services/api/app/models/container.rb

   1 # Copyright (C) The Arvados Authors. All rights reserved.
   2 #
   3 # SPDX-License-Identifier: AGPL-3.0
   4
   5 require 'log_reuse_info'
   6 require 'whitelist_update'
   7 require 'safe_json'
   8 require 'update_priority'
   9
  10 class Container < ArvadosModel
  11   include ArvadosModelUpdates
  12   include HasUuid
  13   include KindAndEtag
  14   include CommonApiTemplate
  15   include WhitelistUpdate
  16   extend CurrentApiClient
  17   extend DbCurrentTime
  18   extend LogReuseInfo
  19
  20   serialize :environment, Hash
  21   serialize :mounts, Hash
  22   serialize :runtime_constraints, Hash
  23   serialize :command, Array
  24   serialize :scheduling_parameters, Hash
  25   serialize :secret_mounts, Hash
  26   serialize :runtime_status, Hash
  27
  28   before_validation :fill_field_defaults, :if => :new_record?
  29   before_validation :set_timestamps
  30   validates :command, :container_image, :output_path, :cwd, :priority, { presence: true }
  31   validates :priority, numericality: { only_integer: true, greater_than_or_equal_to: 0 }
  32   validate :validate_runtime_status
  33   validate :validate_state_change
  34   validate :validate_change
  35   validate :validate_lock
  36   validate :validate_output
  37   after_validation :assign_auth
  38   before_save :sort_serialized_attrs
  39   before_save :update_secret_mounts_md5
  40   before_save :scrub_secrets
  41   before_save :clear_runtime_status_when_queued
  42   after_save :update_cr_logs
  43   after_save :handle_completed
  44   after_save :propagate_priority
  45   after_commit { UpdatePriority.run_update_thread }
  46
  47   has_many :container_requests, :foreign_key => :container_uuid, :class_name => 'ContainerRequest', :primary_key => :uuid
  48   belongs_to :auth, :class_name => 'ApiClientAuthorization', :foreign_key => :auth_uuid, :primary_key => :uuid
  49
  50   api_accessible :user, extend: :common do |t|
  51     t.add :command
  52     t.add :container_image
  53     t.add :cwd
  54     t.add :environment
  55     t.add :exit_code
  56     t.add :finished_at
  57     t.add :locked_by_uuid
  58     t.add :log
  59     t.add :mounts
  60     t.add :output
  61     t.add :output_path
  62     t.add :priority
  63     t.add :progress
  64     t.add :runtime_constraints
  65     t.add :runtime_status
  66     t.add :started_at
  67     t.add :state
  68     t.add :auth_uuid
  69     t.add :scheduling_parameters
  70     t.add :runtime_user_uuid
  71     t.add :runtime_auth_scopes
  72   end
  73
  74   # Supported states for a container
  75   States =
  76     [
  77      (Queued = 'Queued'),
  78      (Locked = 'Locked'),
  79      (Running = 'Running'),
  80      (Complete = 'Complete'),
  81      (Cancelled = 'Cancelled')
  82     ]
  83
  84   State_transitions = {
  85     nil => [Queued],
  86     Queued => [Locked, Cancelled],
  87     Locked => [Queued, Running, Cancelled],
  88     Running => [Complete, Cancelled]
  89   }
  90
  91   def self.limit_index_columns_read
  92     ["mounts"]
  93   end
  94
  95   def self.full_text_searchable_columns
  96     super - ["secret_mounts", "secret_mounts_md5", "runtime_token"]
  97   end
  98
  99   def self.searchable_columns *args
 100     super - ["secret_mounts_md5", "runtime_token"]
 101   end
 102
 103   def logged_attributes
 104     super.except('secret_mounts', 'runtime_token')
 105   end
 106
 107   def state_transitions
 108     State_transitions
 109   end
 110
 111   # Container priority is the highest "computed priority" of any
 112   # matching request. The computed priority of a container-submitted
 113   # request is the priority of the submitting container. The computed
 114   # priority of a user-submitted request is a function of
 115   # user-assigned priority and request creation time.
 116   def update_priority!
 117     return if ![Queued, Locked, Running].include?(state)
 118     p = ContainerRequest.
 119         where('container_uuid=? and priority>0', uuid).
 120         includes(:requesting_container).
 121         lock(true).
