FIPS & DualStack Endpoint Resolver Support (#3938)

* DualStack and FIPS Modeling Support

CHANGELOG_PENDING.md

@@ -1,4 +1,9 @@
 ### SDK Features
+* Support has been added for configuring endpoints with requirements such as FIPS and DualStack. ([#3938](https://github.com/aws/aws-sdk-go/pull/3938))
+  * `AWS_USE_FIPS_ENDPOINT` and `AWS_USE_DUALSTACK_ENDPOINT` can be set to `true` or `false` in the environment to indicate an endpoint with the respective characteristic must be resolved.
+  * `use_fips_endpoint` and `use_dualstack_endpoint` can be set to `true` or `false` in the shared config file to indicate an endpoint with the respective characteristic must be resolved.
+  * Programmatic configuration of FIPS and DualStack endpoint resolution.
+  * For more information see the `aws/session` package documentation.
 
 ### SDK Enhancements
 

aws/client/client.go

@@ -10,12 +10,13 @@ import (
 
 // A Config provides configuration to a service client instance.
 type Config struct {
-	Config        *aws.Config
-	Handlers      request.Handlers
-	PartitionID   string
-	Endpoint      string
-	SigningRegion string
-	SigningName   string
+	Config         *aws.Config
+	Handlers       request.Handlers
+	PartitionID    string
+	Endpoint       string
+	SigningRegion  string
+	SigningName    string
+	ResolvedRegion string
 
 	// States that the signing name did not come from a modeled source but
 	// was derived based on other data. Used by service client constructors

aws/client/metadata/client_info.go

@@ -2,13 +2,14 @@ package metadata
 
 // ClientInfo wraps immutable data from the client.Client structure.
 type ClientInfo struct {
-	ServiceName   string
-	ServiceID     string
-	APIVersion    string
-	PartitionID   string
-	Endpoint      string
-	SigningName   string
-	SigningRegion string
-	JSONVersion   string
-	TargetPrefix  string
+	ServiceName    string
+	ServiceID      string
+	APIVersion     string
+	PartitionID    string
+	Endpoint       string
+	SigningName    string
+	SigningRegion  string
+	JSONVersion    string
+	TargetPrefix   string
+	ResolvedRegion string
 }

aws/config.go

@@ -208,8 +208,19 @@ type Config struct {
 	//     svc := s3.New(sess, &aws.Config{
 	//         UseDualStack: aws.Bool(true),
 	//     })
+	//
+	// Deprecated: This option will continue to function for S3 and S3 Control for backwards compatibility.
+	// UseDualStackEndpoint should be used to enable usage of a service's dual-stack endpoint for all service clients
+	// moving forward. For S3 and S3 Control, when UseDualStackEndpoint is set to a non-zero value it takes higher
+	// precedence then this option.
 	UseDualStack *bool
 
+	// Sets the resolver to resolve a dual-stack endpoint for the service.
+	UseDualStackEndpoint endpoints.DualStackEndpointState
+
+	// UseFIPSEndpoint specifies the resolver must resolve a FIPS endpoint.
+	UseFIPSEndpoint endpoints.FIPSEndpointState
+
 	// SleepDelay is an override for the func the SDK will call when sleeping
 	// during the lifecycle of a request. Specifically this will be used for
 	// request delays. This value should only be used for testing. To adjust
@@ -554,6 +565,10 @@ func mergeInConfig(dst *Config, other *Config) {
 		dst.UseDualStack = other.UseDualStack
 	}
 
+	if other.UseDualStackEndpoint != endpoints.DualStackEndpointStateUnset {
+		dst.UseDualStackEndpoint = other.UseDualStackEndpoint
+	}
+
 	if other.EC2MetadataDisableTimeoutOverride != nil {
 		dst.EC2MetadataDisableTimeoutOverride = other.EC2MetadataDisableTimeoutOverride
 	}
@@ -589,6 +604,14 @@ func mergeInConfig(dst *Config, other *Config) {
 	if other.LowerCaseHeaderMaps != nil {
 		dst.LowerCaseHeaderMaps = other.LowerCaseHeaderMaps
 	}
+
+	if other.UseDualStackEndpoint != endpoints.DualStackEndpointStateUnset {
+		dst.UseDualStackEndpoint = other.UseDualStackEndpoint
+	}
+
+	if other.UseFIPSEndpoint != endpoints.FIPSEndpointStateUnset {
+		dst.UseFIPSEndpoint = other.UseFIPSEndpoint
+	}
 }
 
