Support disable host prefixing in env and shared config (#3237)

Author: mullermp

gems/aws-sdk-core/CHANGELOG.md

@@ -1,6 +1,8 @@
 Unreleased Changes
 ------------------
 
+* Feature - Support `ENV['AWS_DISABLE_HOST_PREFIX_INJECTION']` and `disable_host_prefix_injection` shared config to disable host prefix injection for all services.
+
 3.223.0 (2025-05-01)
 ------------------
 

gems/aws-sdk-core/lib/aws-sdk-core/plugins/endpoint_pattern.rb

@@ -4,62 +4,70 @@ module Aws
   module Plugins
     # @api private
     class EndpointPattern < Seahorse::Client::Plugin
-
-      option(:disable_host_prefix_injection,
+      option(
+        :disable_host_prefix_injection,
         default: false,
         doc_type: 'Boolean',
-        docstring: <<-DOCS
-Set to true to disable SDK automatically adding host prefix
-to default service endpoint when available.
-        DOCS
-      )
+        docstring: 'When `true`, the SDK will not prepend the modeled host prefix to the endpoint.'
+      ) do |cfg|
+        resolve_disable_host_prefix_injection(cfg)
+      end
 
-      def add_handlers(handlers, config)
+      def add_handlers(handlers, _config)
         handlers.add(Handler, priority: 10)
       end
 
-      class Handler < Seahorse::Client::Handler
+      class << self
+        private
+
+        def resolve_disable_host_prefix_injection(cfg)
+          value = ENV['AWS_DISABLE_HOST_PREFIX_INJECTION'] ||
+                  Aws.shared_config.disable_host_prefix_injection(profile: cfg.profile) ||
+                  'false'
+          value = Aws::Util.str_2_bool(value)
+          unless [true, false].include?(value)
+            raise ArgumentError,
+                  'Must provide either `true` or `false` for '\
+                    'disable_host_prefix_injection profile option or for '\
+                    'ENV[\'AWS_DISABLE_HOST_PREFIX_INJECTION\']'
+          end
+          value
+        end
+      end
 
+      # @api private
+      class Handler < Seahorse::Client::Handler
         def call(context)
-          if !context.config.disable_host_prefix_injection
+          unless context.config.disable_host_prefix_injection
             endpoint_trait = context.operation.endpoint_pattern
-            if endpoint_trait && !endpoint_trait.empty?
-              _apply_endpoint_trait(context, endpoint_trait)
-            end
+            apply_endpoint_trait(context, endpoint_trait) if endpoint_trait && !endpoint_trait.empty?
           end
           @handler.call(context)
         end
 
         private
 
-        def _apply_endpoint_trait(context, trait)
-          # currently only support host pattern
-          ori_host = context.http_request.endpoint.host
-          if pattern = trait['hostPrefix']
-            host_prefix = pattern.gsub(/\{.+?\}/) do |label|
-              label = label.delete("{}")
-              _replace_label_value(
-                ori_host, label, context.operation.input, context.params)
-            end
-            context.http_request.endpoint.host = host_prefix + context.http_request.endpoint.host
+        def apply_endpoint_trait(context, trait)
+          pattern = trait['hostPrefix']
+          return unless pattern
+
+          host_prefix = pattern.gsub(/\{.+?}/) do |label|
+            label = label.delete('{}')
+            replace_label_value(label, context.operation.input, context.params)
           end
+          context.http_request.endpoint.host = host_prefix + context.http_request.endpoint.host
         end
 
-        def _replace_label_value(ori, label, input_ref, params)
+        def replace_label_value(label, input_ref, params)
           name = nil
           input_ref.shape.members.each do |m_name, ref|
-            if ref['hostLabel'] && ref['hostLabelName'] == label
-              name = m_name
-            end
-          end
-          if name.nil? || params[name].nil?
-            raise Errors::MissingEndpointHostLabelValue.new(name)
+            name = m_name if ref['hostLabel'] && ref['hostLabelName'] == label
           end
+          raise Errors::MissingEndpointHostLabelValue, name if name.nil? || params[name].nil?
+
           params[name]
         end
-
       end
-
     end
   end
 end

gems/aws-sdk-core/lib/aws-sdk-core/shared_config.rb

@@ -212,6 +212,7 @@ def self.config_reader(*attrs)
       :ec2_metadata_service_endpoint,
       :ec2_metadata_service_endpoint_mode,
       :ec2_metadata_v1_disabled,
+      :disable_host_prefix_injection,
       :max_attempts,
       :retry_mode,
       :adaptive_retry_wait_to_fill,

gems/aws-sdk-core/spec/aws/shared_config_spec.rb

@@ -258,6 +258,17 @@ module Aws
       end
     end
 
+    context 'disable_host_prefix_injection selection' do
+      it 'can resolve disable_host_prefix_injection from config file' do
+        config = SharedConfig.new(
+          config_path: mock_config_file,
+          config_enabled: true,
+          profile_name: 'disable_host_prefix_injection'
+        )
+        expect(config.disable_host_prefix_injection).to eq('true')
+      end
+    end
+
     context 'retry_mode selection' do
       it 'can resolve retry_mode from config file' do
         config = SharedConfig.new(

gems/aws-sdk-core/spec/fixtures/credentials/mock_shared_config

@@ -239,6 +239,9 @@ s3_disable_express_session_auth = true
 [profile s3_do_not_use_express_zonal_auth]
 s3_disable_express_session_auth = false
 
+[profile disable_host_prefix_injection]
+disable_host_prefix_injection = true
+
 [profile retry_mode_legacy]
 retry_mode = legacy