Module: HairTrigger::SchemaDumper

Defined in:
lib/hair_trigger/schema_dumper.rb

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.included(base) ⇒ Object 



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# File 'lib/hair_trigger/schema_dumper.rb', line 78

def self.included(base)
  base.class_eval do
    alias_method_chain :trailer, :triggers
    class << self
      attr_accessor :previous_schema
    end
  end
end

Instance Method Details

#normalize_trigger(name, definition, type) ⇒ Object 



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# File 'lib/hair_trigger/schema_dumper.rb', line 52

def normalize_trigger(name, definition, type)
  @connection = ActiveRecord::Base.connection
  @adapter_name = @connection.adapter_name.downcase.to_sym

  return definition unless @adapter_name == :postgresql
  begin
    # because postgres does not preserve the original CREATE TRIGGER/
    # FUNCTION statements, its decompiled reconstruction will not match
    # ours. we work around it by creating our generated trigger/function,
    # asking postgres for its definition, and then rolling back.
    begin
      @connection.transaction do
        chars = ('a'..'z').to_a + ('0'..'9').to_a + ['_']
        test_name = '_hair_trigger_test_' + (0..43).map{ chars[(rand * chars.size).to_i] }.join
        test_name << (type == :function ? '()' : '')
        @connection.execute(definition.sub(name, test_name))
        definition = @connection.triggers(:only => [test_name], :simple_check => true).values.first
        definition.sub!(test_name, name)
        raise
      end
    rescue
    end
  end
  definition
end

#trailer_with_triggers(stream) ⇒ Object 



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# File 'lib/hair_trigger/schema_dumper.rb', line 3

def trailer_with_triggers(stream)
  triggers(stream)
  trailer_without_triggers(stream)
end

#triggers(stream) ⇒ Object 



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# File 'lib/hair_trigger/schema_dumper.rb', line 8

def triggers(stream)
  @connection = ActiveRecord::Base.connection
  @adapter_name = @connection.adapter_name.downcase.to_sym

  db_triggers = @connection.triggers; nil
  db_trigger_warnings = {}

  migration_triggers = HairTrigger.current_migrations(:in_rake_task => true, :previous_schema => self.class.previous_schema).map do |(name, builder)|
    definitions = []
    builder.generate.each do |statement|
      if statement =~ /\ACREATE(.*TRIGGER| FUNCTION) ([^ \n]+)/
        definitions << [$2, statement, $1 == ' FUNCTION' ? :function : :trigger]
      end
    end
    {:builder => builder, :definitions => definitions}
  end

  migration_triggers.each do |migration|
    next unless migration[:definitions].all? do |(name, definition, type)|
      db_triggers[name] && (db_trigger_warnings[name] = true) && db_triggers[name] == normalize_trigger(name, definition, type)
    end
    migration[:definitions].each do |(name, trigger, type)|
      db_triggers.delete(name)
      db_trigger_warnings.delete(name)
    end

    stream.print migration[:builder].to_ruby('  ', false) + "\n\n"
  end

  db_triggers.to_a.sort_by{ |t| (t.first + 'a').sub(/\(/, '_') }.each do |(name, definition)|
    if db_trigger_warnings[name]
      stream.puts "  # WARNING: generating adapter-specific definition for #{name} due to a mismatch."
      stream.puts "  # either there's a bug in hairtrigger or you've messed up your migrations and/or db :-/"
    else
      stream.puts "  # no candidate create_trigger statement could be found, creating an adapter-specific one"
    end
    if definition =~ /\n/
      stream.print "  execute(<<-TRIGGERSQL)\n#{definition.rstrip}\n  TRIGGERSQL\n\n"
    else
      stream.print "  execute(#{definition.inspect})\n\n"
    end
  end
end