fix: NodeManager.setNode Properly handles adding new node when buck…

…et is full

Logic of adding nodes has been split between `NodeManager` and `NodeGraph`. The `NodeGraph.setNode` just handles adding a node to the bucket where the `NodeManager.setNode` contains the logic of when to add the node

Relates #359

src/nodes/NodeGraph.ts

@@ -245,7 +245,12 @@ class NodeGraph {
     }
   }
 
-
+  /**
+   * Will add a node to the node graph and increment the bucket count.
+   * If the node already existed it will be updated.
+   * @param nodeId NodeId to add to the NodeGraph
+   * @param nodeAddress Address information to add
+   */
   @ready(new nodesErrors.ErrorNodeGraphNotRunning())
   public async setNode(
     nodeId: NodeId,
@@ -258,34 +263,17 @@ class NodeGraph {
       bucketDomain,
       nodesUtils.bucketDbKey(nodeId),
     );
-    // If this is a new entry, check the bucket limit
-    if (nodeData == null) {
-      const count = await this.getBucketMetaProp(bucketIndex, 'count');
-      if (count < this.nodeBucketLimit) {
-        // Increment the bucket count
-        this.setBucketMetaProp(bucketIndex, 'count', count + 1);
-      } else {
-        // Remove the oldest entry in the bucket
-        const lastUpdatedBucketDb = await this.db.level(
-          bucketKey,
-          this.nodeGraphLastUpdatedDb
-        );
-        let oldestLastUpdatedKey: Buffer;
-        let oldestNodeId: NodeId;
-        for await (const key of lastUpdatedBucketDb.createKeyStream({ limit: 1 })) {
-          oldestLastUpdatedKey = key as Buffer;
-          ({ nodeId: oldestNodeId } = nodesUtils.parseLastUpdatedBucketDbKey(key as Buffer));
-        }
-        await this.db.del(bucketDomain, oldestNodeId!.toBuffer());
-        await this.db.del(lastUpdatedDomain, oldestLastUpdatedKey!);
-      }
-    } else {
-      // This is an existing entry, so the index entry must be reset
+    if(nodeData != null){
+      // If the node already exists we want to remove the old `lastUpdated`
       const lastUpdatedKey = nodesUtils.lastUpdatedBucketDbKey(nodeData.lastUpdated, nodeId)
       await this.db.del(
         lastUpdatedDomain,
         lastUpdatedKey
       );
+    } else {
+      // It didn't exist so we want to increment the bucket count
+      const count = await this.getBucketMetaProp(bucketIndex, 'count');
+      await this.setBucketMetaProp(bucketIndex, 'count', count + 1);
     }
     const lastUpdated = getUnixtime();
     await this.db.put(
@@ -296,15 +284,32 @@ class NodeGraph {
         lastUpdated,
       }
     );
-    const lastUpdatedKey = nodesUtils.lastUpdatedBucketDbKey(lastUpdated, nodeId)
+    const newLastUpdatedKey = nodesUtils.lastUpdatedBucketDbKey(lastUpdated, nodeId)
     await this.db.put(
       lastUpdatedDomain,
-      lastUpdatedKey,
+      newLastUpdatedKey,
       nodesUtils.bucketDbKey(nodeId),
       true
     );
   }
 
