how to detect whether my rails is running in migration or not in environment.rb

问题

any easy way to detect it? I want to skip some codes in envirmonment.rb when doing migration rake.

回答1:

I had this problem in a legacy application I was maintaining. There were some observers that were interfering with migrations past a certain point, so I disabled them during migration by checking the application name and arguments

  # Activate observers that should always be running
  # config.active_record.observers = :cacher, :garbage_collector, :forum_observer# observers break a migrate from VERSION xxx - disable them for rake db:migrate
unless ( File.basename($0) == "rake" && ARGV.include?("db:migrate") )
  config.active_record.observers = :user_observer
end

回答2:

i think if u want to skip, just comment (#) on code.

or many choose on migration rake.

for example : rake db:migrate:up VERSION=2000123232 its mean , only 2000123232_create_article do migration.

or rake db:migrate VERSION=2000123232 mean start from after 2000123232

or rake db:migrate:down VERSION=2000123232

just rake help u can see what u need to rake.

Do you mean that?

来源：https://stackoverflow.com/questions/1858230/how-to-detect-whether-my-rails-is-running-in-migration-or-not-in-environment-rb