1 files changed, 74 insertions, 0 deletions
diff --git a/netmodel/util/file.py b/netmodel/util/file.py
new file mode 100644
index 00000000..4204d533
--- /dev/null
+++ b/netmodel/util/file.py
@@ -0,0 +1,74 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+#
+# Copyright (c) 2017 Cisco and/or its affiliates.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at:
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+import errno
+import logging
+import os
+import tempfile
+
+log = logging.getLogger(__name__)
+
+def mkdir(directory):
+    """
+    Create a directory (mkdir -p).
+    Args:
+        directory: A String containing an absolute path.
+    Raises:
+        OSError: If the directory cannot be created.
+    """
+    try:
+        if not os.path.exists(directory):
+            log.info("Creating '%s' directory" % directory)
+        os.makedirs(directory)
+    except OSError as e:
+        if e.errno == errno.EEXIST and os.path.isdir(directory):
+            pass
+        else:
+            raise OSError("Cannot mkdir %s: %s" % (directory, e))
+
+def check_writable_directory(directory):
+    """
+    Tests whether a directory is writable.
+    Args:
+        directory: A String containing an absolute path.
+    Raises:
+        RuntimeError: If the directory does not exists or isn't writable.
+    """
+    if not os.path.exists(directory):
+        raise RuntimeError("Directory '%s' does not exists" % directory)
+    if not os.access(directory, os.W_OK | os.X_OK):
+        raise RuntimeError("Directory '%s' is not writable" % directory)
+    try:
+        with tempfile.TemporaryFile(dir = directory):
+            pass
+    except Exception as e:
+        raise RuntimeError("Cannot write into directory '%s': %s" % (directory, e))
+
+def ensure_writable_directory(directory):
+    """
+    Tests whether a directory exists and is writable. If not,
+    try to create such a directory.
+    Args:
+        directory: A String containing an absolute path.
+    Raises:
+        RuntimeError: If the directory does not exists and cannot be created.
+    """
+    try:
+        check_writable_directory(directory)
+    except RuntimeError as e:
+        mkdir(directory)