add loadbalancing

Author: y21

backend/structures/Loadbalancer.ts

@@ -0,0 +1,47 @@
+import * as WebSocket from "ws";
+
+export default class Loadbalancer {
+    public host: string;
+    public accessToken: string;
+    public interval?: number;
+    public gateway?: WebSocket;
+    public _interval?: NodeJS.Timer;
+    public static OpcodeHello: number = 10;
+
+    constructor(accessToken: string, host: string) {
+        this.host = host;
+        this.accessToken = accessToken;
+    }
+
+    emitStats(): void {
+        if (!this.gateway || this.gateway.readyState !== WebSocket.OPEN)
+            throw new Error("Gateway connection not open");
+        this.gateway.send(JSON.stringify({
+            t: "stats",
+            d: JSON.stringify({
+                accessToken: this.accessToken,
+                // todo...
+                mem: 0,
+                cpu: 0
+            })
+        }));
+    }
+
+    connect(customHost?: string): WebSocket {
+        this.gateway = new WebSocket(customHost || this.host);
+
+        this.gateway.on("message", data => {
+            const parsed: any = JSON.parse(data.toString());
+            if (parsed.op === Loadbalancer.OpcodeHello) {
+                this.interval = parseInt(parsed.d);
+                this._interval = setInterval(() => this.emitStats(), this.interval);
+            }
+        });
+
+        this.gateway.on("close", () => {
+            clearInterval(this._interval);
+        });
+
+        return this.gateway;
+    }
+}