bringup_launch.py

# Copyright (c) 2018 Intel Corporation
#
# 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
 
from ament_index_python.packages import get_package_share_directory
 
from launch import LaunchDescription
from launch.actions import (
    DeclareLaunchArgument,
    GroupAction,
    IncludeLaunchDescription,
    SetEnvironmentVariable,
)
from launch.conditions import IfCondition
from launch.launch_description_sources import PythonLaunchDescriptionSource
from launch.substitutions import LaunchConfiguration, PythonExpression
from launch_ros.actions import Node
from launch_ros.actions import PushROSNamespace
from launch_ros.descriptions import ParameterFile
from nav2_common.launch import ReplaceString, RewrittenYaml
 
 
def generate_launch_description():
    # Get the launch directory
    bringup_dir = get_package_share_directory('nav2_bringup')
    launch_dir = os.path.join(bringup_dir, 'launch')
 
    # Create the launch configuration variables
    namespace = LaunchConfiguration('namespace')
    use_namespace = LaunchConfiguration('use_namespace')
    slam = LaunchConfiguration('slam')
    map_yaml_file = LaunchConfiguration('map')
    use_sim_time = LaunchConfiguration('use_sim_time')
    params_file = LaunchConfiguration('params_file')
    autostart = LaunchConfiguration('autostart')
    use_composition = LaunchConfiguration('use_composition')
    use_respawn = LaunchConfiguration('use_respawn')
    log_level = LaunchConfiguration('log_level')
    use_localization = LaunchConfiguration('use_localization')
 
    # Map fully qualified names to relative ones so the node's namespace can be prepended.
    # In case of the transforms (tf), currently, there doesn't seem to be a better alternative
    # https://github.com/ros/geometry2/issues/32
    # https://github.com/ros/robot_state_publisher/pull/30
    # TODO(orduno) Substitute with `PushNodeRemapping`
    #              https://github.com/ros2/launch_ros/issues/56
    remappings = [('/tf', 'tf'), ('/tf_static', 'tf_static')]
 
    # Only it applys when `use_namespace` is True.
    # '<robot_namespace>' keyword shall be replaced by 'namespace' launch argument
    # in config file 'nav2_multirobot_params.yaml' as a default & example.
    # User defined config file should contain '<robot_namespace>' keyword for the replacements.
    params_file = ReplaceString(
        source_file=params_file,
        replacements={'<robot_namespace>': ('/', namespace)},
        condition=IfCondition(use_namespace),
    )
 
    configured_params = ParameterFile(
        RewrittenYaml(
            source_file=params_file,
            root_key=namespace,
            param_rewrites={},
            convert_types=True,
        ),
        allow_substs=True,
    )
 
    stdout_linebuf_envvar = SetEnvironmentVariable(
        'RCUTILS_LOGGING_BUFFERED_STREAM', '1'
    )
 
    declare_namespace_cmd = DeclareLaunchArgument(
        'namespace', default_value='', description='Top-level namespace'
    )
 
    declare_use_namespace_cmd = DeclareLaunchArgument(
        'use_namespace',
        default_value='false',
        description='Whether to apply a namespace to the navigation stack',
    )
 
    declare_slam_cmd = DeclareLaunchArgument(
        'slam', default_value='False', description='Whether run a SLAM'
    )
 
    declare_map_yaml_cmd = DeclareLaunchArgument(
        'map', default_value='', description='Full path to map yaml file to load'
    )
 
    declare_use_localization_cmd = DeclareLaunchArgument(
        'use_localization', default_value='True',
        description='Whether to enable localization or not'
    )
 
    declare_use_sim_time_cmd = DeclareLaunchArgument(
        'use_sim_time',
        default_value='false',
        description='Use simulation (Gazebo) clock if true',
    )
 
    declare_params_file_cmd = DeclareLaunchArgument(
        'params_file',
        default_value=os.path.join(bringup_dir, 'params', 'nav2_params.yaml'),
        description='Full path to the ROS2 parameters file to use for all launched nodes',
    )
 
    declare_autostart_cmd = DeclareLaunchArgument(
        'autostart',
        default_value='true',
        description='Automatically startup the nav2 stack',
    )
 
    declare_use_composition_cmd = DeclareLaunchArgument(
        'use_composition',
        default_value='True',
        description='Whether to use composed bringup',
    )
 
    declare_use_respawn_cmd = DeclareLaunchArgument(
        'use_respawn',
        default_value='False',
        description='Whether to respawn if a node crashes. Applied when composition is disabled.',
    )
 
    declare_log_level_cmd = DeclareLaunchArgument(
        'log_level', default_value='info', description='log level'
    )
 
    # Specify the actions
    bringup_cmd_group = GroupAction(
        [
            PushROSNamespace(condition=IfCondition(use_namespace), namespace=namespace),
            Node(
                condition=IfCondition(use_composition),
                name='nav2_container',
                package='rclcpp_components',
                executable='component_container_isolated',
                parameters=[configured_params, {'autostart': autostart}],
                arguments=['--ros-args', '--log-level', log_level],
                remappings=remappings,
                output='screen',
            ),
            IncludeLaunchDescription(
                PythonLaunchDescriptionSource(
                    os.path.join(launch_dir, 'slam_launch.py')
                ),
                condition=IfCondition(PythonExpression([slam, ' and ', use_localization])),
                launch_arguments={
                    'namespace': namespace,
                    'use_sim_time': use_sim_time,
                    'autostart': autostart,
                    'use_respawn': use_respawn,
                    'params_file': params_file,
                }.items(),
            ),
            IncludeLaunchDescription(
                PythonLaunchDescriptionSource(
                    os.path.join(launch_dir, 'localization_launch.py')
                ),
                condition=IfCondition(PythonExpression(['not ', slam, ' and ', use_localization])),
                launch_arguments={
                    'namespace': namespace,
                    'map': map_yaml_file,
                    'use_sim_time': use_sim_time,
                    'autostart': autostart,
                    'params_file': params_file,
                    'use_composition': use_composition,
                    'use_respawn': use_respawn,
                    'container_name': 'nav2_container',
                }.items(),
            ),
            IncludeLaunchDescription(
                PythonLaunchDescriptionSource(
                    os.path.join(launch_dir, 'navigation_launch.py')
                ),
                launch_arguments={
                    'namespace': namespace,
                    'use_sim_time': use_sim_time,
                    'autostart': autostart,
                    'params_file': params_file,
                    'use_composition': use_composition,
                    'use_respawn': use_respawn,
                    'container_name': 'nav2_container',
                }.items(),
            ),
        ]
    )
 
    # Create the launch description and populate
    ld = LaunchDescription()
 
    # Set environment variables
    ld.add_action(stdout_linebuf_envvar)
 
    # Declare the launch options
    ld.add_action(declare_namespace_cmd)
    ld.add_action(declare_use_namespace_cmd)
    ld.add_action(declare_slam_cmd)
    ld.add_action(declare_map_yaml_cmd)
    ld.add_action(declare_use_sim_time_cmd)
    ld.add_action(declare_params_file_cmd)
    ld.add_action(declare_autostart_cmd)
    ld.add_action(declare_use_composition_cmd)
    ld.add_action(declare_use_respawn_cmd)
    ld.add_action(declare_log_level_cmd)
    ld.add_action(declare_use_localization_cmd)
 
    # Add the actions to launch all of the navigation nodes
    ld.add_action(bringup_cmd_group)
 
    return ld