add "weed filer.cat" to read files directly from volume servers

weed/command/filer_cat.go

@@ -0,0 +1,118 @@
+package command
+
+import (
+	"context"
+	"fmt"
+	"github.com/chrislusf/seaweedfs/weed/filer"
+	"github.com/chrislusf/seaweedfs/weed/pb"
+	"github.com/chrislusf/seaweedfs/weed/pb/filer_pb"
+	"github.com/chrislusf/seaweedfs/weed/wdclient"
+	"google.golang.org/grpc"
+	"math"
+	"net/url"
+	"os"
+	"strings"
+
+	"github.com/chrislusf/seaweedfs/weed/security"
+	"github.com/chrislusf/seaweedfs/weed/util"
+)
+
+var (
+	filerCat FilerCatOptions
+)
+
+type FilerCatOptions struct {
+	grpcDialOption grpc.DialOption
+	filerAddress   string
+	filerClient    filer_pb.SeaweedFilerClient
+	output         *string
+}
+
+func (fco *FilerCatOptions) GetLookupFileIdFunction() wdclient.LookupFileIdFunctionType {
+	return func(fileId string) (targetUrls []string, err error) {
+		vid := filer.VolumeId(fileId)
+		resp, err := fco.filerClient.LookupVolume(context.Background(), &filer_pb.LookupVolumeRequest{
+			VolumeIds: []string{vid},
+		})
+		if err != nil {
+			return nil, err
+		}
+		locations := resp.LocationsMap[vid]
+		for _, loc := range locations.Locations {
+			targetUrls = append(targetUrls, fmt.Sprintf("http://%s/%s", loc.Url, fileId))
+		}
+		return
+	}
+}
+
+func init() {
+	cmdFilerCat.Run = runFilerCat // break init cycle
+	filerCat.output = cmdFilerCat.Flag.String("o", "", "write to file instead of stdout")
+}
+
+var cmdFilerCat = &Command{
+	UsageLine: "filer.cat [-o <file>] http://localhost:8888/path/to/file",
+	Short:     "copy one file to local",
+	Long: `read one file to stdout or write to a file
+
+`,
+}
+
+func runFilerCat(cmd *Command, args []string) bool {
+
+	util.LoadConfiguration("security", false)
+
+	if len(args) == 0 {
+		return false
+	}
+	filerSource := args[len(args)-1]
+
+	filerUrl, err := url.Parse(filerSource)
+	if err != nil {
+		fmt.Printf("The last argument should be a URL on filer: %v\n", err)
+		return false
+	}
+	urlPath := filerUrl.Path
+	if strings.HasSuffix(urlPath, "/") {
+		fmt.Printf("The last argument should be a file: %v\n", err)
+		return false
+	}
+
+	filerCat.filerAddress = filerUrl.Host
+	filerCat.grpcDialOption = security.LoadClientTLS(util.GetViper(), "grpc.client")
+
+	dir, name := util.FullPath(urlPath).DirAndName()
+
+	writer := os.Stdout
+	if *filerCat.output != "" {
+
+		fmt.Printf("saving %s to %s\n", filerSource, *filerCat.output)
+
+		f, err := os.OpenFile(*filerCat.output, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0755)
+		if err != nil {
+			fmt.Printf("open file %s: %v\n", *filerCat.output, err)
+			return false
+		}
+		defer f.Close()
+		writer = f
+	}
+
+	pb.WithFilerClient(filerCat.filerAddress, filerCat.grpcDialOption, func(client filer_pb.SeaweedFilerClient) error {
+
+		request := &filer_pb.LookupDirectoryEntryRequest{
+			Name:      name,
+			Directory: dir,
+		}
+		respLookupEntry, err := filer_pb.LookupEntry(client, request)
+		if err != nil {
+			return err
+		}
+
+		filerCat.filerClient = client
+
+		return filer.StreamContent(&filerCat, writer, respLookupEntry.Entry.Chunks, 0, math.MaxInt64)
+
+	})
+
+	return true
+}