multipart upload programatically in Go

main.go

package main

import (
	"bytes"
	"fmt"
	"os"

	"github.com/aws/aws-sdk-go/aws"
	"github.com/aws/aws-sdk-go/aws/session"
	"github.com/aws/aws-sdk-go/service/s3"

	"storj.io/common/memory"
	"storj.io/common/testrand"
)

func main() {
	sess, err := session.NewSession(&aws.Config{
		Endpoint: aws.String(os.Getenv("AWS_ENDPOINT")),
		Region:   aws.String("us-east-1"),
	})
	if err != nil {
		panic(err)
	}

	svc := s3.New(sess)

	var (
		testbucket = aws.String("test-files")
		testkey    = aws.String("testkey")
	)

	m, err := svc.CreateMultipartUpload(&s3.CreateMultipartUploadInput{
		Bucket: testbucket,
		Key:    testkey,
	})
	if err != nil {
		panic(err)
	}

	fmt.Printf("started UploadId=%s\n", *m.UploadId)

	var completed []*s3.CompletedPart

	for i := 1; i <= 10; i++ {
		p, err := svc.UploadPart(&s3.UploadPartInput{
			Body:       aws.ReadSeekCloser(bytes.NewReader(testrand.Bytes(memory.KiB * 1))),
			Bucket:     testbucket,
			Key:        testkey,
			PartNumber: aws.Int64(int64(i)),
			UploadId:   m.UploadId,
		})
		if err != nil {
			panic(err)
		}

		completed = append(completed, &s3.CompletedPart{
			ETag:       p.ETag,
			PartNumber: aws.Int64(int64(i)),
		})

		fmt.Printf("uploaded part %d\n", i)
	}

	_, err = svc.CompleteMultipartUpload(&s3.CompleteMultipartUploadInput{
		Bucket:   testbucket,
		Key:      testkey,
		UploadId: m.UploadId,
		MultipartUpload: &s3.CompletedMultipartUpload{
			Parts: completed,
		},
	})
	if err != nil {
		panic(err)
	}
}