Merge branch 'ce-to-ee-2018-11-05' into 'master'

CE upstream - 2018-11-05 23:21 UTC

Closes gitlab-ce#52176

See merge request gitlab-org/gitlab-ee!8242

app/assets/javascripts/commons/gitlab_ui.js

 import Vue from 'vue';
-import { GlLoadingIcon, GlTooltipDirective } from '@gitlab-org/gitlab-ui';
+import { GlLoadingIcon } from '@gitlab-org/gitlab-ui';
 
 Vue.component('gl-loading-icon', GlLoadingIcon);
-
-Vue.directive('gl-tooltip', GlTooltipDirective);

app/assets/javascripts/diffs/components/diff_gutter_avatars.vue

@@ -3,6 +3,7 @@ import { mapActions } from 'vuex';
 import Icon from '~/vue_shared/components/icon.vue';
 import { pluralize, truncate } from '~/lib/utils/text_utility';
 import UserAvatarImage from '~/vue_shared/components/user_avatar/user_avatar_image.vue';
+import { GlTooltipDirective } from '@gitlab-org/gitlab-ui';
 import { COUNT_OF_AVATARS_IN_GUTTER, LENGTH_OF_AVATAR_TOOLTIP } from '../constants';
 
 export default {
@@ -10,6 +11,9 @@ export default {
     Icon,
     UserAvatarImage,
   },
+  directives: {
+    GlTooltip: GlTooltipDirective,
+  },
   props: {
     discussions: {
       type: Array,

app/assets/javascripts/set_status_modal/set_status_modal_wrapper.vue

@@ -5,7 +5,7 @@ import Icon from '~/vue_shared/components/icon.vue';
 import GfmAutoComplete from '~/gfm_auto_complete';
 import { __, s__ } from '~/locale';
 import Api from '~/api';
-import { GlModal } from '@gitlab-org/gitlab-ui';
+import { GlModal, GlTooltipDirective } from '@gitlab-org/gitlab-ui';
 import eventHub from './event_hub';
 import EmojiMenuInModal from './emoji_menu_in_modal';
 
@@ -16,6 +16,9 @@ export default {
     Icon,
     GlModal,
   },
+  directives: {
+    GlTooltip: GlTooltipDirective,
+  },
   props: {
     currentEmoji: {
       type: String,

app/assets/javascripts/vue_shared/components/gl_countdown.vue

 <script>
 import { calculateRemainingMilliseconds, formatTime } from '~/lib/utils/datetime_utility';
+import { GlTooltipDirective } from '@gitlab-org/gitlab-ui';
 
 /**
  * Counts down to a given end date.
  */
 export default {
+  directives: {
+    GlTooltip: GlTooltipDirective,
+  },
   props: {
     endDateString: {
       type: String,

app/assets/stylesheets/framework/blocks.scss

@@ -348,6 +348,7 @@
 
     @include media-breakpoint-down(xs) {
       width: 100%;
+      margin: $btn-side-margin 0;
     }
   }
 }

app/assets/stylesheets/framework/tables.scss

@@ -147,3 +147,9 @@ table {
     }
   }
 }
+
+.top-area + .content-list {
+  th {
+    border-top: 0;
+  }
+}

app/assets/stylesheets/pages/pipeline_schedules.scss

@@ -39,10 +39,6 @@
     white-space: nowrap;
     overflow: hidden;
     text-overflow: ellipsis;
-
-    svg {
-      vertical-align: middle;
-    }
   }
 
   .next-run-cell {
@@ -52,6 +48,10 @@
   a {
     color: $text-color;
   }
+
+  svg {
+    vertical-align: middle;
+  }
 }
 
 .pipeline-schedules-user-callout {

app/finders/personal_access_tokens_finder.rb

@@ -3,7 +3,7 @@
 class PersonalAccessTokensFinder
   attr_accessor :params
 
-  delegate :build, :find, :find_by, :find_by_token, to: :execute
+  delegate :build, :find, :find_by_id, :find_by_token, to: :execute
 
   def initialize(params = {})
     @params = params

app/models/application_setting.rb

@@ -6,6 +6,7 @@ class ApplicationSetting < ActiveRecord::Base
   include TokenAuthenticatable
   include IgnorableColumn
   include ChronicDurationAttribute
+
   prepend EE::ApplicationSetting
 
