distribution/registry/storage/driver/filesystem/driver.go
Tony Holdstock-Brown 33c448f147 Implement regulator in filesystem driver
This commit refactors base.regulator into the 2.4 interfaces and adds a
filesystem configuration option `maxthreads` to configure the regulator.

By default `maxthreads` is set to 100. This means the FS driver is
limited to 100 concurrent blocking file operations. Any subsequent
operations will block in Go until previous filesystem operations
complete.

This ensures that the registry can never open thousands of simultaneous
threads from os filesystem operations.

Note that `maxthreads` can never be less than 25.

Add test case covering parsable string maxthreads

Signed-off-by: Tony Holdstock-Brown <tony@docker.com>
2016-05-03 09:33:22 -07:00

435 lines
10 KiB
Go

package filesystem
import (
"bufio"
"bytes"
"fmt"
"io"
"io/ioutil"
"os"
"path"
"reflect"
"strconv"
"time"
"github.com/docker/distribution/context"
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 = "filesystem"
defaultRootDirectory = "/var/lib/registry"
defaultMaxThreads = uint64(100)
// minThreads is the minimum value for the maxthreads configuration
// parameter. If the driver's parameters are less than this we set
// the parameters to minThreads
minThreads = uint64(25)
)
// DriverParameters represents all configuration options available for the
// filesystem driver
type DriverParameters struct {
RootDirectory string
MaxThreads uint64
}
func init() {
factory.Register(driverName, &filesystemDriverFactory{})
}
// filesystemDriverFactory implements the factory.StorageDriverFactory interface
type filesystemDriverFactory struct{}
func (factory *filesystemDriverFactory) Create(parameters map[string]interface{}) (storagedriver.StorageDriver, error) {
return FromParameters(parameters)
}
type driver struct {
rootDirectory string
}
type baseEmbed struct {
base.Base
}
// Driver is a storagedriver.StorageDriver implementation backed by a local
// filesystem. All provided paths will be subpaths of the RootDirectory.
type Driver struct {
baseEmbed
}
// FromParameters constructs a new Driver with a given parameters map
// Optional Parameters:
// - rootdirectory
// - maxthreads
func FromParameters(parameters map[string]interface{}) (*Driver, error) {
params, err := fromParametersImpl(parameters)
if err != nil || params == nil {
return nil, err
}
return New(*params), nil
}
func fromParametersImpl(parameters map[string]interface{}) (*DriverParameters, error) {
var (
err error
maxThreads = defaultMaxThreads
rootDirectory = defaultRootDirectory
)
if parameters != nil {
if rootDir, ok := parameters["rootdirectory"]; ok {
rootDirectory = fmt.Sprint(rootDir)
}
// Get maximum number of threads for blocking filesystem operations,
// if specified
threads := parameters["maxthreads"]
switch v := threads.(type) {
case string:
if maxThreads, err = strconv.ParseUint(v, 0, 64); err != nil {
return nil, fmt.Errorf("maxthreads parameter must be an integer, %v invalid", threads)
}
case uint64:
maxThreads = v
case int, int32, int64:
maxThreads = uint64(reflect.ValueOf(v).Convert(reflect.TypeOf(threads)).Int())
case uint, uint32:
maxThreads = reflect.ValueOf(v).Convert(reflect.TypeOf(threads)).Uint()
case nil:
// do nothing
default:
return nil, fmt.Errorf("invalid value for maxthreads: %#v", threads)
}
if maxThreads < minThreads {
maxThreads = minThreads
}
}
params := &DriverParameters{
RootDirectory: rootDirectory,
MaxThreads: maxThreads,
}
return params, nil
}
// New constructs a new Driver with a given rootDirectory
func New(params DriverParameters) *Driver {
fsDriver := &driver{rootDirectory: params.RootDirectory}
return &Driver{
baseEmbed: baseEmbed{
Base: base.Base{
StorageDriver: base.NewRegulator(fsDriver, params.MaxThreads),
},
},
}
}
// 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) {
rc, err := d.Reader(ctx, path, 0)
if err != nil {
return nil, err
}
defer rc.Close()
p, err := ioutil.ReadAll(rc)
if err != nil {
return nil, err
}
return p, nil
}
// PutContent stores the []byte content at a location designated by "path".
func (d *driver) PutContent(ctx context.Context, subPath string, contents []byte) error {
writer, err := d.Writer(ctx, subPath, false)
if err != nil {
return err
}
defer writer.Close()
_, err = io.Copy(writer, bytes.NewReader(contents))
if err != nil {
writer.Cancel()
return err
}
return writer.Commit()
}
// 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) {
file, err := os.OpenFile(d.fullPath(path), os.O_RDONLY, 0644)
if err != nil {
if os.IsNotExist(err) {
return nil, storagedriver.PathNotFoundError{Path: path}
}
return nil, err
}
seekPos, err := file.Seek(int64(offset), os.SEEK_SET)
if err != nil {
file.Close()
return nil, err
} else if seekPos < int64(offset) {
file.Close()
return nil, storagedriver.InvalidOffsetError{Path: path, Offset: offset}
