Add ros2 node get_type_description initial implementation

ros2node/package.xml

@@ -19,6 +19,7 @@
 
   <exec_depend>rclpy</exec_depend>
   <exec_depend>ros2cli</exec_depend>
+  <exec_depend>type_description_interfaces</exec_depend>
 
   <test_depend>ament_copyright</test_depend>
   <test_depend>ament_flake8</test_depend>

ros2node/ros2node/verb/get_type_description.py

@@ -0,0 +1,156 @@
+# Copyright 2023 Open Source Robotics Foundation, Inc.
+#
+# 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 os
+
+import rclpy
+from ros2cli.node import NODE_NAME_PREFIX
+from ros2cli.node.strategy import add_arguments
+from ros2node.api import (
+    NodeNameCompleter,
+    parse_node_name,
+)
+from ros2node.verb import VerbExtension
+from type_description_interfaces.msg import FieldType
+from type_description_interfaces.srv import GetTypeDescription
+
+
+def print_field_type(ft):
+    type_name = None
+    type_str = ''
+    for x, y in FieldType.__dict__.items():
+        if y == ft.type_id:
+            type_name = x
+            break
+    if not type_name:
+        raise RuntimeError(f'Could not match FieldType type_id {ft.type_id} to a name')
+
+    type_str = type_name
+    if 'NESTED_TYPE' in type_name:
+        type_str += f' ({ft.nested_type_name})'
+    if ft.string_capacity:
+        type_str += f' - string_capacity {ft.string_capacity}'
+    if ft.capacity:
+        type_str += f' - capacity {ft.capacity}'
+    return type_str
+
+
+def print_individual_type_description(itd, indent=0):
+    def p(line):
+        print(' ' * indent + line)
+
+    print()
+    p(f'{itd.type_name}')
+    p('Fields:')
+    indent += 2
+    for field in itd.fields:
+        field_string = f'{field.name}: {print_field_type(field.type)}'
+        if field.default_value:
+            field_string += f' = {field.default_value}'
+        p(field_string)
+    indent -= 2
+
+
+def print_type_description(td):
+    print_individual_type_description(td.type_description)
+    print()
+    print('Referenced Type Descriptions:')
+    for rtd in td.referenced_type_descriptions:
+        print_individual_type_description(rtd, indent=2)
+
+
+def discover_hash_for_type(node, remote_node_name, type_name):
+    # TODO(emersonknapp) get hashes from names_and_types when that is implemented
+    ns = type_name.split('/')[1]
+    if ns != 'msg':
+        raise RuntimeError(
+            f'Currently cannot auto-discover hashes for "{ns}", only "msg". '
+            'Please provide type_hash value to command.')
+    remote_node = parse_node_name(remote_node_name)
+    nt = node.get_publisher_names_and_types_by_node(remote_node.name, remote_node.namespace)
+    nt += node.get_subscriber_names_and_types_by_node(remote_node.name, remote_node.namespace)
+    discover_topic = None
+    for topic, types in nt:
+        if type_name in types:
+            discover_topic = topic
+    if not discover_topic:
+        raise RuntimeError(
+            f'Could not find type "{type_name}" advertised as a topic type on node '
+            f'"{remote_node_name}"')
+
+    endpoint_infos = node.get_publishers_info_by_topic(discover_topic)
+    endpoint_infos += node.get_subscriptions_info_by_topic(discover_topic)
+    for endpoint_info in endpoint_infos:
+        if (
+            endpoint_info.node_name == remote_node.name and
+            endpoint_info.node_namespace == remote_node.namespace and
+            endpoint_info.topic_type == type_name
+        ):
+            return str(endpoint_info.topic_type_hash)
+    raise RuntimeError(
+        f'Cound not find endpoint type hash for topic "{discover_topic}"')
+
+
+class GetTypeDescriptionVerb(VerbExtension):
+    """Output information about a node."""
+
+    def add_arguments(self, parser, cli_name):
+        add_arguments(parser)
+        argument = parser.add_argument(
+            'node_name',
+            help='Node name to request information from')
+        argument.completer = NodeNameCompleter()
+        parser.add_argument(
+            'type_name',
+            help='Interface type to get description of')
+        parser.add_argument(
+            'type_hash',
+            default=None,
+            nargs='?',
+            help='Hash string of the type. If not provided, will try to determine automatically.')
+        parser.add_argument(
+            '--include-sources', action='store_true',
+            help='Fetch and display the raw source text as well')
+
+    def main(self, *, args):
+        service_name = f'{args.node_name}/get_type_description'
+
+        rclpy.init()
+        node = rclpy.create_node(f'{NODE_NAME_PREFIX}_td_requester_{os.getpid()}')
+        cli = node.create_client(GetTypeDescription, '/talker/get_type_description')
+        if not cli.service_is_ready():
+            print('Waiting for service to become available...')
+            if not cli.wait_for_service(timeout_sec=5.0):
+                raise RuntimeError(f'Service {service_name} not found')
+
+        if args.type_hash:
+            type_hash = args.type_hash
+        else:
+            type_hash = discover_hash_for_type(node, args.node_name, args.type_name)
+            print(f'Requesting type hash {type_hash}')
+
+        request = GetTypeDescription.Request()
+        request.type_name = args.type_name
+        request.type_hash = type_hash
+        request.include_type_sources = args.include_sources
+        print('Sending request...')
+        future = cli.call_async(request)
+        rclpy.spin_until_future_complete(node, future)
+        response = future.result()
+        if not response.successful:
+            raise RuntimeError(
+                f'Failed to get type description: {response.failure_reason}')
+
+        print('Response successful:')
+        print_type_description(response.type_description)

ros2node/setup.py

@@ -42,6 +42,7 @@
         'ros2node.verb': [
             'info = ros2node.verb.info:InfoVerb',
             'list = ros2node.verb.list:ListVerb',
+            'get-type-description = ros2node.verb.get_type_description:GetTypeDescriptionVerb',
         ],
     }
 )