codegen: Add fix to prevent HTTP/2 event stream request hang on error (…

…#4288)

Adds fix addressing an issue where SDK's bi-directional eventstream API
operation request could hang when the HTTP/2 stream was closed by the
service with a non-200 status code.

Go 1.15 through 1.17 have an issue where the HTTP/2 request can hang
while waiting for the HTTP response, and input payload reader. The
Expect: 100-Continue workaround forces the HTTP client to wait for a
`100 continue` or other HTTP status code before attempting to wait for
the request's body to be read. This workaround is not needed for Go
1.18, as a fix to the HTTP client resolves this issue.

Related to aws/aws-sdk-go-v2#1515

CHANGELOG_PENDING.md

@@ -3,3 +3,6 @@
 ### SDK Enhancements
 
 ### SDK Bugs
+* `service/lexruntimev2`: Add fix to prevent HTTP/2 event stream request hang on error with Go 1.15 through 1.17.
+* `service/transcribestreamingservice`: Add fix to prevent HTTP/2 event stream request hang on error with Go 1.15 through 1.17.
+  * Adds fix addressing an issue where SDK's bi-directional eventstream API operation request could hang when the HTTP/2 stream was closed by the service with a non-200 status code.

private/model/api/operation.go

@@ -263,6 +263,7 @@ func (c *{{ .API.StructName }}) {{ .ExportedName }}Request(` +
 					"X-Amz-Content-Sha256": "STREAMING-AWS4-HMAC-SHA256-EVENTS",
 				}))
 				req.Handlers.Build.Swap({{ .API.ProtocolPackage }}.BuildHandler.Name, rest.BuildHandler)
+				eventstreamapi.ApplyHTTPTransportFixes(req)
 				req.Handlers.Send.Swap(client.LogHTTPRequestHandler.Name, client.LogHTTPRequestHeaderHandler)
 				req.Handlers.Unmarshal.PushBack(es.runInputStream)
 

private/protocol/eventstream/eventstreamapi/transport.go

@@ -0,0 +1,10 @@
+//go:build go1.18
+// +build go1.18
+
+package eventstreamapi
+
+import "github.com/aws/aws-sdk-go/aws/request"
+
+// This is a no-op for Go 1.18 and above.
+func ApplyHTTPTransportFixes(r *request.Request) {
+}

private/protocol/eventstream/eventstreamapi/transport_go1.17.go

@@ -0,0 +1,19 @@
+//go:build !go1.18
+// +build !go1.18
+
+package eventstreamapi
+
+import "github.com/aws/aws-sdk-go/aws/request"
+
+// ApplyHTTPTransportFixes applies fixes to the HTTP request for proper event
+// stream functionality. Go 1.15 through 1.17 HTTP client could hang forever
+// when an HTTP/2 connection failed with an non-200 status code and err. Using
+// Expect 100-Continue, allows the HTTP client to gracefully handle the non-200
+// status code, and close the connection.
+//
+// This is a no-op for Go 1.18 and above.
+func ApplyHTTPTransportFixes(r *request.Request) {
+	r.Handlers.Sign.PushBack(func(r *request.Request) {
+		r.HTTPRequest.Header.Set("Expect", "100-Continue")
+	})
+}

service/lexruntimev2/cust_integ_eventstream_test.go

@@ -0,0 +1,42 @@
+//go:build integration
+// +build integration
+
+package lexruntimev2
+
+import (
+	"testing"
+
+	"github.com/aws/aws-sdk-go/aws"
+	"github.com/aws/aws-sdk-go/aws/awserr"
+	"github.com/aws/aws-sdk-go/awstesting/integration"
+)
+
+func TestInteg_StartConversation_errorCase(t *testing.T) {
+	sess := integration.SessionWithDefaultRegion("us-west-2")
+
+	client := New(sess, &aws.Config{
+		Logger:   t,
+		LogLevel: aws.LogLevel(aws.LogDebugWithEventStreamBody | aws.LogDebugWithHTTPBody),
+	})
+
+	_, err := client.StartConversation(&StartConversationInput{
+		BotAliasId: aws.String("mockAlias"),
+		BotId:      aws.String("mockId01234567890"),
+		LocaleId:   aws.String("mockLocale"),
+		SessionId:  aws.String("mockSession"),
+	})
+	if err == nil {
+		t.Fatalf("expect error, got none")
+	}
+
+	aErr, ok := err.(awserr.RequestFailure)
+	if !ok {
+		t.Fatalf("expect %T error, got %T, %v", aErr, err, err)
+	}
+	if aErr.Code() == "" {
+		t.Errorf("expect error code, got none")
+	}
+	if aErr.Message() == "" {
+		t.Errorf("expect error message, got none")
+	}
+}