}
return file, nil
}
func (d *driver) Writer(ctx context.Context, subPath string, append bool) (storagedriver.FileWriter, error) {
fullPath := d.fullPath(subPath)
parentDir := path.Dir(fullPath)
if err := os.MkdirAll(parentDir, 0777); err != nil {
return nil, err
}
fp, err := os.OpenFile(fullPath, os.O_WRONLY|os.O_CREATE, 0666)
if err != nil {
return nil, err
}
var offset int64
if !append {
err := fp.Truncate(0)
if err != nil {
fp.Close()
return nil, err
}
} else {
n, err := fp.Seek(0, os.SEEK_END)
if err != nil {
fp.Close()
return nil, err
}
offset = int64(n)
}
return newFileWriter(fp, offset), nil
}
// Stat retrieves the FileInfo for the given path, including the current size
// in bytes and the creation time.
func (d *driver) Stat(ctx context.Context, subPath string) (storagedriver.FileInfo, error) {
fullPath := d.fullPath(subPath)
fi, err := os.Stat(fullPath)
if err != nil {
if os.IsNotExist(err) {
return nil, storagedriver.PathNotFoundError{Path: subPath}
}
return nil, err
}
return fileInfo{
path: subPath,
FileInfo: fi,
}, nil
}
// List returns a list of the objects that are direct descendants of the given
// path.
func (d *driver) List(ctx context.Context, subPath string) ([]string, error) {
fullPath := d.fullPath(subPath)
dir, err := os.Open(fullPath)
if err != nil {
if os.IsNotExist(err) {
return nil, storagedriver.PathNotFoundError{Path: subPath}
}
return nil, err
}
defer dir.Close()
fileNames, err := dir.Readdirnames(0)
if err != nil {
return nil, err
}
keys := make([]string, 0, len(fileNames))
for _, fileName := range fileNames {
keys = append(keys, path.Join(subPath, fileName))
}
return keys, 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 {
source := d.fullPath(sourcePath)
dest := d.fullPath(destPath)
if _, err := os.Stat(source); os.IsNotExist(err) {
return storagedriver.PathNotFoundError{Path: sourcePath}
}
if err := os.MkdirAll(path.Dir(dest), 0755); err != nil {
return err
}
err := os.Rename(source, dest)
return err
}
// Delete recursively deletes all objects stored at "path" and its subpaths.
func (d *driver) Delete(ctx context.Context, subPath string) error {
fullPath := d.fullPath(subPath)
_, err := os.Stat(fullPath)
if err != nil && !os.IsNotExist(err) {
return err
} else if err != nil {
return storagedriver.PathNotFoundError{Path: subPath}
}
err = os.RemoveAll(fullPath)
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{}
}
// fullPath returns the absolute path of a key within the Driver's storage.
func (d *driver) fullPath(subPath string) string {
return path.Join(d.rootDirectory, subPath)
}
type fileInfo struct {
os.FileInfo
path string
}
var _ storagedriver.FileInfo = fileInfo{}
// Path provides the full path of the target of this file info.
func (fi fileInfo) Path() string {
return fi.path
}
// Size returns current length in bytes of the file. The return value can
// be used to write to the end of the file at path. The value is
// meaningless if IsDir returns true.
func (fi fileInfo) Size() int64 {
if fi.IsDir() {
return 0
}
return fi.FileInfo.Size()
}
// ModTime returns the modification time for the file. For backends that
// don't have a modification time, the creation time should be returned.
func (fi fileInfo) ModTime() time.Time {
return fi.FileInfo.ModTime()
}
// IsDir returns true if the path is a directory.
func (fi fileInfo) IsDir() bool {
return fi.FileInfo.IsDir()
}
type fileWriter struct {
file *os.File
size int64
bw *bufio.Writer
closed bool
committed bool
cancelled bool
}
func newFileWriter(file *os.File, size int64) *fileWriter {
return &fileWriter{
file: file,
size: size,
bw: bufio.NewWriter(file),
}
}
func (fw *fileWriter) Write(p []byte) (int, error) {
if fw.closed {
return 0, fmt.Errorf("already closed")
} else if fw.committed {
return 0, fmt.Errorf("already committed")
} else if fw.cancelled {
return 0, fmt.Errorf("already cancelled")
}
n, err := fw.bw.Write(p)
fw.size += int64(n)
return n, err
}
func (fw *fileWriter) Size() int64 {
return fw.size
}
func (fw *fileWriter) Close() error {
if fw.closed {
return fmt.Errorf("already closed")
}
if err := fw.bw.Flush(); err != nil {
return err
}
if err := fw.file.Sync(); err != nil {
return err
}
if err := fw.file.Close(); err != nil {
return err
}
fw.closed = true
return nil
}
func (fw *fileWriter) Cancel() error {
if fw.closed {
return fmt.Errorf("already closed")
}
fw.cancelled = true
fw.file.Close()
return os.Remove(fw.file.Name())
}
func (fw *fileWriter) Commit() error {
if fw.closed {
return fmt.Errorf("already closed")
} else if fw.committed {
return fmt.Errorf("already committed")
} else if fw.cancelled {
return fmt.Errorf("already cancelled")
}
if err := fw.bw.Flush(); err != nil {
return err
}
if err := fw.file.Sync(); err != nil {
return err
}
fw.committed = true
return nil
}