Take initial parameters from parameters yaml files and constructor arguments.

rclpy/CMakeLists.txt

@@ -13,6 +13,7 @@ endif()
 find_package(ament_cmake REQUIRED)
 find_package(ament_cmake_python REQUIRED)
 find_package(rcl REQUIRED)
+find_package(rcl_yaml_param_parser REQUIRED)
 find_package(rcutils REQUIRED)
 find_package(rmw REQUIRED)
 find_package(rmw_implementation_cmake REQUIRED)
@@ -77,6 +78,7 @@ add_library(
 configure_python_c_extension_library(rclpy)
 ament_target_dependencies(rclpy
   "rcl"
+  "rcl_yaml_param_parser"
   "rcutils"
 )
 

rclpy/package.xml

@@ -19,6 +19,7 @@
 
   <depend>rmw_implementation</depend>
   <depend>rcl</depend>
+  <depend>rcl_yaml_param_parser</depend>
 
   <exec_depend>ament_index_python</exec_depend>
   <exec_depend>builtin_interfaces</exec_depend>

rclpy/rclpy/__init__.py

@@ -51,7 +51,7 @@ def shutdown():
 
 def create_node(
     node_name, *, cli_args=None, namespace=None, use_global_arguments=True,
-    start_parameter_services=True
+    start_parameter_services=True, initial_parameters=None
 ):
     """
     Create an instance of :class:`rclpy.node.Node`.
@@ -60,6 +60,8 @@ def create_node(
     :param cli_args: A list of strings of command line args to be used only by this node.
     :param namespace: The namespace to which relative topic and service names will be prefixed.
     :param use_global_arguments: False if the node should ignore process-wide command line args.
+    :param start_parameter_services: False if the node should not create parameter services.
+    :param initial_parameters: A list of rclpy.parameter.Parameters to be set during node creation.
     :return: An instance of a node
     :rtype: :class:`rclpy.node.Node`
     """
@@ -68,7 +70,8 @@ def create_node(
     return Node(
         node_name, cli_args=cli_args, namespace=namespace,
         use_global_arguments=use_global_arguments,
-        start_parameter_services=start_parameter_services)
+        start_parameter_services=start_parameter_services,
+        initial_parameters=initial_parameters)
 
 
 def spin_once(node, *, timeout_sec=None):

rclpy/rclpy/node.py

@@ -61,7 +61,7 @@ class Node:
 
     def __init__(
         self, node_name, *, cli_args=None, namespace=None, use_global_arguments=True,
-        start_parameter_services=True
+        start_parameter_services=True, initial_parameters=None
     ):
         self._handle = None
         self._parameters = {}
@@ -104,6 +104,13 @@ def __init__(
         self._parameter_event_publisher = self.create_publisher(
             ParameterEvent, 'parameter_events', qos_profile=qos_profile_parameter_events)
 
+        node_parameters = _rclpy.rclpy_get_node_parameters(Parameter, self.handle)
+        # Combine parameters from params files with those from the node constructor and
+        # use the set_parameters_atomically API so a parameter event is published.
+        if initial_parameters is not None:
+            node_parameters.update({p.name: p for p in initial_parameters})
+        self.set_parameters_atomically(node_parameters.values())
+
         if start_parameter_services:
             self._parameter_service = ParameterService(self)