bitbake: hashserv: Add websocket connection implementation

Adds support to the hash equivalence client and server to communicate
over websockets. Since websockets are message orientated instead of
stream orientated, and new connection class is needed to handle them.

Note that websocket support does require the 3rd party websockets python
module be installed on the host, but it should not be required unless
websockets are actually being used.

(Bitbake rev: 56dd2fdbfb6350a9eef43a12aa529c8637887a7e)

Signed-off-by: Joshua Watt <JPEWhacker@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/asyncrpc/serv.py

@@ -12,7 +12,7 @@ import signal
 import socket
 import sys
 import multiprocessing
-from .connection import StreamConnection
+from .connection import StreamConnection, WebsocketConnection
 from .exceptions import ClientError, ServerError, ConnectionClosedError
 
 
@@ -178,6 +178,54 @@ class UnixStreamServer(StreamServer):
         os.unlink(self.path)
 
 
+class WebsocketsServer(object):
+    def __init__(self, host, port, handler, logger):
+        self.host = host
+        self.port = port
+        self.handler = handler
+        self.logger = logger
+
+    def start(self, loop):
+        import websockets.server
+
+        self.server = loop.run_until_complete(
+            websockets.server.serve(
+                self.client_handler,
+                self.host,
+                self.port,
+                ping_interval=None,
+            )
+        )
+
+        for s in self.server.sockets:
+            self.logger.debug("Listening on %r" % (s.getsockname(),))
+
+            # Enable keep alives. This prevents broken client connections
+            # from persisting on the server for long periods of time.
+            s.setsockopt(socket.SOL_SOCKET, socket.SO_KEEPALIVE, 1)
+            s.setsockopt(socket.IPPROTO_TCP, socket.TCP_KEEPIDLE, 30)
+            s.setsockopt(socket.IPPROTO_TCP, socket.TCP_KEEPINTVL, 15)
+            s.setsockopt(socket.IPPROTO_TCP, socket.TCP_KEEPCNT, 4)
+
+        name = self.server.sockets[0].getsockname()
+        if self.server.sockets[0].family == socket.AF_INET6:
+            self.address = "ws://[%s]:%d" % (name[0], name[1])
+        else:
+            self.address = "ws://%s:%d" % (name[0], name[1])
+
+        return [self.server.wait_closed()]
+
+    async def stop(self):
+        self.server.close()
+
+    def cleanup(self):
+        pass
+
+    async def client_handler(self, websocket):
+        socket = WebsocketConnection(websocket, -1)
+        await self.handler(socket)
+
+
 class AsyncServer(object):
     def __init__(self, logger):
         self.logger = logger
@@ -190,6 +238,9 @@ class AsyncServer(object):
     def start_unix_server(self, path):
         self.server = UnixStreamServer(path, self._client_handler, self.logger)
 
+    def start_websocket_server(self, host, port):
+        self.server = WebsocketsServer(host, port, self._client_handler, self.logger)
+
     async def _client_handler(self, socket):
         try:
             client = self.accept_client(socket)