[Enhancement] aws_api_gateway_integration: Add response_transfer_mode argument for response streaming

.changelog/45329.txt

@@ -0,0 +1,3 @@
+```release-note:enhancement
+resource/aws_api_gateway_integration: Add `response_transfer_mode` argument
+```

internal/service/apigateway/integration.go

@@ -122,6 +122,12 @@ func resourceIntegration() *schema.Resource {
 				Required: true,
 				ForceNew: true,
 			},
+			"response_transfer_mode": {
+				Type:             schema.TypeString,
+				Optional:         true,
+				Computed:         true,
+				ValidateDiagFunc: enum.Validate[types.ResponseTransferMode](),
+			},
 			"rest_api_id": {
 				Type:     schema.TypeString,
 				Required: true,
@@ -213,6 +219,10 @@ func resourceIntegrationCreate(ctx context.Context, d *schema.ResourceData, meta
 		input.RequestTemplates = flex.ExpandStringValueMap(v.(map[string]any))
 	}
 
+	if v, ok := d.GetOk("response_transfer_mode"); ok {
+		input.ResponseTransferMode = types.ResponseTransferMode(v.(string))
+	}
+
 	if v, ok := d.GetOk("timeout_milliseconds"); ok {
 		input.TimeoutInMillis = aws.Int32(int32(v.(int)))
 	}
@@ -267,6 +277,11 @@ func resourceIntegrationRead(ctx context.Context, d *schema.ResourceData, meta a
 	requestTemplates := make(map[string]string)
 	maps.Copy(requestTemplates, integration.RequestTemplates)
 	d.Set("request_templates", requestTemplates)
+	if integration.ResponseTransferMode == "" {
+		d.Set("response_transfer_mode", string(types.ResponseTransferModeBuffered))
+	} else {
+		d.Set("response_transfer_mode", integration.ResponseTransferMode)
+	}
 	d.Set("timeout_milliseconds", integration.TimeoutInMillis)
 	d.Set(names.AttrType, integration.Type)
 	d.Set(names.AttrURI, integration.Uri)
@@ -442,6 +457,18 @@ func resourceIntegrationUpdate(ctx context.Context, d *schema.ResourceData, meta
 		})
 	}
 
+	if d.HasChange("response_transfer_mode") {
+		responseTransferMode := d.Get("response_transfer_mode").(string)
+		if responseTransferMode == "" {
+			responseTransferMode = string(types.ResponseTransferModeBuffered)
+		}
+		operations = append(operations, types.PatchOperation{
+			Op:    types.OpReplace,
+			Path:  aws.String("/responseTransferMode"),
+			Value: aws.String(responseTransferMode),
+		})
+	}
+
 	if d.HasChange("timeout_milliseconds") {
 		operations = append(operations, types.PatchOperation{
 			Op:    types.OpReplace,

internal/service/apigateway/integration_test.go

@@ -11,6 +11,7 @@ import (
 
 	"github.com/YakDriver/regexache"
 	"github.com/aws/aws-sdk-go-v2/service/apigateway"
+	awstypes "github.com/aws/aws-sdk-go-v2/service/apigateway/types"
 	sdkacctest "github.com/hashicorp/terraform-plugin-testing/helper/acctest"
 	"github.com/hashicorp/terraform-plugin-testing/helper/resource"
 	"github.com/hashicorp/terraform-plugin-testing/terraform"
@@ -582,6 +583,60 @@ func TestAccAPIGatewayIntegration_TLS_insecureSkipVerification(t *testing.T) {
 	})
 }
 
