distribution/registry/storage/driver/inmemory/driver.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

318 lines
7.1 KiB
Go

package inmemory
import (
"context"
"fmt"
"io"
"io/ioutil"
"sync"
"time"
storagedriver "github.com/docker/distribution/registry/storage/driver"
"github.com/docker/distribution/registry/storage/driver/base"
"github.com/docker/distribution/registry/storage/driver/factory"
)
const driverName = "inmemory"
func init() {
factory.Register(driverName, &inMemoryDriverFactory{})
}
// inMemoryDriverFacotry implements the factory.StorageDriverFactory interface.
type inMemoryDriverFactory struct{}
func (factory *inMemoryDriverFactory) Create(parameters map[string]interface{}) (storagedriver.StorageDriver, error) {
return New(), nil
}
type driver struct {
root *dir
mutex sync.RWMutex
}
// baseEmbed allows us to hide the Base embed.
type baseEmbed struct {
base.Base
}
// Driver is a storagedriver.StorageDriver implementation backed by a local map.
// Intended solely for example and testing purposes.
type Driver struct {
baseEmbed // embedded, hidden base driver.
}
var _ storagedriver.StorageDriver = &Driver{}
// New constructs a new Driver.
func New() *Driver {
return &Driver{
baseEmbed: baseEmbed{
Base: base.Base{
StorageDriver: &driver{
root: &dir{
common: common{
p: "/",
mod: time.Now(),
},
},
},
},
},
}
}
// Implement the storagedriver.StorageDriver interface.
func (d *driver) Name() string {
return driverName
}
// GetContent retrieves the content stored at "path" as a []byte.
func (d *driver) GetContent(ctx context.Context, path string) ([]byte, error) {
d.mutex.RLock()
defer d.mutex.RUnlock()
rc, err := d.Reader(ctx, path, 0)
if err != nil {
return nil, err
}
defer rc.Close()
return ioutil.ReadAll(rc)
}
// PutContent stores the []byte content at a location designated by "path".
func (d *driver) PutContent(ctx context.Context, p string, contents []byte) error {
d.mutex.Lock()
defer d.mutex.Unlock()
normalized := normalize(p)
f, err := d.root.mkfile(normalized)
if err != nil {
// TODO(stevvooe): Again, we need to clarify when this is not a
// directory in StorageDriver API.
return fmt.Errorf("not a file")
}
f.truncate()
f.WriteAt(contents, 0)
return nil
}
// Reader retrieves an io.ReadCloser for the content stored at "path" with a
// given byte offset.
func (d *driver) Reader(ctx context.Context, path string, offset int64) (io.ReadCloser, error) {
d.mutex.RLock()
defer d.mutex.RUnlock()
if offset < 0 {
return nil, storagedriver.InvalidOffsetError{Path: path, Offset: offset}
}
normalized := normalize(path)
found := d.root.find(normalized)
if found.path() != normalized {
return nil, storagedriver.PathNotFoundError{Path: path}
}
if found.isdir() {
return nil, fmt.Errorf("%q is a directory", path)
}
return ioutil.NopCloser(found.(*file).sectionReader(offset)), nil
}
// Writer returns a FileWriter which will store the content written to it
// at the location designated by "path" after the call to Commit.
func (d *driver) Writer(ctx context.Context, path string, append bool) (storagedriver.FileWriter, error) {
d.mutex.Lock()
defer d.mutex.Unlock()
normalized := normalize(path)
f, err := d.root.mkfile(normalized)
if err != nil {
return nil, fmt.Errorf("not a file")
}
if !append {
f.truncate()
}
return d.newWriter(f), nil
}
// Stat returns info about the provided path.
func (d *driver) Stat(ctx context.Context, path string) (storagedriver.FileInfo, error) {
d.mutex.RLock()
defer d.mutex.RUnlock()
normalized := normalize(path)
found := d.root.find(normalized)
if found.path() != normalized {
return nil, storagedriver.PathNotFoundError{Path: path}
}
fi := storagedriver.FileInfoFields{
Path: path,
IsDir: found.isdir(),
ModTime: found.modtime(),
}
if !fi.IsDir {
fi.Size = int64(len(found.(*file).data))
}
return storagedriver.FileInfoInternal{FileInfoFields: fi}, nil
}
// List returns a list of the objects that are direct descendants of the given
// path.
func (d *driver) List(ctx context.Context, path string) ([]string, error) {
d.mutex.RLock()
defer d.mutex.RUnlock()
normalized := normalize(path)
found := d.root.find(normalized)
if !found.isdir() {
return nil, fmt.Errorf("not a directory") // TODO(stevvooe): Need error type for this...
}
entries, err := found.(*dir).list(normalized)
if err != nil {
switch err {
case errNotExists:
return nil, storagedriver.PathNotFoundError{Path: path}
case errIsNotDir:
return nil, fmt.Errorf("not a directory")
default:
return nil, err
}
}
return entries, nil
}
// Move moves an object stored at sourcePath to destPath, removing the original
// object.
func (d *driver) Move(ctx context.Context, sourcePath string, destPath string) error {
d.mutex.Lock()
defer d.mutex.Unlock()
normalizedSrc, normalizedDst := normalize(sourcePath), normalize(destPath)
err := d.root.move(normalizedSrc, normalizedDst)
switch err {
case errNotExists:
return storagedriver.PathNotFoundError{Path: destPath}
default:
return err
}
}
// Delete recursively deletes all objects stored at "path" and its subpaths.
func (d *driver) Delete(ctx context.Context, path string) error {
d.mutex.Lock()
defer d.mutex.Unlock()
normalized := normalize(path)
err := d.root.delete(normalized)
switch err {
case errNotExists:
return storagedriver.PathNotFoundError{Path: path}
default:
return err
}
}
// URLFor returns a URL which may be used to retrieve the content stored at the given path.
// May return an UnsupportedMethodErr in certain StorageDriver implementations.
func (d *driver) URLFor(ctx context.Context, path string, options map[string]interface{}) (string, error) {
return "", storagedriver.ErrUnsupportedMethod{}
}
// Walk traverses a filesystem defined within driver, starting
// from the given path, calling f on each file
func (d *driver) Walk(ctx context.Context, path string, f storagedriver.WalkFn) error {
return storagedriver.WalkFallback(ctx, d, path, f)
}
type writer struct {
d *driver
f *file
closed bool
committed bool
cancelled bool
}
func (d *driver) newWriter(f *file) storagedriver.FileWriter {
return &writer{
d: d,
f: f,
}
}
func (w *writer) Write(p []byte) (int, error) {
if w.closed {
return 0, fmt.Errorf("already closed")
} else if w.committed {
return 0, fmt.Errorf("already committed")
} else if w.cancelled {
return 0, fmt.Errorf("already cancelled")
}
w.d.mutex.Lock()
defer w.d.mutex.Unlock()
return w.f.WriteAt(p, int64(len(w.f.data)))
}
func (w *writer) Size() int64 {
w.d.mutex.RLock()
defer w.d.mutex.RUnlock()
return int64(len(w.f.data))
}
func (w *writer) Close() error {
if w.closed {
return fmt.Errorf("already closed")
}
w.closed = true
return nil
}
func (w *writer) Cancel() error {
if w.closed {
return fmt.Errorf("already closed")
} else if w.committed {
return fmt.Errorf("already committed")
}
w.cancelled = true
w.d.mutex.Lock()
defer w.d.mutex.Unlock()
return w.d.root.delete(w.f.path())
}
func (w *writer) Commit() error {
if w.closed {
return fmt.Errorf("already closed")
} else if w.committed {
return fmt.Errorf("already committed")
} else if w.cancelled {
return fmt.Errorf("already cancelled")
}
w.committed = true
return nil
}