Geo: Replicate Packages::Npm::MetadataCacheUploader

Replicate Packages::Npm::MetadataCache - Blob

This issue is for implementing Geo replication and verification of Packages::Npm::MetadataCache.

For more background, see Geo self-service framework.

In order to implement and test this feature, you need to first set up Geo locally.

There are three main sections below. It is a good idea to structure your merge requests this way as well:

1. Modify database schemas to prepare to add Geo support for Packages::Npm::MetadataCache
2. Implement Geo support of Packages::Npm::MetadataCache behind a feature flag
3. Release Geo support of Packages::Npm::MetadataCache

It is also a good idea to first open a proof-of-concept merge request. It can be helpful for working out kinks and getting initial support and feedback from the Geo team. As an example, see the Proof of Concept to replicate Pipeline Artifacts.

You can look into the following examples of MRs for implementing replication/verification for a new blob type:

• Add db changes and add verification for MR diffs using SSF
• Verify Terraform state versions
• Verify LFS objects

Modify database schemas to prepare to add Geo support for Packages::Npm::MetadataCache

Add the registry table to track replication and verification state

Geo secondary sites have a Geo tracking database independent of the main database. It is used to track the replication and verification state of all replicables. Every Model has a corresponding "registry" table in the Geo tracking database.

• Create the migration file in ee/db/geo/migrate:

  bin/rails generate migration CreatePackagesNpmMetadataCacheRegistry --database geo

• Replace the contents of the migration file with the following. Note that we cannot add a foreign key constraint on packages_npm_metadata_cache_id because the packages_npm_metadata_caches table is in a different database. The application code must handle logic such as propagating deletions.

  # frozen_string_literal: true
  
  class CreatePackagesNpmMetadataCacheRegistry < Gitlab::Database::Migration[2.1]
    def change
      create_table :packages_npm_metadata_cache_registry, id: :bigserial, force: :cascade do |t|
        t.bigint :packages_npm_metadata_cache_id, null: false
        t.datetime_with_timezone :created_at, null: false
        t.datetime_with_timezone :last_synced_at
        t.datetime_with_timezone :retry_at
        t.datetime_with_timezone :verified_at
        t.datetime_with_timezone :verification_started_at
        t.datetime_with_timezone :verification_retry_at
        t.integer :state, default: 0, null: false, limit: 2
        t.integer :verification_state, default: 0, null: false, limit: 2
        t.integer :retry_count, default: 0, limit: 2, null: false
        t.integer :verification_retry_count, default: 0, limit: 2, null: false
        t.boolean :checksum_mismatch, default: false, null: false
        t.binary :verification_checksum
        t.binary :verification_checksum_mismatched
        t.text :verification_failure, limit: 255
        t.text :last_sync_failure, limit: 255
  
        t.index :packages_npm_metadata_cache_id, name: :i_npm_metadata_cache_registry_on_packages_npm_metadata_cache_id, unique: true
        t.index :retry_at
        t.index :state
        # To optimize performance of PackagesNpmMetadataCacheRegistry.verification_failed_batch
        t.index :verification_retry_at,
          name: :packages_npm_metadata_cache_registry_failed_verification,
          order: "NULLS FIRST",
          where: "((state = 2) AND (verification_state = 3))"
        # To optimize performance of PackagesNpmMetadataCacheRegistry.needs_verification_count
        t.index :verification_state,
          name: :packages_npm_metadata_cache_registry_needs_verification,
          where: "((state = 2) AND (verification_state = ANY (ARRAY[0, 3])))"
        # To optimize performance of PackagesNpmMetadataCacheRegistry.verification_pending_batch
        t.index :verified_at,
          name: :packages_npm_metadata_cache_registry_pending_verification,
          order: "NULLS FIRST",
          where: "((state = 2) AND (verification_state = 0))"
      end
    end
  end

• If deviating from the above example, then be sure to order columns according to our guidelines.

