Class: OnlineMigrations::BackgroundMigrations::MigrationRunner

Inherits:
Object
  • Object
show all
Defined in:
lib/online_migrations/background_migrations/migration_runner.rb

Overview

Runs single background migration.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(migration) ⇒ MigrationRunner

Returns a new instance of MigrationRunner.



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# File 'lib/online_migrations/background_migrations/migration_runner.rb', line 9

def initialize(migration)
  @migration = migration
end

Instance Attribute Details

#migration ⇒ Object (readonly)

Returns the value of attribute migration.



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# File 'lib/online_migrations/background_migrations/migration_runner.rb', line 7

def migration
  @migration
end

Instance Method Details

#finish ⇒ Object

Finishes the background migration.

Keep running until the migration is finished.



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# File 'lib/online_migrations/background_migrations/migration_runner.rb', line 80

def finish
  return if migration.completed? || migration.cancelled?

  if migration.composite?
    migration.children.each do |child_migration|
      runner = self.class.new(child_migration)
      runner.finish
    end
  else
    # Mark is as finishing to avoid being picked up
    # by the background migrations scheduler.
    migration.finishing!
    migration.reset_failed_jobs_attempts

    while migration.finishing?
      run_migration_job
    end
  end
end

#run_all_migration_jobs ⇒ Object

Note:

This method should not be used in production environments

Runs the background migration until completion.



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# File 'lib/online_migrations/background_migrations/migration_runner.rb', line 54

def run_all_migration_jobs
  run_inline = OnlineMigrations.config.run_background_migrations_inline
  if run_inline && !run_inline.call
    raise "This method is not intended for use in production environments"
  end

  return if migration.completed? || migration.cancelled?

  mark_as_running

  if migration.composite?
    migration.children.each do |child_migration|
      runner = self.class.new(child_migration)
      runner.run_all_migration_jobs
    end
  else
    while migration.running?
      run_migration_job
    end
  end
end

#run_migration_job ⇒ Object

Runs one background migration job.



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# File 'lib/online_migrations/background_migrations/migration_runner.rb', line 14

def run_migration_job
  raise "Should not be called on a composite (with sharding) migration" if migration.composite?
  return if migration.cancelled? || migration.succeeded?

  mark_as_running if migration.enqueued?
  migration_payload = notifications_payload(migration)

  if !migration.migration_jobs.exists?
    ActiveSupport::Notifications.instrument("started.background_migrations", migration_payload)
  end

  if should_throttle?
    ActiveSupport::Notifications.instrument("throttled.background_migrations", migration_payload)
    return
  end

  next_migration_job = find_or_create_next_migration_job

  if next_migration_job
    job_runner = MigrationJobRunner.new(next_migration_job)
    job_runner.run
  elsif !migration.migration_jobs.active.exists?
    if migration.migration_jobs.failed.exists?
      migration.failed!
    else
      migration.succeeded!
    end

    ActiveSupport::Notifications.instrument("completed.background_migrations", migration_payload)

    complete_parent_if_needed(migration) if migration.parent.present?
  end

  next_migration_job
end