minio/cmd/metacache-walk.go
Harshavardhana 0287711dc9
fix: implement readMetadata common function for re-use (#12353)
Previous PR #12351 added functions to read from the reader
stream to reduce memory usage, use the same technique in
few other places where we are not interested in reading the
data part.
2021-05-21 11:41:25 -07:00

336 lines
10 KiB
Go

// Copyright (c) 2015-2021 MinIO, Inc.
//
// This file is part of MinIO Object Storage stack
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package cmd
import (
"context"
"io"
"net/http"
"net/url"
"os"
"sort"
"strconv"
"strings"
"github.com/gorilla/mux"
xhttp "github.com/minio/minio/cmd/http"
"github.com/minio/minio/cmd/logger"
xioutil "github.com/minio/minio/pkg/ioutil"
)
// WalkDirOptions provides options for WalkDir operations.
type WalkDirOptions struct {
// Bucket to scanner
Bucket string
// Directory inside the bucket.
BaseDir string
// Do a full recursive scan.
Recursive bool
// ReportNotFound will return errFileNotFound if all disks reports the BaseDir cannot be found.
ReportNotFound bool
// FilterPrefix will only return results with given prefix within folder.
// Should never contain a slash.
FilterPrefix string
// ForwardTo will forward to the given object path.
ForwardTo string
}
// WalkDir will traverse a directory and return all entries found.
// On success a sorted meta cache stream will be returned.
// Metadata has data stripped, if any.
func (s *xlStorage) WalkDir(ctx context.Context, opts WalkDirOptions, wr io.Writer) error {
// Verify if volume is valid and it exists.
volumeDir, err := s.getVolDir(opts.Bucket)
if err != nil {
return err
}
// Stat a volume entry.
_, err = os.Lstat(volumeDir)
if err != nil {
if osIsNotExist(err) {
return errVolumeNotFound
} else if isSysErrIO(err) {
return errFaultyDisk
}
return err
}
// Use a small block size to start sending quickly
w := newMetacacheWriter(wr, 16<<10)
defer w.Close()
out, err := w.stream()
if err != nil {
return err
}
defer close(out)
// Fast exit track to check if we are listing an object with
// a trailing slash, this will avoid to list the object content.
if HasSuffix(opts.BaseDir, SlashSeparator) {
metadata, err := s.readMetadata(pathJoin(volumeDir,
opts.BaseDir[:len(opts.BaseDir)-1]+globalDirSuffix,
xlStorageFormatFile))
if err == nil {
// if baseDir is already a directory object, consider it
// as part of the list call, this is a AWS S3 specific
// behavior.
out <- metaCacheEntry{
name: opts.BaseDir,
metadata: metadata,
}
} else {
if st, err := os.Lstat(pathJoin(volumeDir, opts.BaseDir, xlStorageFormatFile)); err == nil && st.Mode().IsRegular() {
return errFileNotFound
}
}
}
prefix := opts.FilterPrefix
forward := opts.ForwardTo
var scanDir func(path string) error
scanDir = func(current string) error {
if contextCanceled(ctx) {
return ctx.Err()
}
entries, err := s.ListDir(ctx, opts.Bucket, current, -1)
if err != nil {
// Folder could have gone away in-between
if err != errVolumeNotFound && err != errFileNotFound {
logger.LogIf(ctx, err)
}
if opts.ReportNotFound && err == errFileNotFound && current == opts.BaseDir {
return errFileNotFound
}
// Forward some errors?
return nil
}
dirObjects := make(map[string]struct{})
for i, entry := range entries {
if len(prefix) > 0 && !strings.HasPrefix(entry, prefix) {
continue
}
if len(forward) > 0 && entry < forward {
continue
}
if strings.HasSuffix(entry, slashSeparator) {
if strings.HasSuffix(entry, globalDirSuffixWithSlash) {
// Add without extension so it is sorted correctly.
entry = strings.TrimSuffix(entry, globalDirSuffixWithSlash) + slashSeparator
dirObjects[entry] = struct{}{}
entries[i] = entry
continue
}
// Trim slash, maybe compiler is clever?
entries[i] = entries[i][:len(entry)-1]
continue
}
// Do do not retain the file.
entries[i] = ""
if contextCanceled(ctx) {
return ctx.Err()
}
// If root was an object return it as such.
if HasSuffix(entry, xlStorageFormatFile) {
var meta metaCacheEntry
meta.metadata, err = s.readMetadata(pathJoin(volumeDir, current, entry))
if err != nil {
logger.LogIf(ctx, err)
continue
}
meta.name = strings.TrimSuffix(entry, xlStorageFormatFile)
meta.name = strings.TrimSuffix(meta.name, SlashSeparator)
meta.name = pathJoin(current, meta.name)
meta.name = decodeDirObject(meta.name)
out <- meta
return nil
}
// Check legacy.
if HasSuffix(entry, xlStorageFormatFileV1) {
var meta metaCacheEntry
meta.metadata, err = xioutil.ReadFile(pathJoin(volumeDir, current, entry))
if err != nil {
logger.LogIf(ctx, err)
continue
}
meta.name = strings.TrimSuffix(entry, xlStorageFormatFileV1)
meta.name = strings.TrimSuffix(meta.name, SlashSeparator)
meta.name = pathJoin(current, meta.name)
out <- meta
return nil
}
// Skip all other files.
