feat(core): persist tasks and recover them after restart

cmd/run.go

@@ -10,6 +10,7 @@ import (
 	"slices"
 
 	"github.com/charmbracelet/log"
+	"github.com/gotd/td/telegram/downloader"
 	"github.com/krau/SaveAny-Bot/api"
 	"github.com/krau/SaveAny-Bot/client/bot"
 	userclient "github.com/krau/SaveAny-Bot/client/user"
@@ -56,6 +57,14 @@ func Run(cmd *cobra.Command, _ []string) {
 		cancel()
 	}()
 
+	core.SetDownloaderProvider(func() downloader.Client {
+		if ectx := bot.ExtContext(); ectx != nil {
+			return ectx.Raw
+		}
+		return nil
+	})
+	core.RecoverTasks(ctx)
+
 	core.Run(ctx)
 
 	<-ctx.Done()
@@ -102,6 +111,15 @@ func cleanCache() {
 			log.Error("Invalid cache directory", "path", config.C().Temp.BasePath)
 			return
 		}
+		unfinished, err := database.CountUnfinishedTasks(context.Background())
+		if err != nil {
+			log.Error("Failed to count unfinished tasks, skipping cache cleanup", "error", err)
+			return
+		}
+		if unfinished > 0 {
+			log.Info("Skipping cache cleanup: unfinished tasks need their cache files for recovery", "tasks", unfinished)
+			return
+		}
 		currentDir, err := os.Getwd()
 		if err != nil {
 			log.Error("Failed to get working directory", "error", err)

core/core.go

@@ -7,6 +7,7 @@ import (
 
 	"github.com/charmbracelet/log"
 	"github.com/krau/SaveAny-Bot/config"
+	"github.com/krau/SaveAny-Bot/database"
 	"github.com/krau/SaveAny-Bot/pkg/enums/tasktype"
 	"github.com/krau/SaveAny-Bot/pkg/queue"
 	"github.com/krau/SaveAny-Bot/pkg/taskevent"
@@ -45,6 +46,9 @@ func worker(ctx context.Context, qe *queue.TaskQueue[Executable], semaphore chan
 		exe := qtask.Data
 		taskCtx := qtask.Context()
 		logger.Infof("Processing task: %s", exe.TaskID())
+		if err := database.UpdateTaskStatus(taskCtx, exe.TaskID(), database.TaskStatusRunning, ""); err != nil {
+			logger.Errorf("Failed to mark task %s as running: %v", exe.TaskID(), err)
+		}
 		taskevent.Emit(taskCtx, taskevent.Event{TaskID: exe.TaskID(), Phase: taskevent.PhaseStart})
 		if err := ExecCommandString(taskCtx, execHooks.TaskBeforeStart); err != nil {
 			logger.Errorf("Failed to execute before start hook for task %s: %v", exe.TaskID(), err)
@@ -70,6 +74,9 @@ func worker(ctx context.Context, qe *queue.TaskQueue[Executable], semaphore chan
 		}
 		taskevent.Emit(taskCtx, taskevent.Event{TaskID: exe.TaskID(), Phase: taskevent.PhaseDone, Err: err})
 		qe.Done(qtask.ID)
+		if err := database.DeleteTask(ctx, exe.TaskID()); err != nil {
+			logger.Errorf("Failed to delete persisted task %s: %v", exe.TaskID(), err)
+		}
 		<-semaphore
 	}
 }
@@ -92,12 +99,21 @@ func Close() {
 }
 
 func AddTask(ctx context.Context, task Executable) error {
+	if err := persistTask(ctx, task); err != nil {
+		log.FromContext(ctx).Errorf("Failed to persist task %s: %v", task.TaskID(), err)
+	}
 	return initQueue().Add(queue.NewTask(ctx, task.TaskID(), task.Title(), task))
 }
 
 func CancelTask(ctx context.Context, id string) error {
 	err := queueInstance.CancelTask(id)
-	return err
+	if err != nil {
+		return err
+	}
+	if err := database.DeleteTask(ctx, id); err != nil {
+		log.FromContext(ctx).Errorf("Failed to delete persisted task %s: %v", id, err)
+	}
+	return nil
 }
 
