feat: Add received prefix counters to neighbor display (#978)

Track per-NLRI counters (received prefixes, withdrawn prefixes) in peer
stats. Displayed in summary (#pfx_in column), extensive (Prefix Statistic
section), and JSON API output.

Counters reset on session down, matching Cisco/Juniper behavior.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: thomas-mangin

src/exabgp/bgp/neighbor/neighbor.py

@@ -432,9 +432,12 @@ class NeighborTemplate:
 
     Message Statistic               Sent        Received
 {messages}
+
+    Prefix Statistic
+{prefixes}
 """.replace('\t', '  ')
 
-    summary_header: ClassVar[str] = 'Peer            AS        up/down state       |     #sent     #recvd'
+    summary_header: ClassVar[str] = 'Peer            AS        up/down state       |     #sent     #recvd    #pfx_in'
     summary_template: ClassVar[str] = '%-15s %-7s %9s %-12s %10d %10d'
 
     @classmethod
@@ -655,6 +658,9 @@ def as_dict(cls, answer: dict[str, Any]) -> dict[str, Any]:
         formated['peer']['id'] = answer['peer-id']
         formated['peer']['hold'] = answer['peer-hold']
 
+        if 'prefixes' in answer:
+            formated['prefixes'] = answer['prefixes']
+
         return formated
 
     @classmethod
@@ -685,6 +691,9 @@ def formated_dict(cls, answer: dict[str, Any]) -> dict[str, Any]:
             'messages': '\n'.join(
                 f'    {f"{k}:":<20} {ms!s:>15} {mr!s:>15} {"":<15}' for k, (ms, mr) in answer['messages'].items()
             ),
+            'prefixes': '\n'.join(
+                f'    {f"{k}:":<20} {v!s:>15} {"":<15} {"":<15}' for k, v in answer.get('prefixes', {}).items()
+            ),
         }
 
         return formated
@@ -709,7 +718,8 @@ def summary(cls, answer: dict[str, Any]) -> str:
         state_str = answer['state'].lower()
         update_in = answer['messages']['update'][0]
         update_out = answer['messages']['update'][1]
-        return f'{peer_addr:<15} {peer_as_str:<7} {duration_str:>9} {state_str:<12} {update_in:>10} {update_out:>10}'
+        prefixes_rcvd = answer.get('prefixes', {}).get('received', 0)
+        return f'{peer_addr:<15} {peer_as_str:<7} {duration_str:>9} {state_str:<12} {update_in:>10} {update_out:>10} {prefixes_rcvd:>10}'
 
 
 # Initialize the empty neighbor singleton

src/exabgp/reactor/peer/context.py

@@ -12,6 +12,7 @@
 if TYPE_CHECKING:
     from exabgp.bgp.neighbor import Neighbor
     from exabgp.bgp.message.open.capability import Negotiated
+    from exabgp.reactor.peer.stats import Stats
     from exabgp.reactor.protocol import Protocol
 
 
@@ -29,3 +30,4 @@ class PeerContext:
     refresh_enhanced: bool
     routes_per_iteration: int
     peer_id: str
+    stats: Stats

src/exabgp/reactor/peer/handlers/update.py

@@ -51,6 +51,7 @@ def handle(self, ctx: PeerContext, message: Message) -> Generator[Message, None,
             nlri = routed.nlri
             route = Route(nlri, parsed.attributes, nexthop=routed.nexthop)
             ctx.neighbor.rib.incoming.update_cache(route)
+            ctx.stats['receive-prefixes'] += 1
             log.debug(
                 lazyformat('update.nlri number=%d nlri=' % self._number, nlri, str),
                 ctx.peer_id,
@@ -59,6 +60,7 @@ def handle(self, ctx: PeerContext, message: Message) -> Generator[Message, None,
         # Process withdraws - use dedicated method
         for nlri in parsed.withdraws:
             ctx.neighbor.rib.incoming.update_cache_withdraw(nlri)
+            ctx.stats['receive-withdraws'] += 1
             log.debug(
                 lazyformat('update.nlri number=%d nlri=' % self._number, nlri, str),
                 ctx.peer_id,
@@ -84,6 +86,7 @@ async def handle_async(self, ctx: PeerContext, message: Message) -> None:
             nlri = routed.nlri
             route = Route(nlri, parsed.attributes, nexthop=routed.nexthop)
             ctx.neighbor.rib.incoming.update_cache(route)
+            ctx.stats['receive-prefixes'] += 1
             log.debug(
                 lazyformat('update.nlri number=%d nlri=' % self._number, nlri, str),
                 ctx.peer_id,
@@ -92,6 +95,7 @@ async def handle_async(self, ctx: PeerContext, message: Message) -> None:
         # Process withdraws - use dedicated method
         for nlri in parsed.withdraws:
             ctx.neighbor.rib.incoming.update_cache_withdraw(nlri)
+            ctx.stats['receive-withdraws'] += 1
             log.debug(
                 lazyformat('update.nlri number=%d nlri=' % self._number, nlri, str),
                 ctx.peer_id,

