Only update hardware stats when necessary (#73)

packages/backend/src/Chain.ts

@@ -44,6 +44,7 @@ export default class Chain {
 
     node.events.on('block', () => this.updateBlock(node));
     node.events.on('stats', () => this.feeds.broadcast(Feed.stats(node)));
+    node.events.on('hardware', () => this.feeds.broadcast(Feed.hardware(node)));
     node.events.on('location', (location) => this.feeds.broadcast(Feed.locatedNode(node, location)));
 
     this.updateBlock(node);

packages/backend/src/Feed.ts

@@ -45,7 +45,7 @@ export default class Feed {
   public static addedNode(node: Node): FeedMessage.Message {
     return {
       action: Actions.AddedNode,
-      payload: [node.id, node.nodeDetails(), node.nodeStats(), node.blockDetails(), node.nodeLocation()]
+      payload: [node.id, node.nodeDetails(), node.nodeStats(), node.nodeHardware(), node.blockDetails(), node.nodeLocation()]
     };
   }
 
@@ -77,6 +77,13 @@ export default class Feed {
     };
   }
 
+  public static hardware(node: Node): FeedMessage.Message {
+    return {
+      action: Actions.NodeHardware,
+      payload: [node.id, node.nodeHardware()]
+    };
+  }
+
   public static timeSync(): FeedMessage.Message {
     return {
       action: Actions.TimeSync,

packages/backend/src/MeanList.ts

@@ -7,12 +7,22 @@ export class MeanList<T extends number> {
   private means = Array<T>(20).fill(0 as T);
   private ticksPerMean = 1;
 
-  public push(val: T) {
+  /**
+   * Push a new value, returns true if a new mean value was produced
+   *
+   * @param  {T}       value
+   *
+   * @return {boolean}
+   */
+  public push(val: T): boolean {
     this.period[this.periodIndex++] = val;
 
     if (this.periodIndex === this.ticksPerMean) {
       this.pushMean();
+      return true;
     }
+
+    return false;
   }
 
   public get(): Array<T> {

packages/backend/src/Node.ts

@@ -179,7 +179,11 @@ export default class Node {
   }
 
   public nodeStats(): Types.NodeStats {
-    return [this.peers, this.txcount, this.memory.get(), this.cpu.get(), this.chartstamps.get()];
+    return [this.peers, this.txcount];
+  }
+
+  public nodeHardware(): Types.NodeHardware {
+    return [this.memory.get(), this.cpu.get(), this.chartstamps.get()];
   }
 
   public blockDetails(): Types.BlockDetails {
@@ -231,16 +235,22 @@ export default class Node {
   private onSystemInterval(message: SystemInterval) {
     const { peers, txcount, cpu, memory } = message;
 
-    this.peers = peers;
-    this.txcount = txcount;
+    if (this.peers !== peers || this.txcount !== txcount) {
+      this.peers = peers;
+      this.txcount = txcount;
 
-    if (cpu != null && memory != null) {
-      this.cpu.push(cpu);
-      this.memory.push(memory);
-      this.chartstamps.push(timestamp());
+      this.events.emit('stats');
     }
 
-    this.events.emit('stats');
+    if (cpu != null && memory != null) {
+      const cpuChange = this.cpu.push(cpu);
+      const memChange = this.memory.push(memory);
+      const stampChange = this.chartstamps.push(timestamp());
+
+      if (cpuChange || memChange || stampChange) {
+        this.events.emit('hardware');
+      }
+    }
   }
 
   private updateLatency(now: Types.Timestamp) {