First draft of backend independent plugins

backend/plugin_protocol.py

@@ -0,0 +1,46 @@
+import json
+import uuid
+from asyncio import Protocol, TimeoutError, get_event_loop, wait_for
+from gc import callbacks
+from subprocess import call
+
+
+class PluginProtocolServer(Protocol):
+  def __init__(self, backend) -> None:
+    super().__init__()
+    self.backend = backend
+    self.callbacks = {}
+
+  def connection_made(self, transport):
+    self.transport = transport
+
+  def data_received(self, data: bytes) -> None:
+    message = json.loads(data.decode("utf-8"))
+    message_id = str(uuid.UUID(message["id"]))
+    message_type = message["type"]
+    payload = message["payload"]
+
+    if message_type == "method_response":
+      get_event_loop().create_task(self.handle_method_response(message_id, payload["success"], payload["result"]))
+
+  async def handle_method_response(self, message_id, success, result):
+    if message_id in self.callbacks:
+      self.callbacks[message_id].set_result(dict(success = success, result = result))
+      del self.callbacks[message_id]
+
+  async def send_message(self, type, payload):
+    id = str(uuid.uuid4())
+    callback = get_event_loop().create_future()
+    message = json.dumps(dict(id = id, type = type, payload = payload))
+
+    self.callbacks[id] = callback
+    self.transport.write(message.encode('utf-8'))
+
+    try:
+      return await wait_for(callback, 10)
+    except TimeoutError as e:
+      del self.callbacks[id]
+      raise e
+
+  def call_method(self, method_name, method_args):
+    return self.send_message("method_call", dict(name = method_name, args = method_args))