Class: Cells::TransactionRecord

Inherits:
Object
  • Object
show all
Defined in:
app/models/cells/transaction_record.rb

Overview

This class is a fake ActiveRecord::Base which implements the interface partially so that it can be used with ActiveRecord::ConnectionAdapters::Transaction#add_record github.com/rails/rails/blob/v7.1.5.2/activerecord/lib/active_record/connection_adapters/abstract/transaction.rb#L147-L155 From there, several methods are required to be implemented:

  • #before_committed!

    • Normally implemented by ActiveRecord::Transactions

  • #committed!

    • Normally implemented by ActiveRecord::Transactions

  • #rolledback!

    • Normally implemented by ActiveRecord::Transactions

  • #trigger_transactional_callbacks?

    • Normally implemented by ActiveRecord::Transactions

    • Overridden by Cells::TransactionRecord to avoid more interfaces needed

  • #destroyed?

    • Normally implemented by ActiveRecord::Persistence but we ignore it

  • #_new_record_before_last_commit

    • Normally implemented by ActiveRecord::Transactions

We ignore some methods because they won’t be called under specific conditions, specifically when the following both return true:

  • #trigger_transactional_callbacks?

Defined Under Namespace

Modules: TransactionExtension

Constant Summary collapse

Error = 
Class.new(RuntimeError)
TIMEOUT_IN_SECONDS = 
0.2

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(connection, transaction) ⇒ TransactionRecord

Returns a new instance of TransactionRecord.



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# File 'app/models/cells/transaction_record.rb', line 61

def initialize(connection, transaction)
  @connection = connection
  @transaction = transaction
  @create_records = []
  @destroy_records = []
  @outstanding_lease = nil
  @done = false
end

Class Method Details

.current_transaction(connection) ⇒ Object

Extend the transaction class with an accessor to store a TransactionRecord in cells_current_transaction_record. Each transaction object is unique, and Rails manages their lifecycle, so explicit cleanup isn’t required. Nested transactions aren’t supported or expected in this design.



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# File 'app/models/cells/transaction_record.rb', line 38

def self.current_transaction(connection)
  return unless Current.cells_claims_leases?

  # The Cells::OutstandingLease requires a transaction to be open
  # to ensure that the lease is only created if the transaction
  # within a transaction and not outside of one
  if connection.current_transaction.closed?
    raise Error, 'The Cells::TransactionRecord requires transaction to be open'
  end

  current_transaction = connection.current_transaction

  instance = current_transaction.cells_current_transaction_record
  return instance if instance

  TransactionRecord.new(connection, current_transaction).tap do |instance|
    current_transaction.cells_current_transaction_record = instance
    # https://api.rubyonrails.org/v7.1.5.2/classes/ActiveRecord/ConnectionAdapters/DatabaseStatements.html#method-i-add_transaction_record
    # https://github.com/rails/rails/blob/v7.1.5.2/activerecord/lib/active_record/connection_adapters/abstract/transaction.rb#L147-L155
    current_transaction.add_record(instance)
  end
end

Instance Method Details

#before_committed! ⇒ Object 



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# File 'app/models/cells/transaction_record.rb', line 90

def before_committed!
  raise Error, 'Already done' if done
  raise Error, 'Already created lease' if outstanding_lease
  raise Error, 'Attributes can now only be claimed on main DB' if Cells::OutstandingLease.connection != @connection

  @outstanding_lease = Cells::OutstandingLease.create_from_request!(
    create_records: sanitize_records_for_grpc(create_records),
    destroy_records: sanitize_records_for_grpc(destroy_records),
    deadline: deadline
  )
rescue GRPC::BadStatus => e
  raise_committing_error!(e)
  raise ActiveRecord::Rollback
end

#committed!(should_run_callbacks: true) ⇒ Object

rubocop:disable Lint/UnusedMethodArgument – this needs to follow the interface

Raises:



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# File 'app/models/cells/transaction_record.rb', line 117

def committed!(should_run_callbacks: true) # rubocop:disable Lint/UnusedMethodArgument -- this needs to follow the interface
  raise Error, 'Already done' if done
  raise Error, 'No lease created' unless outstanding_lease

  outstanding_lease.send_commit_update!(deadline: deadline)
  outstanding_lease.destroy! # the lease is no longer needed
  @done = true
end

#create_record(metadata) ⇒ Object

Raises:



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# File 'app/models/cells/transaction_record.rb', line 70

def create_record(metadata)
  raise Error, 'Lease already created' if outstanding_lease

  create_records << metadata
end

#destroy_record(metadata) ⇒ Object

Raises:



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# File 'app/models/cells/transaction_record.rb', line 76

def destroy_record(metadata)
  raise Error, 'Lease already created' if outstanding_lease

  destroy_records << metadata
end

#rolledback!(force_restore_state: false, should_run_callbacks: true) ⇒ Object

rubocop:disable Lint/UnusedMethodArgument – this needs to follow the interface

Raises:



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# File 'app/models/cells/transaction_record.rb', line 105

def rolledback!(force_restore_state: false, should_run_callbacks: true) # rubocop:disable Lint/UnusedMethodArgument -- this needs to follow the interface
  raise Error, 'Already done' if done

  # It is possible that lease might be not created yet,
  # since the transaction might be rolledback prematurely
  return unless outstanding_lease

  outstanding_lease.send_rollback_update!(deadline: deadline)
  outstanding_lease.destroy! # the lease is no longer needed
  @done = true
end

#trigger_transactional_callbacks? ⇒ Boolean

Always trigger callbacks. See: ActiveRecord::ConnectionAdapters::Transaction#

prepare_instances_to_run_callbacks_on

github.com/rails/rails/blob/v7.1.5.2/activerecord/lib/active_record/connection_adapters/abstract/transaction.rb#L269

Returns:

  • (Boolean) 


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# File 'app/models/cells/transaction_record.rb', line 86

def trigger_transactional_callbacks?
  true
end