Merge pull request #10 from fdlamotte/awolden/connection-manager

Add better connection management

README.md

@@ -111,6 +111,43 @@ meshcore = await MeshCore.create_ble("12:34:56:78:90:AB")
 meshcore = await MeshCore.create_tcp("192.168.1.100", 4000)
 ```
 
+#### Auto-Reconnect and Connection Events
+
+Enable automatic reconnection when connections are lost:
+
+```python
+# Enable auto-reconnect with custom retry limits
+meshcore = await MeshCore.create_tcp(
+    "192.168.1.100", 4000,
+    auto_reconnect=True,
+    max_reconnect_attempts=5
+)
+
+# Subscribe to connection events
+async def on_connected(event):
+    print(f"Connected: {event.payload}")
+    if event.payload.get('reconnected'):
+        print("Successfully reconnected!")
+
+async def on_disconnected(event):
+    print(f"Disconnected: {event.payload['reason']}")
+    if event.payload.get('max_attempts_exceeded'):
+        print("Max reconnection attempts exceeded")
+
+meshcore.subscribe(EventType.CONNECTED, on_connected)
+meshcore.subscribe(EventType.DISCONNECTED, on_disconnected)
+
+# Check connection status
+if meshcore.is_connected:
+    print("Device is currently connected")
+```
+
+**Auto-reconnect features:**
+- Exponential backoff (1s, 2s, 4s, 8s max delay)
+- Configurable retry limits (default: 3 attempts)
+- Automatic disconnect detection (especially useful for TCP connections)
+- Connection events with detailed information
+
 ### Using Commands (Synchronous Style)
 
 Send commands and wait for responses:

examples/connection_events_example.py

@@ -0,0 +1,87 @@
+"""
+Example demonstrating connection events and auto-reconnect functionality.
+"""
+import asyncio
+import logging
+import sys
+from meshcore import MeshCore
+from meshcore.events import EventType
+
+logging.basicConfig(level=logging.DEBUG)
+
+async def main():
+    mc = None
+    # Example with auto-reconnect enabled
+    try:
+        # mc = await MeshCore.create_serial(
+        #     port="/dev/cu.usbmodem1101", 
+        #     auto_reconnect=True, 
+        #     max_reconnect_attempts=3,
+        #     debug=True
+        # )
+        
+        # mc = await MeshCore.create_tcp(
+        #     host="192.168.1.22",
+        #     port=5000, 
+        #     auto_reconnect=True, 
+        #     max_reconnect_attempts=sys.maxsize,
+        #     debug=True
+        # )
+        
+        mc = await MeshCore.create_ble(
+            address="92849669", 
+            auto_reconnect=True, 
+            max_reconnect_attempts=3,
+            debug=True
+        )
+        
+        # Subscribe to connection events
+        async def on_connected(event):
+            print(f"✅ Connected! Info: {event.payload}")
+            if event.payload.get('reconnected'):
+                print("🔄 This was a reconnection!")
+            
+        async def on_disconnected(event):
+            print(f"❌ Disconnected! Reason: {event.payload.get('reason')}")
+            if event.payload.get('max_attempts_exceeded'):
+                print("⚠️  Max reconnection attempts exceeded")
+        
+        mc.subscribe(EventType.CONNECTED, on_connected)
+        mc.subscribe(EventType.DISCONNECTED, on_disconnected)
+        
+        # Check connection status
+        
+        print("\n📱 Disconnect your device now to test auto-reconnect...")
+        print("Press Ctrl+C to exit")
+        
+        # Keep running and periodically test the connection
+        while True:
+            await asyncio.sleep(2)
+            print(f"Connected: {mc.is_connected}")
+            if mc.is_connected:
+                try:
+                    print("🔄 Testing connection by getting battery...")
+                    result = await mc.commands.get_bat()
+                    
+                    if result.type == EventType.ERROR:
+                        print(f"❌ Error getting battery: {result.payload}")
+                    else:
+                        print("✅ Connection test successfeul")
+                except Exception as e:
+                    print(f"❌ Connection test failed: {e}")
+                    # This should trigger the disconnect detection
+            else:
+                print("⏳ Waiting for reconnection...")
+        
+    except KeyboardInterrupt:
+        print("\n🛑 Exiting...")
