Class: OnlineMigrations::BackgroundDataMigrations::MigrationStatusValidator

Inherits:
ActiveModel::Validator
  • Object
show all
Defined in:
lib/online_migrations/background_data_migrations/migration_status_validator.rb

Constant Summary collapse

VALID_STATUS_TRANSITIONS =

Valid status transitions a Migration can make.

{
  "pending" => ["enqueued", "paused", "cancelled"],
  # enqueued -> running occurs when the migration starts performing.
  # enqueued -> paused occurs when the migration is paused before starting.
  # enqueued -> cancelled occurs when the migration is cancelled before starting.
  # enqueued -> failed occurs when the migration job fails to be enqueued, or
  #   if the migration is deleted before is starts running.
  "enqueued" => ["running", "paused", "cancelled", "failed"],
  # running -> enqueued occurs when the migration is stuck and rescheduled by the scheduler.
  # running -> succeeded occurs when the migration completes successfully.
  # running -> pausing occurs when a user pauses the migration as it's performing.
  # running -> cancelling occurs when a user cancels the migration as it's performing.
  # running -> errored occurs when the migration raised an error during the last run.
  # running -> failed occurs when the migration raises an error when running and retry attempts exceeded.
  "running" => [
    "enqueued",
    "succeeded",
    "pausing",
    "cancelling",
    "errored",
    "failed",
  ],
  # pausing -> paused occurs when the migration actually halts performing and
  #   occupies a status of paused.
  # pausing -> cancelling occurs when the user cancels a migration immediately
  #   after it was paused, such that the migration had not actually halted yet.
  # pausing -> succeeded occurs when the migration completes immediately after
  #   being paused. This can happen if the migration is on its last iteration
  #   when it is paused, or if the migration is paused after enqueue but has
  #   nothing in its collection to process.
  # pausing -> failed occurs when the job raises an exception after the
  #   user has paused it.
  "pausing" => ["paused", "cancelling", "succeeded", "errored", "failed"],
  # paused -> pending occurs when the migration is resumed after being paused.
  # paused -> cancelled when the user cancels the migration after it is paused.
  "paused" => ["pending", "cancelled"],
  "errored" => ["running", "failed", "cancelled", "paused"],
  # failed -> pending occurs when the migration is retried after encounting an error.
  "failed" => ["pending"],
  # cancelling -> cancelled occurs when the migration actually halts performing
  #   and occupies a status of cancelled.
  # cancelling -> succeeded occurs when the migration completes immediately after
  #   being cancelled. See description for pausing -> succeeded.
  # cancelling -> failed occurs when the job raises an exception after the
  #   user has cancelled it.
  "cancelling" => ["cancelled", "succeeded", "errored", "failed"],
  # delayed -> pending occurs when the delayed migration was approved by the user to start running.
  # delayed -> cancelled occurs when the delayed migration was cancelled.
  "delayed" => ["pending", "cancelled"],
}

Instance Method Summary collapse

Instance Method Details

#validate(record) ⇒ Object 



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# File 'lib/online_migrations/background_data_migrations/migration_status_validator.rb', line 59

def validate(record)
  return if !record.status_changed?

  previous_status, new_status = record.status_change
  valid_new_statuses = VALID_STATUS_TRANSITIONS.fetch(previous_status, [])

  if !valid_new_statuses.include?(new_status)
    record.errors.add(
      :status,
      "cannot transition data migration from status '#{previous_status}' to '#{new_status}'"
    )
  end
end