homepage-blocky-widget/src/widgets/blocky/proxy.js

import { httpProxy } from "utils/proxy/http";
import getServiceWidget from "utils/service-helpers";
import { formatApiCall } from "utils/proxy/api-helpers";
import createLogger from "utils/logger";

const logger = createLogger("blocky");

function parseMetric(text, name) {
  // Matches bare metric or metric with labels:  my_metric{label="x"} 1.0
  const re = new RegExp(`^${name}(?:{[^}]*})?\\s+([0-9.e+\\-]+)`, "m");
  const m = text.match(re);
  return m ? parseFloat(m[1]) : 0;
}

export default async function blockyProxyHandler(req, res) {
  const { group, service } = req.query;
  const widget = await getServiceWidget(group, service);
  const url = formatApiCall("{url}/metrics", widget);

  const [status, , data] = await httpProxy(url);

  if (status !== 200) {
    logger.error("HTTP %d fetching Blocky metrics from %s", status, url);
    return res.status(status).json({ error: `HTTP ${status}` });
  }

  const text = data.toString();
  const hits = parseMetric(text, "blocky_cache_hits_total");
  const misses = parseMetric(text, "blocky_cache_misses_total");
  const total = hits + misses;

  return res.json({
    enabled: parseMetric(text, "blocky_blocking_enabled") === 1,
    denylistEntries: parseMetric(text, "blocky_denylist_cache_entries"),
    totalQueries: total,
    cacheHitRate: total > 0 ? (hits / total) * 100 : 0,
  });
}