+    except ConnectionError as e:
+        print(f"❌ Failed to connect: {e}")
+    finally:
+        if mc is not None:
+            await mc.disconnect()
+            print(f"Connected after disconnect: {mc.is_connected}")
+            print(f"Connected after disconnect: {mc.is_connected}")
+
+if __name__ == "__main__":
+    asyncio.run(main())

src/meshcore/__init__.py

@@ -5,6 +5,7 @@ logging.basicConfig(level=logging.INFO)
 
 from meshcore.events import EventType
 from meshcore.meshcore import MeshCore, logger
+from meshcore.connection_manager import ConnectionManager
 from meshcore.tcp_cx import TCPConnection
 from meshcore.ble_cx import BLEConnection
 from meshcore.serial_cx import SerialConnection

src/meshcore/ble_cx.py

@@ -21,9 +21,10 @@ class BLEConnection:
     def __init__(self, address):
         """ Constructor : specify address """
         self.address = address
+        self._user_provided_address = address
         self.client = None
         self.rx_char = None
-        self.mc = None
+        self._disconnect_callback = None
 
     async def connect(self):
         """
@@ -31,6 +32,7 @@ class BLEConnection:
 
         Returns : the address used for connection
         """
+        logger.debug(f"Connecting existing connection: {self.client} with address {self.address}")
         def match_meshcore_device(_: BLEDevice, adv: AdvertisementData):
             """ Filter to mach MeshCore devices """
             if not adv.local_name is None\
@@ -39,20 +41,20 @@ class BLEConnection:
                 return True
             return False
 
-        if self.address is None or self.address == "" or len(self.address.split(":")) != 6 :
+        if self.address is None or self.address == "" or len(self.address.split(":")) != 6:
             scanner = BleakScanner()
             logger.info("Scanning for devices")
             device = await scanner.find_device_by_filter(match_meshcore_device)
-            if device is None :
+            if device is None:
                 return None
             logger.info(f"Found device : {device}")
-            self.client = BleakClient(device)
+            self.client = BleakClient(device, disconnected_callback=self.handle_disconnect)
             self.address = self.client.address
         else:
-            self.client = BleakClient(self.address)
+            self.client = BleakClient(self.address, disconnected_callback=self.handle_disconnect)
 
         try:
-            await self.client.connect(disconnected_callback=self.handle_disconnect)
+            await self.client.connect()
         except BleakDeviceNotFoundError:
             return None
         except TimeoutError:
@@ -69,12 +71,19 @@ class BLEConnection:
         logger.info("BLE Connection started")
         return self.address
 
-    def handle_disconnect(self, _: BleakClient):
+    def handle_disconnect(self, client: BleakClient):
         """ Callback to handle disconnection """
-        logger.info("Device was disconnected, goodbye.")
-        # cancelling all tasks effectively ends the program
-        for task in asyncio.all_tasks():
-            task.cancel()
+        logger.debug(f"BLE device disconnected: {client.address} (is_connected: {client.is_connected})")  
+        # Reset the address we found to what user specified
+        # this allows to reconnect to the same device
+        self.address = self._user_provided_address
+        
+        if self._disconnect_callback:
+            asyncio.create_task(self._disconnect_callback("ble_disconnect"))
+            
+    def set_disconnect_callback(self, callback):
+        """Set callback to handle disconnections."""
+        self._disconnect_callback = callback
 
     def set_reader(self, reader) :
         self.reader = reader

src/meshcore/connection_manager.py

@@ -0,0 +1,149 @@
+"""
+Connection manager that orchestrates reconnection logic for any connection type.
+"""
+import asyncio
+import logging
+from typing import Optional, Any, Callable, Protocol
+from .events import Event, EventType
+
+logger = logging.getLogger("meshcore")
+
+class ConnectionProtocol(Protocol):
+    """Protocol defining the interface that connection classes must implement."""
+    
+    async def connect(self) -> Optional[Any]:
+        """Connect and return connection info, or None if failed."""
+        ...
+    
+    async def disconnect(self):
+        """Disconnect from the device/server."""
+        ...
+    
+    async def send(self, data):
+        """Send data through the connection."""
+        ...
+    
+    def set_reader(self, reader):
+        """Set the message reader."""
+        ...
+
+
+class ConnectionManager:
+    """Manages connection lifecycle with auto-reconnect and event emission."""