+func TestAccAPIGatewayIntegration_responseTransferMode(t *testing.T) {
+	ctx := acctest.Context(t)
+	var conf apigateway.GetIntegrationOutput
+	rName := sdkacctest.RandomWithPrefix(acctest.ResourcePrefix)
+	resourceName := "aws_api_gateway_integration.test"
+
+	resource.ParallelTest(t, resource.TestCase{
+		PreCheck:                 func() { acctest.PreCheck(ctx, t); acctest.PreCheckAPIGatewayTypeEDGE(t) },
+		ErrorCheck:               acctest.ErrorCheck(t, names.APIGatewayServiceID),
+		ProtoV5ProviderFactories: acctest.ProtoV5ProviderFactories,
+		CheckDestroy:             testAccCheckIntegrationDestroy(ctx),
+		Steps: []resource.TestStep{
+			{
+				Config: testAccIntegrationConfig_responseTransferMode(rName, string(awstypes.ResponseTransferModeStream)),
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckIntegrationExists(ctx, resourceName, &conf),
+					resource.TestCheckResourceAttr(resourceName, names.AttrType, "HTTP_PROXY"),
+					resource.TestCheckResourceAttr(resourceName, "integration_http_method", "ANY"),
+					resource.TestCheckResourceAttr(resourceName, names.AttrURI, "https://example.com"),
+					resource.TestCheckResourceAttr(resourceName, "response_transfer_mode", string(awstypes.ResponseTransferModeStream)),
+				),
+			},
+			{
+				ResourceName:      resourceName,
+				ImportState:       true,
+				ImportStateIdFunc: testAccIntegrationImportStateIdFunc(resourceName),
+				ImportStateVerify: true,
+			},
+			{
+				// Switch to Buffered
+				Config: testAccIntegrationConfig_responseTransferMode(rName, string(awstypes.ResponseTransferModeBuffered)),
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckIntegrationExists(ctx, resourceName, &conf),
+					resource.TestCheckResourceAttr(resourceName, names.AttrType, "HTTP_PROXY"),
+					resource.TestCheckResourceAttr(resourceName, "integration_http_method", "ANY"),
+					resource.TestCheckResourceAttr(resourceName, names.AttrURI, "https://example.com"),
+					resource.TestCheckResourceAttr(resourceName, "response_transfer_mode", string(awstypes.ResponseTransferModeBuffered)),
+				),
+			},
+			{
+				// Switch back to Stream
+				Config: testAccIntegrationConfig_responseTransferMode(rName, string(awstypes.ResponseTransferModeStream)),
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckIntegrationExists(ctx, resourceName, &conf),
+					resource.TestCheckResourceAttr(resourceName, names.AttrType, "HTTP_PROXY"),
+					resource.TestCheckResourceAttr(resourceName, "integration_http_method", "ANY"),
+					resource.TestCheckResourceAttr(resourceName, names.AttrURI, "https://example.com"),
+					resource.TestCheckResourceAttr(resourceName, "response_transfer_mode", string(awstypes.ResponseTransferModeStream)),
+				),
+			},
+		},
+	})
+}
+
 func TestAccAPIGatewayIntegration_disappears(t *testing.T) {
 	ctx := acctest.Context(t)
 	var conf apigateway.GetIntegrationOutput
@@ -1269,3 +1324,35 @@ resource "aws_api_gateway_integration" "test" {
 }
 `, rName, insecureSkipVerification)
 }
+
+func testAccIntegrationConfig_responseTransferMode(rName, responseTransferMode string) string {
+	return fmt.Sprintf(`
+resource "aws_api_gateway_rest_api" "api" {
+  name = %[1]q
+}
+
+resource "aws_api_gateway_resource" "resource" {
+  path_part   = "resource"
+  parent_id   = aws_api_gateway_rest_api.api.root_resource_id
+  rest_api_id = aws_api_gateway_rest_api.api.id
+}
+
+resource "aws_api_gateway_method" "method" {
+  rest_api_id   = aws_api_gateway_rest_api.api.id
+  resource_id   = aws_api_gateway_resource.resource.id
+  http_method   = "ANY"
+  authorization = "NONE"
+}
+
+resource "aws_api_gateway_integration" "test" {
+  rest_api_id             = aws_api_gateway_rest_api.api.id
+  resource_id             = aws_api_gateway_resource.resource.id
+  http_method             = aws_api_gateway_method.method.http_method
+  integration_http_method = "ANY"
+  type                    = "HTTP_PROXY"
+  uri                     = "https://example.com"
+
+  response_transfer_mode = %[2]q
+}
+`, rName, responseTransferMode)
+}

website/docs/r/api_gateway_integration.html.markdown

@@ -220,6 +220,8 @@ This resource supports the following arguments:
 * `request_templates` - (Optional) Map of the integration's request templates.
 * `request_parameters` - (Optional) Map of request query string parameters and headers that should be passed to the backend responder.
   For example: `request_parameters = { "integration.request.header.X-Some-Other-Header" = "method.request.header.X-Some-Header" }`
+* `response_transfer_mode` – (Optional) Specifies the response transfer mode of the integration. Valid values are `BUFFERED` and `STREAM`. Default to `BUFFERED`.  
+  Once set, setting the value to `BUFFERED` requires explicitly specifying `BUFFERED`, rather than removing this argument.
 * `passthrough_behavior` - (Optional) Integration passthrough behavior (`WHEN_NO_MATCH`, `WHEN_NO_TEMPLATES`, `NEVER`).  **Required** if `request_templates` is used.
 * `cache_key_parameters` - (Optional) List of cache key parameters for the integration.
 * `cache_namespace` - (Optional) Integration's cache namespace.