 122         map do |cr|
 123       if cr.requesting_container
 124         cr.requesting_container.priority
 125       else
 126         (cr.priority << 50) - (cr.created_at.to_time.to_f * 1000).to_i
 127       end
 128     end.max || 0
 129     update_attributes!(priority: p)
 130   end
 131
 132   def propagate_priority
 133     return true unless priority_changed?
 134     act_as_system_user do
 135       # Update the priority of child container requests to match new
 136       # priority of the parent container (ignoring requests with no
 137       # container assigned, because their priority doesn't matter).
 138       ContainerRequest.
 139         where(requesting_container_uuid: self.uuid,
 140               state: ContainerRequest::Committed).
 141         where('container_uuid is not null').
 142         includes(:container).
 143         map(&:container).
 144         map(&:update_priority!)
 145     end
 146   end
 147
 148   # Create a new container (or find an existing one) to satisfy the
 149   # given container request.
 150   def self.resolve(req)
 151     if req.runtime_token.nil?
 152       runtime_user = if req.modified_by_user_uuid.nil?
 153                        current_user
 154                      else
 155                        User.find_by_uuid(req.modified_by_user_uuid)
 156                      end
 157       runtime_auth_scopes = ["all"]
 158     else
 159       auth = ApiClientAuthorization.validate(token: req.runtime_token)
 160       if auth.nil?
 161         raise ArgumentError.new "Invalid runtime token"
 162       end
 163       runtime_user = User.find_by_id(auth.user_id)
 164       runtime_auth_scopes = auth.scopes
 165     end
 166     c_attrs = act_as_user runtime_user do
 167       {
 168         command: req.command,
 169         cwd: req.cwd,
 170         environment: req.environment,
 171         output_path: req.output_path,
 172         container_image: resolve_container_image(req.container_image),
 173         mounts: resolve_mounts(req.mounts),
 174         runtime_constraints: resolve_runtime_constraints(req.runtime_constraints),
 175         scheduling_parameters: req.scheduling_parameters,
 176         secret_mounts: req.secret_mounts,
 177         runtime_token: req.runtime_token,
 178         runtime_user_uuid: runtime_user.uuid,
 179         runtime_auth_scopes: runtime_auth_scopes
 180       }
 181     end
 182     act_as_system_user do
 183       if req.use_existing && (reusable = find_reusable(c_attrs))
 184         reusable
 185       else
 186         Container.create!(c_attrs)
 187       end
 188     end
 189   end
 190
 191   # Return a runtime_constraints hash that complies with requested but
 192   # is suitable for saving in a container record, i.e., has specific
 193   # values instead of ranges.
 194   #
 195   # Doing this as a step separate from other resolutions, like "git
 196   # revision range to commit hash", makes sense only when there is no
 197   # opportunity to reuse an existing container (e.g., container reuse
 198   # is not implemented yet, or we have already found that no existing
 199   # containers are suitable).
 200   def self.resolve_runtime_constraints(runtime_constraints)
 201     rc = {}
 202     defaults = {
 203       'keep_cache_ram' =>
 204       Rails.configuration.container_default_keep_cache_ram,
 205     }
 206     defaults.merge(runtime_constraints).each do |k, v|
 207       if v.is_a? Array
 208         rc[k] = v[0]
 209       else
 210         rc[k] = v
 211       end
 212     end
 213     rc
 214   end
 215
 216   # Return a mounts hash suitable for a Container, i.e., with every
 217   # readonly collection UUID resolved to a PDH.
 218   def self.resolve_mounts(mounts)
 219     c_mounts = {}
 220     mounts.each do |k, mount|
 221       mount = mount.dup
 222       c_mounts[k] = mount
 223       if mount['kind'] != 'collection'
 224         next
 225       end
 226
 227       uuid = mount.delete 'uuid'
 228
 229       if mount['portable_data_hash'].nil? and !uuid.nil?
 230         # PDH not supplied, try by UUID
 231         c = Collection.
 232           readable_by(current_user).
 233           where(uuid: uuid).
 234           select(:portable_data_hash).
 235           first
 236         if !c
 237           raise ArvadosModel::UnresolvableContainerError.new "cannot mount collection #{uuid.inspect}: not found"
 238         end
 239         mount['portable_data_hash'] = c.portable_data_hash
 240       end
 241     end
 242     return c_mounts
 243   end
 244
 245   # Return a container_image PDH suitable for a Container.
