lnpeer: some exception handling clean up

main_loop should dump traces of unexpected exceptions to log.
Coroutines/functions invoked inside main_loop should simply propagate it
up the chain.
Typical exceptions are handled in handle_disconnect without dumping the trace.

electrum/lnpeer.py

@@ -43,6 +43,7 @@ from .lnutil import (Outpoint, LocalConfig, RECEIVED, UpdateAddHtlc,
 from .lntransport import LNTransport, LNTransportBase
 from .lnmsg import encode_msg, decode_msg
 from .lnverifier import verify_sig_for_channel_update
+from .interface import GracefulDisconnect
 
 if TYPE_CHECKING:
     from .lnworker import LNWorker
@@ -172,7 +173,7 @@ class Peer(Logger):
             if flag not in their_flags and get_ln_flag_pair_of_bit(flag) not in their_flags:
                 # they don't have this feature we wanted :(
                 if flag % 2 == 0:  # even flags are compulsory
-                    raise LightningPeerConnectionClosed("remote does not have even flag {}"
+                    raise GracefulDisconnect("remote does not have even flag {}"
                                              .format(str(LnLocalFeatures(1 << flag))))
                 self.localfeatures ^= 1 << flag  # disable flag
         if isinstance(self.transport, LNTransport):
@@ -200,13 +201,16 @@ class Peer(Logger):
         async def wrapper_func(self, *args, **kwargs):
             try:
                 return await func(self, *args, **kwargs)
-            except Exception as e:
-                self.logger.info("Disconnecting: {}".format(repr(e)))
+            except GracefulDisconnect as e:
+                self.logger.log(e.log_level, f"Disconnecting: {repr(e)}")
+            except LightningPeerConnectionClosed as e:
+                self.logger.info(f"Disconnecting: {repr(e)}")
             finally:
                 self.close_and_cleanup()
         return wrapper_func
 
     @ignore_exceptions  # do not kill main_taskgroup
+    @log_exceptions
     @handle_disconnect
     async def main_loop(self):
         async with aiorpcx.TaskGroup() as group:
@@ -214,7 +218,6 @@ class Peer(Logger):
             await group.spawn(self.query_gossip())
             await group.spawn(self.process_gossip())
 
-    @log_exceptions
     async def process_gossip(self):
         # verify in peer's TaskGroup so that we fail the connection
         while True:
@@ -283,11 +286,16 @@ class Peer(Logger):
             if not verify_sig_for_channel_update(payload, payload['start_node']):
                 raise BaseException('verify error')
 
-    @log_exceptions
     async def query_gossip(self):
+        try:
             await asyncio.wait_for(self.initialized.wait(), 10)
+        except asyncio.TimeoutError as e:
+            raise GracefulDisconnect("initialize timed out") from e
         if self.lnworker == self.lnworker.network.lngossip:
+            try:
                 ids, complete = await asyncio.wait_for(self.get_channel_range(), 10)
+            except asyncio.TimeoutError as e:
+                raise GracefulDisconnect("query_channel_range timed out") from e
             self.logger.info('Received {} channel ids. (complete: {})'.format(len(ids), complete))
             self.lnworker.add_new_ids(ids)
             while True:
@@ -400,8 +408,7 @@ class Peer(Logger):
         try:
             await asyncio.wait_for(self.initialize(), 10)
         except (OSError, asyncio.TimeoutError, HandshakeFailed) as e:
-            self.logger.info('initialize failed, disconnecting: {}'.format(repr(e)))
-            return
+            raise GracefulDisconnect(f'initialize failed: {repr(e)}') from e
         async for msg in self.transport.read_messages():
             self.process_message(msg)
             await asyncio.sleep(.01)