   add_authentication_token_field :runners_registration_token

app/models/ci/job_artifact.rb

@@ -17,7 +17,7 @@ module Ci
       metadata: nil,
       trace: nil,
       junit: 'junit.xml',
-      codequality: 'codequality.json',
+      codequality: 'gl-code-quality-report.json',
       sast: 'gl-sast-report.json',
       dependency_scanning: 'gl-dependency-scanning-report.json',
       container_scanning: 'gl-container-scanning-report.json',

app/models/deploy_token.rb

@@ -4,6 +4,7 @@ class DeployToken < ActiveRecord::Base
   include Expirable
   include TokenAuthenticatable
   include PolicyActor
+  include Gitlab::Utils::StrongMemoize
   add_authentication_token_field :token
 
   AVAILABLE_SCOPES = %i(read_repository read_registry).freeze
@@ -49,7 +50,9 @@ class DeployToken < ActiveRecord::Base
   # to a single project, later we're going to extend
   # that to be for multiple projects and namespaces.
   def project
-    projects.first
+    strong_memoize(:project) do
+      projects.first
+    end
   end
 
   def expires_at

app/models/pool_repository.rb

+# frozen_string_literal: true
+
+class PoolRepository < ActiveRecord::Base
+  POOL_PREFIX = '@pools'
+
+  belongs_to :shard
+  validates :shard, presence: true
+
+  # For now, only pool repositories are tracked in the database. However, we may
+  # want to add other repository types in the future
+  self.table_name = 'repositories'
+
+  has_many :pool_member_projects, class_name: 'Project', foreign_key: :pool_repository_id
+
+  def shard_name
+    shard&.name
+  end
+
+  def shard_name=(name)
+    self.shard = Shard.by_name(name)
+  end
+end

app/models/postgresql/replication_slot.rb

@@ -4,6 +4,15 @@ module Postgresql
   class ReplicationSlot < ActiveRecord::Base
     self.table_name = 'pg_replication_slots'
 
+    # Returns true if there are any replication slots in use.
+    # PostgreSQL-compatible databases such as Aurora don't support
+    # replication slots, so this will return false as well.
+    def self.in_use?
+      transaction { exists? }
+    rescue ActiveRecord::StatementInvalid
+      false
+    end
+
     # Returns true if the lag observed across all replication slots exceeds a
     # given threshold.
     #
@@ -11,6 +20,8 @@ module Postgresql
     #       statistics it takes between 1 and 5 seconds to replicate around
     #       100 MB of data.
     def self.lag_too_great?(max = 100.megabytes)
+      return false unless in_use?
+
       lag_function = "#{Gitlab::Database.pg_wal_lsn_diff}" \
         "(#{Gitlab::Database.pg_current_wal_insert_lsn}(), restart_lsn)::bigint"
 

app/models/project.rb

@@ -98,8 +98,7 @@ class Project < ActiveRecord::Base
     unless: :ci_cd_settings,
     if: proc { ProjectCiCdSetting.available? }
 
-  after_create :set_last_activity_at
-  after_create :set_last_repository_updated_at
+  after_create :set_timestamps_for_create
   after_update :update_forks_visibility_level
 
   before_destroy :remove_private_deploy_keys
@@ -127,6 +126,7 @@ class Project < ActiveRecord::Base
   alias_attribute :title, :name
 
   # Relations
+  belongs_to :pool_repository
   belongs_to :creator, class_name: 'User'
   belongs_to :group, -> { where(type: 'Group') }, foreign_key: 'namespace_id'
   belongs_to :namespace
@@ -2101,13 +2101,8 @@ class Project < ActiveRecord::Base
     gitlab_shell.exists?(repository_storage, "#{disk_path}.git")
   end
 
-  # set last_activity_at to the same as created_at
-  def set_last_activity_at
-    update_column(:last_activity_at, self.created_at)
-  end
-
-  def set_last_repository_updated_at
-    update_column(:last_repository_updated_at, self.created_at)
+  def set_timestamps_for_create
+    update_columns(last_activity_at: self.created_at, last_repository_updated_at: self.created_at)
   end
 
   def cross_namespace_reference?(from)

app/models/shard.rb

+# frozen_string_literal: true
+
+class Shard < ActiveRecord::Base
+  # Store shard names from the configuration file in the database. This is not a
+  # list of active shards - we just want to assign an immutable, unique ID to
+  # every shard name for easy indexing / referencing.
+  def self.populate!
+    return unless table_exists?
+
+    # The GitLab config does not change for the lifecycle of the process
+    in_config = Gitlab.config.repositories.storages.keys.map(&:to_s)
+
+    transaction do
+      in_db = all.pluck(:name)
+      missing = in_config - in_db
+
+      missing.map { |name| by_name(name) }
+    end
+  end
+
+  def self.by_name(name)
+    find_or_create_by(name: name)
+  rescue ActiveRecord::RecordNotUnique
+    retry
+  end
+end

app/models/user.rb

@@ -460,12 +460,6 @@ class User < ActiveRecord::Base
       by_username(username).take!
     end
 
