permission api: use _keystore.get_* functions

Proof that we're still completely missing test coverage of some verbs.
Add a basic `create_permissions` test as well.

Signed-off-by: Kyle Fazzari <kyle@canonical.com>

sros2/sros2/api/_permission.py

@@ -34,16 +34,16 @@ def create_permission(keystore_path, identity, policy_file_path):
 
 def create_permissions_from_policy_element(keystore_path, identity, policy_element):
     relative_path = os.path.normpath(identity.lstrip('/'))
-    key_dir = os.path.join(_keystore.keystore_context_dir(keystore_path), relative_path)
+    key_dir = os.path.join(_keystore.get_keystore_context_dir(keystore_path), relative_path)
     print("creating permission file for identity: '%s'" % identity)
     permissions_path = os.path.join(key_dir, 'permissions.xml')
     create_permission_file(permissions_path, _utilities.domain_id(), policy_element)
 
     signed_permissions_path = os.path.join(key_dir, 'permissions.p7s')
     keystore_ca_cert_path = os.path.join(
-        _keystore.keystore_public_dir(keystore_path), 'ca.cert.pem')
+        _keystore.get_keystore_public_dir(keystore_path), 'ca.cert.pem')
     keystore_ca_key_path = os.path.join(
-        _keystore.keystore_private_dir(keystore_path), 'ca.key.pem')
+        _keystore.get_keystore_private_dir(keystore_path), 'ca.key.pem')
     _utilities.create_smime_signed_file(
         keystore_ca_cert_path, keystore_ca_key_path, permissions_path, signed_permissions_path)
 

sros2/test/conftest.py

@@ -13,7 +13,15 @@
 # limitations under the License.
 
 import os
+import pathlib
+
+import pytest
 
 # Disable lxml2 lookup of resources on the internet by configuring it to use a proxy
 # that does not exist
 os.environ['HTTP_PROXY'] = 'http://example.com'
+
+
+@pytest.fixture('session')
+def test_policy_dir():
+    return pathlib.Path(__file__).parent / 'policies'

sros2/test/sros2/commands/security/verbs/test_create_permission.py

@@ -0,0 +1,86 @@
+# Copyright 2020 Canonical Ltd
+#
+# 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 pathlib
+
+import lxml
+
+import pytest
+
+from ros2cli import cli
+from sros2.api import _key, _keystore
+
+
+# This fixture will run once for the entire module (as opposed to once per test)
+@pytest.fixture(scope='module')
+def security_context_dir(tmpdir_factory, test_policy_dir) -> pathlib.Path:
+    keystore_dir = pathlib.Path(str(tmpdir_factory.mktemp('keystore')))
+
+    # First, create the keystore as well as a keypair for the talker
+    assert _keystore.create_keystore(keystore_dir)
+    assert _key.create_key(keystore_dir, '/talker_listener/talker')
+
+    security_files_dir = keystore_dir / 'contexts' / 'talker_listener' / 'talker'
+    assert security_files_dir.is_dir()
+
+    # Now using that keystore, create a permissions file using the sample policy
+    policy_file_path = test_policy_dir / 'sample.policy.xml'
+    assert cli.main(
+        argv=[
+            'security', 'create_permission', str(keystore_dir), '/talker_listener/talker',
+            str(policy_file_path)]) == 0
+
+    # Return path to directory containing the identity's files
+    return security_files_dir
+
+
+def test_create_permission(security_context_dir):
+    assert security_context_dir.joinpath('permissions.xml').is_file()
+    assert security_context_dir.joinpath('permissions.p7s').is_file()
+
+    # Give the generated permissions XML a smoke test
+    tree = lxml.etree.parse(str(security_context_dir.joinpath('permissions.xml')))
+
+    dds = tree.getroot()
+    assert dds.tag == 'dds'
+
+    permissions = list(dds.iterchildren(tag='permissions'))
+    assert len(permissions) == 1
+
+    grants = list(permissions[0].iterchildren(tag='grant'))
+    assert len(grants) == 1
+    assert grants[0].get('name') == '/talker_listener/talker'
+
+    allow_rules = list(grants[0].iterchildren(tag='allow_rule'))
+    assert len(allow_rules) == 1
+
+    publish_rules = list(allow_rules[0].iterchildren(tag='publish'))
+    assert len(publish_rules) == 1
+
+    subscribe_rules = list(allow_rules[0].iterchildren(tag='subscribe'))
+    assert len(subscribe_rules) == 1
+
+    published_topics_set = list(publish_rules[0].iterchildren(tag='topics'))
+    assert len(published_topics_set) == 1
+    published_topics = [c.text for c in published_topics_set[0].iterchildren(tag='topic')]
+    assert len(published_topics) == 15
+
+    subscribed_topics_set = list(subscribe_rules[0].iterchildren(tag='topics'))
+    assert len(subscribed_topics_set) == 1
+    subscribed_topics = list(subscribed_topics_set[0].iterchildren(tag='topic'))
+    assert len(subscribed_topics) == 14
+
+    # Verify that publication is allowed on chatter, but not subscription
+    assert 'rt/chatter' in published_topics
+    assert 'rt/chatter' not in subscribed_topics