feat: filebrowser with encfs

diskcache/cache.go

@@ -0,0 +1,11 @@
+package diskcache
+
+import (
+	"context"
+)
+
+type Interface interface {
+	Store(ctx context.Context, key string, value []byte) error
+	Load(ctx context.Context, key string) (value []byte, exist bool, err error)
+	Delete(ctx context.Context, key string) error
+}

diskcache/file_cache.go

@@ -0,0 +1,110 @@
+package diskcache
+
+import (
+	"context"
+	"crypto/sha1" //nolint:gosec
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"sync"
+
+	"github.com/spf13/afero"
+)
+
+type FileCache struct {
+	fs afero.Fs
+
+	// granular locks
+	scopedLocks struct {
+		sync.Mutex
+		sync.Once
+		locks map[string]sync.Locker
+	}
+}
+
+func New(fs afero.Fs, root string) *FileCache {
+	return &FileCache{
+		fs: afero.NewBasePathFs(fs, root),
+	}
+}
+
+func (f *FileCache) Store(_ context.Context, key string, value []byte) error {
+	mu := f.getScopedLocks(key)
+	mu.Lock()
+	defer mu.Unlock()
+
+	fileName := f.getFileName(key)
+	if err := f.fs.MkdirAll(filepath.Dir(fileName), 0700); err != nil { //nolint:gomnd
+		return err
+	}
+
+	if err := afero.WriteFile(f.fs, fileName, value, 0700); err != nil { //nolint:gomnd
+		return err
+	}
+
+	return nil
+}
+
+func (f *FileCache) Load(_ context.Context, key string) (value []byte, exist bool, err error) {
+	r, ok, err := f.open(key)
+	if err != nil || !ok {
+		return nil, ok, err
+	}
+	defer r.Close()
+
+	value, err = io.ReadAll(r)
+	if err != nil {
+		return nil, false, err
+	}
+	return value, true, nil
+}
+
+func (f *FileCache) Delete(_ context.Context, key string) error {
+	mu := f.getScopedLocks(key)
+	mu.Lock()
+	defer mu.Unlock()
+
+	fileName := f.getFileName(key)
+	if err := f.fs.Remove(fileName); err != nil && !errors.Is(err, os.ErrNotExist) {
+		return err
+	}
+	return nil
+}
+
+func (f *FileCache) open(key string) (afero.File, bool, error) {
+	fileName := f.getFileName(key)
+	file, err := f.fs.Open(fileName)
+	if err != nil {
+		if errors.Is(err, os.ErrNotExist) {
+			return nil, false, nil
+		}
+		return nil, false, err
+	}
+
+	return file, true, nil
+}
+
+// getScopedLocks pull lock from the map if found or create a new one
+func (f *FileCache) getScopedLocks(key string) (lock sync.Locker) {
+	f.scopedLocks.Do(func() { f.scopedLocks.locks = map[string]sync.Locker{} })
+
+	f.scopedLocks.Lock()
+	lock, ok := f.scopedLocks.locks[key]
+	if !ok {
+		lock = &sync.Mutex{}
+		f.scopedLocks.locks[key] = lock
+	}
+	f.scopedLocks.Unlock()
+
+	return lock
+}
+
+func (f *FileCache) getFileName(key string) string {
+	hasher := sha1.New() //nolint:gosec
+	_, _ = hasher.Write([]byte(key))
+	hash := hex.EncodeToString(hasher.Sum(nil))
+	return fmt.Sprintf("%s/%s/%s", hash[:1], hash[1:3], hash)
+}

diskcache/file_cache_test.go

@@ -0,0 +1,55 @@
+package diskcache
+
+import (
+	"context"
+	"path/filepath"
+	"testing"
+
+	"github.com/spf13/afero"
+	"github.com/stretchr/testify/require"
+)
+
+func TestFileCache(t *testing.T) {
+	ctx := context.Background()
+	const (
+		key            = "key"
+		value          = "some text"
+		newValue       = "new text"
+		cacheRoot      = "/cache"
+		cachedFilePath = "a/62/a62f2225bf70bfaccbc7f1ef2a397836717377de"
+	)
+
+	fs := afero.NewMemMapFs()
+	cache := New(fs, "/cache")
+
+	// store new key
+	err := cache.Store(ctx, key, []byte(value))
+	require.NoError(t, err)
+	checkValue(t, ctx, fs, filepath.Join(cacheRoot, cachedFilePath), cache, key, value)
+
+	// update existing key
+	err = cache.Store(ctx, key, []byte(newValue))
+	require.NoError(t, err)
+	checkValue(t, ctx, fs, filepath.Join(cacheRoot, cachedFilePath), cache, key, newValue)
+
+	// delete key
+	err = cache.Delete(ctx, key)
+	require.NoError(t, err)
+	exists, err := afero.Exists(fs, filepath.Join(cacheRoot, cachedFilePath))
+	require.NoError(t, err)
+	require.False(t, exists)
+}
+
+func checkValue(t *testing.T, ctx context.Context, fs afero.Fs, fileFullPath string, cache *FileCache, key, wantValue string) { //nolint:revive
+	t.Helper()
+	// check actual file content
+	b, err := afero.ReadFile(fs, fileFullPath)
+	require.NoError(t, err)
+	require.Equal(t, wantValue, string(b))
+
+	// check cache content
+	b, ok, err := cache.Load(ctx, key)
+	require.NoError(t, err)
+	require.True(t, ok)
+	require.Equal(t, wantValue, string(b))
+}

diskcache/noop_cache.go

@@ -0,0 +1,24 @@
+package diskcache
+
+import (
+	"context"
+)
+
+type NoOp struct {
+}
+
+func NewNoOp() *NoOp {
+	return &NoOp{}
+}
+
+func (n *NoOp) Store(_ context.Context, _ string, _ []byte) error {
+	return nil
+}
+
+func (n *NoOp) Load(_ context.Context, _ string) (value []byte, exist bool, err error) {
+	return nil, false, nil
+}
+
+func (n *NoOp) Delete(_ context.Context, _ string) error {
+	return nil
+}