push backup

.vscode/launch.json

@@ -10,7 +10,7 @@
             "type": "go",
             "request": "launch",
             "mode": "auto",
-            "args": ["list", "-a", "http://localhost:8080"],
+            "args": ["run"],
             "console": "integratedTerminal",
             "program": "${workspaceFolder}/cmd/cli"
         }

cmd/cli/commands/run/run.go

@@ -37,11 +37,7 @@ func (p *RunCmd) Execute(_ context.Context, f *flag.FlagSet, _ ...interface{}) s
 		return subcommands.ExitFailure
 	}
 
-	pg := progressbar.New(len(datastore))
-	defer pg.Close()
-
 	for _, metadata := range datastore {
-		pg.Describe("Scanning " + metadata.Name + "...")
 		metadataPath := filepath.Join(repository.DatastorePath(), metadata.ID)
 		//todo transaction
 		err := archiveIfChanged(metadata.ID, metadata.Path, filepath.Join(metadataPath, "data.tar.gz"), filepath.Join(metadataPath, ".last_run"))
@@ -57,11 +53,8 @@ func (p *RunCmd) Execute(_ context.Context, f *flag.FlagSet, _ ...interface{}) s
 			fmt.Fprintf(os.Stderr, "error: cannot process the data of %s: %s\n", metadata.ID, err)
 			return subcommands.ExitFailure
 		}
-		pg.Add(1)
 	}
 
-	pg.Finish()
-
 	return subcommands.ExitSuccess
 }
 
@@ -69,6 +62,11 @@ func (p *RunCmd) Execute(_ context.Context, f *flag.FlagSet, _ ...interface{}) s
 // in srcDir has a modification time > the last run time stored in stateFile.
 // After archiving, it updates stateFile to the current time.
 func archiveIfChanged(gameID, srcDir, destTarGz, stateFile string) error {
+	pg := progressbar.New(-1)
+	defer pg.Close()
+
+	pg.Describe("Scanning " + gameID + "...")
+
 	// load last run time
 	var lastRun time.Time
 	data, err := os.ReadFile(stateFile)
@@ -99,15 +97,18 @@ func archiveIfChanged(gameID, srcDir, destTarGz, stateFile string) error {
 	}
 
 	if !changed {
+		pg.Finish()
 		return nil
 	}
 
 	// make a backup
+	pg.Describe("Backup current data...")
 	if err := repository.Archive(gameID); err != nil {
 		return fmt.Errorf("failed to archive data: %w", err)
 	}
 
 	// create archive
+	pg.Describe("Archiving new data...")
 	f, err := os.Create(destTarGz)
 	if err != nil {
 		return fmt.Errorf("failed to creating archive file: %w", err)

cmd/cli/commands/sync/sync.go

@@ -65,10 +65,13 @@ func (p *SyncCmd) Execute(_ context.Context, f *flag.FlagSet, _ ...interface{})
 		}
 
 		if !exists {
-			if err := push(r.GameID, g, cli); err != nil {
+			if err := push(g, cli); err != nil {
 				fmt.Fprintln(os.Stderr, "failed to push:", err)
 				return subcommands.ExitFailure
 			}
+			if err := pushBackup(g, cli); err != nil {
+				slog.Warn("failed to push backup files", "err", err)
+			}
 			continue
 		}
 
@@ -96,6 +99,10 @@ func (p *SyncCmd) Execute(_ context.Context, f *flag.FlagSet, _ ...interface{})
 			continue
 		}
 
