Stop Rosbag subprocess

edit

I am able to start up a rosbag subprocess using this setup. However, I am unable to kill the rosbag from within the python code. I have tried the methods suggested in http://answers.ros.org/question/10714... and various methods suggested on stackoverflow yet to no avail.

Can anyone offer a solution?

    import rospy
    import rosbag
    import subprocess
    import time
    import os
    import signal
    from std_msgs.msg import Int32, String

    def callback(data):
    #   rospy.loginfo(rospy.get_caller_id()+"I heard %s",data.data)
        if data.data == "Start Recording":
            rospy.loginfo(rospy.get_caller_id()+"Start Recording!")

            global proc 
            proc = subprocess.Popen(["rosbag", "record", "-a","-o", "Subprocess"], preexec_fn=os.setsid)
        elif data.data == "Stop Recording":
            rospy.loginfo(rospy.get_caller_id()+"STOPPING RECORDING")
            if 'proc' in globals():
                rospy.loginfo(rospy.get_caller_id()+"Killing Rosbag")
                proc.terminate()
                #os.killpg(proc.pid, signal.SIGTERM)
                #proc.send_signal(subprocess.signal.SIGINT)
        else:
            rospy.loginfo(rospy.get_caller_id()+"NO BUENO")

    def listener():

        rospy.init_node('listener', anonymous=True)

        rospy.Subscriber("chatter", String, callback)


        rospy.spin()

    if __name__ == '__main__':
        listener()