-    def find_by_personal_access_token(token_string)
-      return unless token_string
-
-      PersonalAccessTokensFinder.new(state: 'active').find_by_token(token_string)&.user # rubocop: disable CodeReuse/Finder
-    end
-
     # Returns a user for the given SSH key.
     def find_by_ssh_key_id(key_id)
       Key.find_by(id: key_id)&.user

app/views/groups/labels/index.html.haml

@@ -5,7 +5,7 @@
 - subscribed = params[:subscribed]
 - labels_or_filters = @labels.exists? || search.present? || subscribed.present?
 
-- if can_admin_label
+- if @labels.present? && can_admin_label
   - content_for(:header_content) do
     .nav-controls
       = link_to _('New label'), new_group_label_path(@group), class: "btn btn-success"

app/views/projects/labels/index.html.haml

@@ -5,7 +5,7 @@
 - subscribed = params[:subscribed]
 - labels_or_filters = @labels.exists? || @prioritized_labels.exists? || search.present? || subscribed.present?
 
-- if can_admin_label
+- if @labels.present? && can_admin_label
   - content_for(:header_content) do
     .nav-controls
       = link_to _('New label'), new_project_label_path(@project), class: "btn btn-success qa-label-create-new"

app/views/shared/empty_states/_labels.html.haml

@@ -6,6 +6,9 @@
     .text-content
       %h4= _("Labels can be applied to issues and merge requests to categorize them.")
       %p= _("You can also star a label to make it a priority label.")
-      - if can?(current_user, :admin_label, @project)
-        = link_to _('New label'), new_project_label_path(@project), class: 'btn btn-success', title: _('New label'), id: 'new_label_link'
-        = link_to _('Generate a default set of labels'), generate_project_labels_path(@project), method: :post, class: 'btn btn-success btn-inverted', title: _('Generate a default set of labels'), id: 'generate_labels_link'
+      .text-center
+        - if can?(current_user, :admin_label, @project)
+          = link_to _('New label'), new_project_label_path(@project), class: 'btn btn-success', title: _('New label'), id: 'new_label_link'
+          = link_to _('Generate a default set of labels'), generate_project_labels_path(@project), method: :post, class: 'btn btn-success btn-inverted', title: _('Generate a default set of labels'), id: 'generate_labels_link'
+        - if can?(current_user, :admin_label, @group)
+          = link_to _('New label'), new_group_label_path(@group), class: 'btn btn-success', title: _('New label'), id: 'new_label_link'

changelogs/unreleased/52300-pool-repositories.yml

+---
+title: Start tracking shards and pool repositories in the database
+merge_request: 22482
+author:
+type: other

changelogs/unreleased/52925-scheduled-pipelines-ui-problems.yml

+---
+title: Fixing styling issues on the scheduled pipelines page
+merge_request:
+author:
+type: fixed

changelogs/unreleased/53230-remove_personal_access_tokens_finder_find_by_method.yml

+---
+title: Remove PersonalAccessTokensFinder#find_by method
+merge_request: 22617
+author:
+type: fixed

changelogs/unreleased/53362-allow-concurrency-in-puma.yml

+---
+title: Allow Rails concurrency when running in Puma
+merge_request: 22751
+author:
+type: performance

changelogs/unreleased/gl-ui-tooltip.yml

+---
+title: Remove gitlab-ui's tooltip from global
+merge_request:
+author:
+type: performance

changelogs/unreleased/gt-update-project-and-group-labels-empty-state.yml

+---
+title: Update project and group labels empty state
+merge_request: 22745
+author: George Tsiolis
+type: changed

changelogs/unreleased/sh-fix-issue-52176.yml

+---
+title: Disable replication lag check for Aurora PostgreSQL databases
+merge_request: 22786
+author:
+type: fixed

config/environments/development.rb

@@ -45,4 +45,6 @@ Rails.application.configure do
 
   # Do not log asset requests
   config.assets.quiet = true
+
+  config.allow_concurrency = defined?(::Puma)
 end

config/environments/production.rb

@@ -83,5 +83,5 @@ Rails.application.configure do
 
   config.eager_load = true
 
-  config.allow_concurrency = false
+  config.allow_concurrency = defined?(::Puma)
 end

config/initializers/fill_shards.rb

+return unless Shard.connected?
+return if Gitlab::Database.read_only?
+
+Shard.populate!

