config: Add a WithRetryer provider helper to the config loader (#897)

Adds a WithRetryer configuration provider to the config loader as a convenience helper to set the Retryer on the Config when its being loaded.

.changes/next-release/config-feature-1605221765957672000.json

@@ -0,0 +1,9 @@
+{
+ "ID": "config-feature-1605221765957672000",
+ "SchemaVersion": 1,
+ "Module": "config",
+ "Type": "feature",
+ "Description": "Add a WithRetryer provider helper to the config loader",
+ "MinVersion": "",
+ "AffectedModules": null
+}

config/codegen/main.go

@@ -29,6 +29,7 @@ var implAsserts = map[string][]string{
 	"HTTPClientProvider":                       {`WithHTTPClient(nil)`},
 	"AssumeRoleCredentialOptionsProvider":      {`WithAssumeRoleCredentialOptions(nil)`},
 	"WebIdentityRoleCredentialOptionsProvider": {`WithWebIdentityRoleCredentialOptions(nil)`},
+	"RetryProvider":                            {`WithRetryer(nil)`},
 }
 
 var tplProviderTests = template.Must(template.New("tplProviderTests").Funcs(map[string]interface{}{

config/config.go

@@ -24,6 +24,7 @@ var defaultAWSConfigResolvers = []awsConfigResolver{
 	resolveHTTPClient,
 	resolveEndpointResolver,
 	resolveAPIOptions,
+	resolveRetryer,
 
 	resolveRegion,
 	// TODO: Add back EC2 Region Resolver Support

config/provider.go

@@ -608,3 +608,36 @@ func getLogConfigurationWarnings(configs configs) (v bool, found bool, err error
 	}
 	return v, found, err
 }
+
+// RetryProvider is an configuration provider for custom Retryer.
+type RetryProvider interface {
+	GetRetryer() (aws.Retryer, bool, error)
+}
+
+// WithRetryer returns a RetryProvider for the SDK retryer provided.
+func WithRetryer(retryer aws.Retryer) RetryProvider {
+	return retryProvider{retryer: retryer}
+}
+
+type retryProvider struct {
+	retryer aws.Retryer
+}
+
+func (p retryProvider) GetRetryer() (aws.Retryer, bool, error) {
+	return p.retryer, true, nil
+}
+
+func getRetryer(configs configs) (v aws.Retryer, found bool, err error) {
+	for _, c := range configs {
+		if p, ok := c.(RetryProvider); ok {
+			v, found, err = p.GetRetryer()
+			if err != nil {
+				return nil, false, err
+			}
+			if found {
+				break
+			}
+		}
+	}
+	return v, found, err
+}

config/resolve.go

@@ -181,3 +181,17 @@ func resolveClientLogMode(cfg *aws.Config, configs configs) error {
 
 	return nil
 }
+
+func resolveRetryer(cfg *aws.Config, configs configs) error {
+	retryer, found, err := getRetryer(configs)
+	if err != nil {
+		return err
+	}
+	if !found {
+		return nil
+	}
+
+	cfg.Retryer = retryer
+
+	return nil
+}