Add tags to queue selector attributes

Tags are sets of transient annotations for workers. We will change them
more frequently than other worker attributes, and will remove them
completely at times.

For instance, we want to tag workers that require disk I/O. Once no
workers require disk I/O, workers will no longer have the tag indicating
this, but we'll still support the general tags concept.

app/workers/concerns/worker_attributes.rb

@@ -111,6 +111,14 @@ module WorkerAttributes
         1
     end
 
+    def tags(*values)
+      worker_attributes[:tags] = values
+    end
+
+    def get_tags
+      Array(worker_attributes[:tags])
+    end
+
     protected
 
     # Returns a worker attribute declared on this class or its parent class.

changelogs/unreleased/add-tags-to-queue-attributes.yml

+---
+title: Add tags to experimental queue selector attributes
+merge_request: 32651
+author:
+type: added

doc/administration/operations/extra_sidekiq_processes.md

@@ -126,6 +126,8 @@ in a more general way using the following components:
 
 ### Available attributes
 
+- [Introduced](https://gitlab.com/gitlab-com/gl-infra/scalability/-/issues/261) in GitLab 13.1, `tags`.
+
 From the [list of all available
 attributes](https://gitlab.com/gitlab-org/gitlab/-/blob/master/app/workers/all_queues.yml),
 `experimental_queue_selector` allows selecting of queues by the
@@ -147,11 +149,18 @@ following attributes:
 - `resource_boundary` - if the worker is bound by `cpu`, `memory`, or
   `unknown`. For example, the `project_export` queue is memory bound as it has
   to load data in memory before saving it for export.
+- `tags` - short-lived annotations for workers. These are expected to frequently
+  change from release to release, and may be removed entirely.
 
 `has_external_dependencies` is a boolean attribute: only the exact
 string `true` is considered true, and everything else is considered
 false.
 
+`tags` is a set, which means that `=` checks for intersecting sets, and
+`!=` checks for disjoint sets. For example, `tags=a,b` selects queues
+that have tags `a`, `b`, or both. `tags!=a,b` selects queues that have
+neither of those tags.
+
 ### Available operators
 
 `experimental_queue_selector` supports the following operators, listed

lib/gitlab/sidekiq_config.rb

@@ -14,8 +14,8 @@ module Gitlab
     ].compact.freeze
 
     DEFAULT_WORKERS = [
-      DummyWorker.new('default', weight: 1),
-      DummyWorker.new('mailers', weight: 2)
+      DummyWorker.new('default', weight: 1, tags: []),
+      DummyWorker.new('mailers', weight: 2, tags: [])
     ].map { |worker| Gitlab::SidekiqConfig::Worker.new(worker, ee: false) }.freeze
 
     class << self

lib/gitlab/sidekiq_config/cli_methods.rb

@@ -28,6 +28,7 @@ module Gitlab
         has_external_dependencies: lambda { |value| value == 'true' },
         name: :to_s,
         resource_boundary: :to_sym,
+        tags: :to_sym,
         urgency: :to_sym
       }.freeze
 
@@ -117,7 +118,11 @@ module Gitlab
 
         raise UnknownPredicate.new("Unknown predicate: #{lhs}") unless values_block
 
-        lambda { |queue| values.map(&values_block).include?(queue[lhs.to_sym]) }
+        lambda do |queue|
+          comparator = Array(queue[lhs.to_sym]).to_set
+
+          values.map(&values_block).to_set.intersect?(comparator)
+        end
       end
     end
   end

lib/gitlab/sidekiq_config/dummy_worker.rb

@@ -12,7 +12,8 @@ module Gitlab
         urgency: :get_urgency,
         resource_boundary: :get_worker_resource_boundary,
         idempotent: :idempotent?,
-        weight: :get_weight
+        weight: :get_weight,
+        tags: :get_tags
       }.freeze
 
       def initialize(queue, attributes = {})