 246   def self.resolve_container_image(container_image)
 247     coll = Collection.for_latest_docker_image(container_image)
 248     if !coll
 249       raise ArvadosModel::UnresolvableContainerError.new "docker image #{container_image.inspect} not found"
 250     end
 251     coll.portable_data_hash
 252   end
 253
 254   def self.find_reusable(attrs)
 255     log_reuse_info { "starting with #{Container.all.count} container records in database" }
 256     candidates = Container.where_serialized(:command, attrs[:command], md5: true)
 257     log_reuse_info(candidates) { "after filtering on command #{attrs[:command].inspect}" }
 258
 259     candidates = candidates.where('cwd = ?', attrs[:cwd])
 260     log_reuse_info(candidates) { "after filtering on cwd #{attrs[:cwd].inspect}" }
 261
 262     candidates = candidates.where_serialized(:environment, attrs[:environment], md5: true)
 263     log_reuse_info(candidates) { "after filtering on environment #{attrs[:environment].inspect}" }
 264
 265     candidates = candidates.where('output_path = ?', attrs[:output_path])
 266     log_reuse_info(candidates) { "after filtering on output_path #{attrs[:output_path].inspect}" }
 267
 268     image = resolve_container_image(attrs[:container_image])
 269     candidates = candidates.where('container_image = ?', image)
 270     log_reuse_info(candidates) { "after filtering on container_image #{image.inspect} (resolved from #{attrs[:container_image].inspect})" }
 271
 272     candidates = candidates.where_serialized(:mounts, resolve_mounts(attrs[:mounts]), md5: true)
 273     log_reuse_info(candidates) { "after filtering on mounts #{attrs[:mounts].inspect}" }
 274
 275     secret_mounts_md5 = Digest::MD5.hexdigest(SafeJSON.dump(self.deep_sort_hash(attrs[:secret_mounts])))
 276     candidates = candidates.where('secret_mounts_md5 = ?', secret_mounts_md5)
 277     log_reuse_info(candidates) { "after filtering on secret_mounts_md5 #{secret_mounts_md5.inspect}" }
 278
 279     candidates = candidates.where_serialized(:runtime_constraints, resolve_runtime_constraints(attrs[:runtime_constraints]), md5: true)
 280     log_reuse_info(candidates) { "after filtering on runtime_constraints #{attrs[:runtime_constraints].inspect}" }
 281
 282     log_reuse_info { "checking for state=Complete with readable output and log..." }
 283
 284     select_readable_pdh = Collection.
 285       readable_by(current_user).
 286       select(:portable_data_hash).
 287       to_sql
 288
 289     usable = candidates.where(state: Complete, exit_code: 0)
 290     log_reuse_info(usable) { "with state=Complete, exit_code=0" }
 291
 292     usable = usable.where("log IN (#{select_readable_pdh})")
 293     log_reuse_info(usable) { "with readable log" }
 294
 295     usable = usable.where("output IN (#{select_readable_pdh})")
 296     log_reuse_info(usable) { "with readable output" }
 297
 298     usable = usable.order('finished_at ASC').limit(1).first
 299     if usable
 300       log_reuse_info { "done, reusing container #{usable.uuid} with state=Complete" }
 301       return usable
 302     end
 303
 304     # Check for non-failing Running candidates and return the most likely to finish sooner.
 305     log_reuse_info { "checking for state=Running..." }
 306     running = candidates.where(state: Running).
 307               where("(runtime_status->'error') is null").
 308               order('progress desc, started_at asc').
 309               limit(1).first
 310     if running
 311       log_reuse_info { "done, reusing container #{running.uuid} with state=Running" }
 312       return running
 313     else
 314       log_reuse_info { "have no containers in Running state" }
 315     end
 316
 317     # Check for Locked or Queued ones and return the most likely to start first.
 318     locked_or_queued = candidates.
 319                        where("state IN (?)", [Locked, Queued]).
 320                        order('state asc, priority desc, created_at asc').
 321                        limit(1).first
 322     if locked_or_queued
 323       log_reuse_info { "done, reusing container #{locked_or_queued.uuid} with state=#{locked_or_queued.state}" }
 324       return locked_or_queued
 325     else
 326       log_reuse_info { "have no containers in Locked or Queued state" }
 327     end
 328
 329     log_reuse_info { "done, no reusable container found" }
 330     nil
 331   end
 332
 333   def check_lock_fail
 334     if self.state != Queued
 335       raise LockFailedError.new("cannot lock when #{self.state}")
 336     elsif self.priority <= 0
 337       raise LockFailedError.new("cannot lock when priority<=0")
 338     end
 339   end
 340
 341   def lock
 342     # Check invalid state transitions once before getting the lock
 343     # (because it's cheaper that way) and once after getting the lock
 344     # (because state might have changed while acquiring the lock).
