Migrate Go v2 S3 examples from deprecated feature/s3/manager to feature/s3/transfermanager

brmur · brmur · commit 035a42cae573 · 2026-04-29T12:38:48.000Z
Replace the deprecated feature/s3/manager package with the new
feature/s3/transfermanager package across Go v2 S3 examples:

- gov2/s3: Migrate UploadLargeObject and DownloadLargeObject to use
  transfermanager.New(), UploadObject(), and DownloadObject() APIs
- gov2/workflows/s3_object_lock: Migrate S3Actions.S3Manager from
  *manager.Uploader to *transfermanager.Client, update UploadObject()
- Update go.mod dependencies in both modules
- Update comments and documentation references

The feature/s3/manager package was deprecated in February 2026 in favor
of feature/s3/transfermanager, which provides a unified Client for both
uploads and downloads with improved performance.
diff --git a/gov2/s3/actions/bucket_basics.go b/gov2/s3/actions/bucket_basics.go
@@ -14,10 +14,11 @@ import (
 	"io"
 	"log"
 	"os"
+	"sync"
 	"time"
 
 	"github.com/aws/aws-sdk-go-v2/aws"
-	"github.com/aws/aws-sdk-go-v2/feature/s3/manager"
+	"github.com/aws/aws-sdk-go-v2/feature/s3/transfermanager"
 	"github.com/aws/aws-sdk-go-v2/service/s3"
 	"github.com/aws/aws-sdk-go-v2/service/s3/types"
 	"github.com/aws/smithy-go"
@@ -162,15 +163,15 @@ func (basics BucketBasics) UploadFile(ctx context.Context, bucketName string, ob
 
 // snippet-start:[gov2.s3.Upload]
 
-// UploadLargeObject uses an upload manager to upload data to an object in a bucket.
-// The upload manager breaks large data into parts and uploads the parts concurrently.
+// UploadLargeObject uses the S3 transfer manager to upload data to an object in a bucket.
+// The transfer manager breaks large data into parts and uploads the parts concurrently.
 func (basics BucketBasics) UploadLargeObject(ctx context.Context, bucketName string, objectKey string, largeObject []byte) error {
 	largeBuffer := bytes.NewReader(largeObject)
 	var partMiBs int64 = 10
-	uploader := manager.NewUploader(basics.S3Client, func(u *manager.Uploader) {
-		u.PartSize = partMiBs * 1024 * 1024
+	tm := transfermanager.New(basics.S3Client, func(o *transfermanager.Options) {
+		o.PartSizeBytes = partMiBs * 1024 * 1024
 	})
-	_, err := uploader.Upload(ctx, &s3.PutObjectInput{
+	_, err := tm.UploadObject(ctx, &transfermanager.UploadObjectInput{
 		Bucket: aws.String(bucketName),
 		Key:    aws.String(objectKey),
 		Body:   largeBuffer,
@@ -234,18 +235,19 @@ func (basics BucketBasics) DownloadFile(ctx context.Context, bucketName string,
 
 // snippet-start:[gov2.s3.Download]
 
-// DownloadLargeObject uses a download manager to download an object from a bucket.
-// The download manager gets the data in parts and writes them to a buffer until all of
+// DownloadLargeObject uses the S3 transfer manager to download an object from a bucket.
+// The transfer manager gets the data in parts and writes them to a buffer until all of
 // the data has been downloaded.
 func (basics BucketBasics) DownloadLargeObject(ctx context.Context, bucketName string, objectKey string) ([]byte, error) {
 	var partMiBs int64 = 10
-	downloader := manager.NewDownloader(basics.S3Client, func(d *manager.Downloader) {
-		d.PartSize = partMiBs * 1024 * 1024
+	tm := transfermanager.New(basics.S3Client, func(o *transfermanager.Options) {
+		o.PartSizeBytes = partMiBs * 1024 * 1024
 	})
-	buffer := manager.NewWriteAtBuffer([]byte{})
-	_, err := downloader.Download(ctx, buffer, &s3.GetObjectInput{
-		Bucket: aws.String(bucketName),
-		Key:    aws.String(objectKey),
+	buffer := NewWriteAtBuffer([]byte{})
+	_, err := tm.DownloadObject(ctx, &transfermanager.DownloadObjectInput{
+		Bucket:   aws.String(bucketName),
+		Key:      aws.String(objectKey),
+		WriterAt: buffer,
 	})
 	if err != nil {
 		log.Printf("Couldn't download large object from %v:%v. Here's why: %v\n",
@@ -254,6 +256,38 @@ func (basics BucketBasics) DownloadLargeObject(ctx context.Context, bucketName s
 	return buffer.Bytes(), err
 }
 