 func GetLength(ctx context.Context) int {

core/persist.go

@@ -0,0 +1,114 @@
+package core
+
+import (
+	"context"
+	"sync"
+
+	"github.com/charmbracelet/log"
+	"github.com/gotd/td/telegram/downloader"
+
+	"github.com/krau/SaveAny-Bot/database"
+	"github.com/krau/SaveAny-Bot/pkg/enums/tasktype"
+)
+
+// TaskCodec serializes and rebuilds a task from its persisted payload.
+// Task types without a registered codec are dropped with a warning on
+// recovery instead of being silently re-enqueued.
+type TaskCodec interface {
+	Marshal(task Executable) ([]byte, error)
+	Unmarshal(payload []byte) (Executable, error)
+}
+
+var (
+	taskCodecsMu sync.RWMutex
+	taskCodecs   = make(map[tasktype.TaskType]TaskCodec)
+
+	dlerMu       sync.RWMutex
+	dlerProvider func() downloader.Client
+)
+
+func RegisterTaskCodec(t tasktype.TaskType, codec TaskCodec) {
+	taskCodecsMu.Lock()
+	defer taskCodecsMu.Unlock()
+	taskCodecs[t] = codec
+}
+
+func TaskCodecFor(t tasktype.TaskType) (TaskCodec, bool) {
+	taskCodecsMu.RLock()
+	defer taskCodecsMu.RUnlock()
+	codec, ok := taskCodecs[t]
+	return codec, ok
+}
+
+// SetDownloaderProvider registers the download client factory used to
+// rebuild tfile.TGFile values when recovering tasks.
+func SetDownloaderProvider(f func() downloader.Client) {
+	dlerMu.Lock()
+	defer dlerMu.Unlock()
+	dlerProvider = f
+}
+
+// DownloaderClient returns the registered download client, or nil.
+func DownloaderClient() downloader.Client {
+	dlerMu.RLock()
+	defer dlerMu.RUnlock()
+	if dlerProvider == nil {
+		return nil
+	}
+	return dlerProvider()
+}
+
+func persistTask(ctx context.Context, task Executable) error {
+	codec, ok := TaskCodecFor(task.Type())
+	if !ok {
+		return nil
+	}
+	payload, err := codec.Marshal(task)
+	if err != nil {
+		return err
+	}
+	return database.UpsertTask(ctx, &database.Task{
+		ID:      task.TaskID(),
+		Type:    string(task.Type()),
+		Payload: payload,
+		Status:  string(database.TaskStatusQueued),
+	})
+}
+
+// RecoverTasks re-enqueues tasks that were unfinished when the process last
+// exited. Must be called after storages are loaded and before Run. Tasks of
+// types without a registered codec are dropped with a warning.
+func RecoverTasks(ctx context.Context) {
+	logger := log.FromContext(ctx)
+	tasks, err := database.GetUnfinishedTasks(ctx)
+	if err != nil {
+		logger.Errorf("Failed to load unfinished tasks: %v", err)
+		return
+	}
+	for _, t := range tasks {
+		codec, ok := TaskCodecFor(tasktype.TaskType(t.Type))
+		if !ok {
+			logger.Warnf("Dropping unrecoverable task %s (type %s): no codec registered", t.ID, t.Type)
+			if err := database.DeleteTask(ctx, t.ID); err != nil {
+				logger.Errorf("Failed to delete task %s: %v", t.ID, err)
+			}
+			continue
+		}
+		task, err := codec.Unmarshal(t.Payload)
+		if err != nil {
+			logger.Errorf("Dropping task %s: failed to rebuild: %v", t.ID, err)
+			if err := database.DeleteTask(ctx, t.ID); err != nil {
+				logger.Errorf("Failed to delete task %s: %v", t.ID, err)
+			}
+			continue
+		}
+		if err := AddTask(ctx, task); err != nil {
+			logger.Errorf("Dropping task %s: failed to re-enqueue: %v", t.ID, err)
+			if err := database.DeleteTask(ctx, t.ID); err != nil {
+				logger.Errorf("Failed to delete task %s: %v", t.ID, err)
+			}
+			continue
+		}
+		logger.Infof("Recovered task %s (%s)", t.ID, t.Type)
+	}
+}

core/persist_test.go

@@ -0,0 +1,124 @@
+package core
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/krau/SaveAny-Bot/config"
+	"github.com/krau/SaveAny-Bot/database"
+	"github.com/krau/SaveAny-Bot/pkg/enums/tasktype"
+)
+
+const testRecoverType = tasktype.TaskType("test-recover")
+
+type stubTask struct {
+	id string
+}
+
+func (s *stubTask) Type() tasktype.TaskType       { return testRecoverType }
+func (s *stubTask) Title() string                 { return s.id }
+func (s *stubTask) TaskID() string                { return s.id }
+func (s *stubTask) Execute(context.Context) error { return nil }
+
+type stubCodec struct{}
+
+func (stubCodec) Marshal(task Executable) ([]byte, error) {
+	return []byte(task.TaskID()), nil
+}
+
+func (stubCodec) Unmarshal(payload []byte) (Executable, error) {
+	if len(payload) == 0 {
+		return nil, fmt.Errorf("empty payload")
+	}
+	return &stubTask{id: string(payload)}, nil
+}
+
+func initRecoveryEnv(t *testing.T) context.Context {
+	t.Helper()
+	dir := t.TempDir()
+	cfgPath := filepath.Join(dir, "config.toml")
+	content := fmt.Sprintf("[db]\npath = %q\n", filepath.Join(dir, "test.db"))
+	if err := os.WriteFile(cfgPath, []byte(content), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	if err := config.Init(context.Background(), cfgPath); err != nil {
+		t.Fatalf("config init: %v", err)
+	}
+	database.Init(context.Background())
+	RegisterTaskCodec(testRecoverType, stubCodec{})
+	return context.Background()
+}
+
+func TestRecoverTasksReenqueuesAndDropsUnknown(t *testing.T) {
+	ctx := initRecoveryEnv(t)
+
+	if err := database.CreateTask(ctx, &database.Task{
+		ID: "rec-1", Type: string(testRecoverType), Payload: []byte("rec-1"), Status: string(database.TaskStatusQueued),
+	}); err != nil {
+		t.Fatal(err)
+	}
+	if err := database.CreateTask(ctx, &database.Task{
+		ID: "rec-2", Type: string(testRecoverType), Payload: []byte("rec-2"), Status: string(database.TaskStatusRunning),
+	}); err != nil {
+		t.Fatal(err)
+	}
+	if err := database.CreateTask(ctx, &database.Task{
+		ID: "drop-1", Type: "unregistered", Payload: nil, Status: string(database.TaskStatusQueued),
+	}); err != nil {
+		t.Fatal(err)
+	}
+
+	RecoverTasks(ctx)
+
+	ids := map[string]bool{}
+	for _, info := range GetQueuedTasks(ctx) {
+		ids[info.ID] = true
+	}
+	if !ids["rec-1"] || !ids["rec-2"] {
+		t.Fatalf("recovered task ids = %v, want rec-1 and rec-2", ids)
+	}
+
+	unfinished, err := database.GetUnfinishedTasks(ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(unfinished) != 2 {
+		t.Fatalf("unfinished rows = %d, want 2", len(unfinished))
+	}
+	for _, task := range unfinished {
+		if task.ID == "drop-1" {
+			t.Fatalf("unregistered task record was not dropped")
+		}
+		if task.Status != string(database.TaskStatusQueued) {
+			t.Fatalf("recovered task status = %s, want queued", task.Status)
+		}
+	}
+}
+
+func TestRecoverTasksDropsInvalidPayload(t *testing.T) {
+	ctx := initRecoveryEnv(t)
+
+	if err := database.CreateTask(ctx, &database.Task{
+		ID: "bad-1", Type: string(testRecoverType), Payload: nil, Status: string(database.TaskStatusQueued),
+	}); err != nil {
+		t.Fatal(err)
+	}
+	RecoverTasks(ctx)
+
+	// bad-1 must not be enqueued nor remain in the database.
+	for _, info := range GetQueuedTasks(ctx) {
+		if info.ID == "bad-1" {
+			t.Fatalf("task with invalid payload was enqueued")
+		}
+	}
+	count, err := database.CountUnfinishedTasks(ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if count != 0 {
+		t.Fatalf("unfinished rows = %d, want 0", count)
+	}
+}

