feat: expose function to look up last 1000 removed nodes public keys

src/config/server.ts

@@ -175,7 +175,8 @@ const SERVER_CONFIG: StrictServerConfiguration = {
     networkTransactionsToProcessPerCycle: 20,
     getTxTimestampTimeoutOffset: 0,
     dropNGTByGossipEnabled: false,
-    timestampCacheFixSize: 10000
+    timestampCacheFixSize: 10000,
+    removedNodeIDCacheSize: 1000
   },
   ip: {
     externalIp: '0.0.0.0',

src/p2p/NodeList.ts

@@ -3,7 +3,14 @@ import { P2P } from '@shardeum-foundation/lib-types'
 import { Logger } from 'log4js'
 import { isDebugModeMiddleware, isDebugModeMiddlewareLow } from '../network/debugMiddleware'
 import { ShardusEvent } from '../shardus/shardus-types'
-import { binarySearch, getTime, insertSorted, linearInsertSorted, propComparator, propComparator2 } from '../utils'
+import {
+  binarySearch,
+  FIFOCache,
+  insertSorted,
+  linearInsertSorted,
+  propComparator,
+  propComparator2
+} from '../utils'
 import * as Comms from './Comms'
 import { config, crypto, logger, network } from './Context'
 import * as CycleChain from './CycleChain'
@@ -41,6 +48,10 @@ export let readyByTimeAndIdOrder: P2P.NodeListTypes.Node[]
 export let activeOthersByIdOrder: P2P.NodeListTypes.Node[]
 export let potentiallyRemoved: Set<P2P.NodeListTypes.Node['id']>
 export let selectedById: Map<P2P.NodeListTypes.Node['id'], number>
+export let removedNodeIDCache: FIFOCache<
+  P2P.NodeListTypes.Node['id'],
+  P2P.NodeListTypes.Node['publicKey']
+> 
 
 const VERBOSE = false // Use to dump complete NodeList and CycleChain data
 
@@ -179,6 +190,10 @@ export function addNodes(newNodes: P2P.NodeListTypes.Node[], caller: string) {
   }
 }
 
+export function getRemovedNodePubKeyFromCache(nodeId: P2P.NodeListTypes.Node['id']) {
+  return removedNodeIDCache.get(nodeId);
+}
+
 export function removeSelectedNode(id: string) {
   selectedById.delete(id)
   const idx = binarySearch(selectedByIdOrder, { id }, propComparator('id'))
@@ -264,6 +279,14 @@ export function removeNode(
   selectedById.delete(id)
   //readyByTimeAndIdOrder = readyByTimeAndIdOrder.filter((node) => node.id !== id)
 
+  // add to removed node cache
+  if (!removedNodeIDCache) {
+    removedNodeIDCache = new FIFOCache<P2P.NodeListTypes.Node['id'], P2P.NodeListTypes.Node['publicKey']>(
+        config.p2p.removedNodeIDCacheSize
+    )
+  }
+  removedNodeIDCache.set(id, node.publicKey)
+
   Comms.evictCachedSockets([node])
 
   if (raiseEvents) {

src/p2p/Wrapper.ts

@@ -175,6 +175,10 @@ class State extends EventEmitter {
     return NodeList.nodes.get(id)
   }
 
+  getRemovedNodePubKeyFromCache(id: string): P2PTypings.NodeListTypes.Node['publicKey'] | undefined {
+    return NodeList.getRemovedNodePubKeyFromCache(id)
+  }
+
   getNodes() {
     return NodeList.nodes
   }

src/shardus/index.ts

@@ -1814,6 +1814,10 @@ class Shardus extends EventEmitter {
     return this.p2p.state.getNode(id)
   }
 
+  getRemovedNodePubKeyFromCache(id: string): ShardusTypes.Node['publicKey'] | undefined {
+    return this.p2p.state.getRemovedNodePubKeyFromCache(id)
+  }
+
   getNodeByPubKey(id: string): ShardusTypes.Node {
     return this.p2p.state.getNodeByPubKey(id)
   }

src/shardus/shardus-types.ts

@@ -761,7 +761,7 @@ export interface ServerConfiguration {
     enableProblematicNodeRemoval?: boolean
     /** when true, we will remove problematic nodes even when calculateToAcceptV2 says we should not remove any nodes. This is useful in development when testing this feature. */
     enableDangerousProblematicNodeRemoval?: boolean
-    /** enable problematic node removal on a specific cycle. This is to allow the network to stabilize before removing problematic nodes. 
+    /** enable problematic node removal on a specific cycle. This is to allow the network to stabilize before removing problematic nodes.
      * enableProblematicNodeRemoval must be true for this to take effect*/
     enableProblematicNodeRemovalOnCycle?: number
     /** The problematicNodeRemovalCycleFrequency parameter is an Integer specifying the number of cycles between problematic node removals. */
@@ -986,6 +986,8 @@ export interface ServerConfiguration {
     getTxTimestampTimeoutOffset?: number // default timeout is 5 seconds so this can be used to add or subtract time from that
     /** allow dropping NGTs by hitting a single node's endpoint and the drop mesage being sent to other nodes by gossip  */
     dropNGTByGossipEnabled: boolean
+    // cache size for mapping of nodeId to pubKey for the `n` last removed nodes
+    removedNodeIDCacheSize: number
     timestampCacheFixSize: number
   }
   /** Server IP configuration */