• Add the new table to the database dictionary defined in ee/db/geo/docs/:

  table_name: packages_npm_metadata_cache_registry
  description: Description example
  introduced_by_url: Merge request link
  milestone: Milestone example
  feature_categories:
   - Feature category example
  classes:
   - Class example
  gitlab_schema: gitlab_geo

• Run Geo tracking database migrations:

  bin/rake db:migrate:geo

• Be sure to commit the relevant changes in ee/db/geo/structure.sql and the file created under ee/db/geo/schema_migrations

Add verification state fields on the Geo primary site

The Geo primary site needs to checksum every replicable so secondaries can verify their own checksums. To do this, Geo requires fields on the Model. Add verification state fields to a separate table. Consult a database expert if needed.

Add verification state fields to a new table

• Create the migration file in db/migrate:

  bin/rails generate migration PackagesNpmMetadataCacheStates

• Replace the contents of the migration file with:

  # frozen_string_literal: true
  
  class CreatePackagesNpmMetadataCacheStates < Gitlab::Database::Migration[2.1]
    VERIFICATION_STATE_INDEX_NAME = "index_packages_npm_metadata_cache_states_on_verification_state"
    PENDING_VERIFICATION_INDEX_NAME = "index_packages_npm_metadata_cache_states_pending_verification"
    FAILED_VERIFICATION_INDEX_NAME = "index_packages_npm_metadata_cache_states_failed_verification"
    NEEDS_VERIFICATION_INDEX_NAME = "index_packages_npm_metadata_cache_states_needs_verification"
  
    enable_lock_retries!
  
    def up
      create_table :packages_npm_metadata_cache_states, id: false do |t|
        t.datetime_with_timezone :verification_started_at
        t.datetime_with_timezone :verification_retry_at
        t.datetime_with_timezone :verified_at
        t.references :packages_npm_metadata_cache,
          primary_key: true,
          default: nil,
          index: false,
          foreign_key: { on_delete: :cascade }
        t.integer :verification_state, default: 0, limit: 2, null: false
        t.integer :verification_retry_count, default: 0, limit: 2, null: false
        t.binary :verification_checksum, using: 'verification_checksum::bytea'
        t.text :verification_failure, limit: 255
  
        t.index :verification_state, name: VERIFICATION_STATE_INDEX_NAME
        t.index :verified_at,
          where: "(verification_state = 0)",
          order: { verified_at: 'ASC NULLS FIRST' },
          name: PENDING_VERIFICATION_INDEX_NAME
        t.index :verification_retry_at,
          where: "(verification_state = 3)",
          order: { verification_retry_at: 'ASC NULLS FIRST' },
          name: FAILED_VERIFICATION_INDEX_NAME
        t.index :verification_state,
          where: "(verification_state = 0 OR verification_state = 3)",
          name: NEEDS_VERIFICATION_INDEX_NAME
      end
    end
  
    def down
      drop_table :packages_npm_metadata_cache_states
    end
  end

• If deviating from the above example, then be sure to order columns according to our guidelines.

• If packages_npm_metadata_caches is a high-traffic table, follow the database documentation to use with_lock_retries

• Add the new table to the database dictionary defined in db/docs/:

  ---
  table_name: packages_npm_metadata_cache_states
  description: Separate table for packages npm metadata cache verification states
  introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/XXXXX
  milestone: 'XX.Y'
  feature_categories:
   - geo_replication
  classes:
   - Geo::PackagesNpmMetadataCacheState
  gitlab_schema: gitlab_main

• Run database migrations:

  bin/rake db:migrate

• Be sure to commit the relevant changes in db/structure.sql and the file under db/schema_migrations

That's all of the required database changes.

