Investigate the loading impact of the standardizing the location of `config.js` for Helm-Based Kubernetes deployments

[robyngit]

For deployments of MetacatUI using Helm on Kubernetes, we propose standardizing the location of the config.js file to config/config.js. Currently, in some deployments, we are manually editing the index.html to adjust the path defined by var appConfigPath = "/config/config.js"; to point to a theme-specific configuration at var appConfigPath = "/js/themes/THEMENAME/config.js";.

This adjustment is necessary for deployments utilizing a theme config file which contains all base theme configurations, in contrast to the usual config/config.js that contains overrides. We hypothesize that requiring metacatui to load two separate config files might increase loading times, particularly first contentful paint time. This theory needs empirical verification.

This issue will serve as a platform to share insights on the performance implications of this configuration setup.

See also: #2027

[robyngit]

TL;DR:

➡️ The performance implications of using config/config.js vs /js/themes/arctic/config.js are negligible. ⬅️

Test setup:

• Used https://metacatui.test.dataone.org/ on knbvm
• Switched between arctic theme using /js/themes/arctic/config.js and using /config/config.js to point to the arctic theme
• Both tests were repeated
• Performance metrics collected using pagespeed.web.dev - which is a lighthouse-based tool from Google

---

Test 1: Using /config/config.js

index.html:

var appConfigPath = "/config/config.js";

config/config.js:

MetacatUI.AppConfig = {
  root: "/",
  theme: "arctic"
};

Results:

First Contentful Paint: 0.2 s Total Blocking Time: 24,280 ms Largest Contentful Paint: 5.2 s

Full report

Repeated metrics:

Full report

First Contentful Paint 0.2 s Total Blocking Time 26,450 ms Largest Contentful Paint 5.2 s

---

Test 2: Using /js/themes/arctic/config.js

index.html:

var appConfigPath = "/js/themes/arctic/config.js";

no loading of config/config.js

Results:

First Contentful Paint: 0.2 s Total Blocking Time: 23,860 ms Largest Contentful Paint: 5.8 s

Full report

Repeated metrics:

Full report

First Contentful Paint 0.2 s Total Blocking Time 18,270 ms Largest Contentful Paint 3.7 s

---

Conclusion:

• The performance difference between using /config/config.js and /js/themes/arctic/config.js is negligible
• There seems to be more variability within the same testing setup than between the two setups
• I think we can conclude that the performance implications of using two config files are negligible, but I'm open to further testing or suggestions