Supa-dynamic rate-limiting based on data (using supabase)

import {
  ZuploContext,
  ZuploRequest,
  ZoneCache,
  CustomRateLimitDetails,
} from "@zuplo/runtime";
import { createClient } from "@supabase/supabase-js";

const fallBackLimits = {
  requestsAllowed: 10000,
  timeWindowMinutes: 1,
};

const CACHE_NAME = "rate-limit-cache";
const CACHE_KEY = "rate-limit-data";

export async function getRateLimit(
  request: ZuploRequest,
  context: ZuploContext,
  policyName: string,
) {
  const limitResponse: CustomRateLimitDetails = {
    key: request.user.sub,
    ...fallBackLimits,
  };

  const userGroup = request.user.data.rateLimitGroup;
  const cache = new ZoneCache(CACHE_NAME, context);

  const cached: any = await cache.get(CACHE_KEY);

  if (cached) {
    context.log.debug("cache hit");
    const item = cached.find((row) => row.userGroup === userGroup);
    limitResponse.requestsAllowed = item.reqPerMinute;
    return limitResponse;
  }

  context.log.debug("cache miss");
  const supabase = createClient(
    "https://YOUR_SUPABASE_URL.supabase.co",
    "YOUR_SUPABASE_TOKEN",
  );
  const { data, error } = await supabase.from("rate-limits").select();

  if (error) {
    context.log.error(`Error reading data from supabase`, error);
    // return fallback rate-limit - don't want API downtime
    // if this dependency is down.
    return limitResponse;
  }

  const item = data.find((row) => row.userGroup === userGroup);

  if (!item) {
    context.log.warn(`No row rateLimitId '${userGroup}' found, using fallback`);
    // return fallback
    return limitResponse;
  }

  void cache.put(CACHE_KEY, data, 10);

  limitResponse.requestsAllowed = item.reqPerMinute;
  return limitResponse;
}