core/tasks/batchtfile/codec.go

@@ -0,0 +1,106 @@
+package batchtfile
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"path/filepath"
+
+	"github.com/krau/SaveAny-Bot/config"
+	"github.com/krau/SaveAny-Bot/core"
+	"github.com/krau/SaveAny-Bot/pkg/enums/tasktype"
+	tfilepkg "github.com/krau/SaveAny-Bot/pkg/tfile"
+	"github.com/krau/SaveAny-Bot/storage"
+)
+
+type elementPayload struct {
+	ID              string               `json:"id"`
+	Storage         string               `json:"storage"`
+	Path            string               `json:"path"`
+	File            tfilepkg.FilePayload `json:"file"`
+	SourceGroupKey  string               `json:"source_group_key"`
+	SourceCaption   string               `json:"source_caption"`
+	PreserveCaption bool                 `json:"preserve_caption"`
+}
+
+type taskPayload struct {
+	ID           string           `json:"id"`
+	Elements     []elementPayload `json:"elements"`
+	ChatID       int64            `json:"chat_id"`
+	MessageID    int              `json:"message_id"`
+	IgnoreErrors bool             `json:"ignore_errors"`
+}
+
+type taskCodec struct{}
+
+func init() {
+	core.RegisterTaskCodec(tasktype.TaskTypeTgfiles, taskCodec{})
+}
+
+func (taskCodec) Marshal(task core.Executable) ([]byte, error) {
+	t, ok := task.(*Task)
+	if !ok {
+		return nil, fmt.Errorf("unexpected task type %T", task)
+	}
+	p := taskPayload{
+		ID:           t.ID,
+		IgnoreErrors: t.IgnoreErrors,
+	}
+	for _, elem := range t.elems {
+		filePayload, ok := tfilepkg.FilePayloadOf(elem.File)
+		if !ok {
+			return nil, fmt.Errorf("file %T is not serializable", elem.File)
+		}
+		p.Elements = append(p.Elements, elementPayload{
+			ID:              elem.ID,
+			Storage:         elem.Storage.Name(),
+			Path:            elem.Path,
+			File:            filePayload,
+			SourceGroupKey:  elem.sourceGroupKey,
+			SourceCaption:   elem.sourceCaption,
+			PreserveCaption: elem.preserveCaption,
+		})
+	}
+	if progress, ok := t.Progress.(*Progress); ok {
+		p.ChatID = progress.ChatID
+		p.MessageID = progress.MessageID
+	}
+	return json.Marshal(p)
+}
+
+func (taskCodec) Unmarshal(data []byte) (core.Executable, error) {
+	var p taskPayload
+	if err := json.Unmarshal(data, &p); err != nil {
+		return nil, fmt.Errorf("invalid task payload: %w", err)
+	}
+	dler := core.DownloaderClient()
+	if dler == nil {
+		return nil, fmt.Errorf("no downloader client available")
+	}
+	elems := make([]TaskElement, 0, len(p.Elements))
+	for _, ep := range p.Elements {
+		stor, err := storage.GetStorageByName(context.Background(), ep.Storage)
+		if err != nil {
+			return nil, fmt.Errorf("storage %q: %w", ep.Storage, err)
+		}
+		localPath, err := filepath.Abs(filepath.Join(config.C().Temp.BasePath, fmt.Sprintf("%s_%s", ep.ID, ep.File.Name)))
+		if err != nil {
+			return nil, fmt.Errorf("failed to build cache path: %w", err)
+		}
+		elems = append(elems, TaskElement{
+			ID:              ep.ID,
+			Storage:         stor,
+			Path:            ep.Path,
+			File:            tfilepkg.FileFromPayload(ep.File, dler),
+			localPath:       localPath,
+			sourceGroupKey:  ep.SourceGroupKey,
+			sourceCaption:   ep.SourceCaption,
+			preserveCaption: ep.PreserveCaption,
+		})
+	}
+	var progress ProgressTracker
+	if p.ChatID != 0 {
+		progress = NewProgressTracker(p.MessageID, p.ChatID)
+	}
+	return NewBatchTGFileTask(p.ID, context.Background(), elems, progress, p.IgnoreErrors), nil
+}

