Class: StrongMigrations::Checker

Inherits:
Object
  • Object
show all
Includes:
Checks, SafeMethods
Defined in:
lib/strong_migrations/checker.rb

Class Attribute Summary collapse

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from SafeMethods

#disable_transaction, #in_transaction?, #safe_add_check_constraint, #safe_add_foreign_key, #safe_add_index, #safe_add_reference, #safe_by_default_method?, #safe_change_column_null, #safe_remove_index

Constructor Details

#initialize(migration) ⇒ Checker

Returns a new instance of Checker.



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# File 'lib/strong_migrations/checker.rb', line 12

def initialize(migration)
  @migration = migration
  reset
end

Class Attribute Details

.safe ⇒ Object

Returns the value of attribute safe.



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# File 'lib/strong_migrations/checker.rb', line 9

def safe
  @safe
end

Instance Attribute Details

#direction ⇒ Object

Returns the value of attribute direction.



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# File 'lib/strong_migrations/checker.rb', line 6

def direction
  @direction
end

#timeouts_set ⇒ Object

Returns the value of attribute timeouts_set.



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# File 'lib/strong_migrations/checker.rb', line 6

def timeouts_set
  @timeouts_set
end

#transaction_disabled ⇒ Object

Returns the value of attribute transaction_disabled.



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# File 'lib/strong_migrations/checker.rb', line 6

def transaction_disabled
  @transaction_disabled
end

Class Method Details

.safety_assured ⇒ Object 



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# File 'lib/strong_migrations/checker.rb', line 26

def self.safety_assured
  previous_value = safe
  begin
    self.safe = true
    yield
  ensure
    self.safe = previous_value
  end
end

Instance Method Details

#perform(method, *args, &block) ⇒ Object 



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# File 'lib/strong_migrations/checker.rb', line 36

def perform(method, *args, &block)
  return yield if skip?

  check_adapter
  check_version_supported
  set_timeouts
  check_lock_timeout

  if !safe? || safe_by_default_method?(method)
    # TODO better pattern
    # see checks.rb for methods
    case method
    when :add_check_constraint
      check_add_check_constraint(*args)
    when :add_column
      check_add_column(*args)
    when :add_exclusion_constraint
      check_add_exclusion_constraint(*args)
    when :add_foreign_key
      check_add_foreign_key(*args)
    when :add_index
      check_add_index(*args)
    when :add_reference, :add_belongs_to
      check_add_reference(method, *args)
    when :add_unique_constraint
      check_add_unique_constraint(*args)
    when :change_column
      check_change_column(*args)
    when :change_column_default
      check_change_column_default(*args)
    when :change_column_null
      check_change_column_null(*args)
    when :change_table
      check_change_table
    when :create_join_table
      check_create_join_table(*args)
    when :create_table
      check_create_table(*args)
    when :execute
      check_execute
    when :remove_column, :remove_columns, :remove_timestamps, :remove_reference, :remove_belongs_to
      check_remove_column(method, *args)
    when :remove_index
      check_remove_index(*args)
    when :rename_column
      check_rename_column
    when :rename_table
      check_rename_table
    when :validate_check_constraint
      check_validate_check_constraint
    when :validate_foreign_key
      check_validate_foreign_key
    when :commit_db_transaction
      # if committed, likely no longer in DDL transaction
      # and no longer eligible to be retried at migration level
      # okay to have false positives
      @committed = true
    end

    if !safe?
      # custom checks
      StrongMigrations.checks.each do |check|
        @migration.instance_exec(method, args, &check)
      end
    end
  end

  result =
    if retry_lock_timeouts?(method)
      # TODO figure out how to handle methods that generate multiple statements
      # like add_reference(table, ref, index: {algorithm: :concurrently})
      # lock timeout after first statement will cause retry to fail
      retry_lock_timeouts { perform_method(method, *args, &block) }
    else
      perform_method(method, *args, &block)
    end

  # outdated statistics + a new index can hurt performance of existing queries
  if StrongMigrations.auto_analyze && direction == :up && method == :add_index
    adapter.analyze_table(args[0])
  end

  result
end

#perform_method(method, *args) ⇒ Object 



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# File 'lib/strong_migrations/checker.rb', line 121

def perform_method(method, *args)
  if StrongMigrations.remove_invalid_indexes && direction == :up && method == :add_index && postgresql?
    remove_invalid_index_if_needed(*args)
  end
  yield
end

#reset ⇒ Object 



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# File 'lib/strong_migrations/checker.rb', line 17

def reset
  @new_tables = []
  @new_columns = []
  @timeouts_set = false
  @committed = false
  @transaction_disabled = false
  @skip_retries = false
end

#retry_lock_timeouts(check_committed: false) ⇒ Object 



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# File 'lib/strong_migrations/checker.rb', line 128

def retry_lock_timeouts(check_committed: false)
  retries = 0
  begin
    yield
  rescue ActiveRecord::LockWaitTimeout => e
    if retries < StrongMigrations.lock_timeout_retries && !(check_committed && @committed)
      retries += 1
      delay = StrongMigrations.lock_timeout_retry_delay
      @migration.say("Lock timeout. Retrying in #{delay} seconds...")
      sleep(delay)
      retry
    end
    raise e
  end
end

#skip? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/strong_migrations/checker.rb', line 148

def skip?
  StrongMigrations.skipped_databases.map(&:to_s).include?(db_config_name)
end

#version_safe? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/strong_migrations/checker.rb', line 144

def version_safe?
  version && version <= StrongMigrations.start_after
end