spawn_prius.py

import subprocess
import os
import time
import signal
class Prius:
    def on_start(self):
        front_camera = self.get_port_info("front_camera/image_raw")["topic"] # we wii use this to get Block id
        x = self.get_property("x") # get x location form block's property
        y = self.get_property("y") # get y location from block's property
        workspace_path = os.path.join(self.get_property("ws_path"), "") # get the workspace path from the block's property
        self.block_id = front_camera.split("/")[1] # get block id by splitting the topic name ex. ['','b12','front_camera','image_raw']
        self.control_topic = self.get_port_info("prius")["topic"] # get the input port topic name
        if not os.path.isdir(workspace_path + "devel"): # check if ROS workspace is not built
            self.alert("Building ROS workspace", "INFO")
            subprocess.run(
                "cd {} && . /opt/ros/melodic/setup.sh && catkin_make".format(
                    workspace_path
                ),
                shell=True,
            )
        subprocess.Popen(
            "vglrun bash -c 'source {} && roslaunch car_demo spawn_prius.launch block_id:={} x:={} y:={} '".format(
                workspace_path + "devel/setup.bash", self.block_id, x, y
            ),
            shell=True,
        ) # run the launch file and pass the arguments block_id, x, y
        self.relay_p = subprocess.Popen(
            "rosrun topic_tools relay {} {}".format(
                self.control_topic, "/" + self.block_id + "/prius"
            ),
            shell=True,
        ) # create a topic realy to map input topic to block_id/prius topic which the robot is using for control