Implement Geo support of Packages::Npm::MetadataCache behind a feature flag

Step 1. Implement replication and verification

• Add the following lines to the packages_npm_metadata_cache model to accomplish some important tasks:

  • Include ::Geo::ReplicableModel in the Packages::Npm::MetadataCache class, and specify the Replicator class with_replicator Geo::PackagesNpmMetadataCacheReplicator.
  • Include the ::Geo::VerifiableModel concern.
  • Delegate verification related methods to the packages_npm_metadata_cache_state model.
  • For verification, override some scopes to use the packages_npm_metadata_cache_states table instead of the model table.
  • Implement the verification_state_object method to return the object that holds the verification details
  • Override some methods to use the packages_npm_metadata_cache_states table in verification-related queries.

  At this point the Packages::Npm::MetadataCache class should look like this:

  # frozen_string_literal: true
  
  class Packages::Npm::MetadataCache < ApplicationRecord
    ...
    include ::Geo::ReplicableModel
    include ::Geo::VerifiableModel
  
    delegate(*::Geo::VerificationState::VERIFICATION_METHODS, to: :packages_npm_metadata_cache_state)
  
    with_replicator Geo::PackagesNpmMetadataCacheReplicator
  
    mount_uploader :file, Packages::Npm::MetadataCacheUploader
  
    has_one :packages_npm_metadata_cache_state, autosave: false, inverse_of: :packages_npm_metadata_cache, class_name: 'Geo::PackagesNpmMetadataCacheState'
  
    after_save :save_verification_details
  
    # Override the `all` default if not all records can be replicated. For an
    # example of an existing Model that needs to do this, see
    # `EE::MergeRequestDiff`.
    # scope :available_replicables, -> { all }
  
    scope :available_verifiables, -> { joins(:packages_npm_metadata_cache_state) }
  
    scope :checksummed, -> {
      joins(:packages_npm_metadata_cache_state).where.not(packages_npm_metadata_cache_states: { verification_checksum: nil })
    }
  
    scope :not_checksummed, -> {
      joins(:packages_npm_metadata_cache_state).where(packages_npm_metadata_cache_states: { verification_checksum: nil })
    }
  
    scope :with_verification_state, ->(state) {
      joins(:packages_npm_metadata_cache_state)
        .where(packages_npm_metadata_cache_states: { verification_state: verification_state_value(state) })
    }
  
    def verification_state_object
      packages_npm_metadata_cache_state
    end
    ...
  
    class_methods do
      extend ::Gitlab::Utils::Override
      ...
  
      # @param primary_key_in [Range, Packages::Npm::MetadataCache] arg to pass to primary_key_in scope
      # @return [ActiveRecord::Relation<Package::Npm::MetadataCache>] everything that should be synced
      #         to this node, restricted by primary key
      def replicables_for_current_secondary(primary_key_in)
        # This issue template does not help you write this method.
        #
        # This method is called only on Geo secondary sites. It is called when
        # we want to know which records to replicate. This is not easy to automate
        # because for example:
        #
        # * The "selective sync" feature allows admins to choose which namespaces
        #   to replicate, per secondary site. Most Models are scoped to a
        #   namespace, but the nature of the relationship to a namespace varies
        #   between Models.
        # * The "selective sync" feature allows admins to choose which shards to
        #   replicate, per secondary site. Repositories are associated with
        #   shards. Most blob types are not, but Project Uploads are.
        # * Remote stored replicables are not replicated, by default. But the
        #   setting `sync_object_storage` enables replication of remote stored
        #   replicables.
        #
        # Search the codebase for examples, and consult a Geo expert if needed.
      end
  
      override :verification_state_table_class
      def verification_state_table_class
        PackagesNpmMetadataCacheState
      end
    end
  
    def packages_npm_metadata_cache_state
      super || build_packages_npm_metadata_cache_state
    end
  
    ...
  end

• Implement Packages::Npm::MetadataCache.replicables_for_current_secondary above.

• Ensure Packages::Npm::MetadataCache.replicables_for_current_secondary is well-tested. Search the codebase for replicables_for_current_secondary to find examples of parameterized table specs. You may need to add more FactoryBot traits.