core/tasks/batchtfile/execute.go

@@ -134,7 +134,12 @@ func (t *Task) processElements(ctx context.Context, elems []*TaskElement) error
 }
 
 func (t *Task) processBatch(ctx context.Context, group executionGroup) error {
+	// Cache files are kept on failure so a later restart can resume upload.
+	uploaded := false
 	defer func() {
+		if !uploaded {
+			return
+		}
 		for _, elem := range group.elems {
 			if err := os.Remove(elem.localPath); err != nil && !os.IsNotExist(err) {
 				log.FromContext(ctx).Warnf("Failed to cleanup batch cache file %s: %v", elem.localPath, err)
@@ -219,7 +224,11 @@ func (t *Task) processBatch(ctx context.Context, group executionGroup) error {
 	for index, item := range items {
 		t.recordDownloadComplete(successElems[index].ID, item.Size)
 	}
-	return t.saveBatchItems(ctx, successElems, items)
+	err := t.saveBatchItems(ctx, successElems, items)
+	if err == nil {
+		uploaded = true
+	}
+	return err
 }
 
 func (t *Task) saveBatchItems(ctx context.Context, successElems []*TaskElement, items []storagetypes.BatchItem) error {
@@ -289,34 +298,10 @@ func (t *Task) unmarkProcessing(id string) {
 func (t *Task) downloadElement(ctx context.Context, elem *TaskElement) error {
 	logger := log.FromContext(ctx).WithPrefix(fmt.Sprintf("file[%s]", elem.File.Name()))
 	logger.Info("Starting file download")
-	localFile, err := fsutil.CreateFile(elem.localPath)
-	if err != nil {
-		t.markItemFailed(elem.ID, FailureStageCache, err)
+	if err := t.downloadToCache(ctx, elem); err != nil {
+		t.markItemFailed(elem.ID, FailureStageDownload, err)
 		t.notifyStateChange(ctx)
-		return fmt.Errorf("failed to create local file: %w", err)
-	}
-	wrAt := ioutil.NewProgressWriterAt(localFile, func(n int) {
-		t.recordItemDownload(elem.ID, int64(n), time.Now())
-		downloaded := t.downloaded.Add(int64(n))
-		t.notifyProgress(ctx)
-		taskevent.Emit(ctx, taskevent.Event{
-			TaskID:          t.ID,
-			Phase:           taskevent.PhaseProgress,
-			TotalBytes:      t.totalSize,
-			DownloadedBytes: downloaded,
-		})
-	})
-	_, downloadErr := tdler.NewDownloader(elem.File).Parallel(ctx, wrAt)
-	closeErr := localFile.Close()
-	if downloadErr != nil {
-		t.markItemFailed(elem.ID, FailureStageDownload, downloadErr)
-		t.notifyStateChange(ctx)
-		return fmt.Errorf("failed to download file: %w", downloadErr)
-	}
-	if closeErr != nil {
-		t.markItemFailed(elem.ID, FailureStageCache, closeErr)
-		t.notifyStateChange(ctx)
-		return fmt.Errorf("failed to close cache file: %w", closeErr)
+		return fmt.Errorf("failed to download file: %w", err)
 	}
 	logger.Info("File downloaded successfully")
 	if path.Ext(elem.FileName()) == "" {
@@ -387,24 +372,15 @@ func (t *Task) processElement(ctx context.Context, elem TaskElement) error {
 		t.notifyStateChange(ctx)
 		return fmt.Errorf("failed to create local file: %w", err)
 	}
+	success := false
 	defer func() {
-		if err := localFile.CloseAndRemove(); err != nil {
-			logger.Errorf("Failed to close local file: %v", err)
+		if success {
+			if err := localFile.CloseAndRemove(); err != nil {
+				logger.Errorf("Failed to close local file: %v", err)
+			}
 		}
 	}()
-	wrAt := ioutil.NewProgressWriterAt(localFile, func(n int) {
-		t.recordItemDownload(elem.ID, int64(n), time.Now())
-		downloaded := t.downloaded.Add(int64(n))
-		t.notifyProgress(ctx)
-		taskevent.Emit(ctx, taskevent.Event{
-			TaskID:          t.ID,
-			Phase:           taskevent.PhaseProgress,
-			TotalBytes:      t.totalSize,
-			DownloadedBytes: downloaded,
-		})
-	})
-	_, err = tdler.NewDownloader(elem.File).Parallel(ctx, wrAt)
-	if err != nil {
+	if err := t.downloadToCache(ctx, &elem); err != nil {
 		t.markItemFailed(elem.ID, FailureStageDownload, err)
 		t.notifyStateChange(ctx)
 		return fmt.Errorf("failed to download file: %w", err)
@@ -460,6 +436,7 @@ func (t *Task) processElement(ctx context.Context, elem TaskElement) error {
 		onProgress(fileStat.Size(), fileStat.Size())
 		t.markItemCompleted(elem.ID)
 		t.notifyStateChange(vctx)
+		success = true
 	} else {
 		t.markItemFailed(elem.ID, lastFailureStage, err)
 		t.notifyStateChange(vctx)

