Optimize throughput of api to decrease latency (#327)

aioesphomeapi/_frame_helper.py

@@ -1,7 +1,7 @@
 import asyncio
 import base64
 import logging
-from abc import ABC, abstractmethod
+from abc import ABC, abstractmethod, abstractproperty
 from dataclasses import dataclass
 from typing import Optional
 
@@ -29,50 +29,80 @@ class Packet:
 
 
 class APIFrameHelper(ABC):
-    @abstractmethod
+    """Helper class to handle the API frame protocol."""
-    async def close(self) -> None:
-        pass
 
-    @abstractmethod
-    async def write_packet(self, packet: Packet) -> None:
-        pass
-
-    @abstractmethod
-    async def read_packet(self) -> Packet:
-        pass
-
-
-class APIPlaintextFrameHelper(APIFrameHelper):
     def __init__(
         self,
         reader: asyncio.StreamReader,
         writer: asyncio.StreamWriter,
-    ):
+    ) -> None:
+        """Initialize the API frame helper."""
         self._reader = reader
         self._writer = writer
-        self._write_lock = asyncio.Lock()
+        self.read_lock = asyncio.Lock()
-        self._read_lock = asyncio.Lock()
         self._closed_event = asyncio.Event()
 
+    @abstractproperty  # pylint: disable=deprecated-decorator
+    def ready(self) -> bool:
+        """Return if the connection is ready."""
+
+    @abstractmethod
     async def close(self) -> None:
+        """Close the connection."""
+
+    @abstractmethod
+    def write_packet(self, packet: Packet) -> None:
+        """Write a packet to the socket."""
+
+    @abstractmethod
+    async def read_packet_with_lock(self) -> Packet:
+        """Read a packet from the socket, the caller is responsible for having the lock."""
+
+    @abstractmethod
+    async def wait_for_ready(self) -> None:
+        """Wait for the connection to be ready."""
+
+
+class APIPlaintextFrameHelper(APIFrameHelper):
+    """Frame helper for plaintext API connections."""
+
+    async def close(self) -> None:
+        """Close the connection."""
         self._closed_event.set()
         self._writer.close()
 
-    async def write_packet(self, packet: Packet) -> None:
+    @property
-        data = b"\0"
+    def ready(self) -> bool:
-        data += varuint_to_bytes(len(packet.data))
+        """Return if the connection is ready."""
-        data += varuint_to_bytes(packet.type)
+        # Plaintext is always ready
-        data += packet.data
+        return True
-        try:
+
-            async with self._write_lock:
+    def write_packet(self, packet: Packet) -> None:
+        """Write a packet to the socket, the caller should not have the lock.
+
+        The entire packet must be written in a single call to write
+        to avoid locking.
+        """
+        data = (
+            b"\0"
+            + varuint_to_bytes(len(packet.data))
+            + varuint_to_bytes(packet.type)
+            + packet.data
+        )
         _LOGGER.debug("Sending plaintext frame %s", data.hex())
+
+        try:
             self._writer.write(data)
-                await self._writer.drain()
         except (ConnectionResetError, OSError) as err:
             raise SocketAPIError(f"Error while writing data: {err}") from err
 
-    async def read_packet(self) -> Packet:
+    async def wait_for_ready(self) -> None:
-        async with self._read_lock:
+        """Wait for the connection to be ready."""
+        # No handshake for plaintext
+
+    async def read_packet_with_lock(self) -> Packet:
+        """Read a packet from the socket, the caller is responsible for having the lock."""
+        assert self.read_lock.locked(), "read_packet_with_lock called without lock"
         try:
             # Read preamble, which should always 0x00
             # Also try to get the length and msg type
@@ -80,9 +110,7 @@ class APIPlaintextFrameHelper(APIFrameHelper):
             init_bytes = await self._reader.readexactly(3)
             if init_bytes[0] != 0x00:
                 if init_bytes[0] == 0x01:
-                        raise RequiresEncryptionAPIError(
+                    raise RequiresEncryptionAPIError("Connection requires encryption")
-                            "Connection requires encryption"
-                        )
                 raise ProtocolAPIError(f"Invalid preamble {init_bytes[0]:02x}")
 
             if init_bytes[1] & 0x80 == 0x80:
@@ -142,29 +170,43 @@ def _decode_noise_psk(psk: str) -> bytes:
 
 
 class APINoiseFrameHelper(APIFrameHelper):
+    """Frame helper for noise encrypted connections."""
+
     def __init__(
         self,
         reader: asyncio.StreamReader,
         writer: asyncio.StreamWriter,
         noise_psk: str,
-    ):
+    ) -> None:
-        self._reader = reader
+        """Initialize the API frame helper."""
-        self._writer = writer
+        super().__init__(reader, writer)
-        self._write_lock = asyncio.Lock()
-        self._read_lock = asyncio.Lock()
         self._ready_event = asyncio.Event()
-        self._closed_event = asyncio.Event()
         self._proto: Optional[NoiseConnection] = None
         self._noise_psk = noise_psk
 
