cdk8s/lib/_loadurl.mjs

This is the core library of Cloud Development Kit (CDK) for Kubernetes (cdk8s). cdk8s apps synthesize into standard Kubernetes manifests which can be applied to any Kubernetes cluster.

// this is an executable program that downloads a file from a url (with
// redirects) and prints it's output to STDOUT. it is implemented as a program
// because node.js does not support issuing network requests synchronously and
// in the cdk we need everything to be synchronous (it all happens in the
// ctors). so we utilize `spawnSync` to spawn this program as a child process.
// alternatively we could have use `curl` but this is more portable.

import followRedirects from 'follow-redirects';
import { parse } from 'node:url';
import { lstatSync, createReadStream } from 'node:fs';
import process from 'node:process'

const { http, https } = followRedirects;

const url = process.argv[2];
if (!url) {
  console.error(`Usage: ${process.argv[1]} URL`);
  process.exit(1);
}

try {
  if (lstatSync(url).isFile()) {
    createReadStream(url).pipe(process.stdout);
  }
} catch (err) {
  const purl = parse(url);

  if (!purl.protocol) {
    throw new Error(`unable to determine protocol from url: ${url}`);
  }

  const client = getHttpClient(purl.protocol);
  const get = client.get(url, response => {
    if (response.statusCode !== 200) {
      throw new Error(`${response.statusCode} response from http get: ${response.statusMessage}`);
    }

    response.on('data', chunk => process.stdout.write(chunk));
  });

  get.once('error', err => {
    throw new Error(`http error: ${err.message}`);
  });
}

function getHttpClient(protocol) {
  switch (protocol) {
    case 'http:': return http;
    case 'https:': return https;
    default:
      throw new Error(`unsupported protocol "${protocol}" in url: ${url}`);
  }
}