download checkpoint

example/bucket/putPolicy.go

@@ -48,7 +48,7 @@ func main() {
 				Condition: map[string]map[string]interface{}{
 					"ip_not_equal": map[string]interface{}{
 						"qcs:ip": []string{
-							"192.168.1.1",
+							"<ip>",
 						},
 					},
 				},

object.go

@@ -3,6 +3,7 @@ package cos
 import (
 	"context"
 	"crypto/md5"
+	"encoding/json"
 	"encoding/xml"
 	"errors"
 	"fmt"
@@ -568,6 +569,20 @@ type MultiDownloadOptions struct {
 	Opt            *ObjectGetOptions
 	PartSize       int64
 	ThreadPoolSize int
+	CheckPoint     bool
+	CheckPointFile string
+}
+
+type MultiDownloadCPInfo struct {
+	Size             int64             `json:"contentLength,omitempty"`
+	ETag             string            `json:"eTag,omitempty"`
+	CRC64            string            `json:"crc64ecma,omitempty"`
+	LastModified     string            `json:"lastModified,omitempty"`
+	DownloadedBlocks []DownloadedBlock `json:"downloadedBlocks,omitempty"`
+}
+type DownloadedBlock struct {
+	From int64 `json:"from,omitempty"`
+	To   int64 `json:"to,omitempty"`
 }
 
 type Chunk struct {
@@ -584,6 +599,7 @@ type Jobs struct {
 	UploadId   string
 	FilePath   string
 	RetryTimes int
+	VersionId  []string
 	Chunk      Chunk
 	Data       io.Reader
 	Opt        *ObjectUploadPartOptions
@@ -663,7 +679,7 @@ func downloadWorker(s *ObjectService, jobs <-chan *Jobs, results chan<- *Results
 		for {
 			var res Results
 			res.PartNumber = j.Chunk.Number
-			resp, err := s.Get(context.Background(), j.Name, j.DownOpt)
+			resp, err := s.Get(context.Background(), j.Name, j.DownOpt, j.VersionId...)
 			res.err = err
 			res.Resp = resp
 			if err != nil {
@@ -1046,7 +1062,50 @@ func SplitSizeIntoChunks(totalBytes int64, partSize int64) ([]Chunk, int, error)
 	return chunks, int(partNum), nil
 }
 
