Services tutorial :tag:`service` :tag:`socket` ============================================== MORSE has a concept of services: services are remote procedure call commonly used to configure or control the behaviour of the simulation. This tutorial shows how to use those services. Different middleware are supported refer to the :doc:`Middleware support in MORSE <../integration>` (search requests in the :ref:`compatibility-matrix`). Pre-requisites -------------- - You must have completed the :doc:`first tutorial <../beginner_tutorials/tutorial>`. Using the services ------------------ In order to use a service, you have to know the exact name of this service, and its parameters (You can refer to the component page, available :doc:`here <../../../components_library>`). Here is an example using human component (the services available are documented :doc:`here <../others/human>`). Scene description +++++++++++++++++ Let's start to describe the Morse scene. Here, the interesting part is that we activate the service for human using ``add_service`` method. .. code-block:: python from morse.builder import * human = Human() human.add_service('socket') env = Environment('empty', fastmode=True) Controlling the human with telnet +++++++++++++++++++++++++++++++++ Now, let's see how we can control it using telnet:: $ telnet localhost 4000 Trying 127.0.0.1... Connected to localhost.localdomain. Escape character is '^]'. > id1 human move [0.1, 0.0] id1 SUCCESS where ``id1`` is the arbitrary id of the request, ``human`` is the name of the used component, ``move`` and ``[0.1 ,0.0]`` are respectively the name of the request and its parameters. This parameters have to be in a json list. Controlling the human with socket :tag:`socket` +++++++++++++++++++++++++++++++++++++++++++++++ Here is a simple example of using services with sockets in python (available at ``$MORSE_ROOT/tools/simple_exemple.py``): .. code-block:: python import sys import socket import tty, termios HOST = '127.0.0.1' PORT = 4000 def getchar(): """ Returns a single character from standard input """ fd = sys.stdin.fileno() old_settings = termios.tcgetattr(fd) try: tty.setraw(sys.stdin.fileno()) ch = sys.stdin.read(1) finally: termios.tcsetattr(fd, termios.TCSADRAIN, old_settings) return ch def _connect_port(port): """ Establish the connection with the given MORSE port""" sock = None for res in socket.getaddrinfo(HOST, port, socket.AF_UNSPEC, socket.SOCK_STREAM): af, socktype, proto, canonname, sa = res try: sock = socket.socket(af, socktype, proto) except socket.error: sock = None continue try: sock.connect(sa) except socket.error: sock.close() sock = None continue break return sock def main(): sock = _connect_port(PORT) if not sock: sys.exit(1) print("sock connected") print("Please press q to quit and use 8456 to move") esc = 0 _id = 0 while not esc: c = getchar() speed = 0 rot = 0 if (c == "8"): speed = 0.1 elif (c == "5"): speed = -0.1 elif (c == "4"): rot = 0.1 elif (c == "6"): rot = -0.1 if (speed != 0 or rot != 0): data_out = "id%d human move [%f, %f]\n" % (_id, speed, rot) sent = sock.send(data_out) print ("SENT DATA (%d bytes): %s" % (sent, data_out)) _id = _id + 1 if c == "q": esc = 1 sock.close() print("\nBye bye!") main() .. note:: You can find a more complete example of python file using services to move the human here: ``$MORSE_ROOT/tools/wiimote_human_client.py``. (using wiimote to control the human) Controlling the human with pymorse :tag:`pymorse` +++++++++++++++++++++++++++++++++++++++++++++++++ The previous example can be rewritten more easily using the :doc:`pymorse API <../../pymorse>`. .. code-block:: python import sys import tty, termios from pymorse import Morse def getchar(): """ Returns a single character from standard input """ fd = sys.stdin.fileno() old_settings = termios.tcgetattr(fd) try: tty.setraw(sys.stdin.fileno()) ch = sys.stdin.read(1) finally: termios.tcsetattr(fd, termios.TCSADRAIN, old_settings) return ch def main(): with Morse() as morse: print("Please press q to quit and use 8456 to move") esc = 0 while not esc: c = getchar() speed = 0 rot = 0 if (c == "8"): speed = 0.1 elif (c == "5"): speed = -0.1 elif (c == "4"): rot = 0.1 elif (c == "6"): rot = -0.1 if (speed != 0 or rot != 0): morse.rpc('human', 'move', speed, rot) if c == "q": esc = 1 print("\nBye bye!") main() Creating the Service -------------------- Please, refer to :doc:`Services in MORSE <../../dev/services>`.