error while almost simultaneous rospy get/set params about rosbridge_suite

[jihoonl]

== Server side ==

> roslaunch rosbridge_server rosbridge_websocket.launch --screen

== Client side ==

  // Connecting to ROS
  // -----------------
  var ros = new ROSLIB.Ros();

  // If there is an error on the backend, an 'error' emit will be emitted.
  ros.on('error', function(error) {
    console.log(error);
  });

  // Find out exactly when we made a connection.
  ros.on('connection', function() {
    console.log('Connection made!');

  ros.getParams(function(params) {
    console.log(params);
  });

  // First, we create a Param object with the name of the param.
  var maxVelX = new ROSLIB.Param({
    ros : ros,
    name : 'max_vel_y'
  });

  //Then we set the value of the param, which is sent to the ROS Parameter Server.
  maxVelX.set(0.8);
  });

  // Create a connection to the rosbridge WebSocket server.
  ros.connect('ws://localhost:9090');

[jihoonl]

It seems like rospy cannot handle simultaneous get/set param. I have seen similar behavior while investigating this problem.

http://answers.ros.org/question/149531/unable-to-load-the-manifest-for-package/

[megawac]

I'm still getting this error with v0.6.7. The first call it will throw the stack trace below, the second time it will work fine

$ node index --port $(rosparam get /rosbridge_websocket/port)

index.js

var ROS = require("roslibjs");
var RSVP = require("rsvp");
var argv = require("optimist").argv;
var ros = new ROS.Ros({
    url: "ws://localhost:" + argv.port
});
function getParam(name) {
    var $p = RSVP.defer();
    ros.Param({
        name: name
    }).get($p.resolve);
    return $p.promise;
}

RSVP.all([
    getParam("/kf/pose/fusion"),
    getParam("/kf/pose/mru"),
    getParam("/kf/pose/gps"),
    getParam("/kf/pose/sonar"),
    getParam("/kf/pose/gps_precision")
]).then(function(params) {
   // ....
});

Trace

[INFO] [WallTime: 1415130910.310431] Client connected.  1 clients total.
[ERROR] [WallTime: 1415130910.316223] [Client 0] [id: call_service:/rosapi/get_param:3] call_service InvalidPackageException: Unable to load the manifest for package rosapi. Caused by: rosapi
[ERROR] [WallTime: 1415130910.317899] [Client 0] [id: call_service:/rosapi/get_param:4] call_service InvalidPackageException: Unable to load the manifest for package rosapi. Caused by: rosapi
[ERROR] [WallTime: 1415130910.318575] [Client 0] [id: call_service:/rosapi/get_param:2] call_service InvalidPackageException: Unable to load the manifest for package rosapi. Caused by: rosapi
[ERROR] [WallTime: 1415130910.319533] [Client 0] [id: call_service:/rosapi/get_param:5] call_service InvalidPackageException: Unable to load the manifest for package rosapi. Caused by: rosapi

It will work fine if I limit it to one param get at a time