k8s-selector.rb

k8s-selector.rb

#!/usr/bin/env ruby

# Purpose : Select the objects you want from maninfests,
#           as you may not want to deploy everything.
# Author  : Ky-Anh Huynh
# Date    : 2019-12
# Example :
#
#    helm foo | k8s-select kind=Ingress | kubectl diff -f-
#    helm foo | k8s-select metadata.name=someth | kubectl diff -f-
#
require 'yaml'

class NilClass
  def dig(st)
    return nil
  end
end

def doc_query(doc,query)
  key = ""
  val = doc
  query.split(".").each do |k|
    key = "#{key}.#{k}"
    if gs = k.to_s.match("\[([0-9]+)\]")
      val = val.is_a?(Array) ? val[gs[1].to_i] : nil
    else
      val = val.dig(k)
    end
  end
  return val ? val.downcase : nil
end

def match_argv_doc(args,doc)
  args.select{|s| s.include?("=")}.detect do |arg|
    query,value = arg.split("=", 2)
    query_value = doc_query(doc, query)
    query_value.nil? ? nil: query_value.match(value.downcase)
  end
end

docs = YAML.load_stream(STDIN)
docs.each do |doc|
  next if doc.nil? or doc.empty?
  if match_argv_doc(ARGV,doc)
    puts YAML.dump(doc)
  end
end