Module: K8s::Util

Defined in:
lib/k8s/util.rb

Overview

Miscellaneous helpers

Constant Summary collapse

PATH_TR_MAP = 
{ '~' => '~0', '/' => '~1' }.freeze
PATH_REGEX = 
%r{(/|~(?!1))}.freeze

Class Method Summary collapse

Class Method Details

.compact_map(args) {|args| ... } ⇒ Array<nil, Object>

Yield with all non-nil args, returning matching array with corresponding return values or nils.

Args must be usable as hash keys. Duplicate args will all map to the same return value.

Yields:

  • args

Yield Parameters:

  • args (Array<Object>) —

    omitting any nil values



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# File 'lib/k8s/util.rb', line 15

def self.compact_map(args)
  func_args = args.compact

  values = yield func_args

  # Hash{arg => value}
  value_map = Hash[func_args.zip(values)]

  args.map{|arg| value_map[arg] }
end

.json_patch(a, b) ⇒ Object

Produces a set of json-patch operations so that applying the operations on a, gives you the results of b Used in correctly patching the Kube resources on stack updates



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# File 'lib/k8s/util.rb', line 32

def self.json_patch(a, b)
  diffs = HashDiff.diff(a, b, array_path: true)
  ops = []
  # Each diff is like:
  # ["+", ["spec", "selector", "food"], "kebab"]
  # ["-", ["spec", "selector", "drink"], "pepsi"]
  # or
  # ["~", ["spec", "selector", "drink"], "old value", "new value"]
  # the path elements can be symbols too, depending on the input hashes
  diffs.each do |diff|
    operator = diff[0]
    # substitute '/' with '~1' and '~' with '~0'
    # according to RFC 6901
    path = diff[1].map {|p| p.to_s.gsub(PATH_REGEX, PATH_TR_MAP) }
    if operator == '-'
      ops << {
        op: "remove",
        path: "/" + path.join('/')
      }
    elsif operator == '+'
      ops << {
        op: "add",
        path: "/" + path.join('/'),
        value: diff[2]
      }
    elsif operator == '~'
      ops << {
        op: "replace",
        path: "/" + path.join('/'),
        value: diff[3]
      }
    else
      raise "Unknown diff operator: #{operator}!"
    end

  end

  ops
end