 345     check_lock_fail
 346     transaction do
 347       reload
 348       check_lock_fail
 349       update_attributes!(state: Locked, lock_count: self.lock_count+1)
 350     end
 351   end
 352
 353   def check_unlock_fail
 354     if self.state != Locked
 355       raise InvalidStateTransitionError.new("cannot unlock when #{self.state}")
 356     elsif self.locked_by_uuid != current_api_client_authorization.uuid
 357       raise InvalidStateTransitionError.new("locked by a different token")
 358     end
 359   end
 360
 361   def unlock
 362     # Check invalid state transitions twice (see lock)
 363     check_unlock_fail
 364     transaction do
 365       reload(lock: 'FOR UPDATE')
 366       check_unlock_fail
 367       if self.lock_count < Rails.configuration.max_container_dispatch_attempts
 368         update_attributes!(state: Queued)
 369       else
 370         update_attributes!(state: Cancelled,
 371                            runtime_status: {
 372                              error: "Container exceeded 'max_container_dispatch_attempts' (lock_count=#{self.lock_count}."
 373                            })
 374       end
 375     end
 376   end
 377
 378   def self.readable_by(*users_list)
 379     # Load optional keyword arguments, if they exist.
 380     if users_list.last.is_a? Hash
 381       kwargs = users_list.pop
 382     else
 383       kwargs = {}
 384     end
 385     Container.where(ContainerRequest.readable_by(*users_list).where("containers.uuid = container_requests.container_uuid").exists)
 386   end
 387
 388   def final?
 389     [Complete, Cancelled].include?(self.state)
 390   end
 391
 392   def self.for_current_token
 393     return if !current_api_client_authorization
 394     _, _, _, container_uuid = Thread.current[:token].split('/')
 395     if container_uuid.nil?
 396       Container.where(auth_uuid: current_api_client_authorization.uuid).first
 397     else
 398       Container.where('auth_uuid=? or (uuid=? and runtime_token=?)',
 399                       current_api_client_authorization.uuid,
 400                       container_uuid,
 401                       current_api_client_authorization.token).first
 402     end
 403   end
 404
 405   protected
 406
 407   def fill_field_defaults
 408     self.state ||= Queued
 409     self.environment ||= {}
 410     self.runtime_constraints ||= {}
 411     self.mounts ||= {}
 412     self.cwd ||= "."
 413     self.priority ||= 0
 414     self.scheduling_parameters ||= {}
 415   end
 416
 417   def permission_to_create
 418     current_user.andand.is_admin
 419   end
 420
 421   def ensure_owner_uuid_is_permitted
 422     # validate_change ensures owner_uuid can't be changed at all --
 423     # except during create, which requires admin privileges. Checking
 424     # permission here would be superfluous.
 425     true
 426   end
 427
 428   def set_timestamps
 429     if self.state_changed? and self.state == Running
 430       self.started_at ||= db_current_time
 431     end
 432
 433     if self.state_changed? and [Complete, Cancelled].include? self.state
 434       self.finished_at ||= db_current_time
 435     end
 436   end
 437
 438   # Check that well-known runtime status keys have desired data types
 439   def validate_runtime_status
 440     [
 441       'error', 'errorDetail', 'warning', 'warningDetail', 'activity'
 442     ].each do |k|
 443       if self.runtime_status.andand.include?(k) && !self.runtime_status[k].is_a?(String)
 444         errors.add(:runtime_status, "'#{k}' value must be a string")
 445       end
 446     end
 447   end
 448
 449   def validate_change
 450     permitted = [:state]
 451     progress_attrs = [:progress, :runtime_status, :log, :output]
 452     final_attrs = [:exit_code, :finished_at]
 453
 454     if self.new_record?
 455       permitted.push(:owner_uuid, :command, :container_image, :cwd,
 456                      :environment, :mounts, :output_path, :priority,
 457                      :runtime_constraints, :scheduling_parameters,
 458                      :secret_mounts, :runtime_token,
 459                      :runtime_user_uuid, :runtime_auth_scopes)
 460     end
 461
 462     case self.state
 463     when Locked
 464       permitted.push :priority, :runtime_status, :log, :lock_count
 465
 466     when Queued
 467       permitted.push :priority
 468
 469     when Running
 470       permitted.push :priority, *progress_attrs
 471       if self.state_changed?
