Add get_sandbox_key to utils.py

This patch adds get_sandbox_key, which takes the container ID as string
and returns the path to the netns file as string, to utils.py. This
patch also includes the unit test for it.

Change-Id: I931036337d16074b3aa4d5555ba2bf3d178c714f
Signed-off-by: Taku Fukushima <f.tac.mac@gmail.com>

kuryr/tests/test_utils.py

@@ -0,0 +1,31 @@
+# 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 hashlib
+import random
+
+import ddt
+
+from kuryr.tests import base
+from kuryr import utils
+
+
+@ddt.ddt
+class TestKuryrUtils(base.TestKuryrBase):
+    """Unit tests for utilities."""
+
+    @ddt.data(hashlib.sha256(str(random.getrandbits(256))).hexdigest(),
+          '51c75a2515d4' '51c75a')
+    def test_get_sandbox_key(self, fake_container_id):
+        sandbox_key = utils.get_sandbox_key(fake_container_id)
+        expected = '/'.join([utils.DOCKER_NETNS_BASE, fake_container_id[:12]])
+        self.assertEqual(expected, sandbox_key)

kuryr/utils.py

@@ -10,6 +10,8 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
+import os
+
 import flask
 import jsonschema
 from neutronclient.common import exceptions as n_exceptions
@@ -18,6 +20,9 @@ from neutronclient.v2_0 import client as client_v2
 from werkzeug import exceptions as w_exceptions
 
 
+DOCKER_NETNS_BASE = '/var/run/docker/netns'
+
+
 def get_neutron_client_simple(url, token):
     return client.Client('2.0', endpoint_url=url, token=token)
 
@@ -72,3 +77,12 @@ def make_json_app(import_name, **kwargs):
         app.error_handler_spec[None][code] = make_json_error
 
     return app
+
+
+def get_sandbox_key(container_id):
+    """Returns a sandbox key constructed with the given container ID.
+
+    :param container_id: the ID of the Docker container as string
+    :returns: the constructed sandbox key as string
+    """
+    return os.path.join(DOCKER_NETNS_BASE, container_id[:12])