Chef Cookbook：过滤要删除的文件列表

Question

I have a variable storing the files which should be keep

default['keep']['files'] = ['a.txt', 'b.txt']

And bellow files exist on the server

'a.txt', 'b.txt', 'c.txt', 'd.txt'

I want to delete those file which is not in default['keep']['files'], ie c.txt and d.txt
but I am not able to figure out how to get the list of the files to be deleted.

// How should I get the list so that i can loop it?
???.each do |file_name|
  directory "Delete #{file_name}" do
    path my_folder_path
    recursive true
    action :delete
  end
end

Answer 1

You can just subtract keep array from the file list array which will leave you with an array of file names to delete. eg

a1 = ['file1', 'file2']
a2 = ['file1', 'file2', 'file3', 'file4']
a3 = a2 - a1 #results in a3 => ['file3', 'file4']

So you could do something like

files_to_keep = ['a.txt', 'b.txt']
all_files = Dir.entries
files_to_delete = all_files - files_to_keep
files_to_delete.each do |file_name|
  if ! Dir.exist? #Check that the file name is not an actual directory
    # write your code to delete the file named file_name
  end
end

But you might want to sort the arrays first, code is untested but should be fine