concurrent http2 requests return the same response for all requests

[tripodsan]

Description
when issuing several requests at once, they all return the same response, if the hostname resolves to the same IP.

• switching to http1 solves the problem
• adding an explicit host header solves the problem.

To Reproduce
run the following:

const { fetch } = require('@adobe/helix-fetch').context({
  // httpProtocol: 'http1',
  // httpsProtocols: ['http1'],
});
const crypto = require('crypto');

async function request(url) {
  console.log('requesting', url)
  const res = await fetch(url, {
    // headers: {
    //   host: new URL(url).hostname,
    // },
    cache: 'no-store',
  });
  const data = await res.text();
  const md5 = crypto.createHash('md5').update(data).digest().toString('hex');
  console.log('result', url, 'md5=', md5, res.headers.raw());
}

async function run() {
  await Promise.all([
    request('https://lr-landing-davidnuescheler.project-helix.page/'),
    request('https://n2-davidnuescheler.hlx.page/index.html'),
    request('https://theblog--adobe.hlx.page/index.html'),
  ]);
}

run().catch(console.error);

result:

$ node index.js
requesting https://lr-landing-davidnuescheler.project-helix.page/
requesting https://n2-davidnuescheler.hlx.page/index.html
requesting https://theblog--adobe.hlx.page/index.html
result https://theblog--adobe.hlx.page/index.html md5= 22971378ba99ace7ba88e6474e7e0c04 { 'cache-control': 'max-age=604800, must-revalidate, private',
  'content-type': 'text/html; charset=UTF-8',
  link:
   '<https://lr-landing-davidnuescheler.project-helix.page/index.html>; rel="canonical"',
  date: 'Thu, 11 Jun 2020 05:18:39 GMT',
  age: '0',
  vary: 'X-Debug,X-Strain,X-Request-Type',
  'strict-transport-security': 'max-age=31536000',
  'x-version': '332; src=332; cli=5.8.2; rev=online' }
result https://n2-davidnuescheler.hlx.page/index.html md5= 22971378ba99ace7ba88e6474e7e0c04 { 'cache-control': 'max-age=604800, must-revalidate, private',
  'content-type': 'text/html; charset=UTF-8',
  link:
   '<https://lr-landing-davidnuescheler.project-helix.page/index.html>; rel="canonical"',
  date: 'Thu, 11 Jun 2020 05:18:39 GMT',
  age: '0',
  vary: 'X-Debug,X-Strain,X-Request-Type',
  'strict-transport-security': 'max-age=31536000',
  'x-version': '332; src=332; cli=5.8.2; rev=online' }
result https://lr-landing-davidnuescheler.project-helix.page/ md5= 22971378ba99ace7ba88e6474e7e0c04 { 'cache-control': 'max-age=604800, must-revalidate, private',
  'content-type': 'text/html; charset=UTF-8',
  link:
   '<https://lr-landing-davidnuescheler.project-helix.page/index.html>; rel="canonical"',
  date: 'Thu, 11 Jun 2020 05:18:39 GMT',
  age: '0',
  vary: 'X-Debug,X-Strain,X-Request-Type',
  'strict-transport-security': 'max-age=31536000',
  'x-version': '332; src=332; cli=5.8.2; rev=online' }

[stefan-guggisberg]

See fetch-h2 issue.

[stefan-guggisberg]

implemented workaround in 331fcc9

will remove workaround once/if the underlying fetch-h2 issue gets fixed.