intial stab at comparing available instance types

with those listed at ec2instances.info

spec/models/manageiq/providers/amazon/instance_types_spec.rb

@@ -0,0 +1,94 @@
+describe ManageIQ::Providers::Amazon::InstanceTypes do
+  class Attribute
+    attr_accessor :key, :key_other, :processor, :other_proc
+    attr_accessor :convert, :other_convert
+    def initialize(key)
+      if key.is_a? Hash
+        self.key, self.key_other = key.first
+      else
+        self.key = self.key_other = key
+      end
+      yield self if block_given?
+      # self.key_other = key_other || key
+      # self.processor = processor
+    end
+
+    def other_proc(&block)
+      self.other_proc = block
+      self
+    end
+
+    def fetch(instance, key)
+      if processor
+        processor.call(instance.fetch(key))
+      else
+        instance.fetch(key)
+      end
+    end
+
+    def same?(a, b)
+      av, bv = a[key], b[key_other]
+      av = convert.to_proc.call(av) if convert
+      bv = convert.to_proc.call(bv) if convert
+      bv = other_convert.to_proc.call(bv) if other_convert
+      av == bv
+    end
+
+    def format(instance)
+      %Q(:#{key} => "#{fetch(instance, key_other)}")
+    end
+  end
+
+  def format_instance(instance, current_instance, attributes)
+    puts %Q("#{instance[:instance_type]}" => {)
+    attributes.each do |key|
+      if current_instance
+        unless key.same?(current_instance, instance)
+          puts key.format(instance)
+          puts %Q(# was: #{current_instance[key.key]})
+        end
+      else
+        puts key.format(instance)
+      end
+    end
+    puts '}'
+  end
+
+  it "is the same" do
+    require 'open-uri'
+
+    attributes = [
+      Attribute.new(:name => :instance_type),
+      Attribute.new(:family) {|a| a.convert = :downcase },
+      Attribute.new(:description => :pretty_name) {|a| a.convert = :downcase},
+      Attribute.new(:memory) do |a|
+        a.convert = :to_f
+        a.other_convert = Proc.new do |v|
+          v.to_f.gigabytes
+        end
+      end,
+      Attribute.new(:vcpu => :vCPU),
+    ]
+
+    find_instance = Proc.new do |o|
+      described_class.all.find do |i|
+        attributes.all?{|a| a.same?(i, o)}
+      end
+    end
+
+    current_instance = Proc.new do |o|
+      described_class.all.find{|i| i[:name] == o[:instance_type]}
+    end
+
+    # download this to /tmp/instances.json
+    # instances = YAML.safe_load(open('https://raw.githubusercontent.com/powdahound/ec2instances.info/master/www/instances.json').read)
+    instances = YAML.safe_load(open('/tmp/instances.json').read)
+    instances.each do |instance|
+      instance.deep_symbolize_keys!
+      find_instance.call(instance) or
+        format_instance(instance, current_instance.call(instance), attributes)
+    end
+
+  end
+
+end