build: add Docker container

Some changes (like `asound.conf`) are not portable and only work on my
machine. This will be fixed in the future.

ref: N25B-284

.dockerignore

@@ -0,0 +1,9 @@
+.git
+.githooks/
+.idea/
+.venv/
+test/
+typings/
+.dockerignore
+.gitignore
+README.md

Dockerfile

@@ -0,0 +1,12 @@
+FROM python:2.7.18-alpine
+
+WORKDIR /app
+
+COPY install_deps.sh requirements.txt ./
+RUN ./install_deps.sh
+
+COPY . .
+
+ENV PYTHONPATH=src
+
+CMD [ "python2", "-m", "robot_interface.main" ]

asound.conf

@@ -0,0 +1,9 @@
+pcm.!default {
+  type hw
+  card 2
+}
+
+ctl.!default {
+  type hw
+  card 2
+}

install_deps.sh

@@ -0,0 +1,4 @@
+#!/usr/bin/env sh
+apk add portaudio-dev libzmq gcc musl-dev g++ alsa-utils
+
+pip install -r requirements.txt

src/robot_interface/endpoints/main_receiver.py

@@ -45,7 +45,10 @@ class MainReceiver(ReceiverBase):
         if message["endpoint"] == "negotiate/ports":
             return MainReceiver._handle_port_negotiation(message)
 
-        return {"endpoint": "negotiate/error", "data": "The requested endpoint is not implemented."}
+        return {
+            "endpoint": "negotiate/error",
+            "data": "The requested endpoint is not implemented.",
+        }
 
     def handle_message(self, message):
         if message["endpoint"] == "ping":

src/robot_interface/endpoints/socket_base.py

@@ -1,6 +1,5 @@
 from abc import ABCMeta
-
+import os
-import zmq
 
 
 class SocketBase(object):
@@ -19,7 +18,7 @@ class SocketBase(object):
         self.socket = None  # Set later by `create_socket`
         self.bound = None  # Set later by `create_socket`
 
-    def create_socket(self, zmq_context, socket_type, port, options=[], bind=True):
+    def create_socket(self, zmq_context, socket_type, port, options=[], bind=False):
         """
         Create a ZeroMQ socket.
 
@@ -46,14 +45,16 @@ class SocketBase(object):
             self.socket.setsockopt(option, arg)
 
         self.bound = bind
+        host = os.environ.get("CB_HOST", "localhost")
         if bind:
-            self.socket.bind("tcp://*:{}".format(port))
+            self.socket.bind("tcp://{}:{}".format(host, port))
         else:
-            self.socket.connect("tcp://localhost:{}".format(port))
+            self.socket.connect("tcp://{}:{}".format(host, port))
 
     def close(self):
         """Close the ZeroMQ socket."""
-        if not self.socket: return
+        if not self.socket:
+            return
         self.socket.close()
         self.socket = None
 
@@ -65,8 +66,4 @@ class SocketBase(object):
         https://utrechtuniversity.youtrack.cloud/articles/N25B-A-14/RI-CB-Communication#negotiation
         :rtype: dict
         """
-        return {
+        return {"id": self.identifier, "port": self.port, "bind": not self.bound}
-            "id": self.identifier,
-            "port": self.port,
-            "bind": not self.bound
-        }