Bug 1706056 - increase the parallelism of getHSTSPreloadList.js r=releng-reviewers,jmaher

Before this patch, getHSTSPreloadList.js would have no more than 250 requests
in flight at any given time. In the past, this limit was 500. After a refactor
that inadvertantly completely removed the limit, it was reduced to 250.
Presumably increasing it to 500 again will not have negative effects and will
allow the script to run faster.

Differential Revision: https://phabricator.services.mozilla.com/D114019

taskcluster/docker/periodic-updates/scripts/getHSTSPreloadList.js

@@ -8,12 +8,6 @@
 // Note: Running this file outputs a new nsSTSPreloadlist.inc in the current
 //       working directory.
 
-/*
-var Cc = Components.classes;
-var Ci = Components.interfaces;
-var Cu = Components.utils;
-var Cr = Components.results;
-*/
 var gSSService = Cc["@mozilla.org/ssservice;1"].getService(
   Ci.nsISiteSecurityService
 );
@@ -28,7 +22,6 @@ const SOURCE =
 const TOOL_SOURCE =
   "https://hg.mozilla.org/mozilla-central/file/default/taskcluster/docker/periodic-updates/scripts/getHSTSPreloadList.js";
 const OUTPUT = "nsSTSPreloadList.inc";
-const ERROR_OUTPUT = "nsSTSPreloadList.errors";
 const MINIMUM_REQUIRED_MAX_AGE = 60 * 60 * 24 * 7 * 18;
 const MAX_CONCURRENT_REQUESTS = 500;
 const MAX_RETRIES = 1;
@@ -312,15 +305,13 @@ async function probeHSTSStatuses(inHosts) {
   let totalLength = inHosts.length;
   dump("Examining " + totalLength + " hosts.\n");
 
-  // Debug/testing on a small number of hosts
-  // while (inHosts.length > 40000) {
-
-  // Make requests in batches of 250. Otherwise, we have too many in-flight
-  // requests and the time it takes to process them causes them all to time out.
+  // Make requests in batches of MAX_CONCURRENT_REQUESTS. Otherwise, we have
+  // too many in-flight requests and the time it takes to process them causes
+  // them all to time out.
   let allResults = [];
   while (inHosts.length > 0) {
     let promises = [];
-    for (let i = 0; i < 250 && inHosts.length > 0; i++) {
+    for (let i = 0; i < MAX_CONCURRENT_REQUESTS && inHosts.length > 0; i++) {
       let host = inHosts.shift();
       promises.push(getHSTSStatus(host));
     }