Support for Loading Service Specific Configuration from External Sources During Client Creation (#474)

Author: skmcgrail

aws/config.go

@@ -78,6 +78,16 @@ type Config struct {
 	// Disabling this feature is useful when you want to use local endpoints
 	// for testing that do not support the modeled host prefix pattern.
 	DisableEndpointHostPrefix bool
+
+	// ConfigResolver defines how additional configuration can be loaded by clients.
+	AdditionalConfig ConfigResolver
+}
+
+// ConfigResolver is an interface that encapsulates the behavior of loading
+// additional configuration.
+type ConfigResolver interface {
+	// ResolveConfig calls the provide function passing a slice of configuration sources
+	ResolveConfig(func(configs []interface{}) error) error
 }
 
 // NewConfig returns a new Config pointer that can be chained with builder

aws/external/config.go

@@ -100,6 +100,16 @@ func (cs Configs) ResolveAWSConfig(resolvers []AWSConfigResolver) (aws.Config, e
 	return cfg, nil
 }
 
+// ResolveConfig calls the provide function passing slice of configuration sources.
+// This implements the aws.ConfigResolver interface.
+func (cs Configs) ResolveConfig(f func(configs []interface{}) error) error {
+	var cfgs []interface{}
+	for i := range cs {
+		cfgs = append(cfgs, cs[i])
+	}
+	return f(cfgs)
+}
+
 // LoadDefaultAWSConfig reads the SDK's default external configurations, and
 // populates an AWS Config with the values from the external configurations.
 //

aws/external/env_config.go

@@ -1,8 +1,10 @@
 package external
 
 import (
+	"fmt"
 	"io/ioutil"
 	"os"
+	"strings"
 
 	"github.com/aws/aws-sdk-go-v2/aws"
 )
@@ -37,6 +39,8 @@ const (
 	AWSConfigFileEnvVar = "AWS_CONFIG_FILE"
 
 	AWSCustomCABundleEnvVar = "AWS_CA_BUNDLE"
+
+	S3UseARNRegionEnvVar = "AWS_S3_USE_ARN_REGION"
 )
 
 var (
@@ -134,6 +138,12 @@ type EnvConfig struct {
 	//
 	//  AWS_CA_BUNDLE=$HOME/my_custom_ca_bundle
 	CustomCABundle string
+
+	// Specifies if the S3 service should allow ARNs to direct the region
+	// the client's requests are sent to.
+	//
+	// AWS_S3_USE_ARN_REGION=true
+	S3UseARNRegion *bool
 }
 
 // LoadEnvConfig reads configuration values from the OS's environment variables.
@@ -168,6 +178,24 @@ func NewEnvConfig() (EnvConfig, error) {
 
 	cfg.CustomCABundle = os.Getenv(AWSCustomCABundleEnvVar)
 
+	s3UseARNRegion := os.Getenv(S3UseARNRegionEnvVar)
+	if len(s3UseARNRegion) != 0 {
+		var v bool
+
+		switch {
+		case strings.EqualFold(s3UseARNRegion, "false"):
+			v = false
+		case strings.EqualFold(s3UseARNRegion, "true"):
+			v = true
+		default:
+			return cfg, fmt.Errorf(
+				"invalid value for environment variable, %s=%s, need true or false",
+				S3UseARNRegionEnvVar, s3UseARNRegion)
+		}
+
+		cfg.S3UseARNRegion = &v
+	}
+
 	return cfg, nil
 }
 
@@ -226,6 +254,16 @@ func (c EnvConfig) GetCustomCABundle() ([]byte, error) {
 	return ioutil.ReadFile(c.CustomCABundle)
 }
 
+// GetS3UseARNRegion returns whether to allow ARNs to direct the region
+// the S3 client's requests are sent to.
+func (c EnvConfig) GetS3UseARNRegion() (value, ok bool, err error) {
+	if c.S3UseARNRegion == nil {
+		return false, false, nil
+	}
+
+	return *c.S3UseARNRegion, true, nil
+}
+
 func setFromEnvVal(dst *string, keys []string) {
 	for _, k := range keys {
 		if v := os.Getenv(k); len(v) > 0 {

aws/external/env_config_test.go

@@ -215,6 +215,14 @@ func TestNewEnvConfig(t *testing.T) {
 				SharedConfigFile:      "/path/to/config/file",
 			},
 		},
+		{
+			Env: map[string]string{
+				"AWS_S3_USE_ARN_REGION": "true",
+			},
+			Config: EnvConfig{
+				S3UseARNRegion: aws.Bool(true),
+			},
+		},
 	}
 
 	for _, c := range cases {

aws/external/shared_config.go

@@ -26,6 +26,9 @@ const (
 
 	// Additional Config fields
 	regionKey = `region`
+
+	// S3 ARN Region Usage
+	s3UseARNRegionKey = "s3_use_arn_region"
 )
 
 // DefaultSharedConfigProfile is the default profile to be used when
@@ -96,6 +99,22 @@ type SharedConfig struct {
 	//
 	//	region
 	Region string
+
+	// Specifies if the S3 service should allow ARNs to direct the region
+	// the client's requests are sent to.
+	//
+	// s3_use_arn_region=true
+	S3UseARNRegion *bool
+}
+
+// GetS3UseARNRegion retions if the S3 service should allow ARNs to direct the region
+// the client's requests are sent to.
+func (c *SharedConfig) GetS3UseARNRegion() (value, ok bool, err error) {
+	if c.S3UseARNRegion == nil {
+		return false, false, nil
+	}
+
+	return *c.S3UseARNRegion, true, nil
 }
 
 // GetRegion returns the region for the profile if a region is set.
@@ -337,6 +356,12 @@ func (c *SharedConfig) setFromIniFile(profile string, file sharedConfigFile) err
 		c.Region = v
 	}
 
+	// S3 Use ARN Region
+	if section.Has(s3UseARNRegionKey) {
+		v := section.Bool(s3UseARNRegionKey)
+		c.S3UseARNRegion = &v
+	}
+
 	return nil
 }
 

aws/external/shared_config_test.go

@@ -157,6 +157,14 @@ func TestNewSharedConfig(t *testing.T) {
 				Err:      awserr.New("INIParseError", "", nil),
 			},
 		},
+		{
+			Profile:   "valid_arn_region",
+			Filenames: []string{testConfigFilename},
+			Expected: SharedConfig{
+				Profile:        "valid_arn_region",
+				S3UseARNRegion: aws.Bool(true),
+			},
+		},
 	}
 
 	for i, c := range cases {

aws/external/testdata/shared_config

@@ -68,3 +68,6 @@ aws_secret_access_key = assume_role_w_creds_secret
 [assume_role_wo_creds]
 role_arn = assume_role_wo_creds_role_arn
 source_profile = assume_role_wo_creds
+
+[valid_arn_region]
+s3_use_arn_region=true

models/protocol_tests/generate.go

@@ -449,7 +449,7 @@ func generateTestSuite(filename string) string {
 			s.Rename(svcPrefix + "TestShape" + name)
 		}
 
-		svcCode := addImports(suite.API.ServiceGoCode())
+		svcCode := addImports(suite.API.ClientGoCode())
 		if i == 0 {
 			importMatch := reImportRemoval.FindStringSubmatch(svcCode)
 			buf.WriteString(importMatch[0] + "\n\n")