core/tasks/tfile/codec.go

@@ -0,0 +1,85 @@
+package tfile
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"path/filepath"
+
+	"github.com/krau/SaveAny-Bot/config"
+	"github.com/krau/SaveAny-Bot/core"
+	"github.com/krau/SaveAny-Bot/pkg/enums/tasktype"
+	tfilepkg "github.com/krau/SaveAny-Bot/pkg/tfile"
+	"github.com/krau/SaveAny-Bot/storage"
+)
+
+type taskPayload struct {
+	ID        string               `json:"id"`
+	Storage   string               `json:"storage"`
+	Path      string               `json:"path"`
+	File      tfilepkg.FilePayload `json:"file"`
+	ChatID    int64                `json:"chat_id"`
+	MessageID int                  `json:"message_id"`
+}
+
+type taskCodec struct{}
+
+func init() {
+	core.RegisterTaskCodec(tasktype.TaskTypeTgfiles, taskCodec{})
+}
+
+func (taskCodec) Marshal(task core.Executable) ([]byte, error) {
+	t, ok := task.(*Task)
+	if !ok {
+		return nil, fmt.Errorf("unexpected task type %T", task)
+	}
+	filePayload, ok := tfilepkg.FilePayloadOf(t.File)
+	if !ok {
+		return nil, fmt.Errorf("file %T is not serializable", t.File)
+	}
+	p := taskPayload{
+		ID:      t.ID,
+		Storage: t.Storage.Name(),
+		Path:    t.Path,
+		File:    filePayload,
+	}
+	if progress, ok := t.Progress.(*Progress); ok {
+		p.ChatID = progress.ChatID
+		p.MessageID = progress.MessageID
+	}
+	return json.Marshal(p)
+}
+
+func (taskCodec) Unmarshal(data []byte) (core.Executable, error) {
+	var p taskPayload
+	if err := json.Unmarshal(data, &p); err != nil {
+		return nil, fmt.Errorf("invalid task payload: %w", err)
+	}
+	dler := core.DownloaderClient()
+	if dler == nil {
+		return nil, fmt.Errorf("no downloader client available")
+	}
+	file := tfilepkg.FileFromPayload(p.File, dler)
+	stor, err := storage.GetStorageByName(context.Background(), p.Storage)
+	if err != nil {
+		return nil, fmt.Errorf("storage %q: %w", p.Storage, err)
+	}
+	var progress ProgressTracker
+	if p.ChatID != 0 {
+		progress = NewProgressTrack(p.MessageID, p.ChatID)
+	}
+	localPath, err := filepath.Abs(filepath.Join(config.C().Temp.BasePath, fmt.Sprintf("%s_%s", p.ID, file.Name())))
+	if err != nil {
+		return nil, fmt.Errorf("failed to build cache path: %w", err)
+	}
+	return &Task{
+		ID:        p.ID,
+		Ctx:       context.Background(),
+		File:      file,
+		Storage:   stor,
+		Path:      p.Path,
+		Progress:  progress,
+		stream:    false, // recovered tasks always download to cache first
+		localPath: localPath,
+	}, nil
+}

core/tasks/tfile/execute.go

@@ -9,7 +9,6 @@ import (
 
 	"github.com/charmbracelet/log"
 	"github.com/duke-git/lancet/v2/retry"
-	"github.com/krau/SaveAny-Bot/common/tdler"
 	"github.com/krau/SaveAny-Bot/common/utils/fsutil"
 	"github.com/krau/SaveAny-Bot/common/utils/ioutil"
 	"github.com/krau/SaveAny-Bot/config"
@@ -19,8 +18,13 @@ import (
 	"github.com/krau/SaveAny-Bot/storage"
 )
 
-func (t *Task) Execute(ctx context.Context) error {
+func (t *Task) Execute(ctx context.Context) (err error) {
 	logger := log.FromContext(ctx).WithPrefix(fmt.Sprintf("file[%s]", t.File.Name()))
+	defer func() {
+		if t.Progress != nil {
+			t.Progress.OnDone(ctx, t, err)
+		}
+	}()
 	if t.Progress != nil {
 		t.Progress.OnStart(ctx, t)
 	}
@@ -29,35 +33,16 @@ func (t *Task) Execute(ctx context.Context) error {
 	}
 
 	logger.Info("Starting file download")
-	localFile, err := fsutil.CreateFile(t.localPath)
-	if err != nil {
-		return fmt.Errorf("failed to create local file: %w", err)
-	}
-	defer func() {
-		if err := localFile.CloseAndRemove(); err != nil {
-			logger.Errorf("Failed to close local file: %v", err)
-		}
-	}()
-	wrAt := newWriterAt(ctx, localFile, t.Progress, t)
-
-	defer func() {
-		if t.Progress != nil {
-			t.Progress.OnDone(ctx, t, err)
-		}
-	}()
-	_, err = tdler.NewDownloader(t.File).Parallel(ctx, wrAt)
-	if err != nil {
+	if err := t.download(ctx); err != nil {
 		return fmt.Errorf("failed to download file: %w", err)
 	}
-	logger.Infof("File downloaded successfully")
 	if path.Ext(t.File.Name()) == "" {
 		ext := fsutil.DetectFileExt(t.localPath)
 		if ext != "" {
 			t.Path = t.Path + ext
 		}
 	}
-	var fileStat os.FileInfo
-	fileStat, err = os.Stat(t.localPath)
+	fileStat, err := os.Stat(t.localPath)
 	if err != nil {
 		return fmt.Errorf("failed to get file stat: %w", err)
 	}
@@ -97,6 +82,10 @@ func (t *Task) Execute(ctx context.Context) error {
 	if err != nil {
 		return fmt.Errorf("failed to save file after retries: %w", err)
 	}
+	// Cache file is kept on failure so a later restart can resume upload.
+	if err := os.Remove(t.localPath); err != nil {
+		logger.Errorf("Failed to remove cache file: %v", err)
+	}
 	return nil
 }
 

