Find equivalent or simulate a way to log info to ROS from roslibjs

[MartensCedric]

Find a way to log front end logs into ros to mimic the rospy logging behaviour:

• Check in roslibjs library for preexisting ROS logging functions (none exist)
• Create roslibjs issue related to logging (so far only one reply saying to publish to /rosout)
• Implement logging js functions
  • Find definition for ROS log messages
  • Figure out how/what data to generate for each data element
  • Implement functions in ros_helpers.js

[PeterGhimself]

I think if we simply create a publisher to the topic /rosout it should have the same effect, though that might mean we have to format the message properly ourselves.

[joshua-glazer]

here's the roslibjs web documentation for reference, although I don't see anything about ROS logging. I just made an issue in the roslibjs repo 😎 about it. Perhaps it's an opportunity to contribute to open source?

[joshua-glazer]

I managed to publish a message to /rosout from within the GUI but there's a bunch of data in the /rosgraph_msgs/Log message type that I don't yet know how to generate. If we want to do it nicely we could make the logwarn, logerr, loginfo etc functions just like you can do in rospy.

Here's my code. As you can see based on the message definition, when I created the message I left out a lot of data. I imagine that will have an impact on how ROS actually understands the log message and I'm not sure how much is necessary for it to work correctly (possibly all of it) but I don't know how to generate all the data that's in the definition.

ros_logger = new ROSLIB.Topic({
    ros: ros,
    name: 'rosout',
    messageType: 'rosgraph_msgs/Log'
  })
log_msg = new ROSLIB.Message({
    level:2,
    msg:"hello from the gui"
})
ros_logger.publish(log_msg)

[joshua-glazer]

we could make it like:

// Severity level constants
// DEBUG=1 // debug level
// INFO=2  // general level
// WARN=4  // warning level
// ERROR=8 // error level
// FATAL=16 // fatal/critical level

function loginfo(message) {
    ros_logger.publish(
        new ROSLIB.Message({
            level : 2, // INFO
            msg : message
        })
    )
}

or something