• Add the following shared examples to ee/spec/models/ee/packages_npm_metadata_cache_spec.rb:

    include_examples 'a replicable model with a separate table for verification state' do
      let(:verifiable_model_record) { build(:npm_metadata_cache) } # add extra params if needed to make sure the record is in `Geo::ReplicableModel.verifiables` scope
      let(:unverifiable_model_record) { build(:npm_metadata_cache) } # add extra params if needed to make sure the record is NOT included in `Geo::ReplicableModel.verifiables` scope
    end

• Create ee/app/replicators/geo/packages_npm_metadata_cache_replicator.rb. Implement the #carrierwave_uploader method which should return a CarrierWave::Uploader, and implement the class method .model to return the Packages::Npm::MetadataCache class:

  # frozen_string_literal: true
  
  module Geo
    class PackagesNpmMetadataCacheReplicator < Gitlab::Geo::Replicator
      include ::Geo::BlobReplicatorStrategy
      extend ::Gitlab::Utils::Override
  
      def self.model
        ::Packages::Npm::MetadataCache
      end
  
      def carrierwave_uploader
        model_record.file
      end
  
      override :verification_feature_flag_enabled?
      def self.verification_feature_flag_enabled?
        # We are adding verification at the same time as replication, so we
        # don't need to toggle verification separately from replication. When
        # the replication feature flag is off, then verification is also off
        # (see `VerifiableReplicator.verification_enabled?`)
        true
      end
    end
  end

• Generate the feature flag definition file by running the feature flag commands and following the command prompts:

  bin/feature-flag --ee geo_packages_npm_metadata_cache_replication --type development --group 'group::geo'

• Add this replicator class to the method replicator_classes in ee/lib/gitlab/geo.rb:

  REPLICATOR_CLASSES = [
    ::Geo::PackageFileReplicator,
    ::Geo::PackagesNpmMetadataCacheReplicator
  ]

• Create ee/spec/replicators/geo/packages_npm_metadata_cache_replicator_spec.rb and perform the necessary setup to define the model_record variable for the shared examples:

  # frozen_string_literal: true
  
  require 'spec_helper'
  
  RSpec.describe Geo::PackagesNpmMetadataCacheReplicator, feature_category: :geo_replication do
    let(:model_record) { build(:npm_metadata_cache) }
  
    include_examples 'a blob replicator'
    include_examples 'a verifiable replicator'
  end

• Create ee/app/models/geo/packages_npm_metadata_cache_registry.rb:

  # frozen_string_literal: true
  
  module Geo
    class PackagesNpmMetadataCacheRegistry < Geo::BaseRegistry
      include ::Geo::ReplicableRegistry
      include ::Geo::VerifiableRegistry
  
      MODEL_CLASS = ::Packages::Npm::MetadataCache
      MODEL_FOREIGN_KEY = :packages_npm_metadata_cache_id
  
      belongs_to :packages_npm_metadata_cache, class_name: 'Packages::Npm::MetadataCache'
    end
  end

• Update REGISTRY_CLASSES in ee/app/workers/geo/secondary/registry_consistency_worker.rb.

• Add a custom factory name if needed in def model_class_factory_name in ee/spec/support/helpers/ee/geo_helpers.rb.

• Update it 'creates missing registries for each registry class' in ee/spec/workers/geo/secondary/registry_consistency_worker_spec.rb.

• Add packages_npm_metadata_cache_registry to ActiveSupport::Inflector.inflections in config/initializers_before_autoloader/000_inflections.rb.