+// WriteAtBuffer is a thread-safe in-memory io.WriterAt implementation.
+type WriteAtBuffer struct {
+	buf []byte
+	m   sync.Mutex
+}
+
+// NewWriteAtBuffer creates a new WriteAtBuffer with an initial byte slice.
+func NewWriteAtBuffer(buf []byte) *WriteAtBuffer {
+	return &WriteAtBuffer{buf: buf}
+}
+
+// WriteAt writes len(p) bytes to the buffer starting at byte offset off.
+func (b *WriteAtBuffer) WriteAt(p []byte, off int64) (int, error) {
+	b.m.Lock()
+	defer b.m.Unlock()
+	end := int(off) + len(p)
+	if end > len(b.buf) {
+		newBuf := make([]byte, end)
+		copy(newBuf, b.buf)
+		b.buf = newBuf
+	}
+	copy(b.buf[off:], p)
+	return len(p), nil
+}
+
+// Bytes returns the contents of the buffer.
+func (b *WriteAtBuffer) Bytes() []byte {
+	b.m.Lock()
+	defer b.m.Unlock()
+	return b.buf
+}
+
 // snippet-end:[gov2.s3.Download]
 
 // snippet-start:[gov2.s3.CopyObject]
diff --git a/gov2/s3/cmd/main.go b/gov2/s3/cmd/main.go
@@ -24,7 +24,7 @@ import (
 //     Amazon Simple Storage Service (Amazon S3) actions to work with
 //     S3 buckets and objects.
 //   - `largeobjects` - Runs the interactive large objects scenario that shows you how to upload
-//     and download large objects by using a transfer manager.
+//     and download large objects by using the S3 transfer manager.
 //   - `presigning` - 	Runs the interactive presigning scenario that shows you how to
 //     get presigned requests that contain temporary credentials
 //     and can be used to make requests from any HTTP client.
diff --git a/gov2/s3/go.mod b/gov2/s3/go.mod
@@ -5,7 +5,7 @@ go 1.24
 require (
 	github.com/aws/aws-sdk-go-v2 v1.41.5
 	github.com/aws/aws-sdk-go-v2/config v1.27.33
-	github.com/aws/aws-sdk-go-v2/feature/s3/manager v1.17.18
+	github.com/aws/aws-sdk-go-v2/feature/s3/transfermanager v0.1.18
 	github.com/aws/aws-sdk-go-v2/service/s3 v1.97.3
 	github.com/aws/smithy-go v1.24.2
 	github.com/awsdocs/aws-doc-sdk-examples/gov2/demotools v0.0.0-20240907001412-a9375541143b
diff --git a/gov2/s3/scenarios/scenario_large_objects.go b/gov2/s3/scenarios/scenario_large_objects.go
@@ -21,8 +21,8 @@ import (
 // Simple Storage Service (Amazon S3) to upload and download large objects.
 //
 // 1. Create a bucket.
-// 3. Upload a large object to the bucket by using an upload manager.
-// 5. Download a large object by using a download manager.
+// 3. Upload a large object to the bucket by using the S3 transfer manager.
+// 5. Download a large object by using the S3 transfer manager.
 // 8. Delete all objects in the bucket.
 // 9. Delete the bucket.
 //
diff --git a/gov2/s3/scenarios/scenario_large_objects_test.go b/gov2/s3/scenarios/scenario_large_objects_test.go
@@ -30,7 +30,7 @@ func TestRunLargeObjectScenario(t *testing.T) {
 	testtools.RunScenarioTests(&scenTest, t)
 }
 
-// httpErr is used to mock an HTTP error. This is required by the download manager,
+// httpErr is used to mock an HTTP error. This is required by the transfer manager,
 // which calls GetObject until it receives a 415 status code.
 type httpErr struct {
 	statusCode int
diff --git a/gov2/workflows/s3_object_lock/actions/s3_actions.go b/gov2/workflows/s3_object_lock/actions/s3_actions.go
@@ -15,7 +15,7 @@ import (
 	"time"
 
 	"github.com/aws/aws-sdk-go-v2/aws"
-	"github.com/aws/aws-sdk-go-v2/feature/s3/manager"
+	"github.com/aws/aws-sdk-go-v2/feature/s3/transfermanager"
 	"github.com/aws/aws-sdk-go-v2/service/s3"
 	"github.com/aws/aws-sdk-go-v2/service/s3/types"
 	"github.com/aws/smithy-go"
@@ -24,7 +24,7 @@ import (
 // S3Actions wraps S3 service actions.
 type S3Actions struct {
 	S3Client  *s3.Client
-	S3Manager *manager.Uploader
+	S3Manager *transfermanager.Client
 }
 
 // snippet-end:[gov2.workflows.s3.ObjectLock.S3Actions.struct]
@@ -303,16 +303,16 @@ func (actor S3Actions) PutObjectRetention(ctx context.Context, bucket string, ke
 
 // snippet-start:[gov2.workflows.s3.ObjectLock.UploadObject]
 
