example/service/s3/putObjectWithProgress: fix example for file upload…

… with progress (#3377)

Fixes #2468 by ignoring the first read of the progress reader wrapper. Since the first read is used for signing the request, not upload progress.

CHANGELOG_PENDING.md

@@ -1,6 +1,9 @@
 ### SDK Features
 
 ### SDK Enhancements
+* `example/service/s3/putObjectWithProgress`: Fix example for file upload with progress ([#3377](https://github.com/aws/aws-sdk-go/pull/3377))
+  * Fixes [#2468](https://github.com/aws/aws-sdk-go/issues/2468) by ignoring the first read of the progress reader wrapper. Since the first read is used for signing the request, not upload progress.
+  * Updated the example to write progress inline instead of newlines.
 * `service/dynamodb/dynamodbattribute`: Fix typo in package docs ([#3446](https://github.com/aws/aws-sdk-go/pull/3446))
   * Fixes typo in dynamodbattribute package docs.
 

example/service/s3/putObjectWithProcess/README.md

@@ -10,5 +10,5 @@ The example uses the bucket name provided, one key for object, and output the pr
 The Object size should larger than 5M or your will not see the progress
 
 ```sh
-AWS_REGION=<region> go run putObjWithProcess.go <credential> <bucket> <key for object> <local file name>
+AWS_REGION=<region> go run -tags example putObjWithProcess.go <bucket> <key for object> <local file name>
 ```

example/service/s3/putObjectWithProcess/putObjWithProcess.go

@@ -3,20 +3,22 @@
 package main
 
 import (
+	"fmt"
 	"log"
 	"os"
-	"sync/atomic"
+	"sync"
 
 	"github.com/aws/aws-sdk-go/aws"
-	"github.com/aws/aws-sdk-go/aws/credentials"
 	"github.com/aws/aws-sdk-go/aws/session"
 	"github.com/aws/aws-sdk-go/service/s3/s3manager"
 )
 
 type CustomReader struct {
-	fp   *os.File
-	size int64
-	read int64
+	fp      *os.File
+	size    int64
+	read    int64
+	signMap map[int64]struct{}
+	mux     sync.Mutex
 }
 
 func (r *CustomReader) Read(p []byte) (int, error) {
@@ -29,14 +31,16 @@ func (r *CustomReader) ReadAt(p []byte, off int64) (int, error) {
 		return n, err
 	}
 
-	// Got the length have read( or means has uploaded), and you can construct your message
-	atomic.AddInt64(&r.read, int64(n))
-
-	// I have no idea why the read length need to be div 2,
-	// maybe the request read once when Sign and actually send call ReadAt again
-	// It works for me
-	log.Printf("total read:%d    progress:%d%%\n", r.read/2, int(float32(r.read*100/2)/float32(r.size)))
-
+	r.mux.Lock()
+	// Ignore the first signature call
+	if _, ok := r.signMap[off]; ok {
+		// Got the length have read( or means has uploaded), and you can construct your message
+		r.read += int64(n)
+		fmt.Printf("\rtotal read:%d    progress:%d%%", r.read, int(float32(r.read*100)/float32(r.size)))
+	} else {
+		r.signMap[off] = struct{}{}
+	}
+	r.mux.Unlock()
 	return n, err
 }
 
@@ -46,40 +50,34 @@ func (r *CustomReader) Seek(offset int64, whence int) (int64, error) {
 
 func main() {
 	if len(os.Args) < 4 {
-		log.Println("USAGE ERROR: AWS_REGION=us-east-1 go run putObjWithProcess.go <credential> <bucket> <key for object> <local file name>")
+		log.Println("USAGE ERROR: AWS_REGION=us-west-2 go run -tags example putObjWithProcess.go <bucket> <key for object> <local file name>")
 		return
 	}
 
-	credential := os.Args[1]
-	bucket := os.Args[2]
-	key := os.Args[3]
-	fileName := os.Args[4]
+	bucket := os.Args[1]
+	key := os.Args[2]
+	filename := os.Args[3]
 
-	creds := credentials.NewSharedCredentials(credential, "default")
-	if _, err := creds.Get(); err != nil {
-		log.Println("ERROR:", err)
-		return
+	sess, err := session.NewSession()
+	if err != nil {
+		log.Fatalf("failed to load session, %v", err)
 	}
 
-	sess := session.New(&aws.Config{
-		Credentials: creds,
-	})
-
-	file, err := os.Open(fileName)
+	file, err := os.Open(filename)
 	if err != nil {
-		log.Println("ERROR:", err)
-		return
+		log.Fatalf("failed to open file %v, %v", filename, err)
 	}
 
 	fileInfo, err := file.Stat()
 	if err != nil {
-		log.Println("ERROR:", err)
+		log.Fatalf("failed to stat file %v, %v", filename, err)
 		return
 	}
 
 	reader := &CustomReader{
-		fp:   file,
-		size: fileInfo.Size(),
+		fp:      file,
+		size:    fileInfo.Size(),
+		signMap: map[int64]struct{}{},
 	}
 
 	uploader := s3manager.NewUploader(sess, func(u *s3manager.Uploader) {
@@ -92,11 +90,11 @@ func main() {
 		Key:    aws.String(key),
 		Body:   reader,
 	})
-
 	if err != nil {
-		log.Println("ERROR:", err)
+		log.Fatalf("failed to put file %v, %v", filename, err)
 		return
 	}
 
+	fmt.Println()
 	log.Println(output.Location)
 }