+  @ready(new nodesErrors.ErrorNodeGraphNotRunning())
+  public async getOldestNode(bucketIndex: number ): Promise<NodeId | undefined> {
+    const bucketKey = nodesUtils.bucketKey(bucketIndex);
+    // Remove the oldest entry in the bucket
+    const lastUpdatedBucketDb = await this.db.level(
+      bucketKey,
+      this.nodeGraphLastUpdatedDb
+    );
+    let oldestLastUpdatedKey: Buffer;
+    let oldestNodeId: NodeId | undefined;
+    for await (const key of lastUpdatedBucketDb.createKeyStream({ limit: 1 })) {
+      oldestLastUpdatedKey = key as Buffer;
+      ({ nodeId: oldestNodeId } = nodesUtils.parseLastUpdatedBucketDbKey(key as Buffer));
+    }
+    return oldestNodeId;
+  }
+
   @ready(new nodesErrors.ErrorNodeGraphNotRunning())
   public async unsetNode(nodeId: NodeId): Promise<void> {
     const [bucketIndex, bucketKey] = this.bucketIndex(nodeId);
@@ -316,7 +321,7 @@ class NodeGraph {
     );
     if (nodeData != null) {
       const count = await this.getBucketMetaProp(bucketIndex, 'count');
-      this.setBucketMetaProp(bucketIndex, 'count', count - 1);
+      await this.setBucketMetaProp(bucketIndex, 'count', count - 1);
       await this.db.del(
         bucketDomain,
         nodesUtils.bucketDbKey(nodeId)
@@ -750,7 +755,7 @@ class NodeGraph {
    * The bucket key is the string encoded version of bucket index
    * that preserves lexicographic order
    */
-  protected bucketIndex(nodeId: NodeId): [NodeBucketIndex, string] {
+  public bucketIndex(nodeId: NodeId): [NodeBucketIndex, string] {
     const nodeIdOwn = this.keyManager.getNodeId();
     if (nodeId.equals(nodeIdOwn)) {
       throw new nodesErrors.ErrorNodeGraphSameNodeId();

src/nodes/NodeManager.ts

@@ -17,6 +17,8 @@ import * as networkErrors from '../network/errors';
 import * as networkUtils from '../network/utils';
 import * as sigchainUtils from '../sigchain/utils';
 import * as claimsUtils from '../claims/utils';
+import { NodeData } from '../nodes/types';
+import { getUnixtime } from '@/utils';
 
 class NodeManager {
   protected db: DB;
@@ -53,6 +55,10 @@ class NodeManager {
    * Determines whether a node in the Polykey network is online.
    * @return true if online, false if offline
    */
+  // FIXME: We shouldn't be trying to find the node just to ping it
+  //  since we are usually pinging it during the find procedure anyway.
+  //  I think we should be providing the address of what we're trying to ping,
+  //  possibly make it an optional parameter?
   public async pingNode(targetNodeId: NodeId): Promise<boolean> {
     const targetAddress: NodeAddress =
       await this.nodeConnectionManager.findNode(targetNodeId);
@@ -326,13 +332,46 @@ class NodeManager {
   }
 
   /**
-   * Sets a node in the NodeGraph
+   * Adds a node to the node graph.
+   * Updates the node if the node already exists.
+   *
    */
   public async setNode(
     nodeId: NodeId,
     nodeAddress: NodeAddress,
+    force = false,
   ): Promise<void> {
-    return await this.nodeGraph.setNode(nodeId, nodeAddress);
+    // When adding a node we need to handle 3 cases
+    // 1. The node already exists. We need to update it's last updated field
+    // 2. The node doesn't exist and bucket has room.
+    //  We need to add the node to the bucket
+    // 3. The node doesn't exist and the bucket is full.
+    //  We need to ping the oldest node. If the ping succeeds we need to update
+    //  the lastUpdated of the oldest node and drop the new one. If the ping
+    //  fails we delete the old node and add in the new one.
+    const nodeData = await this.nodeGraph.getNode(nodeId);
+    // If this is a new entry, check the bucket limit
+    const [bucketIndex, ] = this.nodeGraph.bucketIndex(nodeId)
+    const count = await this.nodeGraph.getBucketMetaProp(bucketIndex, 'count');
+    if (nodeData == null && count < this.nodeGraph.nodeBucketLimit) {
+      // We want to add a node but the bucket is full
+      // We need to ping the oldest node
+      const oldestNodeId = (await this.nodeGraph.getOldestNode(bucketIndex))!;
+      if (await this.pingNode(oldestNodeId) && !force){
+        // The node responded, we need to update it's info and drop the new node
+        const oldestNode = (await this.nodeGraph.getNode(oldestNodeId))!;
+        await this.nodeGraph.setNode(oldestNodeId, oldestNode.address);
+      } else {
+        // The node could not be contacted or force was set,
+        // we drop it in favor of the new node
+        await this.nodeGraph.unsetNode(oldestNodeId);
+        await this.nodeGraph.setNode(nodeId, nodeAddress);
+      }
+    } else {
+      // Either already exists or has room in the bucket
+      // We want to add or update the node
+      await this.nodeGraph.setNode(nodeId, nodeAddress);
+    }
   }
 
   /**