db/migrate/20180927073410_add_index_to_project_deploy_tokens_deploy_token_id.rb

+# frozen_string_literal: true
+
+class AddIndexToProjectDeployTokensDeployTokenId < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    # MySQL already has index inserted
+    add_concurrent_index :project_deploy_tokens, :deploy_token_id if Gitlab::Database.postgresql?
+  end
+
+  def down
+    remove_concurrent_index(:project_deploy_tokens, :deploy_token_id) if Gitlab::Database.postgresql?
+  end
+end

db/migrate/20181019032400_add_shards_table.rb

+# frozen_string_literal: true
+
+class AddShardsTable < ActiveRecord::Migration
+  DOWNTIME = false
+
+  def change
+    create_table :shards do |t|
+      t.string :name, null: false, index: { unique: true }
+    end
+  end
+end

db/migrate/20181019032408_add_repositories_table.rb

+# frozen_string_literal: true
+
+class AddRepositoriesTable < ActiveRecord::Migration
+  DOWNTIME = false
+
+  def change
+    create_table :repositories, id: :bigserial do |t|
+      t.references :shard, null: false, index: true, foreign_key: { on_delete: :restrict }
+      t.string :disk_path, null: false, index: { unique: true }
+    end
+
+    add_column :projects, :pool_repository_id, :bigint
+    add_index :projects, :pool_repository_id, where: 'pool_repository_id IS NOT NULL'
+  end
+end

db/migrate/20181019105553_add_projects_pool_repository_id_foreign_key.rb

+# frozen_string_literal: true
+
+class AddProjectsPoolRepositoryIdForeignKey < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    add_concurrent_foreign_key(
+      :projects,
+      :repositories,
+      column: :pool_repository_id,
+      on_delete: :nullify
+    )
+  end
+
+  def down
+    remove_foreign_key(:projects, column: :pool_repository_id)
+  end
+end

db/schema.rb

@@ -2156,6 +2156,7 @@ ActiveRecord::Schema.define(version: 20181101144347) do
     t.datetime_with_timezone "created_at", null: false
   end
 
+  add_index "project_deploy_tokens", ["deploy_token_id"], name: "index_project_deploy_tokens_on_deploy_token_id", using: :btree
   add_index "project_deploy_tokens", ["project_id", "deploy_token_id"], name: "index_project_deploy_tokens_on_project_id_and_deploy_token_id", unique: true, using: :btree
 
   create_table "project_features", force: :cascade do |t|
@@ -2317,6 +2318,7 @@ ActiveRecord::Schema.define(version: 20181101144347) do
     t.string "external_webhook_token"
     t.boolean "packages_enabled"
     t.boolean "merge_requests_author_approval"
+    t.integer "pool_repository_id", limit: 8
   end
 
   add_index "projects", ["ci_id"], name: "index_projects_on_ci_id", using: :btree
@@ -2336,6 +2338,7 @@ ActiveRecord::Schema.define(version: 20181101144347) do
   add_index "projects", ["path"], name: "index_projects_on_path", using: :btree
   add_index "projects", ["path"], name: "index_projects_on_path_trigram", using: :gin, opclasses: {"path"=>"gin_trgm_ops"}
   add_index "projects", ["pending_delete"], name: "index_projects_on_pending_delete", using: :btree
+  add_index "projects", ["pool_repository_id"], name: "index_projects_on_pool_repository_id", where: "(pool_repository_id IS NOT NULL)", using: :btree
   add_index "projects", ["repository_storage", "created_at"], name: "idx_project_repository_check_partial", where: "(last_repository_check_at IS NULL)", using: :btree
   add_index "projects", ["repository_storage"], name: "index_projects_on_repository_storage", using: :btree
   add_index "projects", ["runners_token"], name: "index_projects_on_runners_token", using: :btree
@@ -2558,6 +2561,14 @@ ActiveRecord::Schema.define(version: 20181101144347) do
   add_index "remote_mirrors", ["last_successful_update_at"], name: "index_remote_mirrors_on_last_successful_update_at", using: :btree
   add_index "remote_mirrors", ["project_id"], name: "index_remote_mirrors_on_project_id", using: :btree
 
