Merge pull request #1695 from tonyhb/add-regulator-to-filesystem

Add regulator to filesystem

docs/configuration.md

@@ -78,6 +78,7 @@ information about each option that appears later in this page.
     storage:
       filesystem:
         rootdirectory: /var/lib/registry
+		maxthreads: 100
       azure:
         accountname: accountname
         accountkey: base64encodedaccountkey

docs/storage-drivers/filesystem.md

@@ -16,3 +16,7 @@ An implementation of the `storagedriver.StorageDriver` interface which uses the
 `rootdirectory`: (optional) The absolute path to a root directory tree in which
 to store all registry files. The registry stores all its data here so make sure
 there is adequate space available. Defaults to `/var/lib/registry`.
+`maxthreads`: (optional) The maximum number of simultaneous blocking filesystem
+operations permitted within the registry. Each operation spawns a new thread and
+may cause thread exhaustion issues if many are done in parallel. Defaults to
+`100`, and can be no lower than `25`.

registry/proxy/proxyblobstore_test.go

@@ -132,8 +132,15 @@ func makeTestEnv(t *testing.T, name string) *testEnv {
 		t.Fatalf("unable to create tempdir: %s", err)
 	}
 
+	localDriver, err := filesystem.FromParameters(map[string]interface{}{
+		"rootdirectory": truthDir,
+	})
+	if err != nil {
+		t.Fatalf("unable to create filesystem driver: %s", err)
+	}
+
 	// todo: create a tempfile area here
-	localRegistry, err := storage.NewRegistry(ctx, filesystem.New(truthDir), storage.BlobDescriptorCacheProvider(memory.NewInMemoryBlobDescriptorCacheProvider()), storage.EnableRedirect, storage.DisableDigestResumption)
+	localRegistry, err := storage.NewRegistry(ctx, localDriver, storage.BlobDescriptorCacheProvider(memory.NewInMemoryBlobDescriptorCacheProvider()), storage.EnableRedirect, storage.DisableDigestResumption)
 	if err != nil {
 		t.Fatalf("error creating registry: %v", err)
 	}
@@ -142,7 +149,14 @@ func makeTestEnv(t *testing.T, name string) *testEnv {
 		t.Fatalf("unexpected error getting repo: %v", err)
 	}
 
-	truthRegistry, err := storage.NewRegistry(ctx, filesystem.New(cacheDir), storage.BlobDescriptorCacheProvider(memory.NewInMemoryBlobDescriptorCacheProvider()))
+	cacheDriver, err := filesystem.FromParameters(map[string]interface{}{
+		"rootdirectory": cacheDir,
+	})
+	if err != nil {
+		t.Fatalf("unable to create filesystem driver: %s", err)
+	}
+
+	truthRegistry, err := storage.NewRegistry(ctx, cacheDriver, storage.BlobDescriptorCacheProvider(memory.NewInMemoryBlobDescriptorCacheProvider()))
 	if err != nil {
 		t.Fatalf("error creating registry: %v", err)
 	}

