Resolve "Avatar URLs are wrong when using a CDN path and Object Storage"

What does this MR do?

Resolve a problem where if an avatar would be on remote storage and a CDN was configured, it would return an invalid URL.

Are there points in the code the reviewer needs to double check?

When everything will be migrated to object storage, I think we will be able to deprecate the CDN-specific code.

Why was this MR needed?

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests added for this feature/bug
• Review
  • Has been reviewed by UX
  • Has been reviewed by Frontend
  • Has been reviewed by Backend
  • Has been reviewed by Database
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together
• Internationalization required/considered
• End-to-end tests pass (package-and-qa manual pipeline job)

What are the relevant issue numbers?

Closes #44775 (closed)

@smcgivern please review.

assigned to @smcgivern

added 1 commit

• 0a2e9322 - add changelog

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marked the checklist item Changelog entry added, if necessary as completed

approved this merge request

assigned to @mbergeron

added 1 commit

• 31c4dc92 - always return a gitlab-local url for the avatars

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@smcgivern please review.

assigned to @smcgivern

Here is a test I did on staging, basically the current approach is to always return a gitlab-local URL for avatars, so that it may be forwarded to the CDN.

On staging, my avatar is currently on OS. All these URLs works and show the correct avatar.

1. https://staging.gitlab.com/mbergeron
2. https://staging.gitlab.com/uploads/-/system/user/avatar/1491026/avatar.png
3. https://gl-staging.global.ssl.fastly.net/uploads/-/system/user/avatar/1491026/avatar.png

We can see the problem in action currently at https://staging.gitlab.com/gitlab-org/gitlab-ce/issues/38925#note_42948485 because the link is broken. With the new fix, the link at 3) will be used.

@smcgivern WDYT?

@smcgivern are we merging this in 10.7?

assigned to @northrup

resolved all discussions

approved this merge request

mentioned in commit cc0b4e3c

merged

mentioned in commit 2d4a5879

Picked into https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/18647, will merge into 10-7-stable ready for 10.7.3