swift: support files > 5GB - fixes #46

* Write segments to ..._segments container
  * Choice of container and segment names compatible with swift tool
    * See http://docs.openstack.org/developer/swift/overview_large_objects.html
  * Controlled by command line flag --swift-chunk-size
  * Segments removed on delete

swift/swift.go

@@ -2,6 +2,7 @@
 package swift
 
 import (
+	"bytes"
 	"errors"
 	"fmt"
 	"io"
@@ -12,6 +13,12 @@ import (
 
 	"github.com/ncw/rclone/fs"
 	"github.com/ncw/swift"
+	"github.com/spf13/pflag"
+)
+
+// Globals
+var (
+	chunkSize = fs.SizeSuffix(5 * 1024 * 1024 * 1024)
 )
 
 // Register with Fs
@@ -51,9 +58,10 @@ func init() {
 			Name: "region",
 			Help: "Region name - optional",
 		},
-		// snet     = flag.Bool("swift-snet", false, "Use internal service network") // FIXME not implemented
 		},
 	})
+	// snet     = flag.Bool("swift-snet", false, "Use internal service network") // FIXME not implemented
+	pflag.VarP(&chunkSize, "swift-chunk-size", "", "Above this size files will be chunked into a _segments container.")
 }
 
 // FsSwift represents a remote swift server
@@ -381,9 +389,27 @@ func (o *FsObjectSwift) Remote() string {
 
 // Md5sum returns the Md5sum of an object returning a lowercase hex string
 func (o *FsObjectSwift) Md5sum() (string, error) {
+	isManifest, err := o.isManifestFile()
+	if err != nil {
+		return "", err
+	}
+	if isManifest {
+		fs.Debug(o, "Return empty md5 for swift manifest file. Md5 of manifest file calculate as md5 of md5 of it's parts, so it's not original md5")
+		return "", nil
+	}
 	return strings.ToLower(o.info.Hash), nil
 }
 
+// isManifestFile checks for manifest header
+func (o *FsObjectSwift) isManifestFile() (bool, error) {
+	err := o.readMetaData()
+	if err != nil {
+		return false, err
+	}
+	_, isManifestFile := (*o.headers)["X-Object-Manifest"]
+	return isManifestFile, nil
+}
+
 // Size returns the size of an object in bytes
 func (o *FsObjectSwift) Size() int64 {
 	return o.info.Bytes
@@ -457,6 +483,30 @@ func (o *FsObjectSwift) Open() (in io.ReadCloser, err error) {
 	return
 }
 
+// min returns the smallest of x, y
+func min(x, y int64) int64 {
+	if x < y {
+		return x
+	}
+	return y
+}
+
+// nsToSwiftFloatString turns a number of ns into a floating point
+// string in seconds the same way as the "swift" tool
+func nsToSwiftFloatString(ns int64) string {
+	if ns < 0 {
+		return "-" + nsToSwiftFloatString(-ns)
+	}
+	result := fmt.Sprintf("%010d", ns)
+	split := len(result) - 9
+	result, decimals := result[:split], result[split:split+2]
+	if decimals != "" {
+		result += "."
+		result += decimals
+	}
+	return result
+}
+
 // Update the object with the contents of the io.Reader, modTime and size
 //
 // The new object may have been created if an error is returned
@@ -464,18 +514,79 @@ func (o *FsObjectSwift) Update(in io.Reader, modTime time.Time, size int64) erro
 	// Set the mtime
 	m := swift.Metadata{}
 	m.SetModTime(modTime)
+	if size > int64(chunkSize) {
+		segmentsContainerName := o.swift.container + "_segments"
+		left := size
+		i := 0
+		nowFloat := nsToSwiftFloatString(time.Now().UnixNano())
+		for left > 0 {
+			n := min(left, int64(chunkSize))
+			segmentReader := io.LimitReader(in, n)
+			segmentPath := fmt.Sprintf("%s%s/%s/%d/%08d", o.swift.root, o.remote, nowFloat, size, i)
+			_, err := o.swift.c.ObjectPut(segmentsContainerName, segmentPath, segmentReader, true, "", "", m.ObjectHeaders())
+			if err != nil {
+				return err
+			}
+			left -= n
+			i++
+		}
+		manifestHeaders := swift.Headers{"X-Object-Manifest": fmt.Sprintf("%s/%s%s/%s/%d", segmentsContainerName, o.swift.root, o.remote, nowFloat, size)}
+		for k, v := range m.ObjectHeaders() {
+			manifestHeaders[k] = v
+		}
+		emptyReader := bytes.NewReader(nil)
+		manifestName := o.swift.root + o.remote
+		_, err := o.swift.c.ObjectPut(o.swift.container, manifestName, emptyReader, true, "", "", manifestHeaders)
+		if err != nil {
+			return err
+		}
+		// remove old segments
+		segmentsPath := fmt.Sprintf("%s/%s%s/", segmentsContainerName, o.swift.root, o.remote)
+		segmentsFs, err := NewFs(o.swift.name, segmentsPath)
+		if err != nil {
+			return err
+		}
+		for o := range segmentsFs.List() {
+			if !strings.HasPrefix(o.Remote(), nowFloat) {
+				fs.Log(o, "Remove old file segment '%s'", o.Remote())
+				err := o.Remove()
+				if err != nil {
+					return err
+				}
+			}
+		}
+	} else {
 		_, err := o.swift.c.ObjectPut(o.swift.container, o.swift.root+o.remote, in, true, "", "", m.ObjectHeaders())
 		if err != nil {
 			return err
 		}
+	}
 	// Read the metadata from the newly created object
 	o.headers = nil // wipe old metadata
-	err = o.readMetaData()
-	return err
+	return o.readMetaData()
 }
 
 // Remove an object
 func (o *FsObjectSwift) Remove() error {
+	isManifestFile, err := o.isManifestFile()
+	if err != nil {
+		return err
+	}
+	if isManifestFile {
+		// remove segments
+		segmentsContainerName := o.swift.container + "_segments"
+		segmentsPath := fmt.Sprintf("%s/%s%s/", segmentsContainerName, o.swift.root, o.remote)
+		segmentsFs, err := NewFs(o.swift.name, segmentsPath)
+		if err != nil {
+			return err
+		}
+		for o := range segmentsFs.List() {
+			err := o.Remove()
+			if err != nil {
+				return err
+			}
+		}
+	}
 	return o.swift.c.ObjectDelete(o.swift.container, o.swift.root+o.remote)
 }