• Create ee/spec/factories/geo/packages_npm_metadata_cache_registry.rb:

  # frozen_string_literal: true
  
  FactoryBot.define do
    factory :geo_packages_npm_metadata_cache_registry, class: 'Geo::PackagesNpmMetadataCacheRegistry' do
      npm_metadata_cache # This association should have data, like a file or repository
      state { Geo::PackagesNpmMetadataCacheRegistry.state_value(:pending) }
  
      trait :synced do
        state { Geo::PackagesNpmMetadataCacheRegistry.state_value(:synced) }
        last_synced_at { 5.days.ago }
      end
  
      trait :failed do
        state { Geo::PackagesNpmMetadataCacheRegistry.state_value(:failed) }
        last_synced_at { 1.day.ago }
        retry_count { 2 }
        retry_at { 2.hours.from_now }
        last_sync_failure { 'Random error' }
      end
  
      trait :started do
        state { Geo::PackagesNpmMetadataCacheRegistry.state_value(:started) }
        last_synced_at { 1.day.ago }
        retry_count { 0 }
      end
  
      trait :verification_succeeded do
        verification_checksum { 'e079a831cab27bcda7d81cd9b48296d0c3dd92ef' }
        verification_state { Geo::PackagesNpmMetadataCacheRegistry.verification_state_value(:verification_succeeded) }
        verified_at { 5.days.ago }
      end
    end
  end

• Create ee/spec/models/geo/packages_npm_metadata_cache_registry_spec.rb:

  # frozen_string_literal: true
  
  require 'spec_helper'
  
  RSpec.describe Geo::PackagesNpmMetadataCacheRegistry, :geo, type: :model, feature_category: :geo_replication do
    let_it_be(:registry) { create(:geo_packages_npm_metadata_cache_registry) }
  
    specify 'factory is valid' do
      expect(registry).to be_valid
    end
  
    include_examples 'a Geo framework registry'
    include_examples 'a Geo verifiable registry'
  end

• Add the following to spec/factories/packages/npm/metadata_cache.rb:

  # frozen_string_literal: true
  
  FactoryBot.modify do
    factory :npm_metadata_cache do
      trait :verification_succeeded do
          with_file
          verification_checksum { 'abc' }
          verification_state { Packages::Npm::MetadataCache.verification_state_value(:verification_succeeded) }
      end
  
      trait :verification_failed do
          with_file
          verification_failure { 'Could not calculate the checksum' }
          verification_state { Packages::Npm::MetadataCache.verification_state_value(:verification_failed) }
      end
    end
  end

  If there is not an existing factory for the object in spec/factories/packages/npm/metadata_cache.rb, wrap the traits in FactoryBot.create instead of FactoryBot.modify

[ ] Make sure the factory supports the :remote_store trait. If not, add something like

trait :remote_store do
  file_store { Packages::Npm::MetadataCache::FileUploader::Store::REMOTE }
end

• Make sure the factory also allows setting a project attribute. If the model does not have a direct relation to a project, you can use a transient attribute. Check out spec/factories/merge_request_diffs.rb for an example.

• Following the example of Merge Request Diffs add a Geo::PackagesNpmMetadataCacheState model in ee/app/models/geo/packages_npm_metadata_cache_state.rb:

  # frozen_string_literal: true
  
  module Geo
    class PackagesNpmMetadataCacheState < ApplicationRecord
      include ::Geo::VerificationStateDefinition
  
      self.primary_key = :packages_npm_metadata_cache_id
  
      belongs_to :packages_npm_metadata_cache, inverse_of: :packages_npm_metadata_cache_state
  
      validates :verification_failure, length: { maximum: 255 }
      validates :verification_state, :packages_npm_metadata_cache, presence: true
    end
  end

• Add a factory for packages_npm_metadata_cache_state, in ee/spec/factories/geo/packages_npm_metadata_cache_states.rb:

  # frozen_string_literal: true
  
  FactoryBot.define do
    factory :geo_packages_npm_metadata_cache_state, class: 'Geo::PackagesNpmMetadataCacheState' do
      npm_metadata_cache
  
      trait :checksummed do
        verification_checksum { 'abc' }
      end
  
      trait :checksum_failure do
        verification_failure { 'Could not calculate the checksum' }
      end
    end
  end

