Class: Aef::Migrator

Inherits:
Object
  • Object
show all
Defined in:
lib/aef/migrator/migrator.rb

Overview

Class for building general purpose versioning systems in the style of ActiveRecord’s migrations. An adapter object is needed for any instance of this class to have any use. See Adapter and AbstractAdapter for the required interface.

Defined Under Namespace

Modules: Adapter Classes: AbstractAdapter, AdapterError, AdapterMethodMissingError, AdapterMissingError, AlreadyOnBottomError, AlreadyOnTopError, CurrentVersionInvalidError, DownMigrationInvalidError, Error, MigrationError, MigrationUnneccessaryError, TargetVersionInvalidError, UpMigrationInvalidError

Constant Summary collapse

VERSION = 
'1.0.0'

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(adapter) ⇒ Migrator

Returns a new instance of Migrator.



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# File 'lib/aef/migrator/migrator.rb', line 48

def initialize(adapter)
  @adapter = adapter
end

Instance Attribute Details

#adapter ⇒ Object

Returns the value of attribute adapter.



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# File 'lib/aef/migrator/migrator.rb', line 46

def adapter
  @adapter
end

Instance Method Details

#down(target_version = nil) ⇒ Object

Process a down migration

Raises MigratorError in case of invalid actions



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# File 'lib/aef/migrator/migrator.rb', line 92

def down(target_version = nil)
  migrate(target_version, :down)
end

#downable?(target_version = nil) ⇒ Boolean

Checks if a down migration is possible

Returns:

  • (Boolean) 


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# File 'lib/aef/migrator/migrator.rb', line 65

def downable?(target_version = nil)
  migratable?(target_version, :down)
end

#migratable?(target_version, direction = nil) ⇒ Boolean

Checks if a migration is possible

Returns:

  • (Boolean) 


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# File 'lib/aef/migrator/migrator.rb', line 53

def migratable?(target_version, direction = nil)
  !!migration_steps(target_version, direction)
rescue MigrationError
  false
end

#migrate(target_version, direction = nil) ⇒ Object

Process a migration

Raises MigratorError in case of invalid actions



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# File 'lib/aef/migrator/migrator.rb', line 72

def migrate(target_version, direction = nil)
  params = migration_steps(target_version, direction)

  params[:steps].each do |version|
    @adapter.send(params[:action], version)
  end

  self
end

#up(target_version = nil) ⇒ Object

Process an up migration

Raises MigratorError in case of invalid actions



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# File 'lib/aef/migrator/migrator.rb', line 85

def up(target_version = nil)
  migrate(target_version, :up)
end

#upable?(target_version = nil) ⇒ Boolean

Checks if an up migration is possible

Returns:

  • (Boolean) 


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# File 'lib/aef/migrator/migrator.rb', line 60

def upable?(target_version = nil)
  migratable?(target_version, :up)
end

#version ⇒ Object

Current version



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# File 'lib/aef/migrator/migrator.rb', line 97

def version
  @adapter.version
end

#versions ⇒ Object

All possible versions in correct order



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# File 'lib/aef/migrator/migrator.rb', line 102

def versions
  @adapter.versions
end