}
// Process in sort order.
sort.Strings(entries)
dirStack := make([]string, 0, 5)
prefix = "" // Remove prefix after first level.
for _, entry := range entries {
if entry == "" {
continue
}
if contextCanceled(ctx) {
return ctx.Err()
}
meta := metaCacheEntry{name: PathJoin(current, entry)}
// If directory entry on stack before this, pop it now.
for len(dirStack) > 0 && dirStack[len(dirStack)-1] < meta.name {
pop := dirStack[len(dirStack)-1]
out <- metaCacheEntry{name: pop}
if opts.Recursive {
// Scan folder we found. Should be in correct sort order where we are.
forward = ""
if len(opts.ForwardTo) > 0 && strings.HasPrefix(opts.ForwardTo, pop) {
forward = strings.TrimPrefix(opts.ForwardTo, pop)
}
logger.LogIf(ctx, scanDir(pop))
}
dirStack = dirStack[:len(dirStack)-1]
}
// All objects will be returned as directories, there has been no object check yet.
// Check it by attempting to read metadata.
_, isDirObj := dirObjects[entry]
if isDirObj {
meta.name = meta.name[:len(meta.name)-1] + globalDirSuffixWithSlash
}
meta.metadata, err = s.readMetadata(pathJoin(volumeDir, meta.name, xlStorageFormatFile))
switch {
case err == nil:
// It was an object
if isDirObj {
meta.name = strings.TrimSuffix(meta.name, globalDirSuffixWithSlash) + slashSeparator
}
out <- meta
case osIsNotExist(err):
meta.metadata, err = xioutil.ReadFile(pathJoin(volumeDir, meta.name, xlStorageFormatFileV1))
if err == nil {
// Maybe rename? Would make it inconsistent across disks though.
// os.Rename(pathJoin(volumeDir, meta.name, xlStorageFormatFileV1), pathJoin(volumeDir, meta.name, xlStorageFormatFile))
// It was an object
out <- meta
continue
}
// NOT an object, append to stack (with slash)
// If dirObject, but no metadata (which is unexpected) we skip it.
if !isDirObj {
if !isDirEmpty(pathJoin(volumeDir, meta.name+slashSeparator)) {
dirStack = append(dirStack, meta.name+slashSeparator)
}
}
case isSysErrNotDir(err):
// skip
default:
logger.LogIf(ctx, err)
}
}
// If directory entry left on stack, pop it now.
for len(dirStack) > 0 {
pop := dirStack[len(dirStack)-1]
out <- metaCacheEntry{name: pop}
if opts.Recursive {
// Scan folder we found. Should be in correct sort order where we are.
forward = ""
if len(opts.ForwardTo) > 0 && strings.HasPrefix(opts.ForwardTo, pop) {
forward = strings.TrimPrefix(opts.ForwardTo, pop)
}
logger.LogIf(ctx, scanDir(pop))
}
dirStack = dirStack[:len(dirStack)-1]
}
return nil
}
// Stream output.
return scanDir(opts.BaseDir)
}
func (p *xlStorageDiskIDCheck) WalkDir(ctx context.Context, opts WalkDirOptions, wr io.Writer) error {
defer p.updateStorageMetrics(storageMetricWalkDir)()
if err := p.checkDiskStale(); err != nil {
return err
}
return p.storage.WalkDir(ctx, opts, wr)
}
// WalkDir will traverse a directory and return all entries found.
// On success a meta cache stream will be returned, that should be closed when done.
func (client *storageRESTClient) WalkDir(ctx context.Context, opts WalkDirOptions, wr io.Writer) error {
values := make(url.Values)
values.Set(storageRESTVolume, opts.Bucket)
values.Set(storageRESTDirPath, opts.BaseDir)
values.Set(storageRESTRecursive, strconv.FormatBool(opts.Recursive))
values.Set(storageRESTReportNotFound, strconv.FormatBool(opts.ReportNotFound))
values.Set(storageRESTPrefixFilter, opts.FilterPrefix)
values.Set(storageRESTForwardFilter, opts.ForwardTo)
respBody, err := client.call(ctx, storageRESTMethodWalkDir, values, nil, -1)
if err != nil {
logger.LogIf(ctx, err)
return err
}
defer xhttp.DrainBody(respBody)
return waitForHTTPStream(respBody, wr)
}
// WalkDirHandler - remote caller to list files and folders in a requested directory path.
func (s *storageRESTServer) WalkDirHandler(w http.ResponseWriter, r *http.Request) {
if !s.IsValid(w, r) {
return
}
vars := mux.Vars(r)
volume := vars[storageRESTVolume]
dirPath := vars[storageRESTDirPath]
recursive, err := strconv.ParseBool(vars[storageRESTRecursive])
if err != nil {
s.writeErrorResponse(w, err)
return
}
var reportNotFound bool
if v := vars[storageRESTReportNotFound]; v != "" {
reportNotFound, err = strconv.ParseBool(v)
if err != nil {
s.writeErrorResponse(w, err)
return
}
}
prefix := r.URL.Query().Get(storageRESTPrefixFilter)
forward := r.URL.Query().Get(storageRESTForwardFilter)
writer := streamHTTPResponse(w)
writer.CloseWithError(s.storage.WalkDir(r.Context(), WalkDirOptions{
Bucket: volume,
BaseDir: dirPath,
Recursive: recursive,
ReportNotFound: reportNotFound,
FilterPrefix: prefix,
ForwardTo: forward,
}, writer))
}