Fix custom endpoint bug

.changelog/21657.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+provider: Additional fixes to allow setting endpoints with non-standard, legacy keys.
+```

internal/acctest/acctest_test.go

@@ -213,6 +213,29 @@ func TestAccAcctestProvider_fipsEndpoint(t *testing.T) {
 	})
 }
 
+func TestAccAcctestProvider_unusualEndpoints(t *testing.T) {
+	var providers []*schema.Provider
+
+	unusual1 := []string{"es", "elasticsearch", "http://notarealendpoint"}
+	unusual2 := []string{"databasemigration", "dms", "http://alsonotarealendpoint"}
+	unusual3 := []string{"lexmodels", "lexmodelbuilding", "http://kingofspain"}
+
+	resource.ParallelTest(t, resource.TestCase{
+		PreCheck:          func() { PreCheck(t) },
+		ErrorCheck:        ErrorCheck(t),
+		ProviderFactories: FactoriesInternal(&providers),
+		CheckDestroy:      nil,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccUnusualEndpointsConfig(unusual1, unusual2, unusual3),
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckUnusualEndpoints(&providers, unusual1, unusual2, unusual3),
+				),
+			},
+		},
+	})
+}
+
 func TestAccAcctestProvider_IgnoreTags_emptyBlock(t *testing.T) {
 	var providers []*schema.Provider
 
@@ -782,6 +805,81 @@ func testAccCheckEndpoints(providers *[]*schema.Provider) resource.TestCheckFunc
 	}
 }
 
+func testAccCheckUnusualEndpoints(providers *[]*schema.Provider, unusual1, unusual2, unusual3 []string) resource.TestCheckFunc {
+	return func(s *terraform.State) error {
+		if providers == nil {
+			return fmt.Errorf("no providers initialized")
+		}
+
+		// Match conns.AWSClient struct field names to endpoint configuration names
+		endpointFieldNameF := func(key string) func(string) bool {
+			return func(name string) bool {
+				serviceUpper := ""
+				var err error
+				if serviceUpper, err = conns.ServiceProviderNameUpper(key); err != nil {
+					return false
+				}
+
+				// exception to dropping "service" because Config collides with various other "Config"s
+				if name == "ConfigServiceConn" && fmt.Sprintf("%sConn", serviceUpper) == "ConfigConn" {
+					return true
+				}
+
+				return name == fmt.Sprintf("%sConn", serviceUpper)
+			}
+		}
+
+		for _, provo := range *providers {
+			if provo == nil || provo.Meta() == nil || provo.Meta().(*conns.AWSClient) == nil {
+				continue
+			}
+
+			providerClient := provo.Meta().(*conns.AWSClient)
+
+			providerClientField := reflect.Indirect(reflect.ValueOf(providerClient)).FieldByNameFunc(endpointFieldNameF(unusual1[1]))
+
+			if !providerClientField.IsValid() {
+				return fmt.Errorf("unable to match conns.AWSClient struct field name for endpoint name: %s", unusual1[1])
+			}
+
+			actualEndpoint := reflect.Indirect(reflect.Indirect(providerClientField).FieldByName("Config").FieldByName("Endpoint")).String()
+			expectedEndpoint := unusual1[2]
+
+			if actualEndpoint != expectedEndpoint {
+				return fmt.Errorf("expected endpoint (%s) value (%s), got: %s", unusual1[1], expectedEndpoint, actualEndpoint)
+			}
+
+			providerClientField = reflect.Indirect(reflect.ValueOf(providerClient)).FieldByNameFunc(endpointFieldNameF(unusual2[1]))
+
+			if !providerClientField.IsValid() {
+				return fmt.Errorf("unable to match conns.AWSClient struct field name for endpoint name: %s", unusual2[1])
+			}
+
+			actualEndpoint = reflect.Indirect(reflect.Indirect(providerClientField).FieldByName("Config").FieldByName("Endpoint")).String()
+			expectedEndpoint = unusual2[2]
+
+			if actualEndpoint != expectedEndpoint {
+				return fmt.Errorf("expected endpoint (%s) value (%s), got: %s", unusual2[1], expectedEndpoint, actualEndpoint)
+			}
+
+			providerClientField = reflect.Indirect(reflect.ValueOf(providerClient)).FieldByNameFunc(endpointFieldNameF(unusual3[1]))
+
+			if !providerClientField.IsValid() {
+				return fmt.Errorf("unable to match conns.AWSClient struct field name for endpoint name: %s", unusual3[1])
+			}
+
+			actualEndpoint = reflect.Indirect(reflect.Indirect(providerClientField).FieldByName("Config").FieldByName("Endpoint")).String()
+			expectedEndpoint = unusual3[2]
+
+			if actualEndpoint != expectedEndpoint {
+				return fmt.Errorf("expected endpoint (%s) value (%s), got: %s", unusual3[1], expectedEndpoint, actualEndpoint)
+			}
+		}
+
+		return nil
+	}
+}
+
 func testAccEndpointsConfig(endpoints string) string {
 	//lintignore:AT004
 	return ConfigCompose(
@@ -819,6 +917,26 @@ resource "aws_s3_bucket" "test" {
 `, endpoint, rName))
 }
 