+		if err := pushBackup(g, cli); err != nil {
+			slog.Warn("failed to push backup files", "err", err)
+		}
+
 		if hlocal == hremote {
 			if vlocal != remoteMetadata.Version {
 				slog.Debug("version is not the same, but the hash is equal. Updating local database")
@@ -109,7 +116,7 @@ func (p *SyncCmd) Execute(_ context.Context, f *flag.FlagSet, _ ...interface{})
 		}
 
 		if vlocal > remoteMetadata.Version {
-			if err := push(r.GameID, g, cli); err != nil {
+			if err := push(g, cli); err != nil {
 				fmt.Fprintln(os.Stderr, "failed to push:", err)
 				return subcommands.ExitFailure
 			}
@@ -164,7 +171,7 @@ func conflict(gameID string, m, remoteMetadata repository.Metadata, cli *client.
 	switch res {
 	case prompt.My:
 		{
-			if err := push(gameID, m, cli); err != nil {
+			if err := push(m, cli); err != nil {
 				return fmt.Errorf("failed to push: %w", err)
 			}
 		}
@@ -185,10 +192,34 @@ func conflict(gameID string, m, remoteMetadata repository.Metadata, cli *client.
 	return nil
 }
 
-func push(gameID string, m repository.Metadata, cli *client.Client) error {
+func push(m repository.Metadata, cli *client.Client) error {
-	archivePath := filepath.Join(repository.DatastorePath(), gameID, "data.tar.gz")
+	archivePath := filepath.Join(repository.DatastorePath(), m.ID, "data.tar.gz")
 
-	return cli.Push(gameID, archivePath, m)
+	return cli.PushSave(archivePath, m)
+}
+
+func pushBackup(m repository.Metadata, cli *client.Client) error {
+	bs, err := repository.Archives(m.ID)
+	if err != nil {
+		return err
+	}
+
+	for _, b := range bs {
+		binfo, err := cli.ArchiveInfo(m.ID, b.UUID)
+		if err != nil {
+			if !errors.Is(err, client.ErrNotFound) {
+				return fmt.Errorf("failed to get remote information about the backup file: %w", err)
+			}
+		}
+
+		if binfo.MD5 != b.MD5 {
+			if err := cli.PushBackup(b, m); err != nil {
+				return fmt.Errorf("failed to push backup: %w", err)
+			}
+		}
+
+	}
+	return nil
 }
 
 func pull(gameID string, cli *client.Client) error {

cmd/server/api/api.go

@@ -61,7 +61,8 @@ func NewServer(documentRoot string, creds map[string]string, port int) *HTTPServ
 					// Data routes
 					gamesRouter.Group(func(saveRouter chi.Router) {
 						saveRouter.Post("/{id}/data", s.upload)
-						saveRouter.Post("/{id}/hist/data", s.histUpload)
+						saveRouter.Post("/{id}/hist/{uuid}/data", s.histUpload)
+						saveRouter.Get("/{id}/hist/{uuid}/info", s.histExists)
 						saveRouter.Get("/{id}/data", s.download)
 						saveRouter.Get("/{id}/hash", s.hash)
 						saveRouter.Get("/{id}/metadata", s.metadata)
@@ -215,19 +216,14 @@ func (s HTTPServer) histUpload(w http.ResponseWriter, r *http.Request) {
 		sizeLimit int64 = 500 << 20 // 500 MB
 	)
 
-	id := chi.URLParam(r, "id")
+	gameID := chi.URLParam(r, "id")
-	dt, err := formParseDate("date", r.MultipartForm.Value)
+	uuid := chi.URLParam(r, "uuid")
-	if err != nil {
-		fmt.Fprintln(os.Stderr, "error: failed to load payload:", err)
-		badRequest("bad payload", w, r)
-		return
-	}
 
 	// Limit max upload size
 	r.Body = http.MaxBytesReader(w, r.Body, sizeLimit)
 
 	// Parse multipart form
-	err = r.ParseMultipartForm(sizeLimit)
+	err := r.ParseMultipartForm(sizeLimit)
 	if err != nil {
 		fmt.Fprintln(os.Stderr, "error: failed to load payload:", err)
 		badRequest("bad payload", w, r)
@@ -243,7 +239,7 @@ func (s HTTPServer) histUpload(w http.ResponseWriter, r *http.Request) {
 	}
 	defer file.Close()
 
