module Tainers

Public Class Methods

hash(structure) → consistent hash hexdigest click to toggle source

Produces a consistent hash hexdigest string for the input structure, handling arrays, hashes, strings, numbers, nesting of such structures, etc.

Hash keys are sorted prior to computing the digest, to ensure that hashes that would be regarded as equal produce the same digest.

Tainers.hash({"a" => "foo", "b" => "bar"})  #=> "5427f704439548cae1911616e2bec3b7cc2dd11c"

# File lib/tainers/hash.rb, line 15
def self.hash structure
  str = structured_string(structure)
  Digest::SHA1.hexdigest str
end

named_parameters_for(params) click to toggle source

# File lib/tainers/specification.rb, line 202
def self.named_parameters_for params
  p = params.dup
  prefix = p.delete('prefix')
  prefix = if prefix.nil? || prefix == ''
             'Tainers'
           else
             prefix.downcase
           end
  suffix = p.delete('suffix')
  suffix = if suffix.nil?
             ''
           else
             "-#{suffix.downcase}"
           end
  digest = hash(p)
  p['name'] = "#{prefix}-#{digest}#{suffix}"
  p
end

specify(args={}) click to toggle source

Returns an image-pulling container specification from the given parameters.

Enforces the naming conventions such that the name for the container will have prefix, suffix, and spec-derived hash as documented elsewhere.

The result will be an instance of Tainers::Specification::ImagePuller.

# File lib/tainers/specification.rb, line 196
def self.specify args={}
  Specification::ImagePuller.new(
    Specification::Bare.new named_parameters_for(args)
  )
end

Private Class Methods

consistent_structure(structure) click to toggle source

# File lib/tainers/hash.rb, line 22
def self.consistent_structure structure
  if Hash === structure
    s = structure.keys.sort.inject(["{"]) do |a, key|
      a << consistent_structure(key)
      a << consistent_structure(structure[key])
      a
    end
    s << "}"
    s
  elsif Array === structure
    s = structure.collect {|item| consistent_structure item}
    s.unshift "["
    s << "]"
    s
  else
    structure
  end
end

structured_string(structure) click to toggle source

# File lib/tainers/hash.rb, line 41
def self.structured_string structure
  consistent_structure(structure).to_json
end