lib/cloudstrap/config.rb in cloudstrap-0.29.1.pre vs lib/cloudstrap/config.rb in cloudstrap-0.29.5.pre

@@ -7,127 +7,110 @@
     include ::Contracts::Core
     include ::Contracts::Builtin
 
     Contract None => String
     def region
-      @region ||= ENV.fetch('BOOTSTRAP_REGION') do
-        config.fetch('region') do
-          'us-west-2'
-        end
-      end
+      lookup(:region) { 'us-west-2' }
     end
 
     Contract None => String
     def cache_path
-      @cache_path ||= ENV.fetch('BOOTSTRAP_CACHE_PATH') do
-        config.fetch('cache_path') { [workdir, '.cache'].join('/') }
-      end
+      lookup(:cache_path) { [workdir, '.cache'].join('/') }
     end
 
     Contract None => String
     def vpc_cidr_block
-      @vpc_cidr_block ||= ENV.fetch('BOOTSTRAP_VPC_CIDR_BLOCK') do
-        config.fetch('vpc_cidr_block') { '10.0.0.0/16' }
-      end
+      lookup(:vpc_cidr_block) { '10.0.0.0/16' }
     end
 
     Contract None => String
     def public_cidr_block
-      @public_cidr_block ||= ENV.fetch('BOOTSTRAP_PUBLIC_CIDR_BLOCK') do
-        config.fetch('public_cidr_block') do
-          vpc_cidr_block.gsub(/([[:digit:]]{1,3}\.?){2,2}\/[[:digit:]]{1,2}$/, '0.0/24')
-        end
+      lookup(:public_cidr_block) do
+        vpc_cidr_block.gsub(/([[:digit:]]{1,3}\.?){2,2}\/[[:digit:]]{1,2}$/, '0.0/24')
       end
     end
 
     Contract None => String
     def private_cidr_block
-      @private_cidr_block ||= ENV.fetch('BOOTSTRAP_PRIVATE_CIDR_BLOCK') do
-        config.fetch('private_cidr_block') do
-          vpc_cidr_block.gsub(/([[:digit:]]{1,3}\.?){2,2}\/[[:digit:]]{1,2}$/, '1.0/24')
-        end
+      lookup(:private_cidr_block) do
+        vpc_cidr_block.gsub(/([[:digit:]]{1,3}\.?){2,2}\/[[:digit:]]{1,2}$/, '1.0/24')
       end
     end
 
     Contract None => String
     def ami_owner
-      @ami_owner ||= ENV.fetch('BOOTSTRAP_AMI_OWNER') do
-        config.fetch('ami_owner') do
-          '099720109477'
-        end
-      end
+      lookup(:ami_owner) { '099720109477' }
     end
 
     Contract None => String
     def ubuntu_release
-      @distribution ||= ENV.fetch('BOOTSTRAP_UBUNTU_RELEASE') do
-        config.fetch('ubuntu_release') do
-          '14.04'
-        end
-      end
+      lookup(:ubuntu_release) { '14.04' }
     end
 
     Contract None => String
     def instance_type
-      @instance_type ||= ENV.fetch('BOOTSTRAP_INSTANCE_TYPE') do
-        config.fetch('instance_type') do
-          't2.micro'
-        end
-      end
+      lookup(:instance_type) { 't2.micro' }
     end
 
     Contract None => String
     def ssh_dir
-      @ssh_dir ||= File.expand_path(ENV.fetch('BOOTSTRAP_SSH_DIR') do
-        [workdir, '.ssh'].join('/')
-      end)
+      lookup(:ssh_dir) { [workdir, '.ssh'].join('/') }
     end
 
     Contract None => String
     def ssh_username
-      @ssh_username ||= ENV.fetch('BOOTSTRAP_SSH_USERNAME') do
-        config.fetch('ssh_username') do
-          'ubuntu'
-        end
-      end
+      lookup(:ssh_username) { 'ubuntu' }
     end
 
     Contract None => String
     def hdp_dir
       @hdp_dir ||= File.expand_path(ENV.fetch('BOOTSTRAP_HDP_DIR') { dir })
     end
 
     Contract None => String
     def hdp_origin
-      @hdp_origin ||= ENV.fetch('BOOTSTRAP_HDP_BOOTSTRAP_ORIGIN') do
-        config.fetch('hdp_bootstrap_origin')
-      end
+      lookup :hdp_bootstrap_origin
     end
 
     Contract None => String
     def hdp_version
-      @hdp_archive ||= ENV.fetch('BOOTSTRAP_HDP_BOOTSTRAP_VERSION') do
-        config.fetch('hdp_bootstrap_version')
-      end
+      lookup :hdp_bootstrap_version
     end
 
     Contract None => String
     def hdp_package_url
-      @hdp_package_url ||= ENV.fetch('BOOTSTRAP_HDP_BOOTSTRAP_PACKAGE_URL') do
-        config.fetch('hdp_bootstrap_package_url') do
-          "#{hdp_origin}/hcp-bootstrap_#{hdp_version.gsub('+', '%2B')}_amd64.deb"
-        end
+      lookup(:hdp_bootstrap_package_url) do
+        "#{hdp_origin}/hcp-bootstrap_#{hdp_version.gsub('+', '%2B')}_amd64.deb"
       end
     end
 
     Contract None => String
     def bootstrap_properties_seed_url
-      ENV.fetch('BOOTSTRAP_PROPERTIES_SEED_URL') do
-        config.fetch('bootstrap_properties_seed_url')
-      end
+      lookup :bootstrap_properties_seed_url
     end
 
     private
+
+    StringToString = Func[Maybe[String] => Maybe[String]]
+
+    Contract RespondTo[:to_s], Maybe[Or[String, StringToString]] => Maybe[String]
+    def memoize(key, value = nil)
+      key = key.to_s.tap { |k| k.prepend('@') unless k.start_with?('@') }
+      return instance_variable_get(key) if instance_variable_defined?(key)
+
+      instance_variable_set(key, block_given? ? yield(key) : value)
+    end
+
+    Contract RespondTo[:to_s], Maybe[Or[String, StringToString]] => String
+    def lookup(key = __callee__, default = nil)
+      memoize(key) do
+        ENV.fetch("BOOTSTRAP_#{key.to_s.upcase}") do
+          config.fetch(key.to_s) do
+            block_given? ? yield(key) : default
+          end
+        end
+      end
+    end
 
     Contract None => String
     def workdir
       @workdir ||= ENV.fetch('BOOTSTRAP_WORKDIR') { Dir.pwd }
     end