registry/storage/driver/base/regulator.go

@@ -0,0 +1,145 @@
+package base
+
+import (
+	"io"
+	"sync"
+
+	"github.com/docker/distribution/context"
+	storagedriver "github.com/docker/distribution/registry/storage/driver"
+)
+
+type regulator struct {
+	storagedriver.StorageDriver
+	*sync.Cond
+
+	available uint64
+}
+
+// NewRegulator wraps the given driver and is used to regulate concurrent calls
+// to the given storage driver to a maximum of the given limit. This is useful
+// for storage drivers that would otherwise create an unbounded number of OS
+// threads if allowed to be called unregulated.
+func NewRegulator(driver storagedriver.StorageDriver, limit uint64) storagedriver.StorageDriver {
+	return &regulator{
+		StorageDriver: driver,
+		Cond:          sync.NewCond(&sync.Mutex{}),
+		available:     limit,
+	}
+}
+
+func (r *regulator) enter() {
+	r.L.Lock()
+	for r.available == 0 {
+		r.Wait()
+	}
+	r.available--
+	r.L.Unlock()
+}
+
+func (r *regulator) exit() {
+	r.L.Lock()
+	// We only need to signal to a waiting FS operation if we're already at the
+	// limit of threads used
+	if r.available == 0 {
+		r.Signal()
+	}
+	r.available++
+	r.L.Unlock()
+}
+
+// Name returns the human-readable "name" of the driver, useful in error
+// messages and logging. By convention, this will just be the registration
+// name, but drivers may provide other information here.
+func (r *regulator) Name() string {
+	r.enter()
+	defer r.exit()
+
+	return r.StorageDriver.Name()
+}
+
+// GetContent retrieves the content stored at "path" as a []byte.
+// This should primarily be used for small objects.
+func (r *regulator) GetContent(ctx context.Context, path string) ([]byte, error) {
+	r.enter()
+	defer r.exit()
+
+	return r.StorageDriver.GetContent(ctx, path)
+}
+
+// PutContent stores the []byte content at a location designated by "path".
+// This should primarily be used for small objects.
+func (r *regulator) PutContent(ctx context.Context, path string, content []byte) error {
+	r.enter()
+	defer r.exit()
+
+	return r.StorageDriver.PutContent(ctx, path, content)
+}
+
+// Reader retrieves an io.ReadCloser for the content stored at "path"
+// with a given byte offset.
+// May be used to resume reading a stream by providing a nonzero offset.
+func (r *regulator) Reader(ctx context.Context, path string, offset int64) (io.ReadCloser, error) {
+	r.enter()
+	defer r.exit()
+
+	return r.StorageDriver.Reader(ctx, path, offset)
+}
+
+// Writer stores the contents of the provided io.ReadCloser at a
+// location designated by the given path.
+// May be used to resume writing a stream by providing a nonzero offset.
+// The offset must be no larger than the CurrentSize for this path.
+func (r *regulator) Writer(ctx context.Context, path string, append bool) (storagedriver.FileWriter, error) {
+	r.enter()
+	defer r.exit()
+
+	return r.StorageDriver.Writer(ctx, path, append)
+}
+
+// Stat retrieves the FileInfo for the given path, including the current
+// size in bytes and the creation time.
+func (r *regulator) Stat(ctx context.Context, path string) (storagedriver.FileInfo, error) {
+	r.enter()
+	defer r.exit()
+
+	return r.StorageDriver.Stat(ctx, path)
+}
+
+// List returns a list of the objects that are direct descendants of the
+//given path.
+func (r *regulator) List(ctx context.Context, path string) ([]string, error) {
+	r.enter()
+	defer r.exit()
+
+	return r.StorageDriver.List(ctx, path)
+}
+
+// Move moves an object stored at sourcePath to destPath, removing the
+// original object.
+// Note: This may be no more efficient than a copy followed by a delete for
+// many implementations.
+func (r *regulator) Move(ctx context.Context, sourcePath string, destPath string) error {
+	r.enter()
+	defer r.exit()
+
+	return r.StorageDriver.Move(ctx, sourcePath, destPath)
+}
+
+// Delete recursively deletes all objects stored at "path" and its subpaths.
+func (r *regulator) Delete(ctx context.Context, path string) error {
+	r.enter()
+	defer r.exit()
+
+	return r.StorageDriver.Delete(ctx, path)
+}
+
+// URLFor returns a URL which may be used to retrieve the content stored at
+// the given path, possibly using the given options.
+// May return an ErrUnsupportedMethod in certain StorageDriver
+// implementations.
+func (r *regulator) URLFor(ctx context.Context, path string, options map[string]interface{}) (string, error) {
+	r.enter()
+	defer r.exit()
+
+	return r.StorageDriver.URLFor(ctx, path, options)
+}

registry/storage/driver/filesystem/driver.go

@@ -8,6 +8,8 @@ import (
 	"io/ioutil"
 	"os"
 	"path"
+	"reflect"
+	"strconv"
 	"time"
 
 	"github.com/docker/distribution/context"
@@ -16,8 +18,23 @@ import (
 	"github.com/docker/distribution/registry/storage/driver/factory"
 )
 
