分段复制

更新时间： 2019-03-14 10:05

分段复制是分段上传的一种特殊情况，即分段上传任务中的段通过复制OBS指定桶中现有对象（或对象的一部分）来实现。您可以通过ObsClient.CopyPart来复制段。以下代码展示了如何使用分段复制模式复制大对象：

  1. // 引入依赖包
  2. import (
  3.        "fmt"
  4.        "obs"
  5. )
  6.  
  7. var ak = "*** Provide your Access Key ***"
  8. var sk = "*** Provide your Secret Key ***"
  9. var endpoint = "https://your-endpoint"
  10. var destBucketName = "bucketname"
  11. var destObjectKey = "objectkey"
  12. var sourceBucketName = "sourcebucketname"
  13. var sourceObjectKey = "sourceobjectkey"
  14.  
  15. // 创建ObsClient结构体
  16. var obsClient, _ = obs.New(ak, sk, endpoint)
  17.  
  18. func main() {
  19.        // 初始化分段上传任务
  20.        input := &obs.InitiateMultipartUploadInput{}
  21.        input.Bucket = destBucketName
  22.        input.Key = destObjectKey
  23.        output, err := obsClient.InitiateMultipartUpload(input)
  24.  
  25.        if err != nil {
  26.               panic(err)
  27.        }
  28.  
  29.        uploadId := output.UploadId
  30.  
  31.        fmt.Printf("UploadId:%s\n", uploadId)
  32.        fmt.Println()
  33.  
  34.        // 每段复制100MB
  35.        var partSize int64 = 100 * 1024 * 1024
  36.  
  37.        // 获取大对象信息
  38.        getObjectMetadataInput := &obs.GetObjectMetadataInput{}
  39.        getObjectMetadataInput.Bucket = sourceBucketName
  40.        getObjectMetadataInput.Key = sourceObjectKey
  41.        getObjectMetadataOutput, err := obsClient.GetObjectMetadata(getObjectMetadataInput)
  42.  
  43.        if err != nil {
  44.               panic(err)
  45.        }
  46.        objectSize := getObjectMetadataOutput.ContentLength
  47.  
  48.        // 计算需要复制的段数
  49.        partCount := int(objectSize / partSize)
  50.  
  51.        if objectSize%partSize != 0 {
  52.               partCount++
  53.        }
  54.  
  55.        // 执行并发复制段
  56.        partChan := make(chan obs.Part, 5)
  57.  
  58.        for i := 0; i < partCount; i++ {
  59.               partNumber := i + 1
  60.               rangeStart := int64(i) * partSize
  61.               rangeEnd := rangeStart + partSize - 1
  62.               if i+1 == partCount {
  63.                      rangeEnd = objectSize - 1
  64.               }
  65.               go func() {
  66.                      copyPartInput := &obs.CopyPartInput{}
  67.                      copyPartInput.Bucket = destBucketName
  68.                      copyPartInput.Key = destObjectKey
  69.                      copyPartInput.UploadId = uploadId
  70.                      // 分段号
  71.                      copyPartInput.PartNumber = int(partNumber)
  72.                      copyPartInput.CopySourceBucket = sourceBucketName
  73.                      copyPartInput.CopySourceKey = sourceObjectKey
  74.                      // 复制段起始位置
  75.                      copyPartInput.CopySourceRangeStart = rangeStart
  76.                      // 复制段结束位置
  77.                      copyPartInput.CopySourceRangeEnd = rangeEnd
  78.                      copyPartOutput, err := obsClient.CopyPart(copyPartInput)
  79.                      if err == nil {
  80.                            fmt.Printf("%d finished\n", partNumber)
  81.                            partChan <- obs.Part{ETag: copyPartOutput.ETag, PartNumber: copyPartOutput.PartNumber}
  82.                      } else {
  83.                            panic(err)
  84.                      }
  85.               }()
  86.        }
  87.  
  88.        parts := make([]obs.Part, 0, partCount)
  89.  
  90.        // 等待复制完成
  91.        for {
  92.               part, ok := <-partChan
  93.               if !ok {
  94.                      break
  95.               }
  96.               parts = append(parts, part)
  97.  
  98.               if len(parts) == partCount {
  99.                      close(partChan)
  100.               }
  101.        }
  102.  
  103.        completeMultipartUploadInput := &obs.CompleteMultipartUploadInput{}
  104.        completeMultipartUploadInput.Bucket = destBucketName
  105.        completeMultipartUploadInput.Key = destObjectKey
  106.        completeMultipartUploadInput.UploadId = uploadId
  107.        completeMultipartUploadInput.Parts = parts
  108.        // 合并段
  109.        completeMultipartUploadOutput, err := obsClient.CompleteMultipartUpload(completeMultipartUploadInput)
  110.        if err != nil {
  111.               panic(err)
  112.        }
  113.        fmt.Printf("RequestId:%s\n", completeMultipartUploadOutput.RequestId)
  114. }

父主题：上传对象