Implement functions to get publisher and subcription informations like QoS policies from topic name

rclpy/CMakeLists.txt

@@ -209,6 +209,7 @@ if(BUILD_TESTING)
     test/test_time.py
     test/test_timer.py
     test/test_topic_or_service_is_hidden.py
+    test/test_topic_endpoint_info.py
     test/test_utilities.py
     test/test_validate_full_topic_name.py
     test/test_validate_namespace.py

rclpy/rclpy/node.py

@@ -67,6 +67,7 @@
 from rclpy.time_source import TimeSource
 from rclpy.timer import Rate
 from rclpy.timer import Timer
+from rclpy.topic_endpoint_info import TopicEndpointInfo
 from rclpy.type_support import check_for_type_support
 from rclpy.utilities import get_default_context
 from rclpy.validate_full_topic_name import validate_full_topic_name
@@ -1642,7 +1643,7 @@ def get_node_names_and_namespaces(self) -> List[Tuple[str, str]]:
 
     def _count_publishers_or_subscribers(self, topic_name, func):
         fq_topic_name = expand_topic_name(topic_name, self.get_name(), self.get_namespace())
-        validate_topic_name(fq_topic_name)
+        validate_full_topic_name(fq_topic_name)
         with self.handle as node_capsule:
             return func(node_capsule, fq_topic_name)
 
@@ -1681,3 +1682,82 @@ def assert_liveliness(self) -> None:
         """
         with self.handle as capsule:
             _rclpy.rclpy_assert_liveliness(capsule)
+
+    def _get_info_by_topic(
+        self,
+        topic_name: str,
+        no_mangle: bool,
+        func: Callable[[object, str, bool], List[Dict]]
+    ) -> List[TopicEndpointInfo]:
+        with self.handle as node_capsule:
+            if no_mangle:
+                fq_topic_name = topic_name
+            else:
+                fq_topic_name = expand_topic_name(
+                    topic_name, self.get_name(), self.get_namespace())
+                validate_full_topic_name(fq_topic_name)
+                fq_topic_name = _rclpy.rclpy_remap_topic_name(node_capsule, fq_topic_name)
+
+            info_dicts = func(node_capsule, fq_topic_name, no_mangle)
+            infos = [TopicEndpointInfo(**x) for x in info_dicts]
+            return infos
+
+    def get_publishers_info_by_topic(
+        self,
+        topic_name: str,
+        no_mangle: bool = False
+    ) -> List[TopicEndpointInfo]:
+        """
+        Return a list of publishers on a given topic.
+
+        The returned parameter is a list of TopicEndpointInfo objects, where each will contain
+        the node name, node namespace, topic type, topic endpoint's GID, and its QoS profile.
+
+        When the `no_mangle` parameter is `true`, the provided `topic_name` should be a valid topic
+        name for the middleware (useful when combining ROS with native middleware (e.g. DDS) apps).
+        When the `no_mangle` parameter is `false`, the provided `topic_name` should follow
+        ROS topic name conventions.
+
+        `topic_name` may be a relative, private, or fully qualified topic name.
+        A relative or private topic will be expanded using this node's namespace and name.
+        The queried `topic_name` is not remapped.
+
+        :param topic_name: the topic_name on which to find the publishers.
+        :param no_mangle: no_mangle if `true`, `topic_name` needs to be a valid middleware topic
+            name, otherwise it should be a valid ROS topic name. Defaults to `false`.
+        :return: a list of TopicEndpointInfo for all the publishers on this topic.
+        """
+        return self._get_info_by_topic(
+            topic_name,
+            no_mangle,
+            _rclpy.rclpy_get_publishers_info_by_topic)
+
+    def get_subscriptions_info_by_topic(
+        self,
+        topic_name: str,
+        no_mangle: bool = False
+    ) -> List[TopicEndpointInfo]:
+        """
+        Return a list of subscriptions on a given topic.
+
+        The returned parameter is a list of TopicEndpointInfo objects, where each will contain
+        the node name, node namespace, topic type, topic endpoint's GID, and its QoS profile.
+
+        When the `no_mangle` parameter is `true`, the provided `topic_name` should be a valid topic
+        name for the middleware (useful when combining ROS with native middleware (e.g. DDS) apps).
+        When the `no_mangle` parameter is `false`, the provided `topic_name` should follow
+        ROS topic name conventions.
+
+        `topic_name` may be a relative, private, or fully qualified topic name.
+        A relative or private topic will be expanded using this node's namespace and name.
+        The queried `topic_name` is not remapped.
+
+        :param topic_name: the topic_name on which to find the subscriptions.
+        :param no_mangle: no_mangle if `true`, `topic_name` needs to be a valid middleware topic
+            name, otherwise it should be a valid ROS topic name. Defaults to `false`.
+        :return: a list of TopicEndpointInfo for all the subscriptions on this topic.
+        """
+        return self._get_info_by_topic(
+            topic_name,
+            no_mangle,
+            _rclpy.rclpy_get_subscriptions_info_by_topic)