• Add [:packages_npm_metadata_cache, :remote_store] and [:geo_packages_npm_metadata_cache_state, any] to skipped in spec/models/factories_spec.rb

Step 2. Implement metrics gathering

Metrics are gathered by Geo::MetricsUpdateWorker, persisted in GeoNodeStatus for display in the UI, and sent to Prometheus:

• Add the following fields to Geo Node Status example responses in doc/api/geo_nodes.md:

  • packages_npm_metadata_cache_count
  • packages_npm_metadata_cache_checksum_total_count
  • packages_npm_metadata_cache_checksummed_count
  • packages_npm_metadata_cache_checksum_failed_count
  • packages_npm_metadata_cache_synced_count
  • packages_npm_metadata_cache_failed_count
  • packages_npm_metadata_cache_registry_count
  • packages_npm_metadata_cache_verification_total_count
  • packages_npm_metadata_cache_verified_count
  • packages_npm_metadata_cache_verification_failed_count
  • packages_npm_metadata_cache_synced_in_percentage
  • packages_npm_metadata_cache_verified_in_percentage

• Add the same fields to GET /geo_nodes/status example response in ee/spec/fixtures/api/schemas/public_api/v4/geo_node_status.json.

• Add the following fields to the Sidekiq metrics table in doc/administration/monitoring/prometheus/gitlab_metrics.md:

  | `geo_packages_npm_metadata_caches` | Gauge | XX.Y | Number of `Packages::Npm::MetadataCache` on primary | `url` |
  | `geo_packages_npm_metadata_caches_checksum_total` | Gauge | XX.Y | Number of `Packages::Npm::MetadataCache` to checksum on primary | `url` |
  | `geo_packages_npm_metadata_caches_checksummed` | Gauge | XX.Y | Number of `Packages::Npm::MetadataCache` that successfully calculated the checksum on primary | `url` |
  | `geo_packages_npm_metadata_caches_checksum_failed` | Gauge | XX.Y | Number of `Packages::Npm::MetadataCache` that failed to calculate the checksum on primary | `url` |
  | `geo_packages_npm_metadata_caches_synced` | Gauge | XX.Y | Number of syncable `Packages::Npm::MetadataCache` synced on secondary | `url` |
  | `geo_packages_npm_metadata_caches_failed` | Gauge | XX.Y | Number of syncable `Packages::Npm::MetadataCache` failed to sync on secondary | `url` |
  | `geo_packages_npm_metadata_cache_registry` | Gauge | XX.Y | Number of `Packages::Npm::MetadataCache` in the registry | `url` |
  | `geo_packages_npm_metadata_caches_verification_total` | Gauge | XX.Y | Number of `Packages::Npm::MetadataCache` to attempt to verify on secondary | `url` |
  | `geo_packages_npm_metadata_caches_verified` | Gauge | XX.Y | Number of `Packages::Npm::MetadataCache` successfully verified on secondary | `url` |
  | `geo_packages_npm_metadata_cache_verification_failed` | Gauge | XX.Y | Number of `Packages::Npm::MetadataCache` that failed verification on secondary | `url` |

• Run the rake task geo:dev:ssf_metrics and commit the changes to ee/config/metrics/object_schemas/geo_node_usage.json

Packages::Npm::MetadataCache replication and verification metrics should now be available in the API, the Admin > Geo > Sites view, and Prometheus.

Step 3. Implement the GraphQL API

The GraphQL API is used by Admin > Geo > Replication Details views, and is directly queryable by administrators.

