[SE-3401] Upgrades Webpack to v4.44.2 to support content hashing

[nizarmah]

Upgrades Webpack from v2.7.0 to v4.44.2 so that content hashing is possible.

JIRA tickets: SE-3401

Sandbox URL:

• LMS: https://pr265.sandbox.stage.opencraft.hosting/
• Studio: https://studio.pr265.sandbox.stage.opencraft.hosting/

Testing instructions:

1. Spawn multiple instances and add to load-balancer.
2. Open the Developer console for the LMS and Studio and verify there are no 404 messages for commons.js.
3. SSH into the different instances and verify that the output for ls /edx/var/edxapp/staticfiles/studio/bundles/ | grep -i commons is the same among the different instances.
4. Compare the files in /edx/var/edxapp/staticfiles/studio/bundles/ and /edx/var/edxapp/staticfiles/bundles/ between both App Servers and make sure they have the same filename (including hashes).
5. Compare the files in /edx/var/edxapp/staticfiles/studio/bundles/ and /edx/var/edxapp/staticfiles/bundles/ between app servers with old instances (without the fix) and new ones (with the fix) and make sure everything is similar/acting normal.
6. Verify that the assets are getting loaded correctly.

Reviewers

• @pkulkark
• @gabor-boros

[gabor-boros]

👍 🎉

• I tested this: Tested asset loading from a normal window
• I tested this: Tested asset loading from a private window
• I tested this: Tested asset loading from a tor window
• I tested this: Tested asset checksum match on the instances
• I read through the code
  - [ ] NA I checked for accessibility issues
  - [ ] NA Includes documentation
  - [ ] NA I made sure any change in configuration variables is reflected in the corresponding client's configuration-secure repository.

[gabor-boros]

This solves the issue for sure, but the asset is not compressed anymore, which will result in higher load time

[nizarmah]

This solves the issue for sure, but the asset is not compressed anymore, which will result in higher load time

I totally missed that part. Sorry about that! Thanks for paying attention to that!

[nizarmah]

@gabor-boros

This solves the issue for sure, but the asset is not compressed anymore, which will result in higher load time

I compared the file to other instances; I also compared the loading time of the file with other instances. And I can't relate to what you are mentioning. The asset seems to be as "compressed" as it already were. In addition, the loading time is closely similar between different instances.

The cherry-on-top is that this file is the same between the LMS and Studio. So by content-hashing it, it gets cached the first time it loads. Meanwhile, on other instances, the file has to be downloaded on LMS and Studio so that it is cached for each (since it is chunk hashed).

Can you confirm what I said, and compare the file on different instances, so that I can mark this as "Ready for Review" please?

Side note: the commons.js can be found at: /edx/app/edxapp/edx-platform/common/static/bundles/commons.js
It should be almost identical with LMS and Studio from other instances, but it shouldn't have the list of hashes they do.

[gabor-boros]

👍 🎉

• I tested this: Tested asset loading from a normal window
• I tested this: Tested asset loading from a private window
• I tested this: Tested asset loading from a tor window
• I tested this: Tested asset checksum match on the instances
• I read through the code
  - [ ] NA I checked for accessibility issues
  - [ ] NA Includes documentation
  - [ ] NA I made sure any change in configuration variables is reflected in the corresponding client's configuration-secure repository.

Ok, I have to apologize here. It turned out that the output I've seen seems compressed, but a "cool new feature" (which is really good but should be promoted), tricked me. The screenshot below is one line, but displayed as a "formatted" string...

In reality that's just one line. Sorry for the previous.

[nizarmah]

Hahaha no worries 😄 Thanks for the review 👍 and for making sure what I mentioned was correct 🙂

I'll try to search for a core member to review this.

[nizarmah]

I'm closing this PR since it's no longer necessary. And I'll work on this contribution during my own personal time 👍 https://github.com/edx/edx-platform/pull/25635