rosspawn: ROS On-the-fly Node Launcher
======================================

This ROS package provides a node that can start and stop other nodes. It is
intended to be instructed from another node to launch specific nodes.

rosspawn does not try to be another roslaunch. Rather it is meant to provide
tools for a different use case. During development, nodes are started and
stopped frequently while people are working on the node. With roslaunch, this
often means either starting and stopping larger ensembles, or getting a hold
on the controlling machine's terminal for a specific node. rosspawn launches
the nodes by itself, usually instructed by its companion application
rosspawn_gui from any of the developer's machine. It resembles the way Fawkes
plugins are loaded and unloaded. While nodes are running, they are monitored
by rosspawn and status changed are announced. Other developers see if a node
has been stopped by someone else.

rosspawn is mostly a proof of concept at this stage. It lacks some important
features in comparison to roslaunch:
- It makes the assumption of a static configuration, i.e. parameters cannot
  be set and must be set by other means at least once until the parameter
  server is restarted
- It requireds node binaries with user readable names, currently no
  description can be provided
- The code is POSIX (and possibly Linux) specific. It most likely will not
  work on other operating systems.
- Nodes are currently not automatically respawn if they die in error.

Since the number of binaries grows big very fast, rosspawn allows to create a
module file which contains the names of the modules which should be announced
by rosspawn.

This is a proof of concept implementation and probably not useful in its
current state. Comments and patches welcome.

Requirements
------------
The following software packages are needed on your system in order to
use actionlib_lua. Requirements marked with (*) have specific information
further down below.

- ROS 1.1			http://www.ros.org

Usage
-----
Run bin/rosspawn. Then run rosspawn_gui and click on any node name to get it
started or stopped. Usually no modifications are necessary to the nodes.
Nodes which are started without using rosspawn are currently not recognized.