+    @property
+    def ready(self) -> bool:
+        """Return if the connection is ready."""
+        return self._ready_event.is_set()
+
     async def close(self) -> None:
+        """Close the connection."""
+        # Make sure we set the ready event if its not already set
+        # so that we don't block forever on the ready event if we
+        # are waiting for the handshake to complete.
+        self._ready_event.set()
         self._closed_event.set()
         self._writer.close()
 
-    async def _write_frame(self, frame: bytes) -> None:
+    def _write_frame(self, frame: bytes) -> None:
-        try:
+        """Write a packet to the socket, the caller should not have the lock.
-            async with self._write_lock:
+
+        The entire packet must be written in a single call to write
+        to avoid locking.
+        """
         _LOGGER.debug("Sending frame %s", frame.hex())
+
+        try:
             header = bytes(
                 [
                     0x01,
@@ -173,13 +215,13 @@ class APINoiseFrameHelper(APIFrameHelper):
                 ]
             )
             self._writer.write(header + frame)
-                await self._writer.drain()
         except OSError as err:
             raise SocketAPIError(f"Error while writing data: {err}") from err
 
-    async def _read_frame(self) -> bytes:
+    async def _read_frame_with_lock(self) -> bytes:
+        """Read a frame from the socket, the caller is responsible for having the lock."""
+        assert self.read_lock.locked(), "_read_frame_with_lock called without lock"
         try:
-            async with self._read_lock:
             header = await self._reader.readexactly(3)
             if header[0] != 0x01:
                 raise ProtocolAPIError(f"Marker byte invalid: {header[0]}")
@@ -199,10 +241,12 @@ class APINoiseFrameHelper(APIFrameHelper):
         return frame
 
     async def _perform_handshake(self, expected_name: Optional[str]) -> None:
-        await self._write_frame(b"")  # ClientHello
+        """Perform the handshake with the server, the caller is responsible for having the lock."""
+        assert self.read_lock.locked(), "_perform_handshake called without lock"
+        self._write_frame(b"")  # ClientHello
         prologue = b"NoiseAPIInit" + b"\x00\x00"
 
-        server_hello = await self._read_frame()  # ServerHello
+        server_hello = await self._read_frame_with_lock()  # ServerHello
         if not server_hello:
             raise HandshakeAPIError("ServerHello is empty")
 
@@ -238,9 +282,9 @@ class APINoiseFrameHelper(APIFrameHelper):
         while not self._proto.handshake_finished:
             if do_write:
                 msg = self._proto.write_message()
-                await self._write_frame(b"\x00" + msg)
+                self._write_frame(b"\x00" + msg)
             else:
-                msg = await self._read_frame()
+                msg = await self._read_frame_with_lock()
                 if not msg:
                     raise HandshakeAPIError("Handshake message too short")
                 if msg[0] != 0:
@@ -256,16 +300,16 @@ class APINoiseFrameHelper(APIFrameHelper):
         self._ready_event.set()
 
     async def perform_handshake(self, expected_name: Optional[str]) -> None:
+        """Perform the handshake with the server."""
         # Allow up to 60 seconds for handhsake
         try:
-            async with async_timeout.timeout(60.0):
+            async with self.read_lock, async_timeout.timeout(60.0):
                 await self._perform_handshake(expected_name)
         except asyncio.TimeoutError as err:
             raise HandshakeAPIError("Timeout during handshake") from err
 
-    async def write_packet(self, packet: Packet) -> None:
+    def write_packet(self, packet: Packet) -> None:
-        # Wait for handshake to complete
+        """Write a packet to the socket."""
-        await self._ready_event.wait()
         padding = 0
         data = (
             bytes(
@@ -281,12 +325,15 @@ class APINoiseFrameHelper(APIFrameHelper):
         )
         assert self._proto is not None
         frame = self._proto.encrypt(data)
-        await self._write_frame(frame)
+        self._write_frame(frame)
 
