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Is it possible to shutdown the system from within a ROS node?
In my case, I would like to shutdown the system once the battery level reaches a certain point, however I don't know how to do it or if it is even possible.
Just to add to the answer by @FooBar (ROS nodes are really just regular Linux programs that have chosen to communicate with each other via the ROS middleware): shutting down a Linux system with a desktop environment is often possible without using something like shutdown (which requires special privileges). See "Linux: Programatically shutdown or reboot computer from a user-level process" on stackoverflow for an example where they use ConsoleKit / DBus:
dbus-send \
--system \
---dest=org.freedesktop.ConsoleKit \
--type=method_call \
--print-reply \
--reply-timeout=2000 \
/org/freedesktop/ConsoleKit/Manager \
org.freedesktop.ConsoleKit.Manager.Stop
You could invoke dbus-send using the system(..) function call in C/C++, or execute it from a Python node.
For Python there are better (more integrated) ways to interface with ConsoleKit / DBus (copied from "shutting down computer (linux) using python" on stackoverflow):
import dbus
sys_bus = dbus.SystemBus()
ck_srv = sys_bus.get_object('org.freedesktop.ConsoleKit',
'/org/freedesktop/ConsoleKit/Manager')
ck_iface = dbus.Interface(ck_srv, 'org.freedesktop.ConsoleKit.Manager')
stop_method = ck_iface.get_dbus_method("Stop")
stop_method()
You could fi wrap the call to stop_method() (which is just an example) in a ROS service call (I wouldn't use parameters for this, it is clearly a synchronous action).
A ROS-Node is a normal program that uses the ROS-Stuff. So you can (and have to) do whatever you want in your node, but there is nothing special in ROS that shuts down your computer.
You could create a service (the ubuntu-version, not a ROS-Service) that will be launched with root-rights (you'll need them to shutdown the system), that e.g. checks a ros-param. If you set this param, the service could shutdown the machine. Otherwise, you'd have to start you node with root-rights.
Asked: 2015-07-25 09:10:11 -0500
Seen: 2,084 times
Last updated: Jul 26 '15
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