Hi users,
In our reseach project, we would like to be able to record
bags "automatically" (e.g recording when our UAV is
flying).
So, I'm trying to write a simple node (recorder_interface)
with two services "start_record" and "stop_record", where
"start_record" callback launch the rosbag::recorder::run()
in a child process using fork(). The "stop_record"
callback just sends the SIGINT signal to recorder PID to
stop recording ... but nothing happen. It seems that the
ROS node forked doesn't handle SIGINT signals.
Also, when checking available nodes with "rosnode list",
I've only the recorder_interface node. I should
have also something like "record_1283279499007996727",
which is the rosbag record node.
I'm wondering if a node can launch others nodes??
Here, the console output and code:
[ INFO] [1283279481.648585599]: Recorder_interface
spinning: ready to record.
[ INFO] [1283279499.006083281]: Request to record topics:
test
[ INFO] [1283279499.007996722]: Child: pid = 10497
[ INFO] [1283279499.008979878]: Subscribing to /fake_alti
[ INFO] [1283279499.009749320]: Recording to
test_2010-08-31-14-31-39.bag.
#include <signal.h>
#include "ros/ros.h"
#include "recorder_interface/rec_interface.h"
#include "rosbag/recorder.h"
#include "rosbag/exceptions.h"
bool recording;
int recorder_exit_code;
pid_t rosbag_pid;
void rosbagRecord (rosbag::RecorderOptions opts)
{
char ** argv = NULL;
int argc=0;
ros::init(argc, argv, "record",
ros::init_options::AnonymousName);
// **** Run the recorder
rosbag::Recorder recorder(opts);
recorder_exit_code = recorder.run();
ROS_INFO("recorder_exit_code:
%d\n",recorder_exit_code);
}
bool startRec(recorder_interface::rec_interface::Request
&req,
recorder_interface::rec_interface::Response &res)
{
if(!recording)
{
recording=true;
ROS_INFO("Request to record topics: %s",
req.topics.c_str ());
// **** Fill rosbag options
rosbag::RecorderOptions opts;
opts.record_all = false;
opts.quiet = true;
opts.prefix = req.prefix;
opts.append_date = true;
opts.topics.push_back("/fake_alti");
rosbag_pid = fork();
if(rosbag_pid == -1)
{
// **** ouch, fork() failed
perror("fork");
exit(-1);
}
else if(rosbag_pid == 0)
{
// **** child
ROS_INFO("Child: pid = %d\n",
(int)getpid());
rosbagRecord(opts);
exit(-1);
}
}
else
{
ROS_WARN("Already recording!");
}
return true;
}
bool stopRec(recorder_interface::rec_interface::Request
&req,
recorder_interface::rec_interface::Response &res)
{
if(recording)
{
int err = kill(rosbag_pid, SIGINT);
ROS_INFO("err = %d\n",err);
if(err==0)
{
res.ans=recorder_exit_code;
recording=false;
}
}
else
{
ROS_WARN("Not recording!");
}
return true;
}
int main(int argc, char **argv)
{
recording=false;
ros::init(argc, argv, "recorder_interface");
ros::NodeHandle n;
ros::ServiceServer serviceStart,serviceStop;
serviceStart = n.advertiseService("start_record",
startRec);
serviceStop = n.advertiseService("stop_record",
stopRec);
ROS_INFO("Recorder_interface spinning: ready to
record.");
ros::spin();
return 0;
}
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