distribution/registry/storage/walk.go
Sargun Dhillon 32ac467992 Introduce Walk Method Per Storage Driver
Move the Walk types into registry/storage/driver, and add a Walk method to each
storage driver. Although this is yet another API to implement, there is a fall
back implementation that relies on List and Stat. For some filesystems this is
very slow.

Also, this WalkDir Method conforms better do a traditional WalkDir (a la filepath).

This change is in preparation for refactoring.

Signed-off-by: Sargun Dhillon <sargun@sargun.me>
2018-01-07 22:45:17 -08:00

51 lines
1.4 KiB
Go

package storage
import (
"context"
"fmt"
"sort"
storageDriver "github.com/docker/distribution/registry/storage/driver"
)
// Walk traverses a filesystem defined within driver, starting
// from the given path, calling f on each file
// If the returned error from the WalkFn is ErrSkipDir and fileInfo refers
// to a directory, the directory will not be entered and Walk
// will continue the traversal. Otherwise Walk will return
// the error
func Walk(ctx context.Context, driver storageDriver.StorageDriver, from string, f storageDriver.WalkFn) error {
children, err := driver.List(ctx, from)
if err != nil {
return err
}
sort.Stable(sort.StringSlice(children))
for _, child := range children {
// TODO(stevvooe): Calling driver.Stat for every entry is quite
// expensive when running against backends with a slow Stat
// implementation, such as s3. This is very likely a serious
// performance bottleneck.
fileInfo, err := driver.Stat(ctx, child)
if err != nil {
return err
}
err = f(fileInfo)
skipDir := (err == storageDriver.ErrSkipDir)
if err != nil && !skipDir {
return err
}
if fileInfo.IsDir() && !skipDir {
if err := Walk(ctx, driver, child, f); err != nil {
return err
}
}
}
return nil
}
// pushError formats an error type given a path and an error
// and pushes it to a slice of errors
func pushError(errors []error, path string, err error) []error {
return append(errors, fmt.Errorf("%s: %s", path, err))
}