From 30b8d3d0ab62a846fb075c0fc25a8697346d0e3e Mon Sep 17 00:00:00 2001
From: LouisLam <louislam@users.noreply.github.com>
Date: Thu, 19 Aug 2021 18:33:52 +0800
Subject: [PATCH] prevent all monitors making requests at the same moment when
 start the server

---
 server/server.js |  7 +++++--
 src/util.js      | 12 +++++++++++-
 src/util.ts      | 22 ++++++++++++++++++++++
 3 files changed, 38 insertions(+), 3 deletions(-)

diff --git a/server/server.js b/server/server.js
index 5920d1bb1..e65117627 100644
--- a/server/server.js
+++ b/server/server.js
@@ -1,7 +1,7 @@
 console.log("Welcome to Uptime Kuma");
 console.log("Node Env: " + process.env.NODE_ENV);
 
-const { sleep, debug, TimeLogger } = require("../src/util");
+const { sleep, debug, TimeLogger, getRandomInt } = require("../src/util");
 
 console.log("Importing Node libraries")
 const fs = require("fs");
@@ -755,8 +755,11 @@ async function startMonitors() {
     let list = await R.find("monitor", " active = 1 ")
 
     for (let monitor of list) {
-        monitor.start(io)
+        monitor.start(io);
         monitorList[monitor.id] = monitor;
+
+        // Give some delays, so all monitors won't make request at the same moment when just start the server.
+        await sleep(getRandomInt(300, 1000));
     }
 }
 
diff --git a/src/util.js b/src/util.js
index 44eaebc69..14c683218 100644
--- a/src/util.js
+++ b/src/util.js
@@ -1,6 +1,6 @@
 "use strict";
 Object.defineProperty(exports, "__esModule", { value: true });
-exports.TimeLogger = exports.polyfill = exports.debug = exports.ucfirst = exports.sleep = exports.flipStatus = exports.PENDING = exports.UP = exports.DOWN = exports.appName = exports.isDev = void 0;
+exports.getRandomInt = exports.getRandomArbitrary = exports.TimeLogger = exports.polyfill = exports.debug = exports.ucfirst = exports.sleep = exports.flipStatus = exports.PENDING = exports.UP = exports.DOWN = exports.appName = exports.isDev = void 0;
 const _dayjs = require("dayjs");
 const dayjs = _dayjs;
 exports.isDev = process.env.NODE_ENV === "development";
@@ -58,3 +58,13 @@ class TimeLogger {
     }
 }
 exports.TimeLogger = TimeLogger;
+function getRandomArbitrary(min, max) {
+    return Math.random() * (max - min) + min;
+}
+exports.getRandomArbitrary = getRandomArbitrary;
+function getRandomInt(min, max) {
+    min = Math.ceil(min);
+    max = Math.floor(max);
+    return Math.floor(Math.random() * (max - min + 1)) + min;
+}
+exports.getRandomInt = getRandomInt;
diff --git a/src/util.ts b/src/util.ts
index add9f1935..7d7b8e01d 100644
--- a/src/util.ts
+++ b/src/util.ts
@@ -81,3 +81,25 @@ export class TimeLogger {
         }
     }
 }
+
+/**
+ * Returns a random number between min (inclusive) and max (exclusive)
+ */
+export function getRandomArbitrary(min, max) {
+    return Math.random() * (max - min) + min;
+}
+
+/**
+ * From: https://stackoverflow.com/questions/1527803/generating-random-whole-numbers-in-javascript-in-a-specific-range
+ *
+ * Returns a random integer between min (inclusive) and max (inclusive).
+ * The value is no lower than min (or the next integer greater than min
+ * if min isn't an integer) and no greater than max (or the next integer
+ * lower than max if max isn't an integer).
+ * Using Math.round() will give you a non-uniform distribution!
+ */
+export function getRandomInt(min, max) {
+    min = Math.ceil(min);
+    max = Math.floor(max);
+    return Math.floor(Math.random() * (max - min + 1)) + min;
+}