core/tasks/transfer/codec.go

@@ -0,0 +1,92 @@
+package transfer
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+
+	"github.com/krau/SaveAny-Bot/core"
+	"github.com/krau/SaveAny-Bot/pkg/enums/tasktype"
+	"github.com/krau/SaveAny-Bot/pkg/storagetypes"
+	"github.com/krau/SaveAny-Bot/storage"
+)
+
+type elementPayload struct {
+	ID            string                `json:"id"`
+	SourceStorage string                `json:"source_storage"`
+	SourcePath    string                `json:"source_path"`
+	FileInfo      storagetypes.FileInfo `json:"file_info"`
+	TargetStorage string                `json:"target_storage"`
+	TargetPath    string                `json:"target_path"`
+}
+
+type taskPayload struct {
+	ID           string           `json:"id"`
+	Elements     []elementPayload `json:"elements"`
+	ChatID       int64            `json:"chat_id"`
+	MessageID    int              `json:"message_id"`
+	IgnoreErrors bool             `json:"ignore_errors"`
+}
+
+type taskCodec struct{}
+
+func init() {
+	core.RegisterTaskCodec(tasktype.TaskTypeTransfer, taskCodec{})
+}
+
+func (taskCodec) Marshal(task core.Executable) ([]byte, error) {
+	t, ok := task.(*Task)
+	if !ok {
+		return nil, fmt.Errorf("unexpected task type %T", task)
+	}
+	p := taskPayload{
+		ID:           t.ID,
+		IgnoreErrors: t.IgnoreErrors,
+	}
+	for _, elem := range t.elems {
+		p.Elements = append(p.Elements, elementPayload{
+			ID:            elem.ID,
+			SourceStorage: elem.SourceStorage.Name(),
+			SourcePath:    elem.SourcePath,
+			FileInfo:      elem.FileInfo,
+			TargetStorage: elem.TargetStorage.Name(),
+			TargetPath:    elem.TargetPath,
+		})
+	}
+	if progress, ok := t.Progress.(*Progress); ok {
+		p.ChatID = progress.ChatID
+		p.MessageID = progress.MessageID
+	}
+	return json.Marshal(p)
+}
+
+func (taskCodec) Unmarshal(data []byte) (core.Executable, error) {
+	var p taskPayload
+	if err := json.Unmarshal(data, &p); err != nil {
+		return nil, fmt.Errorf("invalid task payload: %w", err)
+	}
+	elems := make([]TaskElement, 0, len(p.Elements))
+	for _, ep := range p.Elements {
+		source, err := storage.GetStorageByName(context.Background(), ep.SourceStorage)
+		if err != nil {
+			return nil, fmt.Errorf("source storage %q: %w", ep.SourceStorage, err)
+		}
+		target, err := storage.GetStorageByName(context.Background(), ep.TargetStorage)
+		if err != nil {
+			return nil, fmt.Errorf("target storage %q: %w", ep.TargetStorage, err)
+		}
+		elems = append(elems, TaskElement{
+			ID:            ep.ID,
+			SourceStorage: source,
+			SourcePath:    ep.SourcePath,
+			FileInfo:      ep.FileInfo,
+			TargetStorage: target,
+			TargetPath:    ep.TargetPath,
+		})
+	}
+	var progress ProgressTracker
+	if p.ChatID != 0 {
+		progress = NewProgressTracker(p.MessageID, p.ChatID)
+	}
+	return NewTransferTask(p.ID, context.Background(), elems, progress, p.IgnoreErrors), nil
+}

database/db.go

@@ -35,7 +35,7 @@ func Init(ctx context.Context) {
 		logger.Fatal("Failed to open database: ", err)
 	}
 	logger.Debug("Database connected")
-	if err := db.AutoMigrate(&User{}, &Dir{}, &Rule{}, &WatchChat{}); err != nil {
+	if err := db.AutoMigrate(&User{}, &Dir{}, &Rule{}, &WatchChat{}, &Task{}); err != nil {
 		logger.Fatal("Database migration failed; if upgrading from an old version, try deleting the database file and retrying", "error", err)
 	}
 	if err := syncUsers(ctx); err != nil {