+func testAccUnusualEndpointsConfig(unusual1, unusual2, unusual3 []string) string {
+	//lintignore:AT004
+	return ConfigCompose(
+		testAccProviderConfigBase,
+		fmt.Sprintf(`
+provider "aws" {
+  skip_credentials_validation = true
+  skip_get_ec2_platforms      = true
+  skip_metadata_api_check     = true
+  skip_requesting_account_id  = true
+
+  endpoints {
+    %[1]s = %[2]q
+    %[3]s = %[4]q
+    %[5]s = %[6]q
+  }
+}
+`, unusual1[0], unusual1[2], unusual2[0], unusual2[2], unusual3[0], unusual3[2]))
+}
+
 func testAccIgnoreTagsKeys0Config() string {
 	//lintignore:AT004
 	return ConfigCompose(

internal/conns/conns.go

@@ -44,7 +44,6 @@ import (
 	"github.com/aws/aws-sdk-go/service/clouddirectory"
 	"github.com/aws/aws-sdk-go/service/cloudformation"
 	"github.com/aws/aws-sdk-go/service/cloudfront"
-	"github.com/aws/aws-sdk-go/service/cloudhsm"
 	"github.com/aws/aws-sdk-go/service/cloudhsmv2"
 	"github.com/aws/aws-sdk-go/service/cloudsearch"
 	"github.com/aws/aws-sdk-go/service/cloudsearchdomain"
@@ -321,7 +320,6 @@ const (
 	CloudDirectory                = "clouddirectory"
 	CloudFormation                = "cloudformation"
 	CloudFront                    = "cloudfront"
-	CloudHSM                      = "cloudhsm"
 	CloudHSMV2                    = "cloudhsmv2"
 	CloudSearch                   = "cloudsearch"
 	CloudSearchDomain             = "cloudsearchdomain"
@@ -609,7 +607,6 @@ func init() {
 	serviceData[CloudDirectory] = &ServiceDatum{AWSClientName: "CloudDirectory", AWSServiceName: clouddirectory.ServiceName, AWSEndpointsID: clouddirectory.EndpointsID, AWSServiceID: clouddirectory.ServiceID, ProviderNameUpper: "CloudDirectory", HCLKeys: []string{"clouddirectory"}}
 	serviceData[CloudFormation] = &ServiceDatum{AWSClientName: "CloudFormation", AWSServiceName: cloudformation.ServiceName, AWSEndpointsID: cloudformation.EndpointsID, AWSServiceID: cloudformation.ServiceID, ProviderNameUpper: "CloudFormation", HCLKeys: []string{"cloudformation"}}
 	serviceData[CloudFront] = &ServiceDatum{AWSClientName: "CloudFront", AWSServiceName: cloudfront.ServiceName, AWSEndpointsID: cloudfront.EndpointsID, AWSServiceID: cloudfront.ServiceID, ProviderNameUpper: "CloudFront", HCLKeys: []string{"cloudfront"}}
-	serviceData[CloudHSM] = &ServiceDatum{AWSClientName: "CloudHSM", AWSServiceName: cloudhsm.ServiceName, AWSEndpointsID: cloudhsm.EndpointsID, AWSServiceID: cloudhsm.ServiceID, ProviderNameUpper: "CloudHSM", HCLKeys: []string{"cloudhsmv1"}}
 	serviceData[CloudHSMV2] = &ServiceDatum{AWSClientName: "CloudHSMV2", AWSServiceName: cloudhsmv2.ServiceName, AWSEndpointsID: cloudhsmv2.EndpointsID, AWSServiceID: cloudhsmv2.ServiceID, ProviderNameUpper: "CloudHSMV2", HCLKeys: []string{"cloudhsm", "cloudhsmv2"}}
 	serviceData[CloudSearch] = &ServiceDatum{AWSClientName: "CloudSearch", AWSServiceName: cloudsearch.ServiceName, AWSEndpointsID: cloudsearch.EndpointsID, AWSServiceID: cloudsearch.ServiceID, ProviderNameUpper: "CloudSearch", HCLKeys: []string{"cloudsearch"}}
 	serviceData[CloudSearchDomain] = &ServiceDatum{AWSClientName: "CloudSearchDomain", AWSServiceName: cloudsearchdomain.ServiceName, AWSEndpointsID: cloudsearchdomain.EndpointsID, AWSServiceID: cloudsearchdomain.ServiceID, ProviderNameUpper: "CloudSearchDomain", HCLKeys: []string{"cloudsearchdomain"}}
@@ -919,7 +916,6 @@ type AWSClient struct {
 	CloudDirectoryConn                *clouddirectory.CloudDirectory
 	CloudFormationConn                *cloudformation.CloudFormation
 	CloudFrontConn                    *cloudfront.CloudFront
-	CloudHSMConn                      *cloudhsm.CloudHSM
 	CloudHSMV2Conn                    *cloudhsmv2.CloudHSMV2
 	CloudSearchConn                   *cloudsearch.CloudSearch
 	CloudSearchDomainConn             *cloudsearchdomain.CloudSearchDomain
@@ -1273,7 +1269,6 @@ func (c *Config) Client() (interface{}, error) {
 		CloudDirectoryConn:                clouddirectory.New(sess.Copy(&aws.Config{Endpoint: aws.String(c.Endpoints[CloudDirectory])})),
 		CloudFormationConn:                cloudformation.New(sess.Copy(&aws.Config{Endpoint: aws.String(c.Endpoints[CloudFormation])})),
 		CloudFrontConn:                    cloudfront.New(sess.Copy(&aws.Config{Endpoint: aws.String(c.Endpoints[CloudFront])})),
-		CloudHSMConn:                      cloudhsm.New(sess.Copy(&aws.Config{Endpoint: aws.String(c.Endpoints[CloudHSM])})),
 		CloudHSMV2Conn:                    cloudhsmv2.New(sess.Copy(&aws.Config{Endpoint: aws.String(c.Endpoints[CloudHSMV2])})),
 		CloudSearchConn:                   cloudsearch.New(sess.Copy(&aws.Config{Endpoint: aws.String(c.Endpoints[CloudSearch])})),
 		CloudSearchDomainConn:             cloudsearchdomain.New(sess.Copy(&aws.Config{Endpoint: aws.String(c.Endpoints[CloudSearchDomain])})),
@@ -1883,7 +1878,7 @@ func ReverseDNS(hostname string) string {
 // This is a global MutexKV for use within this plugin.
 var GlobalMutexKV = NewMutexKV()
 
