fix: loader missing sub-resource integrity hashes

[patrickhousley]

Sub-resource integrity hashes were not being properly generated and included in the loader for async chunks related to session replay. This would cause a warning to appear in the browser console but would not block those chunks from loading. This would have only affected customers taking part in the session replay limited preview.

Overview

This problem was caused by a couple of issues:

1. The webpack plugin that we relied on to generate the SRI hashes was not picking up the recorder and compressor chunks so no hash was being generated.
2. We had post build scripts that modified the files after the webpack build finished. While this issue was not seen before, it would have been if we did not move those processes internal to webpack after fixing the SRI hash generation.

Change Highlights:

• Moved all the post build scripts into individual webpack plugins.
• Wrote a new SRI plugin that correctly generates and injects hashes for all async chunks.
  • While this plugin does not have nearly as much functionality as the original, it does work for our needs and I doubt we will ever need the additional functionality around HMR and the HTML plugin.

Related Issue(s)

https://new-relic.atlassian.net/browse/NR-189746

Testing

The SRI integration test has been updated to force session replay and verify all chunks were loaded with integrity hashes.

[github-actions]

Asset Size Report

Merging this pull request will result in the following asset size changes:

Agent	Asset	Previous Size	New Size	Diff
lite	loader	30.39 kB / 10.55 kB (gzip)	30.36 kB / 10.54 kB (gzip)	-0.1% / -0.02% (gzip)
lite	async-chunk	45.58 kB / 15.05 kB (gzip)	45.58 kB / 15.05 kB (gzip)	0% / 0% (gzip)
pro	loader	47.79 kB / 15.97 kB (gzip)	47.96 kB / 16.15 kB (gzip)	0.36% / 1.15% (gzip)
pro	async-chunk	74.48 kB / 23.75 kB (gzip)	74.48 kB / 23.75 kB (gzip)	0% / 0% (gzip)
spa	loader	54.24 kB / 17.95 kB (gzip)	54.42 kB / 18.13 kB (gzip)	0.32% / 1.02% (gzip)
spa	async-chunk	89.25 kB / 28.16 kB (gzip)	89.25 kB / 28.16 kB (gzip)	0% / 0% (gzip)
lite-polyfills	loader	122.23 kB / 39.63 kB (gzip)	122.19 kB / 39.6 kB (gzip)	-0.04% / -0.09% (gzip)
lite-polyfills	async-chunk	57.97 kB / 17.25 kB (gzip)	57.97 kB / 17.25 kB (gzip)	0% / 0% (gzip)
pro-polyfills	loader	141.79 kB / 45.4 kB (gzip)	141.75 kB / 45.36 kB (gzip)	-0.03% / -0.08% (gzip)
pro-polyfills	async-chunk	101.74 kB / 27.34 kB (gzip)	101.74 kB / 27.34 kB (gzip)	0% / 0% (gzip)
spa-polyfills	loader	149.81 kB / 47.54 kB (gzip)	149.77 kB / 47.5 kB (gzip)	-0.03% / -0.08% (gzip)
spa-polyfills	async-chunk	117.31 kB / 31.93 kB (gzip)	117.31 kB / 31.93 kB (gzip)	0% / 0% (gzip)

[github-actions]

Last ran on December 14, 2023 09:37:03 CST
Checking merge of (b0dc65a) into main (3e3b810)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (3e3b810) 78.24% compared to head (b0dc65a) 78.24%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #837   +/-   ##
=======================================
  Coverage   78.24%   78.24%           
=======================================
  Files         142      142           
  Lines        6358     6358           
  Branches     1228     1228           
=======================================
  Hits         4975     4975           
  Misses       1176     1176           
  Partials      207      207           

Flag	Coverage Δ
integration-tests	88.26% <ø> (ø)
unit-tests	55.10% <ø> (ø)

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[cwli24]

Built & confirmed each plugins is doing its work.