lib/gitlab/sidekiq_config/worker.rb

@@ -6,7 +6,7 @@ module Gitlab
       include Comparable
 
       attr_reader :klass
-      delegate :feature_category_not_owned?, :get_feature_category,
+      delegate :feature_category_not_owned?, :get_feature_category, :get_tags,
                :get_urgency, :get_weight, :get_worker_resource_boundary,
                :idempotent?, :queue, :queue_namespace,
                :worker_has_external_dependencies?,
@@ -52,7 +52,8 @@ module Gitlab
           urgency: get_urgency,
           resource_boundary: get_worker_resource_boundary,
           weight: get_weight,
-          idempotent: idempotent?
+          idempotent: idempotent?,
+          tags: get_tags
         }
       end
 

spec/lib/gitlab/sidekiq_config/cli_methods_spec.rb

@@ -117,28 +117,32 @@ describe Gitlab::SidekiqConfig::CliMethods do
           feature_category: :category_a,
           has_external_dependencies: false,
           urgency: :low,
-          resource_boundary: :cpu
+          resource_boundary: :cpu,
+          tags: [:no_disk_io, :git_access]
         },
         {
           name: 'a:2',
           feature_category: :category_a,
           has_external_dependencies: false,
           urgency: :high,
-          resource_boundary: :none
+          resource_boundary: :none,
+          tags: [:git_access]
         },
         {
           name: 'b',
           feature_category: :category_b,
           has_external_dependencies: true,
           urgency: :high,
-          resource_boundary: :memory
+          resource_boundary: :memory,
+          tags: [:no_disk_io]
         },
         {
           name: 'c',
           feature_category: :category_c,
           has_external_dependencies: false,
           urgency: :throttled,
-          resource_boundary: :memory
+          resource_boundary: :memory,
+          tags: []
         }
       ]
     end
@@ -177,6 +181,18 @@ describe Gitlab::SidekiqConfig::CliMethods do
         'resource_boundary=memory|resource_boundary=cpu' | %w(a b c)
         'resource_boundary!=memory,cpu' | %w(a:2)
 
+        # tags
+        'tags=no_disk_io' | %w(a b)
+        'tags=no_disk_io,git_access' | %w(a a:2 b)
+        'tags=no_disk_io|tags=git_access' | %w(a a:2 b)
+        'tags=no_disk_io&tags=git_access' | %w(a)
+        'tags!=no_disk_io' | %w(a:2 c)
+        'tags!=no_disk_io,git_access' | %w(c)
+        'tags=unknown_tag' | []
+        'tags!=no_disk_io' | %w(a:2 c)
+        'tags!=no_disk_io,git_access' | %w(c)
+        'tags!=unknown_tag' | %w(a a:2 b c)
+
         # combinations
         'feature_category=category_a&urgency=high' | %w(a:2)
         'feature_category=category_a&urgency=high|feature_category=category_c' | %w(a:2 c)

spec/lib/gitlab/sidekiq_config/worker_spec.rb

@@ -13,7 +13,8 @@ describe Gitlab::SidekiqConfig::Worker do
       get_worker_resource_boundary: attributes[:resource_boundary],
       get_urgency: attributes[:urgency],
       worker_has_external_dependencies?: attributes[:has_external_dependencies],
-      idempotent?: attributes[:idempotent]
+      idempotent?: attributes[:idempotent],
+      get_tags: attributes[:tags]
     )
 
     described_class.new(inner_worker, ee: false)
@@ -91,7 +92,8 @@ describe Gitlab::SidekiqConfig::Worker do
         urgency: :low,
         resource_boundary: :memory,
         weight: 2,
-        idempotent: true
+        idempotent: true,
+        tags: []
       }
 
       attributes_b = {
@@ -100,7 +102,8 @@ describe Gitlab::SidekiqConfig::Worker do
         urgency: :high,
         resource_boundary: :unknown,
         weight: 3,
-        idempotent: false
+        idempotent: false,
+        tags: [:no_disk_io]
       }
 
       worker_a = create_worker(queue: 'a', **attributes_a)