-	if err := data.WriteHist(id, s.documentRoot, dt, file); err != nil {
+	if err := data.WriteHist(gameID, s.documentRoot, uuid, file); err != nil {
 		fmt.Fprintln(os.Stderr, "error: failed to write file to disk:", err)
 		internalServerError(w, r)
 		return
@@ -253,6 +249,24 @@ func (s HTTPServer) histUpload(w http.ResponseWriter, r *http.Request) {
 	w.WriteHeader(http.StatusCreated)
 }
 
+func (s HTTPServer) histExists(w http.ResponseWriter, r *http.Request) {
+	gameID := chi.URLParam(r, "id")
+	uuid := chi.URLParam(r, "uuid")
+
+	finfo, err := data.ArchiveInfo(gameID, s.documentRoot, uuid)
+	if err != nil {
+		if errors.Is(err, data.ErrBackupNotExists) {
+			notFound("backup not found", w, r)
+			return
+		}
+		fmt.Fprintln(os.Stderr, "error: failed to read data:", err)
+		internalServerError(w, r)
+		return
+	}
+
+	ok(finfo, w, r)
+}
+
 func (s HTTPServer) hash(w http.ResponseWriter, r *http.Request) {
 	id := chi.URLParam(r, "id")
 	path := filepath.Clean(filepath.Join(s.documentRoot, "data", id))
@@ -374,21 +388,3 @@ func parseFormMetadata(gameID string, values map[string][]string) (repository.Me
 		Date:    date,
 	}, nil
 }
-
-func formParseDate(key string, values map[string][]string) (time.Time, error) {
-	var date time.Time
-	if v, ok := values[key]; ok {
-		if len(v) == 0 {
-			return time.Time{}, fmt.Errorf("error: corrupted metadata")
-		}
-		if v, err := time.Parse(time.RFC3339, v[0]); err == nil {
-			date = v
-		} else {
-			return time.Time{}, err
-		}
-	} else {
-		return time.Time{}, fmt.Errorf("error: cannot find metadata in the form")
-	}
-
-	return date, nil
-}

cmd/server/data/data.go

@@ -2,12 +2,17 @@ package data
 
 import (
 	"cloudsave/pkg/repository"
+	"cloudsave/pkg/tools/hash"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"os"
 	"path/filepath"
-	"time"
+)
+
+var (
+	ErrBackupNotExists error = errors.New("backup not found")
 )
 
 func Write(gameID, documentRoot string, r io.Reader) error {
@@ -40,15 +45,19 @@ func Write(gameID, documentRoot string, r io.Reader) error {
 	return nil
 }
 
-func WriteHist(gameID, documentRoot string, dt time.Time, r io.Reader) error {
+func WriteHist(gameID, documentRoot, uuid string, r io.Reader) error {
-	dataFolderPath := filepath.Join(documentRoot, "data", gameID, "hist")
+	dataFolderPath := filepath.Join(documentRoot, "data", gameID, "hist", uuid)
-	partPath := filepath.Join(dataFolderPath, dt.Format("2006-01-02T15-04-05Z07-00")+".data.tar.gz.part")
+	partPath := filepath.Join(dataFolderPath, "data.tar.gz.part")
-	finalFilePath := filepath.Join(dataFolderPath, dt.Format("2006-01-02T15-04-05Z07-00")+".data.tar.gz")
+	finalFilePath := filepath.Join(dataFolderPath, "data.tar.gz")
 
 	if err := makeDataFolder(gameID, documentRoot); err != nil {
 		return err
 	}
 
+	if err := os.MkdirAll(dataFolderPath, 0740); err != nil {
+		return err
+	}
+
 	f, err := os.OpenFile(partPath, os.O_CREATE|os.O_WRONLY, 0740)
 	if err != nil {
 		return err
@@ -86,6 +95,29 @@ func UpdateMetadata(gameID, documentRoot string, m repository.Metadata) error {
 	return e.Encode(m)
 }
 