rclpy/rclpy/qos.py

@@ -276,6 +276,8 @@ class HistoryPolicy(QoSPolicyEnum):
     KEEP_LAST = RMW_QOS_POLICY_HISTORY_KEEP_LAST
     RMW_QOS_POLICY_HISTORY_KEEP_ALL = 2
     KEEP_ALL = RMW_QOS_POLICY_HISTORY_KEEP_ALL
+    RMW_QOS_POLICY_HISTORY_UNKNOWN = 3
+    UNKNOWN = RMW_QOS_POLICY_HISTORY_UNKNOWN
 
 
 # Alias with the old name, for retrocompatibility
@@ -295,6 +297,8 @@ class ReliabilityPolicy(QoSPolicyEnum):
     RELIABLE = RMW_QOS_POLICY_RELIABILITY_RELIABLE
     RMW_QOS_POLICY_RELIABILITY_BEST_EFFORT = 2
     BEST_EFFORT = RMW_QOS_POLICY_RELIABILITY_BEST_EFFORT
+    RMW_QOS_POLICY_RELIABILITY_UNKNOWN = 3
+    UNKNOWN = RMW_QOS_POLICY_RELIABILITY_UNKNOWN
 
 
 # Alias with the old name, for retrocompatibility
@@ -314,6 +318,8 @@ class DurabilityPolicy(QoSPolicyEnum):
     TRANSIENT_LOCAL = RMW_QOS_POLICY_DURABILITY_TRANSIENT_LOCAL
     RMW_QOS_POLICY_DURABILITY_VOLATILE = 2
     VOLATILE = RMW_QOS_POLICY_DURABILITY_VOLATILE
+    RMW_QOS_POLICY_DURABILITY_UNKNOWN = 3
+    UNKNOWN = RMW_QOS_POLICY_DURABILITY_UNKNOWN
 
 
 # Alias with the old name, for retrocompatibility
@@ -335,11 +341,15 @@ class LivelinessPolicy(QoSPolicyEnum):
     MANUAL_BY_NODE = RMW_QOS_POLICY_LIVELINESS_MANUAL_BY_NODE
     RMW_QOS_POLICY_LIVELINESS_MANUAL_BY_TOPIC = 3
     MANUAL_BY_TOPIC = RMW_QOS_POLICY_LIVELINESS_MANUAL_BY_TOPIC
+    RMW_QOS_POLICY_LIVELINESS_UNKNOWN = 4
+    UNKNOWN = RMW_QOS_POLICY_LIVELINESS_UNKNOWN
 
 
 # Alias with the old name, for retrocompatibility
 QoSLivelinessPolicy = LivelinessPolicy
 
+qos_profile_unknown = QoSProfile(**_rclpy.rclpy_get_rmw_qos_profile(
+    'qos_profile_unknown'))
 qos_profile_system_default = QoSProfile(**_rclpy.rclpy_get_rmw_qos_profile(
     'qos_profile_system_default'))
 qos_profile_sensor_data = QoSProfile(**_rclpy.rclpy_get_rmw_qos_profile(
@@ -350,11 +360,12 @@ class LivelinessPolicy(QoSPolicyEnum):
     'qos_profile_parameters'))
 qos_profile_parameter_events = QoSProfile(**_rclpy.rclpy_get_rmw_qos_profile(
     'qos_profile_parameter_events'))
-qos_profile_action_status_default = QoSProfile(
-    **_rclpy_action.rclpy_action_get_rmw_qos_profile('rcl_action_qos_profile_status_default'))
+qos_profile_action_status_default = QoSProfile(**_rclpy_action.rclpy_action_get_rmw_qos_profile(
+    'rcl_action_qos_profile_status_default'))
 
 
 class QoSPresetProfiles(Enum):
+    UNKNOWN = qos_profile_unknown
     SYSTEM_DEFAULT = qos_profile_system_default
     SENSOR_DATA = qos_profile_sensor_data
     SERVICES_DEFAULT = qos_profile_services_default

