Class: Mongo::Migration

Inherits:
Object
  • Object
show all
Defined in:
lib/mongo_migration/migration.rb,
lib/mongo_migration.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(adapter = nil) ⇒ Migration

Returns a new instance of Migration.



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# File 'lib/mongo_migration/migration.rb', line 4

def initialize adapter = nil
  @adapter = adapter
end

Instance Attribute Details

#adapter ⇒ Object

Returns the value of attribute adapter.



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# File 'lib/mongo_migration/migration.rb', line 2

def adapter
  @adapter
end

Instance Method Details

#define(version, database_name = :default, &block) ⇒ Object 



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# File 'lib/mongo_migration/migration.rb', line 8

def define version, database_name = :default, &block    
  raise "version should be an Integer! (but you provided '#{version}' instad)!" unless version.is_a? Integer
  definition = Definition.new
  block.call definition
  definitions[database_name][version] = definition
end

#definitions ⇒ Object 



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# File 'lib/mongo_migration/migration.rb', line 35

def definitions
  @definitions ||= Hash.new{|h, k| h[k] = []} 
end

#metadata(db) ⇒ Object 



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# File 'lib/mongo_migration/migration.rb', line 30

def metadata db
  col = db.collection 'db_metadata'
  col.find_one || {'version' => 0}
end

#update(version, database_name = :default) ⇒ Object 



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# File 'lib/mongo_migration/migration.rb', line 15

def update version, database_name = :default
  db = adapter.database database_name
  
  if metadata(db)['version'] == version
    adapter.logger.info "Database '#{database_name}' already is of #{version} version, no migration needed"
    return false
  else
    adapter.logger.info "Migration for '#{database_name}', updating to #{version}"
  end
  
  increase_db_version database_name, db while metadata(db)['version'] < version
  decrease_db_version database_name, db while metadata(db)['version'] > version
  true
end