Cron job functionality to monitor elastic agent count

src/monitor-elastic-agents.js

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+import _ from "lodash-es";
+import chalk from "chalk";
+import dayjs from "dayjs";
+import config from "config";
+import axios from "axios";
+import * as cheerio from "cheerio";
+import { CronJob } from "cron";
+
+const now = () => dayjs().format("HH:mm:ss");
+const url = config.get("go.url") + "/go/admin/status_reports/com.thoughtworks.gocd.elastic-agent.ecs/cluster/CI";
+
+const MAX_PENDING_TASKS = 20;
+const MAX_HOST_MACHINES = 40;
+
+async function check() {
+    const response = await axios.get(url, { auth: { ...config.get("go") } });
+    if (response.data) {
+        const $ = cheerio.load(response.data);
+        const getCount = (name) => {
+            return Number($(`div.cluster-properties label:contains('${name}')`).siblings("span").text());
+        };
+
+        console.log(`${now()} GoCD Elastic Agent Status`);
+
+        process.stdout.write(chalk.bold("    Tasks "));
+        const runningTasks = getCount("Running tasks");
+        const pendingTasks = getCount("Pending tasks");
+        console.log(`Running: ${runningTasks}   Pending: ${pendingTasks}`);
+        if (Number(pendingTasks) >= MAX_PENDING_TASKS) {
+            console.log("    ", chalk.bgRed.white.bold(`Too many pending tasks (${pendingTasks})`));
+        }
+
+        process.stdout.write(chalk.bold("Instances "));
+        const spot = getCount("Registered linux spot instances");
+        const onDemand = getCount("Registered linux on-demand instances");
+        const total = spot + onDemand;
+        const hasTotal = spot > 0 && onDemand > 0;
+        console.log(`   Spot: ${spot} On Demand: ${onDemand} ${hasTotal ? chalk.bold(`Total: ${total}`) : ""}`);
+        if (total >= MAX_HOST_MACHINES) {
+            console.log("    ", chalk.bgGreen.white.bold(`Max limit reached: ${total}`));
+        }
+
+        // TODO: Get errors from the page when or if they show up. I don't know the selector for that yet
+        // Guess based on https://github.com/gocd/gocd-ecs-elastic-agent/blob/master/src/main/resources/error.template.ftlh#L45
+        if ($(`div.error-container`).length > 0) {
+            const text = $(`div.error-container`).text();
+            console.log(chalk.red("Possible error on status page. Please check."));
+            console.log(text);
+            console.log();
+        }
+    } else {
+        console.log(response.status);
+    }
+    console.log();
+}
+
+if (process.argv[2] === "start") {
+    const expr = "*/1 * * * 1-5";
+    console.log(`${now()} 🚀 Starting Cron Job (${expr})`);
+    check();
+    const job = new CronJob(expr, check);
+    job.start();
+} else {
+    check();
+}