Merge pull request ethereum#625 from pipermerriam/piper/provide-all-connected-peers-to-candidate-backends

Candidate backend API now provides all connected remotes

Author: pipermerriam

p2p/peer_backend.py

@@ -1,6 +1,7 @@
 from abc import ABC, abstractmethod
 from typing import (
-    Iterable,
+    Set,
+    Tuple,
 )
 
 from lahja import (
@@ -24,7 +25,7 @@ class BasePeerBackend(ABC):
     @abstractmethod
     async def get_peer_candidates(self,
                                   num_requested: int,
-                                  num_connected_peers: int) -> Iterable[Node]:
+                                  connected_remotes: Set[Node]) -> Tuple[Node, ...]:
         pass
 
 
@@ -37,12 +38,16 @@ def __init__(self, event_bus: Endpoint) -> None:
 
     async def get_peer_candidates(self,
                                   num_requested: int,
-                                  num_connected_peers: int) -> Iterable[Node]:
+                                  connected_remotes: Set[Node]) -> Tuple[Node, ...]:
         response = await self.event_bus.request(
             PeerCandidatesRequest(num_requested),
             TO_DISCOVERY_BROADCAST_CONFIG,
         )
-        return response.candidates
+        return tuple(
+            candidate
+            for candidate in response.candidates
+            if candidate not in connected_remotes
+        )
 
 
 class BootnodesPeerBackend(BasePeerBackend):
@@ -51,13 +56,17 @@ def __init__(self, event_bus: Endpoint) -> None:
 
     async def get_peer_candidates(self,
                                   num_requested: int,
-                                  num_connected_peers: int) -> Iterable[Node]:
-        if num_connected_peers == 0:
+                                  connected_remotes: Set[Node]) -> Tuple[Node, ...]:
+        if len(connected_remotes) == 0:
             response = await self.event_bus.request(
                 RandomBootnodeRequest(),
                 TO_DISCOVERY_BROADCAST_CONFIG
             )
 
-            return response.candidates
+            return tuple(
+                candidate
+                for candidate in response.candidates
+                if candidate not in connected_remotes
+            )
         else:
             return ()

p2p/peer_pool.py

@@ -161,10 +161,13 @@ async def _add_peers_from_backend(self, backend: BasePeerBackend) -> None:
         available_slots = self.max_peers - len(self)
 
         try:
+            connected_remotes = {
+                peer.remote for peer in self.connected_nodes.values()
+            }
             candidates = await self.wait(
                 backend.get_peer_candidates(
                     num_requested=available_slots,
-                    num_connected_peers=len(self),
+                    connected_remotes=connected_remotes,
                 ),
                 timeout=REQUEST_PEER_CANDIDATE_TIMEOUT,
             )