Merge pull request #353 from palfrey/one-api-call-at-a-time

Uses a Semaphore to limit API calls to one at a time to avoid KLF issues

pyvlx/api/api_event.py

@@ -23,12 +23,18 @@ def __init__(self, pyvlx: "PyVLX", timeout_in_seconds: int = 10):
 
     async def do_api_call(self) -> None:
         """Start. Sending and waiting for answer."""
-        self.pyvlx.connection.register_frame_received_cb(self.response_rec_callback)
-        await self.send_frame()
-        await self.start_timeout()
-        await self.response_received_or_timeout.wait()
-        await self.stop_timeout()
-        self.pyvlx.connection.unregister_frame_received_cb(self.response_rec_callback)
+        # We check for connection before entering the semaphore section
+        # because otherwise we might try to connect, which calls this, and we get stuck on
+        # the semaphore.
+        await self.pyvlx.check_connected()
+
+        async with self.pyvlx.api_call_semaphore:
+            self.pyvlx.connection.register_frame_received_cb(self.response_rec_callback)
+            await self.send_frame()
+            await self.start_timeout()
+            await self.response_received_or_timeout.wait()
+            await self.stop_timeout()
+            self.pyvlx.connection.unregister_frame_received_cb(self.response_rec_callback)
 
     async def handle_frame(self, frame: FrameBase) -> bool:
         """Handle incoming API frame, return True if this was the expected frame."""

pyvlx/api/get_all_nodes_information.py

@@ -15,7 +15,7 @@
 
 
 class GetAllNodesInformation(ApiEvent):
-    """Class for retrieving node informationfrom API."""
+    """Class for retrieving node information from API."""
 
     def __init__(self, pyvlx: "PyVLX"):
         """Initialize SceneList class."""

pyvlx/pyvlx.py

@@ -41,6 +41,7 @@ def __init__(self,
         self.version = None
         self.protocol_version = None
         self.klf200 = Klf200Gateway(pyvlx=self)
+        self.api_call_semaphore = asyncio.Semaphore(1)  # Limit parallel commands
 
     async def connect(self) -> None:
         """Connect to KLF 200."""
@@ -67,10 +68,14 @@ async def reboot_gateway(self) -> None:
         PYVLXLOG.warning("KLF 200 reboot initiated")
         await self.klf200.reboot()
 
-    async def send_frame(self, frame: FrameBase) -> None:
-        """Send frame to API via connection."""
+    async def check_connected(self) -> None:
+        """Check we're connected, and if not, connect."""
         if not self.connection.connected:
             await self.connect()
+
+    async def send_frame(self, frame: FrameBase) -> None:
+        """Send frame to API via connection."""
+        await self.check_connected()
         self.connection.write(frame)
 
     async def disconnect(self) -> None: