[Feature flag] Enable rate limit on username update
Summary
This issue is to rollout rate limiting of username update on production,
that is currently behind the rate_limit_profile_update_username
feature flag.
The rate limit is enforced in order to mitigate misuse of the feature, for example to mass discover which usernames are in use (by checking if they are disallowed by the uniqueness validation).
Owners
- Team: group::optimize
- Most appropriate slack channel to reach out to:
#g_manage_optimize
- Best individual to reach out to: @m_frankiewicz
- PM: @hdelalic
Stakeholders
- The Security Team
Expectations
What are we expecting to happen?
The ProfilesController#update_username
action, used to change the username, will be rate-limited to maximum 10 calls per minute per logged-in user.
If the rate limit turns out to be too stringent, it is possible that some legitimate user is being limited in how frequently they can call this action. In that case, the feature should be turned off, and a higher limit should be applied, after agreeing with security on what is appropriate.
What can we monitor to detect problems with this?
An increase of 429 response statuses on calls to ProfilesController#update_username
could indicate either an attempt to misuse the feature that is correctly stopped by this rate limit, or possibly a legitimate user that is hitting the limit.
What can we check for monitoring production after rollouts?
Production logs for 429 response statuses on calls to ProfilesController#update_username
. A high number of those would indicate that we are possibly limiting too many users.
Rollout Steps
Rollout on non-production environments
- Ensure that the feature MRs have been deployed to non-production environments.
-
/chatops run auto_deploy status <merge-commit-of-your-feature>
-
-
Enable the feature globally on non-production environments. -
/chatops run feature set <feature-flag-name> true --dev
-
/chatops run feature set <feature-flag-name> true --staging
-
-
Verify that the feature works as expected. Posting the QA result in this issue is preferable.
Specific rollout on production
- Ensure that the feature MRs have been deployed to both production and canary.
-
/chatops run auto_deploy status <merge-commit-of-your-feature>
-
- If you're using project-actor, you must enable the feature on these entries:
-
/chatops run feature set --project=gitlab-org/gitlab <feature-flag-name> true
-
/chatops run feature set --project=gitlab-org/gitlab-foss <feature-flag-name> true
-
/chatops run feature set --project=gitlab-com/www-gitlab-com <feature-flag-name> true
-
- If you're using group-actor, you must enable the feature on these entries:
-
/chatops run feature set --group=gitlab-org <feature-flag-name> true
-
/chatops run feature set --group=gitlab-com <feature-flag-name> true
-
- If you're using user-actor, you must enable the feature on these entries:
-
/chatops run feature set --user=<your-username> <feature-flag-name> true
-
-
Verify that the feature works on the specific entries. Posting the QA result in this issue is preferable.
Preparation before global rollout
-
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. -
Ensure that documentation has been updated (More info). MR with documentation changes: !78548 (merged) -
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 <feature-flag-name> <rollout-percentage> --actors
-
- If the feature flag in code does NOT have an actor, perform time-based rollout (random rollout).
-
/chatops run feature set <feature-flag-name> <rollout-percentage>
-
- Enable the feature globally on production environment.
-
/chatops run feature set <feature-flag-name> true
-
- If the feature flag in code has an actor, perform actor-based rollout.
-
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. -
Set the default_enabled
attribute in the feature flag definition totrue
. -
Create a changelog entry.
-
-
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 <feature-flag-name>
". -
Execute the /copy_metadata <this-rollout-issue-link>
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.
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.
-
Create a merge request to remove <feature-flag-name>
feature flag. Ask for review and merge it.-
Remove all references to the feature flag from the codebase. -
Remove the YAML definitions for the feature from the repository. -
Create a changelog entry.
-
-
Ensure that the cleanup 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-cleanup-mr>
-
-
Close the feature issue to indicate the feature will be released in the current milestone. -
Clean up the feature flag from all environments by running these chatops command in #production
channel:-
/chatops run feature delete <feature-flag-name> --dev
-
/chatops run feature delete <feature-flag-name> --staging
-
/chatops run feature delete <feature-flag-name>
-
-
Close this rollout issue.
Rollback Steps
-
This feature can be disabled by running the following Chatops command:
/chatops run feature set <feature-flag-name> false
Availability and Testing
For more details, see discussion in comments
- Tests at the controller level exist for testing the rate limit of this specific endpoint.
- An issue is currently opened for extending QA tests for rate limits in general: #350898 (closed)
- Rollout and rollback steps concerning availability are already outlined in description above.