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Rollout :refactor_blob_viewer feature flag

What

As we come to the end of refactoring the repository browser into a Vue app, we need to remove the feature flag.

Feature flag name: :refactor_blob_viewer.

Owners

  • Team: groupsource code
  • Most appropriate slack channel to reach out to: #g_create_source-code
  • Best individual to reach out to: @jerasmus @andr3

Expectations

No visual changes are expected from this rollout, the UI should perform faster a since the blob viewer will now be Vue-based.

What are we expecting to happen?

Faster UI, the blob viewer should look exactly like it looked before.

What might happen if this goes wrong?

  • Clicking on a file in the repository file browser does not load the next screen.
  • When viewing a blob (file) the file does not load.
  • Blob header buttons do not work.

Roll Out Steps

Rollout on non-production environments

  • Enable on dev (/chatops run feature set refactor_blob_viewer true --dev)
  • Test on dev
  • Enable on staging (/chatops run feature set refactor_blob_viewer true --staging)
  • Test on staging

Specific rollout on production

  • /chatops run feature set --project=jerasmus/test-project-blob-refactor-enabled refactor_blob_viewer true
  • /chatops run feature set --project=gitlab-org/gitlab refactor_blob_viewer true
  • /chatops run feature set --project=gitlab-org/gitlab-foss refactor_blob_viewer true
  • /chatops run feature set --project=gitlab-com/www-gitlab-com refactor_blob_viewer true

Preparation before global rollout

  • Ensure that you or a representative in development can be available for at least 2 hours after feature flag updates in production. If a different developer will be covering, or an exception is needed, please inform the oncall SRE by using the @sre-oncall Slack alias.
  • Ensure that documentation has been updated (More info).
  • Announce on the feature issue an estimated time this will be enabled on GitLab.com.
  • Notify #support_gitlab-com and your team channel (more guidance when this is necessary in the dev docs).

Global rollout on production

For visibility, all /chatops commands that target production should be executed in the #production slack channel and cross-posted (with the command results) to the responsible team's slack channel (#g_TEAM_NAME).

  • Incrementally roll out the feature.
    • If the feature flag in code has an actor, perform actor-based rollout.
      • /chatops run feature set refactor_blob_viewer 25 --actors
      • /chatops run feature set refactor_blob_viewer 50 --actors
      • /chatops run feature set refactor_blob_viewer 75 --actors
    • Enable the feature globally on production environment.
      • /chatops run feature set refactor_blob_viewer true
      • Run through the production checklist one last time
  • Announce on the feature issue that the feature has been globally enabled.
  • Wait for at least one day for the verification term.

(Optional) Release the feature with the feature flag

If you're still unsure whether the feature is deemed stable but want to release it in the current milestone, you can change the default state of the feature flag to be enabled. To do so, follow these steps:

  • Create a merge request with the following changes. Ask for review and merge it.
  • Ensure that the default-enabling MR has been deployed to both production and canary. If the merge request was deployed before the code cutoff, the feature can be officially announced in a release blog post.
    • /chatops run auto_deploy status <merge-commit-of-default-enabling-mr>
  • Close the feature issue to indicate the feature will be released in the current milestone.
  • Set the next milestone to this rollout issue for scheduling the flag removal.
  • (Optional) You can create a separate issue for scheduling the steps below to Release the feature.
    • Set the title to "[Feature flag] Cleanup refactor_blob_viewer".
    • Execute the /copy_metadata https://gitlab.com/gitlab-org/gitlab/-/issues/324351 quick action to copy the labels from this rollout issue.
    • Link this rollout issue as a related issue.
    • Close this rollout issue.

WARNING: This approach has the downside that it makes it difficult for us to clean up the flag. For example, on-premise users could disable the feature on their GitLab instance. But when you remove the flag at some point, they suddenly see the feature as enabled and they can't roll it back to the previous behavior. To avoid this potential breaking change, use this approach only for urgent matters.

Rollback Steps

  • This feature can be disabled by running the following Chatops command:
/chatops run feature set refactor_blob_viewer false
Edited by Jacques Erasmus