limit concurrency (#404)

Author: carrolp

lib/BaseDownloadController.js

@@ -1,5 +1,5 @@
 /*
- * Copyright 2019 IBM Corp. All Rights Reserved.
+ * Copyright 2019, 2024 IBM Corp. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,6 +21,13 @@ const hash = require('object-hash');
 const clone = require('clone');
 const pLimit = require('p-limit');
 
+// Limit concurrent check and save of kube resources in `_saveChild()`.
+// This limit will apply across separate BaseDownloadController instances,
+// e.g. to prevent either large numbers of RemoteResources OR large
+// numbers of kube resources in RemoteResources from flooding the 
+// Kubernetes API.
+const globalLimit = pLimit(10);
+
 const CompositeController = require('./CompositeController');
 
 const FetchEnvs = require('./FetchEnvs');
@@ -29,11 +36,6 @@ module.exports = class BaseDownloadController extends CompositeController {
   constructor(params) {
     params.finalizerString = params.finalizerString || 'children.downloads.deploy.razee.io';
     super(params);
-    this._limit = pLimit(5);
-  }
-
-  get limit() {
-    return this._limit;
   }
 
   async added() {
@@ -282,7 +284,8 @@ module.exports = class BaseDownloadController extends CompositeController {
   }
 
   async _saveChild(child) {
-    let res = await this.limit(async () => {
+    // Limit concurrency to prevent flooding the Kubernetes API
+    let res = await globalLimit(async () => {
       return await this.applyChild(child);
     });