From 280e0f5c9c30a43e9cda455f7b9b9c080f66b6dc Mon Sep 17 00:00:00 2001
From: maciejhirsz <maciej.hirsz@gmail.com>
Date: Thu, 19 Jul 2018 15:23:10 +0200
Subject: [PATCH] Send ping to the node

---
 packages/backend/src/Aggregator.ts |  6 ++++--
 packages/backend/src/Chain.ts      |  6 ++----
 packages/backend/src/Node.ts       | 28 +++++++++++++++++++++++-----
 3 files changed, 29 insertions(+), 11 deletions(-)

diff --git a/packages/backend/src/Aggregator.ts b/packages/backend/src/Aggregator.ts
index 2c879ba..d769b69 100644
--- a/packages/backend/src/Aggregator.ts
+++ b/packages/backend/src/Aggregator.ts
@@ -2,7 +2,7 @@ import Chain from './Chain';
 import Node from './Node';
 import Feed from './Feed';
 import FeedSet from './FeedSet';
-import { Types, FeedMessage } from '@dotstats/common';
+import { Types, FeedMessage, timestamp } from '@dotstats/common';
 
 export default class Aggregator {
   private readonly chains = new Map<Types.ChainLabel, Chain>();
@@ -83,8 +83,10 @@ export default class Aggregator {
   private timeoutCheck() {
     const empty: Types.ChainLabel[] = [];
 
+    const now = timestamp();
+
     for (const chain of this.chains.values()) {
-      chain.timeoutCheck();
+      chain.timeoutCheck(now);
     }
   }
 }
diff --git a/packages/backend/src/Chain.ts b/packages/backend/src/Chain.ts
index 9863da8..26ae587 100644
--- a/packages/backend/src/Chain.ts
+++ b/packages/backend/src/Chain.ts
@@ -2,7 +2,7 @@ import * as EventEmitter from 'events';
 import Node from './Node';
 import Feed from './Feed';
 import FeedSet from './FeedSet';
-import { timestamp, Maybe, Types, FeedMessage } from '@dotstats/common';
+import { Maybe, Types, FeedMessage } from '@dotstats/common';
 
 const BLOCK_TIME_HISTORY = 10;
 
@@ -69,9 +69,7 @@ export default class Chain {
     return this.nodes.values();
   }
 
-  public timeoutCheck() {
-    const now = timestamp();
-
+  public timeoutCheck(now: Types.Timestamp) {
     for (const node of this.nodes.values()) {
       node.timeoutCheck(now);
     }
diff --git a/packages/backend/src/Node.ts b/packages/backend/src/Node.ts
index 13858d8..a301a5d 100644
--- a/packages/backend/src/Node.ts
+++ b/packages/backend/src/Node.ts
@@ -14,6 +14,8 @@ export interface NodeEvents {
   emit(event: 'location', location: Location): void;
 }
 
+function noop() {}
+
 export default class Node {
   public readonly id: Types.NodeId;
   public readonly name: Types.NodeName;
@@ -40,6 +42,7 @@ export default class Node {
   private readonly socket: WebSocket;
   private blockTimes: Array<number> = new Array(BLOCK_TIME_HISTORY);
   private lastBlockAt: Maybe<Date> = null;
+  private pingStart = 0 as Types.Timestamp;
 
   constructor(
     ip: string,
@@ -61,6 +64,8 @@ export default class Node {
     this.lastMessage = timestamp();
     this.socket = socket;
 
+    let start = Date.now();
+
     socket.on('message', (data) => {
       const message = parseMessage(data);
 
@@ -83,6 +88,11 @@ export default class Node {
       this.disconnect();
     });
 
+    socket.on('pong', () => {
+      this.latency = (timestamp() - this.pingStart) as Types.Milliseconds;
+      this.pingStart = 0 as Types.Timestamp;
+    });
+
     // Handle cached messages
     for (const message of messages) {
       this.onMessage(message);
@@ -135,7 +145,7 @@ export default class Node {
       const timeout = setTimeout(() => {
         cleanup();
 
-        socket.close();
+        socket.terminate();
 
         return reject(new Error('Timeout on waiting for system.connected message'));
       }, 5000);
@@ -145,6 +155,8 @@ export default class Node {
   public timeoutCheck(now: Types.Timestamp) {
     if (this.lastMessage + TIMEOUT < now) {
       this.disconnect();
+    } else {
+      this.updateLatency(now);
     }
   }
 
@@ -194,14 +206,13 @@ export default class Node {
 
   private disconnect() {
     this.socket.removeAllListeners();
-    this.socket.close();
+    this.socket.terminate();
 
     this.events.emit('disconnect');
   }
 
   private onMessage(message: Message) {
     this.lastMessage = timestamp();
-    this.updateLatency(message.ts);
 
     const update = getBestBlock(message);
 
@@ -225,8 +236,15 @@ export default class Node {
     }
   }
 
-  private updateLatency(time: Date) {
-    this.latency = (this.lastMessage - +time) as Types.Milliseconds;
+  private updateLatency(now: Types.Timestamp) {
+    // if (this.pingStart) {
+    //   console.error(`${this.name} timed out on ping message.`);
+    //   this.disconnect();
+    //   return;
+    // }
+
+    this.pingStart = now;
+    this.socket.ping(noop);
   }
 
   private updateBestBlock(update: BestBlock) {