[bgpmon]: Fix exception in bgpmon caused by duplicate bgp neighbor ID (…

…#6546)

* Fix exception in bgpmon caused by duplicate keys
It is possible that BGP neighbors in IPv4 and IPv6 address families
share the same name (such as bgp monitor). However, such case is not
handled in bgpmon, and an Exception will be raised. This commit will
address the issue by Using set instead of list to avoid duplicate keys.

src/sonic-bgpcfgd/bgpmon/bgpmon.py

@@ -4,20 +4,20 @@
 Description: bgpmon.py -- populating bgp related information in stateDB.
     script is started by supervisord in bgp docker when the docker is started.
 
-    Initial creation of this daemon is to assist SNMP agent in obtaining the 
+    Initial creation of this daemon is to assist SNMP agent in obtaining the
     BGP related information for its MIB support. The MIB that this daemon is
     assisting is for the CiscoBgp4MIB (Neighbor state only). If there are other
-    BGP related items that needs to be updated in a periodic manner in the 
+    BGP related items that needs to be updated in a periodic manner in the
     future, then more can be added into this process.
 
     The script check if there are any bgp activities by monitoring the bgp
     frr.log file timestamp.  If activity is detected, then it will request bgp
-    neighbor state via vtysh cli interface. This bgp activity monitoring is 
+    neighbor state via vtysh cli interface. This bgp activity monitoring is
     done periodically (every 15 second). When triggered, it looks specifically
     for the neighbor state in the json output of show ip bgp neighbors json
     and update the state DB for each neighbor accordingly.
     In order to not disturb and hold on to the State DB access too long and
-    removal of the stale neighbors (neighbors that was there previously on 
+    removal of the stale neighbors (neighbors that was there previously on
     previous get request but no longer there in the current get request), a
     "previous" neighbor dictionary will be kept and used to determine if there
     is a need to perform update or the peer is stale to be removed from the
@@ -34,13 +34,13 @@
 
 class BgpStateGet:
     def __init__(self):
-        # list peer_l stores the Neighbor peer Ip address
+        # set peer_l stores the Neighbor peer Ip address
         # dic peer_state stores the Neighbor peer state entries
-        # list new_peer_l stores the new snapshot of Neighbor peer ip address
+        # set new_peer_l stores the new snapshot of Neighbor peer ip address
         # dic new_peer_state stores the new snapshot of Neighbor peer states
-        self.peer_l = []
+        self.peer_l = set()
         self.peer_state = {}
-        self.new_peer_l = []
+        self.new_peer_l = set()
         self.new_peer_state = {}
         self.cached_timestamp = 0
         self.db = swsssdk.SonicV2Connector()
@@ -67,7 +67,7 @@ def bgp_activity_detected(self):
 
     def update_new_peer_states(self, peer_dict):
         peer_l = peer_dict["peers"].keys()
-        self.new_peer_l.extend(peer_l)
+        self.new_peer_l.update(peer_l)
         for peer in peer_l:
             self.new_peer_state[peer] = peer_dict["peers"][peer]["state"]
 
@@ -80,8 +80,8 @@ def get_all_neigh_states(self):
             return
 
         peer_info = json.loads(output)
-        # cmd ran successfully, safe to Clean the "new" lists/dic for new snapshot
-        del self.new_peer_l[:]
+        # cmd ran successfully, safe to Clean the "new" set/dict for new snapshot
+        self.new_peer_l.clear()
         self.new_peer_state.clear()
         for key, value in peer_info.items():
             if key == "ipv4Unicast" or key == "ipv6Unicast":
@@ -115,8 +115,7 @@ def flush_pipe(self, data):
 
     def update_neigh_states(self):
         data = {}
-        for i in range (0, len(self.new_peer_l)):
-            peer = self.new_peer_l[i]
+        for peer in self.new_peer_l:
             key = "NEIGH_STATE_TABLE|%s" % peer
             if peer in self.peer_l:
                 # only update the entry if state changed
@@ -125,7 +124,7 @@ def update_neigh_states(self):
                     state = self.new_peer_state[peer]
                     data[key] = {'state':state}
                     self.peer_state[peer] = state
-                # remove this neighbor from old list since it is accounted for
+                # remove this neighbor from old set since it is accounted for
                 self.peer_l.remove(peer)
             else:
                 # New neighbor found case. Add to dictionary and state DB
@@ -135,19 +134,19 @@ def update_neigh_states(self):
             if len(data) > PIPE_BATCH_MAX_COUNT:
                 self.flush_pipe(data)
         # Check for stale state entries to be cleaned up
-        while len(self.peer_l) > 0:
+        for peer in self.peer_l:
             # remove this from the stateDB and the current neighbor state entry
-            peer = self.peer_l.pop(0)
             del_key = "NEIGH_STATE_TABLE|%s" % peer
             data[del_key] = None
-            del self.peer_state[peer]
+            if peer in self.peer_state:
+                del self.peer_state[peer]
             if len(data) > PIPE_BATCH_MAX_COUNT:
                 self.flush_pipe(data)
         # If anything in the pipeline not yet flushed, flush them now
         if len(data) > 0:
             self.flush_pipe(data)
-        # Save the new List
-        self.peer_l = self.new_peer_l[:]
+        # Save the new set
+        self.peer_l = self.new_peer_l.copy()
 
 def main():