Merge branch 'master' into feature/porting-to-trio

libp2p/network/swarm.py

@@ -21,6 +21,7 @@ from libp2p.transport.transport_interface import ITransport
 from libp2p.transport.upgrader import TransportUpgrader
 from libp2p.typing import StreamHandlerFn
 
+from ..exceptions import MultiError
 from .connection.raw_connection import RawConnection
 from .connection.swarm_connection import SwarmConn
 from .exceptions import SwarmException
@@ -95,21 +96,51 @@ class Swarm(INetwork, Service):
         try:
             # Get peer info from peer store
             addrs = self.peerstore.addrs(peer_id)
-        except PeerStoreError:
-            raise SwarmException(f"No known addresses to peer {peer_id}")
+        except PeerStoreError as error:
+            raise SwarmException(f"No known addresses to peer {peer_id}") from error
 
         if not addrs:
             raise SwarmException(f"No known addresses to peer {peer_id}")
 
-        multiaddr = addrs[0]
+        exceptions: List[SwarmException] = []
+
+        # Try all known addresses
+        for multiaddr in addrs:
+            try:
+                return await self.dial_addr(multiaddr, peer_id)
+            except SwarmException as e:
+                exceptions.append(e)
+                logger.debug(
+                    "encountered swarm exception when trying to connect to %s, "
+                    "trying next address...",
+                    multiaddr,
+                    exc_info=e,
+                )
+
+        # Tried all addresses, raising exception.
+        raise SwarmException(
+            f"unable to connect to {peer_id}, no addresses established a successful connection "
+            "(with exceptions)"
+        ) from MultiError(exceptions)
+
+    async def dial_addr(self, addr: Multiaddr, peer_id: ID) -> INetConn:
+        """
+        dial_addr try to create a connection to peer_id with addr.
+
+        :param addr: the address we want to connect with
+        :param peer_id: the peer we want to connect to
+        :raises SwarmException: raised when an error occurs
+        :return: network connection
+        """
+
         # Dial peer (connection to peer does not yet exist)
         # Transport dials peer (gets back a raw conn)
         try:
-            raw_conn = await self.transport.dial(multiaddr)
+            raw_conn = await self.transport.dial(addr)
         except OpenConnectionError as error:
             logger.debug("fail to dial peer %s over base transport", peer_id)
             raise SwarmException(
-                "fail to open connection to peer %s", peer_id
+                f"fail to open connection to peer {peer_id}"
             ) from error
 
         logger.debug("dialed peer %s over base transport", peer_id)
@@ -146,7 +177,6 @@ class Swarm(INetwork, Service):
     async def new_stream(self, peer_id: ID) -> INetStream:
         """
         :param peer_id: peer_id of destination
-        :param protocol_id: protocol id
         :raises SwarmException: raised when an error occurs
         :return: net stream instance
         """
@@ -164,13 +194,15 @@ class Swarm(INetwork, Service):
         :return: true if at least one success
 
         For each multiaddr
-            Check if a listener for multiaddr exists already
-            If listener already exists, continue
-            Otherwise:
-                Capture multiaddr in conn handler
-                Have conn handler delegate to stream handler
-                Call listener listen with the multiaddr
-                Map multiaddr to listener
+
+          - Check if a listener for multiaddr exists already
+          - If listener already exists, continue
+          - Otherwise:
+
+              - Capture multiaddr in conn handler
+              - Have conn handler delegate to stream handler
+              - Call listener listen with the multiaddr
+              - Map multiaddr to listener
         """
         for maddr in multiaddrs:
             if str(maddr) in self.listeners:
@@ -251,7 +283,7 @@ class Swarm(INetwork, Service):
         # TODO: Should be changed to close multisple connections,
         #   if we have several connections per peer in the future.
         connection = self.connections[peer_id]
-        # NOTE: `connection.close` will perform `del self.connections[peer_id]`
+        # NOTE: `connection.close` will delete `peer_id` from `self.connections`
         # and `notify_disconnected` for us.
         await connection.close()