6b73a9ab89
It's possible to run into a race condition in which the enumerator lists lots of repositories and then starts the long process of enumerating through them. In that time if someone deletes a repo, the enumerator may error out. Signed-off-by: Ryan Abrams <rdabrams@gmail.com>
61 lines
1.9 KiB
Go
61 lines
1.9 KiB
Go
package driver
|
|
|
|
import (
|
|
"context"
|
|
"errors"
|
|
"sort"
|
|
|
|
"github.com/sirupsen/logrus"
|
|
)
|
|
|
|
// ErrSkipDir is used as a return value from onFileFunc to indicate that
|
|
// the directory named in the call is to be skipped. It is not returned
|
|
// as an error by any function.
|
|
var ErrSkipDir = errors.New("skip this directory")
|
|
|
|
// WalkFn is called once per file by Walk
|
|
type WalkFn func(fileInfo FileInfo) error
|
|
|
|
// WalkFallback traverses a filesystem defined within driver, starting
|
|
// from the given path, calling f on each file. It uses the List method and Stat to drive itself.
|
|
// 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. If fileInfo refers to a normal file, processing stops
|
|
func WalkFallback(ctx context.Context, driver StorageDriver, from string, f 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 {
|
|
switch err.(type) {
|
|
case PathNotFoundError:
|
|
// repository was removed in between listing and enumeration. Ignore it.
|
|
logrus.WithField("path", child).Infof("ignoring deleted path")
|
|
continue
|
|
default:
|
|
return err
|
|
}
|
|
}
|
|
err = f(fileInfo)
|
|
if err == nil && fileInfo.IsDir() {
|
|
if err := WalkFallback(ctx, driver, child, f); err != nil {
|
|
return err
|
|
}
|
|
} else if err == ErrSkipDir {
|
|
// Stop iteration if it's a file, otherwise noop if it's a directory
|
|
if !fileInfo.IsDir() {
|
|
return nil
|
|
}
|
|
} else if err != nil {
|
|
return err
|
|
}
|
|
}
|
|
return nil
|
|
}
|