message: server side req tracing & monitoring
diff: 'use strict';
  -const TTL = 30 * 60;
  +const TTL = 3 * 60;
  async function cache(ctx, next) {
  if (ctx.method !== 'GET') {
  return await next();
  }
  - const cached = ctx.cache[ctx.url];
  + const cached = ctx.cache[ctx.path];
  if (cached !== undefined && cached.ts && cached.ts + TTL * 1000 > Date.now()) {
  ctx.status = 200;
  @@ -18,7 +18,7 @@ async function cache(ctx, next) {
  await next();
  ctx.set('Cache-Control', `no-cache, no-store`);
  - ctx.cache[ctx.url] = {
  + ctx.cache[ctx.path] = {
  ts: Date.now(),
  body: ctx.body,
  };
  