refactor: removed hardcoded IP and port and moved video functions from main to the VideoSender class

ref: N25B-171

src/robot_interface/endpoints/socket_base.py

@@ -15,7 +15,7 @@ class SocketBase(object):
         self.name = name
         self.socket = None
 
-    def create_socket(self, zmq_context, socket_type, port):
+    def create_socket(self, zmq_context, socket_type, port, options=[]):
         """
         Create a ZeroMQ socket.
 
@@ -27,8 +27,16 @@ class SocketBase(object):
 
         :param port: The port to use.
         :type port: int
+
+        :param options: A list of options to be set on the socket. The list contains tuples where the first element contains the option
+        and the second the value, for example (zmq.CONFLATE, 1).
+        :type options: [(zmq socket option, option value)]
         """
         self.socket = zmq_context.socket(socket_type)
+
+        for option, arg in options:
+            self.socket.setsockopt(option,arg)
+
         self.socket.connect("tcp://localhost:{}".format(port))
 
     def close(self):

src/robot_interface/endpoints/video_sender.py

@@ -1,8 +1,61 @@
 import zmq
+import threading
+import qi
+import logging
 
 from robot_interface.endpoints.socket_base import SocketBase
+from robot_interface.state import state
+
 
 class VideoSender(SocketBase):
     def __init__(self, zmq_context, port=5556):
         super(VideoSender, self).__init__("video")
-        self.create_socket(zmq_context, zmq.PUB, port)
+        self.create_socket(zmq_context, zmq.PUB, port, [(zmq.CONFLATE,1)])
+    
+    def start_video_rcv(self):
+        """
+        Prepares arguments for retrieving video images from Pepper and starts video loop on a separate thread.
+
+        :param robot_ip: The ip address of the robot to connect with.
+        :type robot_ip: String
+        
+        :param port: The port of the robot.
+        :type port: int
+
+        :param socket: The ZMQ socket to send the video images over.
+        :type: VideoSender
+        """        
+        app = qi.Application()
+        app.start()
+        session = app.session
+
+        video = session.service("ALVideoDevice")
+
+        camera_index = 0
+        kQVGA = 2
+        kRGB = 11
+        FPS = 15
+        vid_stream_name = video.subscribeCamera("Pepper Video", camera_index, kQVGA, kRGB, FPS)
+        thread = threading.Thread(target=self.video_rcv_loop, args=(video, vid_stream_name))
+        thread.start()
+
+    def video_rcv_loop(self, vid_service, vid_stream_name):
+        """
+        The main loop of retrieving video images from the robot.
+
+        :param vid_stream: The name of a camera subscription on the video service object vid_service
+        :type vid_stream: String
+
+        :param vid_service: The video service object that the active Qi session is connected to. 
+        :type vid_service: Object (Qi service object)
+
+        :param socket: The ZMQ socket to send the video images over.
+        :type: VideoSender
+        """
+        while not state.exit_event.is_set():
+            try:
+                img = vid_service.getImageRemote(vid_stream_name)
+                #Possibly limit images sent if queuing issues arise
+                self.socket.send(img[6])
+            except:
+                logging.warn("Failed to retrieve video image from robot.")