 472         permitted.push :started_at
 473       end
 474
 475     when Complete
 476       if self.state_was == Running
 477         permitted.push *final_attrs, *progress_attrs
 478       end
 479
 480     when Cancelled
 481       case self.state_was
 482       when Running
 483         permitted.push :finished_at, *progress_attrs
 484       when Queued, Locked
 485         permitted.push :finished_at, :log, :runtime_status
 486       end
 487
 488     else
 489       # The state_transitions check will add an error message for this
 490       return false
 491     end
 492
 493     if self.state == Running &&
 494        !current_api_client_authorization.nil? &&
 495        (current_api_client_authorization.uuid == self.auth_uuid ||
 496         current_api_client_authorization.token == self.runtime_token)
 497       # The contained process itself can write final attrs but can't
 498       # change priority or log.
 499       permitted.push *final_attrs
 500       permitted = permitted - [:log, :priority]
 501     elsif self.locked_by_uuid && self.locked_by_uuid != current_api_client_authorization.andand.uuid
 502       # When locked, progress fields cannot be updated by the wrong
 503       # dispatcher, even though it has admin privileges.
 504       permitted = permitted - progress_attrs
 505     end
 506     check_update_whitelist permitted
 507   end
 508
 509   def validate_lock
 510     if [Locked, Running].include? self.state
 511       # If the Container was already locked, locked_by_uuid must not
 512       # changes. Otherwise, the current auth gets the lock.
 513       need_lock = locked_by_uuid_was || current_api_client_authorization.andand.uuid
 514     else
 515       need_lock = nil
 516     end
 517
 518     # The caller can provide a new value for locked_by_uuid, but only
 519     # if it's exactly what we expect. This allows a caller to perform
 520     # an update like {"state":"Unlocked","locked_by_uuid":null}.
 521     if self.locked_by_uuid_changed?
 522       if self.locked_by_uuid != need_lock
 523         return errors.add :locked_by_uuid, "can only change to #{need_lock}"
 524       end
 525     end
 526     self.locked_by_uuid = need_lock
 527   end
 528
 529   def validate_output
 530     # Output must exist and be readable by the current user.  This is so
 531     # that a container cannot "claim" a collection that it doesn't otherwise
 532     # have access to just by setting the output field to the collection PDH.
 533     if output_changed?
 534       c = Collection.
 535             readable_by(current_user, {include_trash: true}).
 536             where(portable_data_hash: self.output).
 537             first
 538       if !c
 539         errors.add :output, "collection must exist and be readable by current user."
 540       end
 541     end
 542   end
 543
 544   def update_cr_logs
 545     # If self.final?, this update is superfluous: the final log/output
 546     # update will be done when handle_completed calls finalize! on
 547     # each requesting CR.
 548     return if self.final? || !self.log_changed?
 549     leave_modified_by_user_alone do
 550       ContainerRequest.where(container_uuid: self.uuid).each do |cr|
 551         cr.update_collections(container: self, collections: ['log'])
 552         cr.save!
 553       end
 554     end
 555   end
 556
 557   def assign_auth
 558     if self.auth_uuid_changed?
 559          return errors.add :auth_uuid, 'is readonly'
 560     end
 561     if not [Locked, Running].include? self.state
 562       # don't need one
 563       self.auth.andand.update_attributes(expires_at: db_current_time)
 564       self.auth = nil
 565       return
 566     elsif self.auth
 567       # already have one
 568       return
 569     end
 570     if self.runtime_token.nil?
 571       if self.runtime_user_uuid.nil?
 572         # legacy behavior, we don't have a runtime_user_uuid so get
 573         # the user from the highest priority container request, needed
 574         # when performing an upgrade and there are queued containers,
 575         # and some tests.
 576         cr = ContainerRequest.
 577                where('container_uuid=? and priority>0', self.uuid).
 578                order('priority desc').
 579                first
 580         if !cr
 581           return errors.add :auth_uuid, "cannot be assigned because priority <= 0"
 582         end
 583         self.runtime_user_uuid = cr.modified_by_user_uuid
 584         self.runtime_auth_scopes = ["all"]
 585       end
 586
 587       # generate a new token
 588       self.auth = ApiClientAuthorization.