• Add a new field to GeoNodeType in ee/app/graphql/types/geo/geo_node_type.rb:

  field :packages_npm_metadata_cache_registries, ::Types::Geo::PackagesNpmMetadataCacheRegistryType.connection_type,
        null: true,
        resolver: ::Resolvers::Geo::PackagesNpmMetadataCacheRegistriesResolver,
        description: 'Find Packages::Npm::MetadataCache registries on this Geo node. '\
                     'Ignored if `geo_packages_npm_metadata_cache_replication` feature flag is disabled.',
        alpha: { milestone: '15.5' } # Update the milestone

• Add the new packages_npm_metadata_cache_registries field name to the expected_fields array in ee/spec/graphql/types/geo/geo_node_type_spec.rb.

• Create ee/app/graphql/resolvers/geo/packages_npm_metadata_cache_registries_resolver.rb:

  # frozen_string_literal: true
  
  module Resolvers
    module Geo
      class PackagesNpmMetadataCacheRegistriesResolver < BaseResolver
        type ::Types::Geo::GeoNodeType.connection_type, null: true
  
        include RegistriesResolver
      end
    end
  end

• Create ee/spec/graphql/resolvers/geo/packages_npm_metadata_cache_registries_resolver_spec.rb:

  # frozen_string_literal: true
  
  require 'spec_helper'
  
  RSpec.describe Resolvers::Geo::PackagesNpmMetadataCacheRegistriesResolver, feature_category: :geo_replication do
    it_behaves_like 'a Geo registries resolver', :geo_packages_npm_metadata_cache_registry
  end

• Create ee/app/finders/geo/packages_npm_metadata_cache_registry_finder.rb:

  # frozen_string_literal: true
  
  module Geo
    class PackagesNpmMetadataCacheRegistryFinder
      include FrameworkRegistryFinder
    end
  end

• Create ee/spec/finders/geo/packages_npm_metadata_cache_registry_finder_spec.rb:

  # frozen_string_literal: true
  
  require 'spec_helper'
  
  RSpec.describe Geo::PackagesNpmMetadataCacheRegistryFinder, feature_category: :geo_replication do
    it_behaves_like 'a framework registry finder', :geo_packages_npm_metadata_cache_registry
  end

• Create ee/app/graphql/types/geo/packages_npm_metadata_cache_registry_type.rb:

  # frozen_string_literal: true
  
  module Types
    module Geo
      # rubocop:disable Graphql/AuthorizeTypes because it is included
      class PackagesNpmMetadataCacheRegistryType < BaseObject
        graphql_name 'Packages::Npm::MetadataCacheRegistry'
  
        include ::Types::Geo::RegistryType
  
        description 'Represents the Geo replication and verification state of a packages_npm_metadata_cache'
  
        field :packages_npm_metadata_cache_id, GraphQL::Types::ID, null: false, description: 'ID of the PackagesNpmMetadataCache.'
      end
      # rubocop:enable Graphql/AuthorizeTypes
    end
  end

• Create ee/spec/graphql/types/geo/packages_npm_metadata_cache_registry_type_spec.rb:

  # frozen_string_literal: true
  
  require 'spec_helper'
  
  RSpec.describe GitlabSchema.types['PackagesNpmMetadataCacheRegistry'], feature_category: :geo_replication do
    it_behaves_like 'a Geo registry type'
  
    it 'has the expected fields (other than those included in RegistryType)' do
      expected_fields = %i[packages_npm_metadata_cache_id]
  
      expect(described_class).to have_graphql_fields(*expected_fields).at_least
    end
  end

• Add integration tests for providing PackagesNpmMetadataCache registry data to the frontend via the GraphQL API, by duplicating and modifying the following shared examples in ee/spec/requests/api/graphql/geo/registries_spec.rb:

  it_behaves_like 'gets registries for', {
    field_name: 'packagesNpmMetadataCacheRegistries',
    registry_class_name: 'PackagesNpmMetadataCacheRegistry',
    registry_factory: :geo_packages_npm_metadata_cache_registry,
    registry_foreign_key_field_name: 'packagesNpmMetadataCacheId'
  }

• Update the GraphQL reference documentation:

  bundle exec rake gitlab:graphql:compile_docs

Individual PackagesNpmMetadataCache replication and verification data should now be available via the GraphQL API.