+func ArchiveInfo(gameID, documentRoot, uuid string) (repository.Backup, error) {
+	dataFolderPath := filepath.Join(documentRoot, "data", gameID, "hist", uuid, "data.tar.gz")
+
+	finfo, err := os.Stat(dataFolderPath)
+	if err != nil {
+		if errors.Is(err, os.ErrNotExist) {
+			return repository.Backup{}, ErrBackupNotExists
+		}
+		return repository.Backup{}, err
+	}
+
+	h, err := hash.FileMD5(dataFolderPath)
+	if err != nil {
+		return repository.Backup{}, fmt.Errorf("failed to calculate file md5: %w", err)
+	}
+
+	return repository.Backup{
+		CreatedAt: finfo.ModTime(),
+		UUID:      uuid,
+		MD5:       h,
+	}, nil
+}
+
 func makeDataFolder(gameID, documentRoot string) error {
 	if err := os.MkdirAll(filepath.Join(documentRoot, "data", gameID), 0740); err != nil {
 		return err

go.mod

@@ -5,6 +5,7 @@ go 1.24
 require (
 	github.com/go-chi/chi/v5 v5.2.1
 	github.com/google/subcommands v1.2.0
+	github.com/google/uuid v1.6.0
 	github.com/schollz/progressbar/v3 v3.18.0
 	golang.org/x/crypto v0.38.0
 	golang.org/x/term v0.32.0

go.sum

@@ -6,6 +6,8 @@ github.com/go-chi/chi/v5 v5.2.1 h1:KOIHODQj58PmL80G2Eak4WdvUzjSJSm0vG72crDCqb8=
 github.com/go-chi/chi/v5 v5.2.1/go.mod h1:L2yAIGWB3H+phAw1NxKwWM+7eUH/lU8pOMm5hHcoops=
 github.com/google/subcommands v1.2.0 h1:vWQspBTo2nEqTUFita5/KeEWlUL8kQObDFbub/EN9oE=
 github.com/google/subcommands v1.2.0/go.mod h1:ZjhPrFU+Olkh9WazFPsl27BQ4UPiG37m3yTrtFlrHVk=
+github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
+github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/mattn/go-runewidth v0.0.16 h1:E5ScNMtiwvlvB5paMFdw9p4kSQzbXFikJ5SQO6TULQc=
 github.com/mattn/go-runewidth v0.0.16/go.mod h1:Jdepj2loyihRzMpdS35Xk/zdY8IAYHsh153qUoGf23w=
 github.com/mitchellh/colorstring v0.0.0-20190213212951-d06e56a500db h1:62I3jR2EmQ4l5rM/4FEfDWcRD+abF5XlKShorW5LRoQ=

pkg/remote/client/client.go

@@ -35,6 +35,10 @@ type (
 	}
 )
 
+var (
+	ErrNotFound error = errors.New("not found")
+)
+
 func New(baseURL, username, password string) *Client {
 	return &Client{
 		baseURL:  baseURL,
@@ -141,59 +145,45 @@ func (c *Client) Metadata(gameID string) (repository.Metadata, error) {
 	return repository.Metadata{}, errors.New("invalid payload sent by the server")
 }
 
-func (c *Client) Push(gameID, archivePath string, m repository.Metadata) error {
+func (c *Client) PushSave(archivePath string, m repository.Metadata) error {
-	u, err := url.JoinPath(c.baseURL, "api", "v1", "games", gameID, "data")
+	u, err := url.JoinPath(c.baseURL, "api", "v1", "games", m.ID, "data")
 	if err != nil {
 		return err
 	}
 
-	f, err := os.OpenFile(archivePath, os.O_RDONLY, 0)
+	return c.push(u, archivePath, m)
-	if err != nil {
-		return fmt.Errorf("failed to open file: %w", err)
 }
-	defer f.Close()
 
-	buf := new(bytes.Buffer)
+func (c *Client) PushBackup(archiveMetadata repository.Backup, m repository.Metadata) error {
-	writer := multipart.NewWriter(buf)
+	u, err := url.JoinPath(c.baseURL, "api", "v1", "games", m.ID, "hist", archiveMetadata.UUID, "data")
-
-	part, err := writer.CreateFormFile("payload", "data.tar.gz")
 	if err != nil {
 		return err
 	}
 