database/task.go

@@ -0,0 +1,92 @@
+package database
+
+import (
+	"context"
+	"errors"
+	"time"
+)
+
+var errNotInitialized = errors.New("database not initialized")
+
+type TaskStatus string
+
+const (
+	TaskStatusQueued    TaskStatus = "queued"
+	TaskStatusRunning   TaskStatus = "running"
+	TaskStatusFailed    TaskStatus = "failed"
+	TaskStatusCancelled TaskStatus = "cancelled"
+)
+
+// Task is the persisted record of a queued or running task, used to recover
+// unfinished work after a process restart. Completed tasks are deleted on
+// finish, so the table only ever holds queued/running rows.
+type Task struct {
+	ID        string `gorm:"primaryKey;size:64"`
+	Type      string `gorm:"size:32;index"`
+	Payload   []byte
+	Status    string `gorm:"size:16;index"`
+	Error     string
+	CreatedAt time.Time
+	UpdatedAt time.Time
+}
+
+func CreateTask(ctx context.Context, task *Task) error {
+	if db == nil {
+		return errNotInitialized
+	}
+	return db.WithContext(ctx).Create(task).Error
+}
+
+// UpsertTask inserts the task or replaces the existing row with the same ID.
+func UpsertTask(ctx context.Context, task *Task) error {
+	if db == nil {
+		return errNotInitialized
+	}
+	return db.WithContext(ctx).Save(task).Error
+}
+
+func UpdateTaskStatus(ctx context.Context, id string, status TaskStatus, errMsg string) error {
+	if db == nil {
+		return errNotInitialized
+	}
+	return db.WithContext(ctx).Model(&Task{}).
+		Where("id = ?", id).
+		Updates(map[string]any{
+			"status":     status,
+			"error":      errMsg,
+			"updated_at": time.Now(),
+		}).Error
+}
+
+func DeleteTask(ctx context.Context, id string) error {
+	if db == nil {
+		return errNotInitialized
+	}
+	return db.WithContext(ctx).Delete(&Task{}, "id = ?", id).Error
+}
+
+// GetUnfinishedTasks returns all tasks that were not finished when the
+// process stopped, i.e. tasks that must be re-enqueued on startup.
+func GetUnfinishedTasks(ctx context.Context) ([]Task, error) {
+	if db == nil {
+		return nil, errNotInitialized
+	}
+	var tasks []Task
+	err := db.WithContext(ctx).
+		Where("status IN ?", []string{string(TaskStatusQueued), string(TaskStatusRunning)}).
+		Order("created_at").
+		Find(&tasks).Error
+	return tasks, err
+}
+
+func CountUnfinishedTasks(ctx context.Context) (int64, error) {
+	if db == nil {
+		return 0, errNotInitialized
+	}
+	var count int64
+	err := db.WithContext(ctx).
+		Model(&Task{}).
+		Where("status IN ?", []string{string(TaskStatusQueued), string(TaskStatusRunning)}).
+		Count(&count).Error
+	return count, err
+}

database/task_test.go

@@ -0,0 +1,110 @@
+package database
+
+import (
+	"context"
+	"path/filepath"
+	"testing"
+
+	"github.com/ncruces/go-sqlite3/gormlite"
+	"gorm.io/gorm"
+)
+
+func newTestDB(t *testing.T) {
+	t.Helper()
+	d, err := gorm.Open(gormlite.Open(filepath.Join(t.TempDir(), "test.db")), &gorm.Config{})
+	if err != nil {
+		t.Fatalf("open test db: %v", err)
+	}
+	if err := d.AutoMigrate(&Task{}); err != nil {
+		t.Fatalf("migrate: %v", err)
+	}
+	old := db
+	db = d
+	t.Cleanup(func() { db = old })
+}
+
+func TestTaskCRUD(t *testing.T) {
+	newTestDB(t)
+	ctx := context.Background()
+
+	task := &Task{
+		ID:      "task-1",
+		Type:    "tfile",
+		Payload: []byte(`{"file":"x"}`),
+		Status:  string(TaskStatusQueued),
+	}
+	if err := CreateTask(ctx, task); err != nil {
+		t.Fatalf("create: %v", err)
+	}
+
+	unfinished, err := GetUnfinishedTasks(ctx)
+	if err != nil {
+		t.Fatalf("get unfinished: %v", err)
+	}
+	if len(unfinished) != 1 || unfinished[0].ID != "task-1" {
+		t.Fatalf("got %+v, want 1 task task-1", unfinished)
+	}
+
+	if err := UpdateTaskStatus(ctx, "task-1", TaskStatusRunning, ""); err != nil {
+		t.Fatalf("update: %v", err)
+	}
+	unfinished, err = GetUnfinishedTasks(ctx)
+	if err != nil {
+		t.Fatalf("get unfinished after update: %v", err)
+	}
+	if len(unfinished) != 1 || unfinished[0].Status != string(TaskStatusRunning) {
+		t.Fatalf("running status not persisted: %+v", unfinished)
+	}
+
+	if err := DeleteTask(ctx, "task-1"); err != nil {
+		t.Fatalf("delete: %v", err)
+	}
+	count, err := CountUnfinishedTasks(ctx)
+	if err != nil {
+		t.Fatalf("count: %v", err)
+	}
+	if count != 0 {
+		t.Fatalf("count = %d, want 0", count)
+	}
+}
+
+func TestTaskUpsert(t *testing.T) {
+	newTestDB(t)
+	ctx := context.Background()
+
+	task := &Task{ID: "task-2", Type: "tfile", Status: string(TaskStatusQueued)}
+	if err := UpsertTask(ctx, task); err != nil {
+		t.Fatalf("upsert create: %v", err)
+	}
+	task.Status = string(TaskStatusRunning)
+	task.Payload = []byte("new")
+	if err := UpsertTask(ctx, task); err != nil {
+		t.Fatalf("upsert update: %v", err)
+	}
+	unfinished, err := GetUnfinishedTasks(ctx)
+	if err != nil {
+		t.Fatalf("get unfinished: %v", err)
+	}
+	if len(unfinished) != 1 || unfinished[0].Status != string(TaskStatusRunning) || string(unfinished[0].Payload) != "new" {
+		t.Fatalf("upsert did not replace: %+v", unfinished)
+	}
+}
+
+func TestGetUnfinishedTasksExcludesFinished(t *testing.T) {
+	newTestDB(t)
+	ctx := context.Background()
+
+	if err := CreateTask(ctx, &Task{ID: "done", Type: "tfile", Status: string(TaskStatusFailed)}); err != nil {
+		t.Fatal(err)
+	}
+	if err := CreateTask(ctx, &Task{ID: "pending", Type: "tfile", Status: string(TaskStatusQueued)}); err != nil {
+		t.Fatal(err)
+	}
+	unfinished, err := GetUnfinishedTasks(ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(unfinished) != 1 || unfinished[0].ID != "pending" {
+		t.Fatalf("got %+v, want only pending", unfinished)
+	}
+}