+  create_table "repositories", id: :bigserial, force: :cascade do |t|
+    t.integer "shard_id", null: false
+    t.string "disk_path", null: false
+  end
+
+  add_index "repositories", ["disk_path"], name: "index_repositories_on_disk_path", unique: true, using: :btree
+  add_index "repositories", ["shard_id"], name: "index_repositories_on_shard_id", using: :btree
+
   create_table "repository_languages", id: false, force: :cascade do |t|
     t.integer "project_id", null: false
     t.integer "programming_language_id", null: false
@@ -2649,6 +2660,12 @@ ActiveRecord::Schema.define(version: 20181101144347) do
   add_index "services", ["project_id"], name: "index_services_on_project_id", using: :btree
   add_index "services", ["template"], name: "index_services_on_template", using: :btree
 
+  create_table "shards", force: :cascade do |t|
+    t.string "name", null: false
+  end
+
+  add_index "shards", ["name"], name: "index_shards_on_name", unique: true, using: :btree
+
   create_table "site_statistics", force: :cascade do |t|
     t.integer "repositories_count", default: 0, null: false
   end
@@ -3363,6 +3380,7 @@ ActiveRecord::Schema.define(version: 20181101144347) do
   add_foreign_key "project_mirror_data", "projects", name: "fk_d1aad367d7", on_delete: :cascade
   add_foreign_key "project_repository_states", "projects", on_delete: :cascade
   add_foreign_key "project_statistics", "projects", on_delete: :cascade
+  add_foreign_key "projects", "repositories", column: "pool_repository_id", name: "fk_6e5c14658a", on_delete: :nullify
   add_foreign_key "prometheus_alert_events", "projects", on_delete: :cascade
   add_foreign_key "prometheus_alert_events", "prometheus_alerts", on_delete: :cascade
   add_foreign_key "prometheus_alerts", "environments", on_delete: :cascade
@@ -3391,6 +3409,7 @@ ActiveRecord::Schema.define(version: 20181101144347) do
   add_foreign_key "push_rules", "projects", name: "fk_83b29894de", on_delete: :cascade
   add_foreign_key "releases", "projects", name: "fk_47fe2a0596", on_delete: :cascade
   add_foreign_key "remote_mirrors", "projects", name: "fk_43a9aa4ca8", on_delete: :cascade
+  add_foreign_key "repositories", "shards", on_delete: :restrict
   add_foreign_key "repository_languages", "projects", on_delete: :cascade
   add_foreign_key "resource_label_events", "epics", on_delete: :cascade
   add_foreign_key "resource_label_events", "issues", on_delete: :cascade

lib/api/users.rb

@@ -518,11 +518,9 @@ module API
               PersonalAccessTokensFinder.new({ user: user, impersonation: true }.merge(options))
             end
 
-            # rubocop: disable CodeReuse/ActiveRecord
             def find_impersonation_token
-              finder.find_by(id: declared_params[:impersonation_token_id]) || not_found!('Impersonation Token')
+              finder.find_by_id(declared_params[:impersonation_token_id]) || not_found!('Impersonation Token')
             end
-            # rubocop: enable CodeReuse/ActiveRecord
           end
 
           before { authenticated_as_admin! }

lib/gitlab/import_export/import_export.yml

@@ -95,6 +95,7 @@ excluded_attributes:
     - :path
     - :namespace_id
     - :creator_id
+    - :pool_repository_id
     - :import_url
     - :import_status
     - :avatar

spec/finders/personal_access_tokens_finder_spec.rb

@@ -92,7 +92,7 @@ describe PersonalAccessTokensFinder do
       end
 
       describe 'with id' do
-        subject { finder(params).find_by(id: active_personal_access_token.id) }
+        subject { finder(params).find_by_id(active_personal_access_token.id) }
 
         it { is_expected.to eq(active_personal_access_token) }
 
@@ -106,7 +106,7 @@ describe PersonalAccessTokensFinder do
       end
 
       describe 'with token' do
-        subject { finder(params).find_by(token: active_personal_access_token.token) }
+        subject { finder(params).find_by_token(active_personal_access_token.token) }
 