+    
+    def __init__(self, connection: ConnectionProtocol, event_dispatcher=None, 
+                 auto_reconnect: bool = False, max_reconnect_attempts: int = 3):
+        self.connection = connection
+        self.event_dispatcher = event_dispatcher
+        self.auto_reconnect = auto_reconnect
+        self.max_reconnect_attempts = max_reconnect_attempts
+        
+        self._reconnect_attempts = 0
+        self._is_connected = False
+        self._reconnect_task = None
+        self._disconnect_callback: Optional[Callable] = None
+        
+    def set_disconnect_callback(self, callback: Callable):
+        """Set a callback to be called when disconnection is detected."""
+        self._disconnect_callback = callback
+        
+    async def connect(self) -> Optional[Any]:
+        """Connect with event handling and state management."""
+        result = await self.connection.connect()
+        
+        if result is not None:
+            self._is_connected = True
+            self._reconnect_attempts = 0
+            await self._emit_event(EventType.CONNECTED, {"connection_info": result})
+            logger.debug(f"Connected successfully: {result}")
+        else:
+            logger.debug("Connection failed")
+            
+        return result
+    
+    async def disconnect(self):
+        """Disconnect with proper cleanup."""
+        if self._reconnect_task:
+            self._reconnect_task.cancel()
+            try:
+                await self._reconnect_task
+            except asyncio.CancelledError:
+                pass
+            self._reconnect_task = None
+            
+        if self._is_connected:
+            await self.connection.disconnect()
+            self._is_connected = False
+            await self._emit_event(EventType.DISCONNECTED, {"reason": "manual_disconnect"})
+    
+    async def handle_disconnect(self, reason: str = "unknown"):
+        """Handle unexpected disconnections with optional auto-reconnect."""
+        if not self._is_connected:
+            return
+            
+        self._is_connected = False
+        logger.debug(f"Connection lost: {reason}")
+        
+        if self.auto_reconnect and self._reconnect_attempts < self.max_reconnect_attempts:
+            self._reconnect_task = asyncio.create_task(self._attempt_reconnect())
+        else:
+            await self._emit_event(EventType.DISCONNECTED, {
+                "reason": reason,
+                "reconnect_failed": self._reconnect_attempts >= self.max_reconnect_attempts
+            })
+    
+    async def _attempt_reconnect(self):
+        """Attempt to reconnect with flat delay."""
+        logger.debug(f"Attempting reconnection ({self._reconnect_attempts + 1}/{self.max_reconnect_attempts})")
+        self._reconnect_attempts += 1
+        
+        # Flat 1 second delay for all attempts
+        await asyncio.sleep(1)
+        
+        try:
+            result = await self.connection.connect()
+            if result is not None:
+                self._is_connected = True
+                self._reconnect_attempts = 0
+                await self._emit_event(EventType.CONNECTED, {
+                    "connection_info": result,
+                    "reconnected": True
+                })
+                logger.debug(f"Reconnected successfully")
+            else:
+                # Reconnection failed, try again if we haven't exceeded max attempts
+                if self._reconnect_attempts < self.max_reconnect_attempts:
+                    self._reconnect_task = asyncio.create_task(self._attempt_reconnect())
+                else:
+                    await self._emit_event(EventType.DISCONNECTED, {
+                        "reason": "reconnect_failed",
+                        "max_attempts_exceeded": True
+                    })
+        except Exception as e:
+            logger.debug(f"Reconnection attempt failed: {e}")
+            if self._reconnect_attempts < self.max_reconnect_attempts:
+                self._reconnect_task = asyncio.create_task(self._attempt_reconnect())
+            else:
+                await self._emit_event(EventType.DISCONNECTED, {
+                    "reason": f"reconnect_error: {e}",
+                    "max_attempts_exceeded": True
+                })
+    
+    async def _emit_event(self, event_type: EventType, payload: dict):
+        """Emit connection events if dispatcher is available."""
+        if self.event_dispatcher:
+            event = Event(event_type, payload)
+            await self.event_dispatcher.dispatch(event)
+    
+    @property
+    def is_connected(self) -> bool:
+        """Check if the connection is active."""
+        return self._is_connected
+    
+    async def send(self, data):
+        """Send data through the managed connection."""
+        return await self.connection.send(data)
+    
+    def set_reader(self, reader):
+        """Set the message reader on the underlying connection."""