src/exabgp/reactor/peer/peer.py

@@ -194,6 +194,8 @@ def __init__(self, neighbor: 'Neighbor', reactor: 'Reactor') -> None:
                 'send-refresh': 0,
                 'receive-keepalive': 0,
                 'send-keepalive': 0,
+                'receive-prefixes': 0,
+                'receive-withdraws': 0,
             },
         )
 
@@ -241,6 +243,8 @@ def _close(self, message: str = '', error: str | Exception = '') -> None:
                 'send-refresh': 0,
                 'receive-keepalive': 0,
                 'send-keepalive': 0,
+                'receive-prefixes': 0,
+                'receive-withdraws': 0,
             },
         )
 
@@ -665,6 +669,7 @@ async def _main(self) -> int:
             refresh_enhanced=refresh_enhanced,
             routes_per_iteration=routes_per_iteration,
             peer_id=self.id(),
+            stats=self.stats,
         )
         update_handler = UpdateHandler()
         route_refresh_handler = RouteRefreshHandler(self.resend)
@@ -981,6 +986,11 @@ def cli_data(self) -> dict[str, Any]:
             messages[message] = (sent, rcvd)
         messages['total'] = (total_sent, total_rcvd)
 
+        prefixes = {
+            'received': self.stats['receive-prefixes'],
+            'withdrawn': self.stats['receive-withdraws'],
+        }
+
         return {
             'down': int(self.stats['reset'] - self.stats['creation']),
             'duration': (int(time.time() - self.stats['complete']) if self.stats['complete'] else 0),
@@ -996,4 +1006,5 @@ def cli_data(self) -> dict[str, Any]:
             'capabilities': capabilities,
             'families': families,
             'messages': messages,
+            'prefixes': prefixes,
         }

tests/unit/reactor/peer/handlers/test_update.py

@@ -20,6 +20,7 @@ def mock_context(self) -> PeerContext:
         ctx.neighbor.rib = Mock()
         ctx.neighbor.rib.incoming = Mock()
         ctx.peer_id = 'test-peer'
+        ctx.stats = {'receive-prefixes': 0, 'receive-withdraws': 0}
         return ctx
 
     def test_can_handle_update(self, handler: UpdateHandler) -> None:
@@ -48,6 +49,8 @@ def test_handle_stores_nlris(self, handler: UpdateHandler, mock_context: PeerCon
         list(handler.handle(mock_context, update))
 
         assert mock_context.neighbor.rib.incoming.update_cache.call_count == 2
+        assert mock_context.stats['receive-prefixes'] == 2
+        assert mock_context.stats['receive-withdraws'] == 0
 
     def test_handle_empty_nlris(self, handler: UpdateHandler, mock_context: PeerContext) -> None:
         """UpdateHandler handles updates with no NLRIs."""
@@ -84,6 +87,21 @@ def test_reset_clears_counter(self, handler: UpdateHandler) -> None:
         handler.reset()
         assert handler._number == 0
 
+    def test_handle_counts_withdraws(self, handler: UpdateHandler, mock_context: PeerContext) -> None:
+        """UpdateHandler increments withdraw counter per NLRI."""
+        parsed = Mock()
+        parsed.announces = []
+        parsed.withdraws = [Mock(), Mock(), Mock()]
+        parsed.attributes = Mock()
+        update = Mock()
+        update.TYPE = UpdateCollection.TYPE
+        update.data = parsed
+
+        list(handler.handle(mock_context, update))
+
+        assert mock_context.stats['receive-prefixes'] == 0
+        assert mock_context.stats['receive-withdraws'] == 3
+
     def test_handle_is_generator(self, handler: UpdateHandler, mock_context: PeerContext) -> None:
         """handle() returns a generator."""
         parsed = Mock()
@@ -112,6 +130,7 @@ def mock_context(self) -> PeerContext:
         ctx.neighbor.rib = Mock()
         ctx.neighbor.rib.incoming = Mock()
         ctx.peer_id = 'test-peer'
+        ctx.stats = {'receive-prefixes': 0, 'receive-withdraws': 0}
         return ctx
 
     @pytest.mark.asyncio