<<PackageHeader(watchdog_timer)>>
<<TOC(4)>>

## AUTOGENERATED DON'T DELETE
## CategoryPackage

This package contains an implementation of a "remote" watchdog. There exists one watchdog monitor that monitors all watchdogs and many watchdogs.

== Implementing a Watchdog in your node ==

To implement a watchdog timer into your code, you should first add the watchdog_timer package as a dependency to your package.

Then you should include the 

{{{
#include "watchdog_timer/Watchdog.h"
}}}

in your code.

In addition, at the CMakeLists.txt file you should link your executable to the Watchdog library 

{{{
rosbuild_add_link_flags(executable_name -lWatchdog)
}}}

=== Creating a Watchdog ===

To create a watchdog object (and register it at the watchdog monitor), create a watchdog object

{{{
  Watchdog theWatchdogName("nameOfWatchdog",ros::Duration(10));
}}}

Where the first argument of the constructor is the unique name of the watchdog and the second argument is the amount of time that the timer will countdown, until it resets. 

=== Starting, Stopping and Reseting a Watchdog ===
Having your watchdog timer you can start/ stop/ reset the timer by using the objects methods.

By calling the 
{{{
theWatchdogName.start();
}}}
you can start the watchdog.

Similarly:

{{{
theWatchdogName.stop();
}}}

{{{
theWatchdogName.reset();
}}}

=== When a watchdog times out ===

When a watchdog times-out the watchdog monitor will emit a ROS_ERROR and will publish a message at the /robot/watchdogResets topic.

== Starting the Watchdog monitor ==

To start the watchdog monitor you can run 

{{{
  rosrun watchdog_timer wdtMonitor
}}}

or you could include it in a .launch file

== Technical Information ==

This watchdog implementation does not try to reset any nodes or perform any other action. It's sole purpose is to notify that a node has failed to reset in time a watchdog. 

The watchdog implementation has a couple of services and topics. At the /robot/watchdogRegistry service a watchdog can register/ start/ stop itself. This is taken care by the client watchdog implementation. The /robot/watchdog topic is used for the watchdog client to publish their resets, to be heard by the watchdog monitor.