+        self.connection.set_reader(reader)

src/meshcore/events.py

@@ -40,6 +40,10 @@ class EventType(Enum):
     # Command response types
     OK = "command_ok"
     ERROR = "command_error"
+    
+    # Connection events
+    CONNECTED = "connected"
+    DISCONNECTED = "disconnected"
 
 
 @dataclass

src/meshcore/meshcore.py

@@ -5,6 +5,7 @@ from typing import Optional, Dict, Any, Union
 from .events import EventDispatcher, EventType
 from .reader import MessageReader
 from .commands import CommandHandler
+from .connection_manager import ConnectionManager
 from .ble_cx import BLEConnection
 from .tcp_cx import TCPConnection
 from .serial_cx import SerialConnection
@@ -16,9 +17,14 @@ class MeshCore:
     """
     Interface to a MeshCore device
     """
-    def __init__(self, cx, debug=False, default_timeout=None):
-        self.cx = cx
+    def __init__(self, cx, debug=False, default_timeout=None, auto_reconnect=False, max_reconnect_attempts=3):
+        # Wrap connection with ConnectionManager
         self.dispatcher = EventDispatcher()
+        self.connection_manager = ConnectionManager(
+            cx, self.dispatcher, auto_reconnect, max_reconnect_attempts
+        )
+        self.cx = self.connection_manager  # For backward compatibility
+        
         self._reader = MessageReader(self.dispatcher)
         self.commands = CommandHandler(default_timeout=default_timeout)
         
@@ -29,7 +35,7 @@ class MeshCore:
             logger.setLevel(logging.INFO)
         
         # Set up connections
-        self.commands.set_connection(cx)
+        self.commands.set_connection(self.connection_manager)
         
         # Set the dispatcher in the command handler
         self.commands.set_dispatcher(self.dispatcher)
@@ -43,47 +49,54 @@ class MeshCore:
         # Set up event subscriptions to track data
         self._setup_data_tracking()
         
-        cx.set_reader(self._reader)
+        self.connection_manager.set_reader(self._reader)
+        
+        # Set up disconnect callback
+        cx.set_disconnect_callback(self.connection_manager.handle_disconnect)
     
     @classmethod
-    async def create_tcp(cls, host: str, port: int, debug: bool = False, default_timeout=None) -> 'MeshCore':
+    async def create_tcp(cls, host: str, port: int, debug: bool = False, default_timeout=None, 
+                        auto_reconnect: bool = False, max_reconnect_attempts: int = 3) -> 'MeshCore':
         """Create and connect a MeshCore instance using TCP connection"""        
         connection = TCPConnection(host, port)
-        await connection.connect()
         
-        mc = cls(connection, debug=debug, default_timeout=default_timeout)
+        mc = cls(connection, debug=debug, default_timeout=default_timeout,
+                auto_reconnect=auto_reconnect, max_reconnect_attempts=max_reconnect_attempts)
         await mc.connect()
         return mc
     
     @classmethod
-    async def create_serial(cls, port: str, baudrate: int = 115200, debug: bool = False, default_timeout=None) -> 'MeshCore':
+    async def create_serial(cls, port: str, baudrate: int = 115200, debug: bool = False, default_timeout=None,
+                           auto_reconnect: bool = False, max_reconnect_attempts: int = 3) -> 'MeshCore':
         """Create and connect a MeshCore instance using serial connection"""
         connection = SerialConnection(port, baudrate)
-        await connection.connect()
         await asyncio.sleep(0.1)  # Time for transport to establish
         
-        mc = cls(connection, debug=debug, default_timeout=default_timeout)
+        mc = cls(connection, debug=debug, default_timeout=default_timeout,
+                auto_reconnect=auto_reconnect, max_reconnect_attempts=max_reconnect_attempts)
         await mc.connect()
         return mc
     
     @classmethod
-    async def create_ble(cls, address: Optional[str] = None, debug: bool = False, default_timeout=None) -> 'MeshCore':
+    async def create_ble(cls, address: Optional[str] = None, debug: bool = False, default_timeout=None,
+                        auto_reconnect: bool = False, max_reconnect_attempts: int = 3) -> 'MeshCore':
         """Create and connect a MeshCore instance using BLE connection
         
         If address is None, it will scan for and connect to the first available MeshCore device.