 589                     create!(user_id: User.find_by_uuid(self.runtime_user_uuid).id,
 590                             api_client_id: 0,
 591                             scopes: self.runtime_auth_scopes)
 592     end
 593   end
 594
 595   def sort_serialized_attrs
 596     if self.environment_changed?
 597       self.environment = self.class.deep_sort_hash(self.environment)
 598     end
 599     if self.mounts_changed?
 600       self.mounts = self.class.deep_sort_hash(self.mounts)
 601     end
 602     if self.runtime_constraints_changed?
 603       self.runtime_constraints = self.class.deep_sort_hash(self.runtime_constraints)
 604     end
 605     if self.scheduling_parameters_changed?
 606       self.scheduling_parameters = self.class.deep_sort_hash(self.scheduling_parameters)
 607     end
 608     if self.runtime_auth_scopes_changed?
 609       self.runtime_auth_scopes = self.runtime_auth_scopes.sort
 610     end
 611   end
 612
 613   def update_secret_mounts_md5
 614     if self.secret_mounts_changed?
 615       self.secret_mounts_md5 = Digest::MD5.hexdigest(
 616         SafeJSON.dump(self.class.deep_sort_hash(self.secret_mounts)))
 617     end
 618   end
 619
 620   def scrub_secrets
 621     # this runs after update_secret_mounts_md5, so the
 622     # secret_mounts_md5 will still reflect the secrets that are being
 623     # scrubbed here.
 624     if self.state_changed? && self.final?
 625       self.secret_mounts = {}
 626       self.runtime_token = nil
 627     end
 628   end
 629
 630   def clear_runtime_status_when_queued
 631     # Avoid leaking status messages between different dispatch attempts
 632     if self.state_was == Locked && self.state == Queued
 633       self.runtime_status = {}
 634     end
 635   end
 636
 637   def handle_completed
 638     # This container is finished so finalize any associated container requests
 639     # that are associated with this container.
 640     if self.state_changed? and self.final?
 641       act_as_system_user do
 642
 643         if self.state == Cancelled
 644           retryable_requests = ContainerRequest.where("container_uuid = ? and priority > 0 and state = 'Committed' and container_count < container_count_max", uuid)
 645         else
 646           retryable_requests = []
 647         end
 648
 649         if retryable_requests.any?
 650           c_attrs = {
 651             command: self.command,
 652             cwd: self.cwd,
 653             environment: self.environment,
 654             output_path: self.output_path,
 655             container_image: self.container_image,
 656             mounts: self.mounts,
 657             runtime_constraints: self.runtime_constraints,
 658             scheduling_parameters: self.scheduling_parameters,
 659             secret_mounts: self.secret_mounts_was,
 660             runtime_token: self.runtime_token_was,
 661             runtime_user_uuid: self.runtime_user_uuid,
 662             runtime_auth_scopes: self.runtime_auth_scopes
 663           }
 664           c = Container.create! c_attrs
 665           retryable_requests.each do |cr|
 666             cr.with_lock do
 667               leave_modified_by_user_alone do
 668                 # Use row locking because this increments container_count
 669                 cr.container_uuid = c.uuid
 670                 cr.save!
 671               end
 672             end
 673           end
 674         end
 675
 676         # Notify container requests associated with this container
 677         ContainerRequest.where(container_uuid: uuid,
 678                                state: ContainerRequest::Committed).each do |cr|
 679           leave_modified_by_user_alone do
 680             cr.finalize!
 681           end
 682         end
 683
 684         # Cancel outstanding container requests made by this container.
 685         ContainerRequest.
 686           includes(:container).
 687           where(requesting_container_uuid: uuid,
 688                 state: ContainerRequest::Committed).each do |cr|
 689           leave_modified_by_user_alone do
 690             cr.update_attributes!(priority: 0)
 691             cr.container.reload
 692             if cr.container.state == Container::Queued || cr.container.state == Container::Locked
 693               # If the child container hasn't started yet, finalize the
 694               # child CR now instead of leaving it "on hold", i.e.,
 695               # Queued with priority 0.  (OTOH, if the child is already
 696               # running, leave it alone so it can get cancelled the
 697               # usual way, get a copy of the log collection, etc.)
 698               cr.update_attributes!(state: ContainerRequest::Final)
 699             end
 700           end
 701         end
 702       end
 703     end
 704   end
 705 end