storlet_logger.activate():
+                    self.protocol._send_execute_command()
 
         with mock.patch('storlets.gateway.gateways.docker.runtime.SBusClient.'
                         'execute') as execute:
             execute.return_value = SBusResponse(False, 'NG', 'someid')
             with self.assertRaises(StorletRuntimeException):
-                self.protocol._send_execute_command()
+                with self.protocol.storlet_logger.activate():
+                    self.protocol._send_execute_command()
 
         with mock.patch('storlets.gateway.gateways.docker.runtime.SBusClient.'
                         'execute') as execute:
             execute.side_effect = SBusClientIOError()
             with self.assertRaises(StorletRuntimeException):
-                self.protocol._send_execute_command()
+                with self.protocol.storlet_logger.activate():
+                    self.protocol._send_execute_command()
 
     def test_invocation_protocol(self):
         # os.pipe will be called 3 times
@@ -572,7 +576,8 @@ class TestStorletInvocationProtocol(unittest.TestCase):
             self.storlet_id, {}, {}, iter(StringIO()), options=self.options)
         protocol = StorletInvocationProtocol(
             storlet_request, self.pipe_path, self.log_file, 1, self.logger)
-        self.assertEqual(4, len(protocol.remote_fds))
+        with protocol.storlet_logger.activate():
+            self.assertEqual(4, len(protocol.remote_fds))
 
         # extra_resources expands the remote_fds
         storlet_request = DockerStorletRequest(
@@ -580,7 +585,8 @@ class TestStorletInvocationProtocol(unittest.TestCase):
         protocol = StorletInvocationProtocol(
             storlet_request, self.pipe_path, self.log_file, 1, self.logger,
             extra_sources=[storlet_request])
-        self.assertEqual(5, len(protocol.remote_fds))
+        with protocol.storlet_logger.activate():
+            self.assertEqual(5, len(protocol.remote_fds))
 
         # 2 more extra_resources expands the remote_fds
         storlet_request = DockerStorletRequest(
@@ -588,7 +594,8 @@ class TestStorletInvocationProtocol(unittest.TestCase):
         protocol = StorletInvocationProtocol(
             storlet_request, self.pipe_path, self.log_file, 1, self.logger,
             extra_sources=[storlet_request] * 3)
-        self.assertEqual(7, len(protocol.remote_fds))
+        with protocol.storlet_logger.activate():
+            self.assertEqual(7, len(protocol.remote_fds))
 
     def test_open_writer_with_invalid_fd(self):
         invalid_fds = (