         """
         
         connection = BLEConnection(address)
-        result = await connection.connect()
-        if result is None:
-            raise ConnectionError("Failed to connect to BLE device")
         
-        mc = cls(connection, debug=debug, default_timeout=default_timeout)
+        mc = cls(connection, debug=debug, default_timeout=default_timeout,
+                auto_reconnect=auto_reconnect, max_reconnect_attempts=max_reconnect_attempts)
         await mc.connect()
         return mc
         
     async def connect(self):
         await self.dispatcher.start()
+        result = await self.connection_manager.connect()
+        if result is None:
+            raise ConnectionError("Failed to connect to device")
         return await self.commands.send_appstart()
     
     async def disconnect(self):
@@ -96,8 +109,7 @@ class MeshCore:
             await self.stop_auto_message_fetching()
             
         # Disconnect the connection object
-        if self.cx:
-            await self.cx.disconnect()
+        await self.connection_manager.disconnect()
     
     def stop(self):
         """Synchronously stop the event dispatcher task"""
@@ -195,6 +207,11 @@ class MeshCore:
         """Get the current device time"""
         return self._time
         
+    @property
+    def is_connected(self):
+        """Check if the connection is active"""
+        return self.connection_manager.is_connected
+        
     @property
     def default_timeout(self):
         """Get the default timeout for commands"""

src/meshcore/serial_cx.py

@@ -17,6 +17,7 @@ class SerialConnection:
         self.transport = None
         self.header = b""
         self.inframe = b""
+        self._disconnect_callback = None
 
     class MCSerialClientProtocol(asyncio.Protocol):
         def __init__(self, cx):
@@ -32,7 +33,9 @@ class SerialConnection:
             self.cx.handle_rx(data)    
     
         def connection_lost(self, exc):
-            logger.info('port closed')
+            logger.debug('Serial port closed')
+            if self.cx._disconnect_callback:
+                asyncio.create_task(self.cx._disconnect_callback("serial_disconnect"))
     
         def pause_writing(self):
             logger.debug('pause writing')
@@ -93,4 +96,8 @@ class SerialConnection:
         if self.transport:
             self.transport.close()
             self.transport = None
-            logger.debug("Serial Connection closed")
+            logger.debug("Serial Connection closed")
+            
+    def set_disconnect_callback(self, callback):
+        """Set callback to handle disconnections."""
+        self._disconnect_callback = callback

src/meshcore/tcp_cx.py

@@ -7,6 +7,9 @@ import logging
 # Get logger
 logger = logging.getLogger("meshcore")
 
+# TCP disconnect detection threshold
+TCP_DISCONNECT_THRESHOLD = 5
+
 class TCPConnection:
     def __init__(self, host, port):
         self.host = host
@@ -16,6 +19,9 @@ class TCPConnection:
         self.frame_size = 0
         self.header = b""
         self.inframe = b""
+        self._disconnect_callback = None
+        self._send_count = 0
+        self._receive_count = 0
 
     class MCClientProtocol(asyncio.Protocol):
         def __init__(self, cx):
@@ -23,17 +29,23 @@ class TCPConnection:
 
         def connection_made(self, transport):
             self.cx.transport = transport
+            # Reset counters on new connection
+            self.cx._send_count = 0
+            self.cx._receive_count = 0
             logger.debug('connection established')
     
         def data_received(self, data):
             logger.debug('data received')
+            self.cx._receive_count += 1
             self.cx.handle_rx(data)
 
         def error_received(self, exc):
             logger.error(f'Error received: {exc}')
     
         def connection_lost(self, exc):
-            logger.info('The server closed the connection')
+            logger.debug('TCP server closed the connection')
+            if self.cx._disconnect_callback:
+                asyncio.create_task(self.cx._disconnect_callback("tcp_disconnect"))
 
     async def connect(self):
         """
@@ -80,7 +92,19 @@ class TCPConnection:
     async def send(self, data):
         if not self.transport:
             logger.error("Transport not connected, cannot send data")
+            if self._disconnect_callback:
+                await self._disconnect_callback("tcp_transport_lost")
             return
+        
+        self._send_count += 1
+        
+        # Check if we've sent packets without any responses
+        if self._send_count - self._receive_count >= TCP_DISCONNECT_THRESHOLD:
+            logger.debug(f"TCP disconnect detected: sent {self._send_count}, received {self._receive_count}")
+            if self._disconnect_callback:
+                await self._disconnect_callback("tcp_no_response")
+            return
+            
         size = len(data)
         pkt = b"\x3c" + size.to_bytes(2, byteorder="little") + data
         logger.debug(f"sending pkt : {pkt}")
@@ -92,3 +116,7 @@ class TCPConnection:
             self.transport.close()
             self.transport = None
             logger.debug("TCP Connection closed")
+            
+    def set_disconnect_callback(self, callback):
+        """Set callback to handle disconnections."""
+        self._disconnect_callback = callback