         it { is_expected.to eq(active_personal_access_token) }
 
@@ -207,7 +207,7 @@ describe PersonalAccessTokensFinder do
       end
 
       describe 'with id' do
-        subject { finder(params).find_by(id: active_personal_access_token.id) }
+        subject { finder(params).find_by_id(active_personal_access_token.id) }
 
         it { is_expected.to eq(active_personal_access_token) }
 
@@ -221,7 +221,7 @@ describe PersonalAccessTokensFinder do
       end
 
       describe 'with token' do
-        subject { finder(params).find_by(token: active_personal_access_token.token) }
+        subject { finder(params).find_by_token(active_personal_access_token.token) }
 
         it { is_expected.to eq(active_personal_access_token) }
 

spec/lib/gitlab/ci/config/entry/reports_spec.rb

@@ -33,7 +33,7 @@ describe Gitlab::Ci::Config::Entry::Reports do
 
       where(:keyword, :file) do
         :junit | 'junit.xml'
-        :codequality | 'codequality.json'
+        :codequality | 'gl-code-quality-report.json'
         :sast | 'gl-sast-report.json'
         :dependency_scanning | 'gl-dependency-scanning-report.json'
         :container_scanning | 'gl-container-scanning-report.json'

spec/lib/gitlab/import_export/all_models.yml

@@ -298,6 +298,7 @@ project:
 - ci_cd_settings
 - import_export_upload
 - repository_languages
+- pool_repository
 award_emoji:
 - awardable
 - user

spec/models/postgresql/replication_slot_spec.rb

@@ -3,7 +3,27 @@
 require 'spec_helper'
 
 describe Postgresql::ReplicationSlot, :postgresql do
+  describe '.in_use?' do
+    it 'returns true when replication slots are present' do
+      expect(described_class).to receive(:exists?).and_return(true)
+      expect(described_class.in_use?).to be_truthy
+    end
+
+    it 'returns false when replication slots are not present' do
+      expect(described_class.in_use?).to be_falsey
+    end
+
+    it 'returns false if the existence check is invalid' do
+      expect(described_class).to receive(:exists?).and_raise(ActiveRecord::StatementInvalid.new('PG::FeatureNotSupported'))
+      expect(described_class.in_use?).to be_falsey
+    end
+  end
+
   describe '.lag_too_great?' do
+    before do
+      expect(described_class).to receive(:in_use?).and_return(true)
+    end
+
     it 'returns true when replication lag is too great' do
       expect(described_class)
         .to receive(:pluck)

spec/models/project_spec.rb

@@ -8,6 +8,7 @@ describe Project do
     it { is_expected.to belong_to(:group) }
     it { is_expected.to belong_to(:namespace) }
     it { is_expected.to belong_to(:creator).class_name('User') }
+    it { is_expected.to belong_to(:pool_repository) }
     it { is_expected.to have_many(:users) }
     it { is_expected.to have_many(:services) }
     it { is_expected.to have_many(:events) }

spec/models/shard_spec.rb

+# frozen_string_literals: true
+require 'spec_helper'
+
+describe Shard do
+  describe '.populate!' do
+    it 'creates shards based on the config file' do
+      expect(described_class.all).to be_empty
+
+      stub_storage_settings(foo: {}, bar: {}, baz: {})
+
+      described_class.populate!
+
+      expect(described_class.all.map(&:name)).to match_array(%w[default foo bar baz])
+    end
+  end
+
+  describe '.by_name' do
+    let(:default_shard) { described_class.find_by(name: 'default') }
+
+    before do
+      described_class.populate!
+    end
+
+    it 'returns an existing shard' do
+      expect(described_class.by_name('default')).to eq(default_shard)
+    end
+
+    it 'creates a new shard' do
+      result = described_class.by_name('foo')
+
+      expect(result).not_to eq(default_shard)
+      expect(result.name).to eq('foo')
+    end
+
+    it 'retries if creation races' do
+      expect(described_class)
+        .to receive(:find_or_create_by)
+        .with(name: 'default')
+        .and_raise(ActiveRecord::RecordNotUnique, 'fail')
+        .once
+
+      expect(described_class)
+        .to receive(:find_or_create_by)
+        .with(name: 'default')
+        .and_call_original
+
+      expect(described_class.by_name('default')).to eq(default_shard)
+    end
+  end
+end