pkg/tfile/payload.go

@@ -0,0 +1,86 @@
+package tfile
+
+import (
+	"github.com/gotd/td/telegram/downloader"
+	"github.com/gotd/td/tg"
+)
+
+// Payloadable is implemented by TGFile implementations that can serialize
+// themselves for task recovery.
+type Payloadable interface {
+	Payload() FilePayload
+}
+
+// FilePayloadOf returns the serializable form of f.
+func FilePayloadOf(f TGFile) (FilePayload, bool) {
+	p, ok := f.(Payloadable)
+	if !ok {
+		return FilePayload{}, false
+	}
+	return p.Payload(), true
+}
+
+// FilePayload is the minimal serializable representation of a TGFile,
+// used to rebuild tasks after a process restart.
+type FilePayload struct {
+	Kind          string `json:"kind"` // "document" | "photo"
+	ID            int64  `json:"id"`
+	AccessHash    int64  `json:"access_hash"`
+	FileReference []byte `json:"file_reference"`
+	ThumbSize     string `json:"thumb_size"`
+	Size          int64  `json:"size"`
+	Name          string `json:"name"`
+}
+
+// Payload returns the serializable representation of the file.
+func (f *tgFile) Payload() FilePayload {
+	p := FilePayload{
+		Size: f.size,
+		Name: f.name,
+	}
+	switch loc := f.location.(type) {
+	case *tg.InputDocumentFileLocation:
+		p.Kind = "document"
+		p.ID = loc.ID
+		p.AccessHash = loc.AccessHash
+		p.FileReference = loc.FileReference
+		p.ThumbSize = loc.ThumbSize
+	case *tg.InputPhotoFileLocation:
+		p.Kind = "photo"
+		p.ID = loc.ID
+		p.AccessHash = loc.AccessHash
+		p.FileReference = loc.FileReference
+		p.ThumbSize = loc.ThumbSize
+	}
+	return p
+}
+
+// Location rebuilds the Telegram file location from the payload.
+func (p FilePayload) Location() tg.InputFileLocationClass {
+	switch p.Kind {
+	case "photo":
+		return &tg.InputPhotoFileLocation{
+			ID:            p.ID,
+			AccessHash:    p.AccessHash,
+			FileReference: p.FileReference,
+			ThumbSize:     p.ThumbSize,
+		}
+	default:
+		return &tg.InputDocumentFileLocation{
+			ID:            p.ID,
+			AccessHash:    p.AccessHash,
+			FileReference: p.FileReference,
+			ThumbSize:     p.ThumbSize,
+		}
+	}
+}
+
+// FileFromPayload rebuilds a TGFile from its serialized payload.
+func FileFromPayload(p FilePayload, dler downloader.Client) TGFile {
+	return &tgFile{
+		location: p.Location(),
+		dler:     dler,
+		size:     p.Size,
+		name:     p.Name,
+	}
+}

pkg/tfile/payload_test.go

@@ -0,0 +1,61 @@
+package tfile
+
+import (
+	"reflect"
+	"testing"
+
+	"github.com/gotd/td/tg"
+)
+
+func TestFilePayloadDocumentRoundTrip(t *testing.T) {
+	file := NewTGFile(
+		&tg.InputDocumentFileLocation{
+			ID:            6287403840090150101,
+			AccessHash:    -8452541528324991878,
+			FileReference: []byte{0x02, 0x0e, 0x80, 0xd6},
+			ThumbSize:     "",
+		},
+		nil,
+		4194304000,
+		"常轨脱离Creative凸.7z.001",
+	)
+	p, ok := FilePayloadOf(file)
+	if !ok {
+		t.Fatalf("FilePayloadOf failed")
+	}
+	rebuilt := FileFromPayload(p, nil)
+	if !reflect.DeepEqual(rebuilt.Location(), file.Location()) {
+		t.Fatalf("location mismatch:\n got %#v\nwant %#v", rebuilt.Location(), file.Location())
+	}
+	if rebuilt.Size() != file.Size() || rebuilt.Name() != file.Name() {
+		t.Fatalf("size/name mismatch: got %d %q, want %d %q", rebuilt.Size(), rebuilt.Name(), file.Size(), file.Name())
+	}
+	if p.Kind != "document" {
+		t.Fatalf("kind = %q, want document", p.Kind)
+	}
+}
+
+func TestFilePayloadPhotoRoundTrip(t *testing.T) {
+	file := NewTGFile(
+		&tg.InputPhotoFileLocation{
+			ID:            123,
+			AccessHash:    456,
+			FileReference: []byte{0xaa, 0xbb},
+			ThumbSize:     "y",
+		},
+		nil,
+		0,
+		"photo_123.png",
+	)
+	p, ok := FilePayloadOf(file)
+	if !ok {
+		t.Fatalf("FilePayloadOf failed")
+	}
+	if p.Kind != "photo" {
+		t.Fatalf("kind = %q, want photo", p.Kind)
+	}
+	rebuilt := FileFromPayload(p, nil)
+	if !reflect.DeepEqual(rebuilt.Location(), file.Location()) {
+		t.Fatalf("location mismatch:\n got %#v\nwant %#v", rebuilt.Location(), file.Location())
+	}
+}