Sailsd

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Sailsd is a simple daemon which simulates a small sailing boat in real time using libsailing. Information about the boat's current sensor readings (position, heading and wind conditions), and commands to move the rudder and sails can be accessed over a socket.

The intended purpose of sailsd is to be a component of a testing framework for evaluating the behaviour of autonomous sailing boats.

Protocol

Sailsd uses a simple protocol consisting of JSON message sent over TCP on port 3333.

Current values can be requested with "request":

{"request": ["version"]}

{"request": ["latitude", "longitude"]}

Another JSON message is returned, which contains an object containing the requested attributes. This can be quickly tested using netcat:

$ echo '{"request": ["heading"]}' | nc localhost 3333
{"heading": 0.36001499947321913}

Values can be set using "set":

{"set": {"rudder": 0}}

{"set": {"rudder": 0, "sail": 10}}

{"set": {"latitude": 0, "longitude": 0}}

Setting and requesting can be combined in the same message, for example:

{"set": {"rudder-angle": 0.2}, "request": ["heading", "rudder-angle"]}

Available values:

• version
• latitude
• longitude
• sail-angle
• heading
• rudder-angle
• wind-speed
• wind-angle
• speed
• sheet-length

Installing locally

Make sure libsailing is installed by cloning this repository with

$ git clone --recursive https://github.com/sails-simulator/sailsd.git

Install dependencies (jansson for JSON parsing):

MacOS

$ xcode-select --install
$ brew install jansson

Debian and ubuntu

$ sudo apt install libjansson-dev

Fedora and other red hat distros

$ sudo dnf install jansson-devel

NixOS

$ nix-shell --pure -p pkgconfig jansson

Then compile using make:

$ make

Alternatively, install Nix and run

$ nix-env -i sailsd

Build and run with Docker

$ docker build -t quay.io/sails/sailsd .
$ docker run -p 3333:3333 quay.io/sails/sailsd
$ echo '{"request": ["version"]}' | nc localhost 3333
  {"version": "1.0"}

Code styling

Sailsd uses astyle to automate style conformity. Run:

$ astyle --style=linux --indent=tab *.c

Licence

Copyright © 2014-2017 Louis Taylor

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.