-func ServiceKeyForHCLKey(s string) (string, error) {
+func ServiceForHCLKey(s string) (string, error) {
 	for k, v := range serviceData {
 		for _, hclKey := range v.HCLKeys {
 			if s == hclKey {
@@ -1907,6 +1902,16 @@ func ServiceKeys() []string {
 	return keys
 }
 
+func HCLKeys() []string {
+	keys := make([]string, 0)
+
+	for _, v := range serviceData {
+		keys = append(keys, v.HCLKeys...)
+	}
+
+	return keys
+}
+
 func ServiceProviderNameUpper(key string) (string, error) {
 	if v, ok := serviceData[key]; ok {
 		return v.ProviderNameUpper, nil

internal/provider/provider.go

@@ -1,6 +1,7 @@
 package provider
 
 import (
+	"fmt"
 	"log"
 
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
@@ -1828,8 +1829,17 @@ func providerConfigure(d *schema.ResourceData, terraformVersion string) (interfa
 
 	for _, endpointsSetI := range endpointsSet.List() {
 		endpoints := endpointsSetI.(map[string]interface{})
-		for _, serviceKey := range conns.ServiceKeys() {
-			config.Endpoints[serviceKey] = endpoints[serviceKey].(string)
+
+		for _, hclKey := range conns.HCLKeys() {
+			var serviceKey string
+			var err error
+			if serviceKey, err = conns.ServiceForHCLKey(hclKey); err != nil {
+				return nil, fmt.Errorf("failed to assign endpoint (%s): %w", hclKey, err)
+			}
+
+			if config.Endpoints[serviceKey] == "" && endpoints[hclKey].(string) != "" {
+				config.Endpoints[serviceKey] = endpoints[hclKey].(string)
+			}
 		}
 	}
 
@@ -1911,7 +1921,7 @@ func assumeRoleSchema() *schema.Schema {
 func endpointsSchema() *schema.Schema {
 	endpointsAttributes := make(map[string]*schema.Schema)
 
-	for _, serviceKey := range conns.ServiceKeys() {
+	for _, serviceKey := range conns.HCLKeys() {
 		endpointsAttributes[serviceKey] = &schema.Schema{
 			Type:        schema.TypeString,
 			Optional:    true,

website/docs/guides/custom-service-endpoints.html.md

@@ -43,7 +43,20 @@ If multiple, different Terraform AWS Provider configurations are required, see t
 
 ## Available Endpoint Customizations
 
-The Terraform AWS Provider allows the following endpoints to be customized. **Note:** The Provider allows some service endpoints to be customized before supporting those services.
+The Terraform AWS Provider allows the following endpoints to be customized.
+
+**Note:** The Provider allows some service endpoints to be customized despite not supporting those services.
+
+**Note:** For backward compatibility, some endpoints can be assigned using multiple service "keys" (_e.g._, `dms`, `databasemigration`, or `databasemigrationservice`). If you use more than one equivalent service key in your configuration, the provider will use the _first_ endpoint value set. For example, in the configuration below we have set the DMS service endpoints using both `dms` and `databasemigration`. The provider will set the endpoint to whichever appears first. Subsequent values are ignored.
+
+```terraform
+provider "aws" {
+  endpoints {
+    dms               = "http://this.value.will.be.used.com"
+    databasemigration = "http://this.value.will.be.ignored.com"
+  }
+}
+```
 
 <!-- markdownlint-disable MD033 -->
 <!--