-    async def read_packet(self) -> Packet:
+    async def wait_for_ready(self) -> None:
-        # Wait for handshake to complete
+        """Wait for the connection to be ready."""
         await self._ready_event.wait()
-        frame = await self._read_frame()
+
+    async def read_packet_with_lock(self) -> Packet:
+        """Read a packet from the socket, the caller is responsible for having the lock."""
+        frame = await self._read_frame_with_lock()
         assert self._proto is not None
         msg = self._proto.decrypt(frame)
         if len(msg) < 4:

aioesphomeapi/connection.py

@@ -49,6 +49,8 @@ _LOGGER = logging.getLogger(__name__)
 
 BUFFER_SIZE = 1024 * 1024  # Set buffer limit to 1MB
 
+INTERNAL_MESSAGE_TYPES = (GetTimeRequest, PingRequest, DisconnectRequest)
+
 
 @dataclass
 class ConnectionParams:
@@ -105,7 +107,7 @@ class APIConnection:
 
         self._ping_stop_event = asyncio.Event()
 
-        self._to_process: asyncio.Queue[Packet] = asyncio.Queue()
+        self._to_process: asyncio.Queue[Optional[Packet]] = asyncio.Queue()
 
         self._process_task: Optional[asyncio.Task[None]] = None
 
@@ -120,6 +122,9 @@ class APIConnection:
 
         async def _do_cleanup() -> None:
             async with self._connect_lock:
+                # Tell the process loop to stop
+                self._to_process.put_nowait(None)
+
                 if self._frame_helper is not None:
                     await self._frame_helper.close()
                     self._frame_helper = None
@@ -388,10 +393,13 @@ class APIConnection:
         encoded = msg.SerializeToString()
         _LOGGER.debug("%s: Sending %s: %s", self._params.address, type(msg), str(msg))
 
+        frame_helper = self._frame_helper
+        assert frame_helper is not None
+        if not frame_helper.ready:
+            await frame_helper.wait_for_ready()
+
         try:
-            assert self._frame_helper is not None
+            frame_helper.write_packet(
-            # pylint: disable=undefined-loop-variable
-            await self._frame_helper.write_packet(
                 Packet(
                     type=message_type,
                     data=encoded,
@@ -512,48 +520,60 @@ class APIConnection:
         await self._cleanup()
 
     async def _process_loop(self) -> None:
+        to_process = self._to_process
         while True:
-            if not self._is_socket_open:
-                # Socket closed but task isn't cancelled yet
-                break
-
             try:
-                pkt = await self._to_process.get()
+                pkt = await to_process.get()
             except RuntimeError:
                 break
 
+            if pkt is None:
+                # Socket closed but task isn't cancelled yet
+                break
+
             msg_type = pkt.type
-            raw_msg = pkt.data
             if msg_type not in MESSAGE_TYPE_TO_PROTO:
                 _LOGGER.debug("%s: Skipping message type %s", self.log_name, msg_type)
                 continue
 
             msg = MESSAGE_TYPE_TO_PROTO[msg_type]()
             try:
-                msg.ParseFromString(raw_msg)
+                msg.ParseFromString(pkt.data)
             except Exception as e:
                 await self._report_fatal_error(
                     ProtocolAPIError(f"Invalid protobuf message: {e}")
                 )
                 raise
+
             _LOGGER.debug(
                 "%s: Got message of type %s: %s", self.log_name, type(msg), msg
             )
 
             for handler in self._message_handlers[:]:
                 handler(msg)
+
+            # Pre-check the message type to avoid awaiting
+            # since most messages are not internal messages
+            if isinstance(msg, INTERNAL_MESSAGE_TYPES):
                 await self._handle_internal_messages(msg)
 
     async def _read_loop(self) -> None:
-        assert self._frame_helper is not None
+        frame_helper = self._frame_helper
+        assert frame_helper is not None
+        await frame_helper.wait_for_ready()
+        to_process = self._to_process
         try:
+            # Once its ready, we hold the lock for the duration of the
+            # connection so we don't have to keep locking/unlocking
+            async with frame_helper.read_lock:
                 while True:
-                if not self._is_socket_open:
+                    to_process.put_nowait(await frame_helper.read_packet_with_lock())
-                    # Socket closed but task isn't cancelled yet
-                    break
-                self._to_process.put_nowait(await self._frame_helper.read_packet())
         except SocketClosedAPIError as err:
             # don't log with info, if closed the site that closed the connection should log
+            if not self._is_socket_open:
+                # If we expected the socket to be closed, don't log
+                # the error.
+                return
             _LOGGER.debug(
                 "%s: Socket closed, stopping read loop",
                 self.log_name,