Step 4. Handle batch destroy

If batch destroy logic is implemented for a replicable, then that logic must be "replicated" by Geo secondaries. The easiest way to do this is use Geo::BatchEventCreateWorker to bulk insert a delete event for each replicable.

For example, if FastDestroyAll is used, then you may be able to use begin_fast_destroy and finalize_fast_destroy hooks, like we did for uploads.

Or if a special service is used to batch delete records and their associated data, then you probably need to hook into that service, like we did for job artifacts.

As illustrated by the above two examples, batch destroy logic cannot be handled automatically by Geo secondaries without restricting the way other teams perform batch destroys. It is up to you to produce Geo::BatchEventCreateWorker attributes before the records are deleted, and then enqueue Geo::BatchEventCreateWorker after the records are deleted.

• Ensure that any batch destroy of this replicable is replicated to secondary sites
• Regardless of implementation details, please verify in specs that when the parent object is removed, the new Geo::Event records are created:

  describe '#destroy' do
    subject { create(:packages_npm_metadata_cache) }

    context 'when running in a Geo primary node' do
      let_it_be(:primary) { create(:geo_node, :primary) }
      let_it_be(:secondary) { create(:geo_node) }

      it 'logs an event to the Geo event log when bulk removal is used', :sidekiq_inline do
        stub_current_geo_node(primary)

        expect { subject.project.destroy! }.to change(Geo::Event.where(replicable_name: :packages_npm_metadata_cache, event_name: :deleted), :count).by(1)

        payload = Geo::Event.where(replicable_name: :packages_npm_metadata_cache, event_name: :deleted).last.payload

        expect(payload['model_record_id']).to eq(subject.id)
        expect(payload['blob_path']).to eq(subject.relative_path)
        expect(payload['uploader_class']).to eq('Package::Npm::MetadataCacheUploader')
      end
    end
  end

Code Review

When requesting review from database reviewers:

• Include a comment mentioning that the change is based on a documented template.
• replicables_for_current_secondary and available_replicables may differ per Model. If their queries are new, then add query plans to the MR description. An easy place to gather SQL queries is your GDK's log/test.log when running tests of these methods.

Release Geo support of Packages::Npm::MetadataCache

• In the rollout issue you created when creating the feature flag, modify the Roll Out Steps:

  • Cross out any steps related to testing on production GitLab.com, because Geo is not running on production GitLab.com at the moment.
  • Add a step to Test replication and verification of PackagesNpmMetadataCache on a non-GDK-deployment. For example, using GitLab Environment Toolkit.
  • Add a step to Ping the Geo PM and EM to coordinate testing. For example, you might add steps to generate PacakgesNpmMetadataCache, and then a Geo engineer may take it from there.

• In ee/config/feature_flags/development/geo_packages_npm_metadata_cache_replication.yml, set default_enabled: true

• In ee/app/graphql/types/geo/geo_node_type.rb, remove the alpha option for the released type:

  field :packages_npm_metadata_cache_registries, ::Types::Geo::PackagesNpmMetadataCacheRegistryType.connection_type,
        null: true,
        resolver: ::Resolvers::Geo::PackagesNpmMetadataCacheRegistriesResolver,
        description: 'Find PacakgesNpmMetadataCache registries on this Geo node. '\
                     'Ignored if `geo_packages_npm_metadata_cache_replication` feature flag is disabled.',
        alpha: { milestone: '15.5' } # Update the milestone

• Run bundle exec rake gitlab:graphql:compile_docs after the step above to regenerate the GraphQL docs.

• Add a row for PacakgesNpmMetadataCache to the Data types table in Geo data types support

• Add a row for PacakgesNpmMetadataCache to the Limitations on replication/verification table in Geo data types support. If the row already exists, then update it to show that Replication and Verification is released in the current version.