added start point demo

Author: JaimeSalas

06-monitoring/00-prometheus/02-gauges-counters/.start/batch/.dockerignore

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+node_modules
+*.md 
+Dockerfile

06-monitoring/00-prometheus/02-gauges-counters/.start/batch/Dockerfile

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+FROM node:16-alpine 
+
+WORKDIR /opt/app
+
+COPY . .
+
+RUN npm ci 
+
+CMD ["npm", "start"]

06-monitoring/00-prometheus/02-gauges-counters/.start/batch/batch.js

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+const getRandom = (start, end) => Math.floor((Math.random() * end) + start);
+
+const randomBatchProcess = () => {
+  const jobs = getRandom(50, 500);
+  const failed = getRandom(1, 50);
+  const processed = jobs - failed;
+  return { jobs, failed, processed };
+};
+
+module.exports.batch = () => {
+  const intervalId = setInterval(() => {
+    const { jobs, failed, processed } = randomBatchProcess();
+    console.log(jobs, failed, processed);
+  }, 5_000);
+
+  return intervalId;
+};

06-monitoring/00-prometheus/02-gauges-counters/.start/batch/config.js

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+module.exports = ({
+  port: +process.env.PORT || 3000,
+});

06-monitoring/00-prometheus/02-gauges-counters/.start/batch/index.js

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+const express = require('express');
+const { port } = require('./config');
+const { batch } = require('./batch');
+
+const intervalId = batch();
+const app = express();
+
+app.get('/metrics', async (_, res) => {
+  try {
+    res.send('Not implemented yet');
+  } catch (ex) {
+    res.status(500).end(ex);
+  }
+});
+
+app.post('/stop', (_, res) => {
+  clearInterval(intervalId);
+  res.send('batch process stopped');
+});
+
+app.listen(port, () => {
+  console.log(`Listening at ${port}`);
+});