Question

I’m trying to understand how and when the before_symlink is run, particularly if there is a failure. Take this block:

deploy_revision "foo" do
  action :deploy
  deploy_to "/opt/foo"
  ...
  symlink_before_migrate(app_symlinks.merge({
  ...     }))
  purge_before_symlink([])
  create_dirs_before_symlink([])
  symlinks({})
  before_symlink do
    current_release = release_path

    bash "foo_buildout_install" do
      user "foo"
      cwd current_release
      code <<-EOH
         ...
      EOH
    end
  end
  restart_command do
    current_release = release_path
    bash "foo_foreman_install_and_restart" do
        restart foo || start foo
      EOH
    end
  end
end

Under what conditions does the before_symlink block get run? Eg, if the build fails, then chef is re-provisioned – will it get run again? What if the symlink is created, does it ever get called again?

(I’m still learning Chef, and I don’t do ruby development, so please don’t assume I understand anything about how deploy_revision works, or the rails deployment model.)

Answer 1

I believe it will get run every time you ‘deploy’, which I believe happens each time you provision via Chef.

If you want to research further for yourself, find the Chef install in your Ruby gems path and look inside for ./lib/chef/provider/deploy.rb

The deploy method pretty much explains itself:

  def deploy
    enforce_ownership
    verify_directories_exist
    update_cached_repo
    copy_cached_repo
    install_gems
    enforce_ownership
    callback(:before_migrate, @new_resource.before_migrate)
    migrate
    callback(:before_symlink, @new_resource.before_symlink)
    symlink
    callback(:before_restart, @new_resource.before_restart)
    restart
    callback(:after_restart, @new_resource.after_restart)
    cleanup!
    Chef::Log.info "#{@new_resource} deployed to #{@new_resource.deploy_to}"
  end