-// UploadObject uses the S3 upload manager to upload an object to a bucket.
+// UploadObject uses the S3 transfer manager to upload an object to a bucket.
 func (actor S3Actions) UploadObject(ctx context.Context, bucket string, key string, contents string) (string, error) {
 	var outKey string
-	input := &s3.PutObjectInput{
+	input := &transfermanager.UploadObjectInput{
 		Bucket:            aws.String(bucket),
 		Key:               aws.String(key),
 		Body:              bytes.NewReader([]byte(contents)),
-		ChecksumAlgorithm: types.ChecksumAlgorithmSha256,
+		ChecksumAlgorithm: "SHA256",
 	}
-	output, err := actor.S3Manager.Upload(ctx, input)
+	output, err := actor.S3Manager.UploadObject(ctx, input)
 	if err != nil {
 		var noBucket *types.NoSuchBucket
 		if errors.As(err, &noBucket) {
diff --git a/gov2/workflows/s3_object_lock/actions/s3_actions_test.go b/gov2/workflows/s3_object_lock/actions/s3_actions_test.go
@@ -13,7 +13,7 @@ import (
 	"time"
 
 	"github.com/aws/aws-sdk-go-v2/aws"
-	"github.com/aws/aws-sdk-go-v2/feature/s3/manager"
+	"github.com/aws/aws-sdk-go-v2/feature/s3/transfermanager"
 	"github.com/aws/aws-sdk-go-v2/service/s3"
 	"github.com/aws/aws-sdk-go-v2/service/s3/types"
 	"github.com/aws/smithy-go"
@@ -142,7 +142,7 @@ func TestUploadObject(t *testing.T) {
 	ctx, stubber, actor := enterTest()
 	defer testtools.ExitTest(stubber, t)
 
-	actor.S3Manager = manager.NewUploader(actor.S3Client)
+	actor.S3Manager = transfermanager.New(actor.S3Client)
 	expectedErr, stubErr := wrapErr(&types.NoSuchBucket{})
 	checksum := types.ChecksumAlgorithmSha256
 	stubber.Add(stubs.StubPutObject("amzn-s3-demo-bucket", "test-key", &checksum, stubErr))
diff --git a/gov2/workflows/s3_object_lock/go.mod b/gov2/workflows/s3_object_lock/go.mod
@@ -5,7 +5,7 @@ go 1.24
 require (
 	github.com/aws/aws-sdk-go-v2 v1.41.5
 	github.com/aws/aws-sdk-go-v2/config v1.27.33
-	github.com/aws/aws-sdk-go-v2/feature/s3/manager v1.17.18
+	github.com/aws/aws-sdk-go-v2/feature/s3/transfermanager v0.1.18
 	github.com/aws/aws-sdk-go-v2/service/s3 v1.97.3
 	github.com/aws/smithy-go v1.24.2
 	github.com/awsdocs/aws-doc-sdk-examples/gov2/demotools v0.0.0-20240907001412-a9375541143b
diff --git a/gov2/workflows/s3_object_lock/workflows/s3_object_lock.go b/gov2/workflows/s3_object_lock/workflows/s3_object_lock.go
@@ -14,7 +14,7 @@ import (
 	"s3_object_lock/actions"
 
 	"github.com/aws/aws-sdk-go-v2/aws"
-	"github.com/aws/aws-sdk-go-v2/feature/s3/manager"
+	"github.com/aws/aws-sdk-go-v2/feature/s3/transfermanager"
 	"github.com/aws/aws-sdk-go-v2/service/s3"
 	"github.com/aws/aws-sdk-go-v2/service/s3/types"
 	"github.com/awsdocs/aws-doc-sdk-examples/gov2/demotools"
@@ -36,7 +36,7 @@ func NewObjectLockScenario(sdkConfig aws.Config, questioner demotools.IQuestione
 		s3Actions:  &actions.S3Actions{S3Client: s3.NewFromConfig(sdkConfig)},
 		sdkConfig:  sdkConfig,
 	}
-	scenario.s3Actions.S3Manager = manager.NewUploader(scenario.s3Actions.S3Client)
+	scenario.s3Actions.S3Manager = transfermanager.New(scenario.s3Actions.S3Client)
 	scenario.resources.init(scenario.s3Actions, questioner)
 	return scenario
 }

Original file line number	Diff line number	Diff line change
`@@ -30,7 +30,7 @@ func TestRunLargeObjectScenario(t *testing.T) {`
`30`	`30`	`testtools.RunScenarioTests(&scenTest, t)`
`31`	`31`	`}`
`32`	`32`
`33`		`-// httpErr is used to mock an HTTP error. This is required by the download manager,`
	`33`	`+// httpErr is used to mock an HTTP error. This is required by the transfer manager,`
`34`	`34`	`// which calls GetObject until it receives a 415 status code.`
`35`	`35`	`type httpErr struct {`
`36`	`36`	`statusCode int`