[Feature flag] Rollout of `npm_allow_packages_in_multiple_projects`

Enable NPM metadata instance endpoint support for packages with the same name across multiple projects

Summary

This issue is to rollout the bugfix on production, that is currently behind the npm_allow_packages_in_multiple_projects feature flag.

Owners

Team: Package::Package Registry
Most appropriate slack channel to reach out to: #g_package-registry
Best individual to reach out to: @radbatnag
PM: @trizzi

Stakeholders

Expectations

What are we expecting to happen?

The NPM metadata instance endpoint will return the correct set of packages for the NPM instance endpoint.

There should be no increase in error rates or HTTP 403 responses.

What might happen if this goes wrong?

Increased error rates in NPM package install operations

The NPM is the most-used package format in the Package Registry, and the metadata endpoint is the most-used endpoint. If the code behind the feature flag introduces buggy behavior or performance issues, we should turn off the feature flag.

What can we monitor to detect problems with this?

HTTP 200s on npm instance endpoint(internal)

HTTP 500s on npm instance endpoint(internal)

HTTP 500 on npm instance endpoint for a namespace that encountered errors during last rollout (internal)

Package Registry Error Budget Dashboard

What can we check for monitoring production after rollouts?

See dashboards above.

Rollout Steps

Note: Please make sure to run the chatops commands in the slack channel that gets impacted by the command.

Rollout on non-production environments

Verify the MR with the feature flag is merged to master.
Verify that the feature MRs have been deployed to non-production environments with:
- /chatops run auto_deploy status <merge-commit-of-your-feature>
Enable the feature globally on non-production environments.
- /chatops run feature set npm_allow_packages_in_multiple_projects true --dev --staging --staging-ref
Verify that the feature works as expected. Posting the QA result in this issue is preferable. The best environment to validate the feature in is staging-canary as this is the first environment deployed to. Note you will need to make sure you are configured to use canary as outlined here when accessing the staging environment in order to make sure you are testing appropriately.

Specific 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).

Ensure that the feature MRs have been deployed to both production and canary.
- /chatops run auto_deploy status <merge-commit-of-your-feature>
This feature flag does uses a group actor. It will be incrementally rolled out with /chatops run feature set npm_allow_packages_in_multiple_projects [10|25|50|75] --actors, then rolled out globally with /chatops run feature set npm_allow_packages_in_multiple_projects true
Verify that the feature works on the specific entries. Posting the QA result in this issue is preferable.

Preparation before global rollout

Set a milestone to the rollout issue to signal for enabling and removing the feature flag when it is stable.
Check if the feature flag change needs to be accompanied with a change management issue. Cross link the issue here if it does.
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.
Leave a comment on the feature issue announcing estimated time when this feature flag will be enabled on GitLab.com.
Ensure that any breaking changes have been announced following the release post process to ensure GitLab customers are aware.
Notify #support_gitlab-com and your team channel (more guidance when this is necessary in the dev docs).
Ensure that the feature flag rollout plan is reviewed by another developer familiar with the domain.

Global rollout on production

(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:

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.

Release the feature

After the feature has been deemed stable, the clean up should be done as soon as possible to permanently enable the feature and reduce complexity in the codebase.

You can either create a follow-up issue for Feature Flag Cleanup or use the checklist below in this same issue.

Rollback Steps

This feature can be disabled by running the following Chatops command:

/chatops run feature set npm_allow_packages_in_multiple_projects false

Edited May 22, 2024 by Radamanthus Batnag