-const driverName = "filesystem"
-const defaultRootDirectory = "/var/lib/registry"
+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{})
@@ -27,7 +44,7 @@ func init() {
 type filesystemDriverFactory struct{}
 
 func (factory *filesystemDriverFactory) Create(parameters map[string]interface{}) (storagedriver.StorageDriver, error) {
-	return FromParameters(parameters), nil
+	return FromParameters(parameters)
 }
 
 type driver struct {
@@ -47,25 +64,72 @@ type Driver struct {
 // FromParameters constructs a new Driver with a given parameters map
 // Optional Parameters:
 // - rootdirectory
-func FromParameters(parameters map[string]interface{}) *Driver {
-	var rootDirectory = defaultRootDirectory
+// - 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 {
-		rootDir, ok := parameters["rootdirectory"]
-		if ok {
+		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:
+			val := reflect.ValueOf(v).Convert(reflect.TypeOf(threads)).Int()
+			// If threads is negative casting to uint64 will wrap around and
+			// give you the hugest thread limit ever. Let's be sensible, here
+			if val > 0 {
+				maxThreads = uint64(val)
+			}
+		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
+		}
 	}
-	return New(rootDirectory)
+
+	params := &DriverParameters{
+		RootDirectory: rootDirectory,
+		MaxThreads:    maxThreads,
+	}
+	return params, nil
 }
 
 // New constructs a new Driver with a given rootDirectory
-func New(rootDirectory string) *Driver {
+func New(params DriverParameters) *Driver {
+	fsDriver := &driver{rootDirectory: params.RootDirectory}
+
 	return &Driver{
 		baseEmbed: baseEmbed{
 			Base: base.Base{
-				StorageDriver: &driver{
-					rootDirectory: rootDirectory,
-				},
+				StorageDriver: base.NewRegulator(fsDriver, params.MaxThreads),
 			},
 		},
 	}

registry/storage/driver/filesystem/driver_test.go

@@ -3,6 +3,7 @@ package filesystem
 import (
 	"io/ioutil"
 	"os"
+	"reflect"
 	"testing"
 
 	storagedriver "github.com/docker/distribution/registry/storage/driver"
@@ -20,7 +21,93 @@ func init() {
 	}
 	defer os.Remove(root)
 
+	driver, err := FromParameters(map[string]interface{}{
+		"rootdirectory": root,
+	})
+	if err != nil {
+		panic(err)
+	}
+
 	testsuites.RegisterSuite(func() (storagedriver.StorageDriver, error) {
-		return New(root), nil
+		return driver, nil
 	}, testsuites.NeverSkip)
 }
+
+func TestFromParametersImpl(t *testing.T) {
+
+	tests := []struct {
+		params   map[string]interface{} // techincally the yaml can contain anything
+		expected DriverParameters
+		pass     bool
+	}{
+		// check we use default threads and root dirs
+		{
+			params: map[string]interface{}{},
+			expected: DriverParameters{
+				RootDirectory: defaultRootDirectory,
+				MaxThreads:    defaultMaxThreads,
+			},
+			pass: true,
+		},
+		// Testing initiation with a string maxThreads which can't be parsed
+		{
+			params: map[string]interface{}{
+				"maxthreads": "fail",
+			},
+			expected: DriverParameters{},
+			pass:     false,
+		},
+		{
+			params: map[string]interface{}{
+				"maxthreads": "100",
+			},
+			expected: DriverParameters{
+				RootDirectory: defaultRootDirectory,
+				MaxThreads:    uint64(100),
+			},
+			pass: true,
+		},
+		{
+			params: map[string]interface{}{
+				"maxthreads": 100,
+			},
+			expected: DriverParameters{
+				RootDirectory: defaultRootDirectory,
+				MaxThreads:    uint64(100),
+			},
+			pass: true,
+		},
+		// check that we use minimum thread counts
+		{
+			params: map[string]interface{}{
+				"maxthreads": 1,
+			},
+			expected: DriverParameters{
+				RootDirectory: defaultRootDirectory,
+				MaxThreads:    minThreads,
+			},
+			pass: true,
+		},
+	}
+
+	for _, item := range tests {
+		params, err := fromParametersImpl(item.params)
+
+		if !item.pass {
+			// We only need to assert that expected failures have an error
+			if err == nil {
+				t.Fatalf("expected error configuring filesystem driver with invalid param: %+v", item.params)
+			}
+			continue
+		}
+
+		if err != nil {
+			t.Fatalf("unexpected error creating filesystem driver: %s", err)
+		}
+		// Note that we get a pointer to params back
+		if !reflect.DeepEqual(*params, item.expected) {
+			t.Fatalf("unexpected params from filesystem driver. expected %+v, got %+v", item.expected, params)
+		}
+	}
+
+}