 // Copy will return a shallow copy of the Config object. If any additional

aws/endpoints/decode.go

@@ -81,7 +81,6 @@ func decodeV3Endpoints(modelDef modelDefinition, opts DecodeModelOptions) (Resol
 	// Customization
 	for i := 0; i < len(ps); i++ {
 		p := &ps[i]
-		custAddS3DualStack(p)
 		custRegionalS3(p)
 		custRmIotDataService(p)
 		custFixAppAutoscalingChina(p)
@@ -91,15 +90,6 @@ func decodeV3Endpoints(modelDef modelDefinition, opts DecodeModelOptions) (Resol
 	return ps, nil
 }
 
-func custAddS3DualStack(p *partition) {
-	if !(p.ID == "aws" || p.ID == "aws-cn" || p.ID == "aws-us-gov") {
-		return
-	}
-
-	custAddDualstack(p, "s3")
-	custAddDualstack(p, "s3-control")
-}
-
 func custRegionalS3(p *partition) {
 	if p.ID != "aws" {
 		return
@@ -110,35 +100,28 @@ func custRegionalS3(p *partition) {
 		return
 	}
 
+	const awsGlobal = "aws-global"
+	const usEast1 = "us-east-1"
+
 	// If global endpoint already exists no customization needed.
-	if _, ok := service.Endpoints["aws-global"]; ok {
+	if _, ok := service.Endpoints[endpointKey{Region: awsGlobal}]; ok {
 		return
 	}
 
-	service.PartitionEndpoint = "aws-global"
-	service.Endpoints["us-east-1"] = endpoint{}
-	service.Endpoints["aws-global"] = endpoint{
+	service.PartitionEndpoint = awsGlobal
+	if _, ok := service.Endpoints[endpointKey{Region: usEast1}]; !ok {
+		service.Endpoints[endpointKey{Region: usEast1}] = endpoint{}
+	}
+	service.Endpoints[endpointKey{Region: awsGlobal}] = endpoint{
 		Hostname: "s3.amazonaws.com",
 		CredentialScope: credentialScope{
-			Region: "us-east-1",
+			Region: usEast1,
 		},
 	}
 
 	p.Services["s3"] = service
 }
 
-func custAddDualstack(p *partition, svcName string) {
-	s, ok := p.Services[svcName]
-	if !ok {
-		return
-	}
-
-	s.Defaults.HasDualStack = boxedTrue
-	s.Defaults.DualStackHostname = "{service}.dualstack.{region}.{dnsSuffix}"
-
-	p.Services[svcName] = s
-}
-
 func custRmIotDataService(p *partition) {
 	delete(p.Services, "data.iot")
 }
@@ -155,12 +138,13 @@ func custFixAppAutoscalingChina(p *partition) {
 	}
 
 	const expectHostname = `autoscaling.{region}.amazonaws.com`
-	if e, a := s.Defaults.Hostname, expectHostname; e != a {
+	serviceDefault := s.Defaults[defaultKey{}]
+	if e, a := expectHostname, serviceDefault.Hostname; e != a {
 		fmt.Printf("custFixAppAutoscalingChina: ignoring customization, expected %s, got %s\n", e, a)
 		return
 	}
-
-	s.Defaults.Hostname = expectHostname + ".cn"
+	serviceDefault.Hostname = expectHostname + ".cn"
+	s.Defaults[defaultKey{}] = serviceDefault
 	p.Services[serviceName] = s
 }
 
@@ -175,18 +159,25 @@ func custFixAppAutoscalingUsGov(p *partition) {
 		return
 	}
 
-	if a := s.Defaults.CredentialScope.Service; a != "" {
+	serviceDefault := s.Defaults[defaultKey{}]
+	if a := serviceDefault.CredentialScope.Service; a != "" {
 		fmt.Printf("custFixAppAutoscalingUsGov: ignoring customization, expected empty credential scope service, got %s\n", a)
 		return
 	}
 
-	if a := s.Defaults.Hostname; a != "" {
+	if a := serviceDefault.Hostname; a != "" {
 		fmt.Printf("custFixAppAutoscalingUsGov: ignoring customization, expected empty hostname, got %s\n", a)
 		return
 	}
 
-	s.Defaults.CredentialScope.Service = "application-autoscaling"
-	s.Defaults.Hostname = "autoscaling.{region}.amazonaws.com"
+	serviceDefault.CredentialScope.Service = "application-autoscaling"
+	serviceDefault.Hostname = "autoscaling.{region}.amazonaws.com"
+
+	if s.Defaults == nil {
+		s.Defaults = make(endpointDefaults)
+	}
+
+	s.Defaults[defaultKey{}] = serviceDefault
 
 	p.Services[serviceName] = s
 }