Copy objects by using multipart copy

func (c *Client) UploadPartCopy(ctx context.Context, request *UploadPartCopyRequest, optFns ...func(*Options)) (*UploadPartCopyResult, error)

package main

import (
	"context"
	"flag"
	"log"
	"sync"

	"github.com/aliyun/alibabacloud-oss-go-sdk-v2/oss"
	"github.com/aliyun/alibabacloud-oss-go-sdk-v2/oss/credentials"
)

// Specify the global variables.
var (
	region         string // The region.
	srcBucketName string // The name of the source bucket.
	srcObjectName string // The name of the source object.
	destBucketName string // The name of the destination bucket.
	destObjectName string // The name of the destination object.
)

// Specify the init function used to initialize command line parameters.
func init() {
	flag.StringVar(&region, "region", "", "The region in which the bucket is located.")
	flag.StringVar(&srcBucketName, "src-bucket", "", "The name of the source bucket.")
	flag.StringVar(&srcObjectName, "src-object", "", "The name of the source object.")
	flag.StringVar(&destBucketName, "dest-bucket", "", "The name of the destination bucket.")
	flag.StringVar(&destObjectName, "dest-object", "", "The name of the destination object.")
}

func main() {
	// Parse command line parameters.
	flag.Parse()

	// Specify the upload ID.
	var uploadId string

	// Check whether the source bucket name is empty.
	if len(srcBucketName) == 0 {
		flag.PrintDefaults()
		log.Fatalf("invalid parameters, source bucket name required")
	}

	// Check whether the region is empty.
	if len(region) == 0 {
		flag.PrintDefaults()
		log.Fatalf("invalid parameters, region required")
	}

	// If the destination bucket name is not specified, the source bucket name is used.
	if len(destBucketName) == 0 {
		destBucketName = srcBucketName
	}

	// Check whether the source object name is empty.
	if len(srcObjectName) == 0 {
		flag.PrintDefaults()
		log.Fatalf("invalid parameters, source object name required")
	}

	// Check whether the destination object name is empty.
	if len(destObjectName) == 0 {
		flag.PrintDefaults()
		log.Fatalf("invalid parameters, destination object name required")
	}

	// Load the default configurations and specify the credential provider and region.
	cfg := oss.LoadDefaultConfig().
		WithCredentialsProvider(credentials.NewEnvironmentVariableCredentialsProvider()).
		WithRegion(region)

	// Create an OSS client.
	client := oss.NewClient(cfg)

	// Initialize the multipart upload request.
	initRequest := &oss.InitiateMultipartUploadRequest{
		Bucket: oss.Ptr(destBucketName),
		Key:    oss.Ptr(destObjectName),
	}
	initResult, err := client.InitiateMultipartUpload(context.TODO(), initRequest)
	if err != nil {
		log.Fatalf("failed to initiate multipart upload %v", err)
	}

	// Display the result of multipart copy.
	log.Printf("initiate multipart upload result:%#v\n", *initResult.UploadId)
	uploadId = *initResult.UploadId

	// Initialize the wait group and mutual exclusion (mutex).
	var wg sync.WaitGroup
	var parts []oss.UploadPart
	count := 3
	var mu sync.Mutex

	// Start multiple goroutines for multipart upload.
	for i := 0; i < count; i++ {
		wg.Add(1)
		go func(partNumber int, i int) {
			defer wg.Done()

			// Create the multipart upload request.
			partRequest := &oss.UploadPartCopyRequest{
				Bucket:       oss.Ptr(destBucketName), // The name of the destination bucket.
				Key:          oss.Ptr(destObjectName), // The name of the destination object.
				SourceBucket: oss.Ptr(srcBucketName), // The name of the source bucket.
				SourceKey:     oss.Ptr(srcObjectName), // The name of the source object.
				PartNumber: int32(partNumber), // The part number.
				const uploadId = '<Upload Id>'; // The upload ID of the multipart upload task.
			}

			// Send the multipart upload request.
			partResult, err := client.UploadPartCopy(context.TODO(), partRequest)
			if err != nil {
				log.Fatalf("failed to upload part copy %d: %v", partNumber, err)
			}

			// Record the multipart upload result.
			part := oss.UploadPart{
				PartNumber: partRequest.PartNumber,
				ETag:       partResult.ETag,
			}

			// Use the mutex to protect shared data.
			mu.Lock()
			parts = append(parts, part)
			mu.Unlock()
		}(i+1, i)
	}

	// Wait until all goroutines are complete.
	wg.Wait()

	// Complete the multipart upload request.
	request := &oss.CompleteMultipartUploadRequest{
		Bucket:   oss.Ptr(destBucketName),
		Key:      oss.Ptr(destObjectName),
		UploadId: oss.Ptr(uploadId),
		CompleteMultipartUpload: &oss.CompleteMultipartUpload{
			Parts: parts,
		},
	}
	result, err := client.CompleteMultipartUpload(context.TODO(), request)
	if err != nil {
		log.Fatalf("failed to complete multipart upload %v", err)
	}

	// Display the result.
	log.Printf("complete multipart upload result:%#v\n", result)
}