rclpy/rclpy/topic_endpoint_info.py

@@ -0,0 +1,174 @@
+# Copyright 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+#
+# 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.
+
+from enum import IntEnum
+
+from rclpy.qos import QoSProfile, QoSPresetProfiles
+
+
+class TopicEndpointTypeEnum(IntEnum):
+    """
+    Enum for possible types of topic endpoints.
+
+    This enum matches the one defined in rmw/types.h
+    """
+
+    INVALID = 0
+    PUBLISHER = 1
+    SUBSCRIPTION = 2
+
+
+class TopicEndpointInfo:
+    """Information on a topic endpoint."""
+
+    __slots__ = [
+        '_node_name',
+        '_node_namespace',
+        '_topic_type',
+        '_endpoint_type',
+        '_endpoint_gid',
+        '_qos_profile'
+    ]
+
+    def __init__(self, **kwargs):
+        assert all('_' + key in self.__slots__ for key in kwargs.keys()), \
+            'Invalid arguments passed to constructor: %r' % kwargs.keys()
+
+        self.node_name = kwargs.get('node_name', '')
+        self.node_namespace = kwargs.get('node_namespace', '')
+        self.topic_type = kwargs.get('topic_type', '')
+        self.endpoint_type = kwargs.get('endpoint_type', TopicEndpointTypeEnum.INVALID)
+        self.endpoint_gid = kwargs.get('endpoint_gid', list())
+        self.qos_profile = kwargs.get('qos_profile', QoSPresetProfiles.UNKNOWN.value)
+
+    @property
+    def node_name(self):
+        """
+        Get field 'node_name'.
+
+        :returns: node_name attribute
+        :rtype: str
+        """
+        return self._node_name
+
+    @node_name.setter
+    def node_name(self, value):
+        assert isinstance(value, str)
+        self._node_name = value
+
+    @property
+    def node_namespace(self):
+        """
+        Get field 'node_namespace'.
+
+        :returns: node_namespace attribute
+        :rtype: str
+        """
+        return self._node_namespace
+
+    @node_namespace.setter
+    def node_namespace(self, value):
+        assert isinstance(value, str)
+        self._node_namespace = value
+
+    @property
+    def topic_type(self):
+        """
+        Get field 'topic_type'.
+
+        :returns: topic_type attribute
+        :rtype: str
+        """
+        return self._topic_type
+
+    @topic_type.setter
+    def topic_type(self, value):
+        assert isinstance(value, str)
+        self._topic_type = value
+
+    @property
+    def endpoint_type(self):
+        """
+        Get field 'endpoint_type'.
+
+        :returns: endpoint_type attribute
+        :rtype: TopicEndpointTypeEnum
+        """
+        return self._endpoint_type
+
+    @endpoint_type.setter
+    def endpoint_type(self, value):
+        if isinstance(value, TopicEndpointTypeEnum):
+            self._endpoint_type = value
+        elif isinstance(value, int):
+            self._endpoint_type = TopicEndpointTypeEnum(value)
+        else:
+            assert False
+
+    @property
+    def endpoint_gid(self):
+        """
+        Get field 'endpoint_gid'.
+
+        :returns: endpoint_gid attribute
+        :rtype: list
+        """
+        return self._endpoint_gid
+
+    @endpoint_gid.setter
+    def endpoint_gid(self, value):
+        assert all(isinstance(x, int) for x in value)
+        self._endpoint_gid = value
+
+    @property
+    def qos_profile(self):
+        """
+        Get field 'qos_profile'.
+
+        :returns: qos_profile attribute
+        :rtype: QoSProfile
+        """
+        return self._qos_profile
+
+    @qos_profile.setter
+    def qos_profile(self, value):
+        if isinstance(value, QoSProfile):
+            self._qos_profile = value
+        elif isinstance(value, dict):
+            self._qos_profile = QoSProfile(**value)
+        else:
+            assert False
+
+    def __eq__(self, other):
+        if not isinstance(other, TopicEndpointInfo):
+            return False
+        return all(
+            self.__getattribute__(slot) == other.__getattribute__(slot)
+            for slot in self.__slots__)
+
+    def __str__(self):
+        result = 'Node name: %s\n' % self.node_name
+        result += 'Node namespace: %s\n' % self.node_namespace
+        result += 'Topic type: %s\n' % self.topic_type
+        result += 'Endpoint type: %s\n' % self.endpoint_type.name
+        result += 'GID: %s\n' % '.'.join(format(x, '02x') for x in self.endpoint_gid)
+        result += 'QoS profile:\n'
+        result += '  Reliability: %s\n' % self.qos_profile.reliability.name
+        result += '  Durability: %s\n' % self.qos_profile.durability.name
+        result += '  Lifespan: %d nanoseconds\n' % self.qos_profile.lifespan.nanoseconds
+        result += '  Deadline: %d nanoseconds\n' % self.qos_profile.deadline.nanoseconds
+        result += '  Liveliness: %s\n' % self.qos_profile.liveliness.name
+        result += '  Liveliness lease duration: %d nanoseconds' % \
+            self.qos_profile.liveliness_lease_duration.nanoseconds
+        return result