k8s 에서 node-exporter 를 통한 nextjs 서버 모니터링

import promClient from 'prom-client';

// count of http request
const httpRequestCounter = new promClient.Counter({
    name: 'nodejs_http_request_total',
    help: 'Total count of NodeJS HTTP requests',
    labelNames: ['method', 'route', 'statusCode'],
});
// histogram of response duration
const responseTimeHistogram = new promClient.Histogram({
    name: 'nodejs_response_duration_seconds',
    help: 'NodeJS response duration in seconds',
    labelNames: ['method', 'route', 'statusCode'],
    buckets: [0.05, 0.1, 0.25, 0.5, 1.0, 2.5, 5.0, 10.0, 20.0],
});

promClient.register.registerMetric(httpRequestCounter);
promClient.register.registerMetric(responseTimeHistogram);

promClient.collectDefaultMetrics({
    register: promClient.register,
});

// endpoint for prometheus to scrape
app.get('/metrics', async (req, res) => {
    res.setHeader('Content-Type', promClient.register.contentType);
    res.setHeader('Cache-Control', 'no-store');
    const metrics = await promClient.register.metrics();

    res.send(metrics);
});

app.use((req, res, next) => {
    const isL7CheckReq = getIsL7Check(req.url);
    const isMetricsReq = getIsMetrics(req.url);

    if (!isL7CheckReq && !isMetricsReq) {
        const labels = {
            method: req.method,
            route: req.path,
            statusCode: res.statusCode,
        };
        httpRequestCounter.labels(labels).inc();

        const endTime = responseTimeHistogram.startTimer();
        res.on('finish', () => {
            endTime(labels);
        });
    }

    next();
});

function getIsMetrics(url: string) {
    return url === '/metrics';
}