gitlab-org--gitlab-foss/doc/development/sidekiq/logging.md

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Sidekiq logging

Worker context

Introduced in GitLab 12.8.

To have some more information about workers in the logs, we add metadata to the jobs in the form of an ApplicationContext. In most cases, when scheduling a job from a request, this context is already deducted from the request and added to the scheduled job.

When a job runs, the context that was active when it was scheduled is restored. This causes the context to be propagated to any job scheduled from within the running job.

All this means that in most cases, to add context to jobs, we don't need to do anything.

There are however some instances when there would be no context present when the job is scheduled, or the context that is present is likely to be incorrect. For these instances, we've added RuboCop rules to draw attention and avoid incorrect metadata in our logs.

As with most our cops, there are perfectly valid reasons for disabling them. In this case it could be that the context from the request is correct. Or maybe you've specified a context already in a way that isn't picked up by the cops. In any case, leave a code comment pointing to which context to use when disabling the cops.

When you do provide objects to the context, make sure that the route for namespaces and projects is pre-loaded. This can be done by using the .with_route scope defined on all Routables.

Cron workers

The context is automatically cleared for workers in the cronjob queue (include CronjobQueue), even when scheduling them from requests. We do this to avoid incorrect metadata when other jobs are scheduled from the cron worker.

Cron workers themselves run instance wide, so they aren't scoped to users, namespaces, projects, or other resources that should be added to the context.

However, they often schedule other jobs that do require context.

That is why there needs to be an indication of context somewhere in the worker. This can be done by using one of the following methods somewhere within the worker:

1. Wrap the code that schedules jobs in the with_context helper:

     def perform
       deletion_cutoff = Gitlab::CurrentSettings
                           .deletion_adjourned_period.days.ago.to_date
       projects = Project.with_route.with_namespace
                    .aimed_for_deletion(deletion_cutoff)
   
       projects.find_each(batch_size: 100).with_index do |project, index|
         delay = index * INTERVAL
   
         with_context(project: project) do
           AdjournedProjectDeletionWorker.perform_in(delay, project.id)
         end
       end
     end
   

2. Use the a batch scheduling method that provides context:

     def schedule_projects_in_batch(projects)
       ProjectImportScheduleWorker.bulk_perform_async_with_contexts(
         projects,
         arguments_proc: -> (project) { project.id },
         context_proc: -> (project) { { project: project } }
       )
     end
   

   Or, when scheduling with delays:

     diffs.each_batch(of: BATCH_SIZE) do |diffs, index|
       DeleteDiffFilesWorker
         .bulk_perform_in_with_contexts(index *  5.minutes,
                                        diffs,
                                        arguments_proc: -> (diff) { diff.id },
                                        context_proc: -> (diff) { { project: diff.merge_request.target_project } })
     end
   

Jobs scheduled in bulk

Often, when scheduling jobs in bulk, these jobs should have a separate context rather than the overarching context.

If that is the case, bulk_perform_async can be replaced by the bulk_perform_async_with_context helper, and instead of bulk_perform_in use bulk_perform_in_with_context.

For example:

    ProjectImportScheduleWorker.bulk_perform_async_with_contexts(
      projects,
      arguments_proc: -> (project) { project.id },
      context_proc: -> (project) { { project: project } }
    )

Each object from the enumerable in the first argument is yielded into 2 blocks:

• The arguments_proc which needs to return the list of arguments the job needs to be scheduled with.

• The context_proc which needs to return a hash with the context information for the job.

Arguments logging

As of GitLab 13.6, Sidekiq job arguments are logged by default, unless SIDEKIQ_LOG_ARGUMENTS is disabled.

By default, the only arguments logged are numeric arguments, because arguments of other types could contain sensitive information. To override this, use loggable_arguments inside a worker with the indexes of the arguments to be logged. (Numeric arguments do not need to be specified here.)

For example:

class MyWorker
  include ApplicationWorker

  loggable_arguments 1, 3

  # object_id will be logged as it's numeric
  # string_a will be logged due to the loggable_arguments call
  # string_b will be filtered from logs
  # string_c will be logged due to the loggable_arguments call
  def perform(object_id, string_a, string_b, string_c)
  end
end