-func (s *ObjectService) Download(ctx context.Context, name string, filepath string, opt *MultiDownloadOptions) (*Response, error) {
+func (s *ObjectService) checkDownloadedParts(opt *MultiDownloadCPInfo, chfile string, chunks []Chunk) (*MultiDownloadCPInfo, bool) {
+	var defaultRes MultiDownloadCPInfo
+	defaultRes = *opt
+
+	fd, err := os.Open(chfile)
+	// checkpoint 文件不存在
+	if err != nil && os.IsNotExist(err) {
+		// 创建 checkpoint 文件
+		fd, _ = os.OpenFile(chfile, os.O_RDONLY|os.O_CREATE|os.O_TRUNC, 0660)
+		fd.Close()
+		return &defaultRes, false
+	}
+	if err != nil {
+		return &defaultRes, false
+	}
+	defer fd.Close()
+
+	var res MultiDownloadCPInfo
+	err = json.NewDecoder(fd).Decode(&res)
+	if err != nil {
+		return &defaultRes, false
+	}
+	// 与COS的文件比较
+	if res.CRC64 != opt.CRC64 || res.ETag != opt.ETag || res.Size != opt.Size || res.LastModified != opt.LastModified || len(res.DownloadedBlocks) == 0 {
+		return &defaultRes, false
+	}
+	// len(chunks) 大于1，否则为简单下载, chunks[0].Size为partSize
+	partSize := chunks[0].Size
+	for _, v := range res.DownloadedBlocks {
+		index := v.From / partSize
+		to := chunks[index].OffSet + chunks[index].Size - 1
+		if chunks[index].OffSet != v.From || to != v.To {
+			// 重置chunks
+			for i, _ := range chunks {
+				chunks[i].Done = false
+			}
+			return &defaultRes, false
+		}
+		chunks[index].Done = true
+	}
+	return &res, true
+}
+
+func (s *ObjectService) Download(ctx context.Context, name string, filepath string, opt *MultiDownloadOptions, id ...string) (*Response, error) {
 	// 参数校验
 	if opt == nil {
 		opt = &MultiDownloadOptions{}
@@ -1056,7 +1115,7 @@ func (s *ObjectService) Download(ctx context.Context, name string, filepath stri
 	}
 	// 获取文件长度和CRC
 	var coscrc string
-	resp, err := s.Head(ctx, name, nil)
+	resp, err := s.Head(ctx, name, nil, id...)
 	if err != nil {
 		return resp, err
 	}
@@ -1075,7 +1134,7 @@ func (s *ObjectService) Download(ctx context.Context, name string, filepath stri
 	}
 	// 直接下载到文件
 	if partNum == 0 || partNum == 1 {
-		rsp, err := s.GetToFile(ctx, name, filepath, opt.Opt)
+		rsp, err := s.GetToFile(ctx, name, filepath, opt.Opt, id...)
 		if err != nil {
 			return rsp, err
 		}
@@ -1096,12 +1155,39 @@ func (s *ObjectService) Download(ctx context.Context, name string, filepath stri
 		}
 		return rsp, err
 	}
+	// 断点续载
+	var resumableFlag bool
+	var resumableInfo *MultiDownloadCPInfo
+	var cpfd *os.File
+	var cpfile string
+	if opt.CheckPoint {
+		cpInfo := &MultiDownloadCPInfo{
+			LastModified: resp.Header.Get("Last-Modified"),
+			ETag:         resp.Header.Get("ETag"),
+			CRC64:        coscrc,
+			Size:         totalBytes,
+		}
+		cpfile = opt.CheckPointFile
+		if cpfile == "" {
+			cpfile = fmt.Sprintf("%s.cosresumabletask", filepath)
+		}
+		resumableInfo, resumableFlag = s.checkDownloadedParts(cpInfo, cpfile, chunks)
+		cpfd, err = os.OpenFile(cpfile, os.O_RDWR, 0660)
+		if err != nil {
+			return nil, fmt.Errorf("Open CheckPoint File[%v] Failed:%v", cpfile, err)
+		}
+	}
+	if !resumableFlag {
 		// 创建文件
 		nfile, err := os.OpenFile(filepath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0660)
 		if err != nil {
+			if cpfd != nil {
+				cpfd.Close()
+			}
 			return resp, err
 		}
 		nfile.Close()
+	}
 
 	var poolSize int
 	if opt.ThreadPoolSize > 0 {
@@ -1117,6 +1203,9 @@ func (s *ObjectService) Download(ctx context.Context, name string, filepath stri
 
 	go func() {
 		for _, chunk := range chunks {
+			if chunk.Done {
+				continue
+			}
 			var downOpt ObjectGetOptions
 			if opt.Opt != nil {
 				downOpt = *opt.Opt
@@ -1129,23 +1218,42 @@ func (s *ObjectService) Download(ctx context.Context, name string, filepath stri
 				Chunk:      chunk,
 				DownOpt:    &downOpt,
 			}
+			if len(id) > 0 {
+				job.VersionId = append(job.VersionId, id...)
+			}
 			chjobs <- job
 		}
 		close(chjobs)
 	}()
-
 	err = nil
 	for i := 0; i < partNum; i++ {
+		if chunks[i].Done {
+			continue
+		}
 		res := <-chresults
 		if res.Resp == nil || res.err != nil {
 			err = fmt.Errorf("part %d get resp Content. error: %s", res.PartNumber, res.err.Error())
 			continue
 		}
+		// Dump CheckPoint Info
+		if opt.CheckPoint {
+			cpfd.Truncate(0)
+			cpfd.Seek(0, os.SEEK_SET)
+			resumableInfo.DownloadedBlocks = append(resumableInfo.DownloadedBlocks, DownloadedBlock{From: chunks[i].OffSet, To: chunks[i].OffSet + chunks[i].Size - 1})
+			json.NewEncoder(cpfd).Encode(resumableInfo)
+		}
 	}
 	close(chresults)
+	if cpfd != nil {
+		cpfd.Close()
+	}
 	if err != nil {
 		return nil, err
 	}
+    // 下载成功，删除checkpoint文件
+	if opt.CheckPoint {
+		os.Remove(cpfile)
+	}
 	if coscrc != "" && s.client.Conf.EnableCRC {
 		icoscrc, _ := strconv.ParseUint(coscrc, 10, 64)
 		fd, err := os.Open(filepath)