-	if _, err := io.Copy(part, f); err != nil {
+	return c.push(u, archiveMetadata.ArchivePath, m)
-		return fmt.Errorf("failed to copy data: %w", err)
 }
 
-	writer.WriteField("name", m.Name)
+func (c *Client) ArchiveInfo(gameID, uuid string) (repository.Backup, error) {
-	writer.WriteField("version", strconv.Itoa(m.Version))
+	u, err := url.JoinPath(c.baseURL, "api", "v1", "games", gameID, "hist", uuid, "info")
-	writer.WriteField("date", m.Date.Format(time.RFC3339))
-
-	if err := writer.Close(); err != nil {
-		return err
-	}
-
-	cli := http.Client{}
-
-	req, err := http.NewRequest("POST", u, buf)
 	if err != nil {
-		return err
+		return repository.Backup{}, err
 	}
 
-	req.SetBasicAuth(c.username, c.password)
+	o, err := c.get(u)
-	req.Header.Set("Content-Type", writer.FormDataContentType())
-
-	res, err := cli.Do(req)
 	if err != nil {
-		return err
+		return repository.Backup{}, err
-	}
-	defer res.Body.Close()
-
-	if res.StatusCode != 201 {
-		return fmt.Errorf("server returns an unexpected status code: %s (expected 201)", res.Status)
 	}
 
-	return nil
+	if m, ok := (o.Data).(map[string]any); ok {
+		b := repository.Backup{
+			UUID:      m["uuid"].(string),
+			CreatedAt: customtime.MustParse(time.RFC3339, m["created_at"].(string)),
+			MD5:       m["md5"].(string),
+		}
+		return b, nil
+	}
+
+	return repository.Backup{}, errors.New("invalid payload sent by the server")
 }
 
 func (c *Client) Pull(gameID, archivePath string) error {
@@ -318,6 +308,10 @@ func (c *Client) get(url string) (obj.HTTPObject, error) {
 	}
 	defer res.Body.Close()
 
+	if res.StatusCode == 404 {
+		return obj.HTTPObject{}, ErrNotFound
+	}
+
 	if res.StatusCode != 200 {
 		return obj.HTTPObject{}, fmt.Errorf("server returns an unexpected status code: %d %s (expected 200)", res.StatusCode, res.Status)
 	}
@@ -331,3 +325,53 @@ func (c *Client) get(url string) (obj.HTTPObject, error) {
 
 	return httpObject, nil
 }
+
+func (c *Client) push(u, archivePath string, m repository.Metadata) error {
+	f, err := os.OpenFile(archivePath, os.O_RDONLY, 0)
+	if err != nil {
+		return fmt.Errorf("failed to open file: %w", err)
+	}
+	defer f.Close()
+
+	buf := new(bytes.Buffer)
+	writer := multipart.NewWriter(buf)
+
+	part, err := writer.CreateFormFile("payload", "data.tar.gz")
+	if err != nil {
+		return err
+	}
+
+	if _, err := io.Copy(part, f); err != nil {
+		return fmt.Errorf("failed to copy data: %w", err)
+	}
+
+	writer.WriteField("name", m.Name)
+	writer.WriteField("version", strconv.Itoa(m.Version))
+	writer.WriteField("date", m.Date.Format(time.RFC3339))
+
+	if err := writer.Close(); err != nil {
+		return err
+	}
+
+	cli := http.Client{}
+
+	req, err := http.NewRequest("POST", u, buf)
+	if err != nil {
+		return err
+	}
+
+	req.SetBasicAuth(c.username, c.password)
+	req.Header.Set("Content-Type", writer.FormDataContentType())
+
+	res, err := cli.Do(req)
+	if err != nil {
+		return err
+	}
+	defer res.Body.Close()
+
+	if res.StatusCode != 201 {
+		return fmt.Errorf("server returns an unexpected status code: %s (expected 201)", res.Status)
+	}
+
+	return nil
+}

pkg/repository/repository.go

@@ -1,16 +1,17 @@
 package repository
 
 import (
+	"cloudsave/pkg/tools/hash"
 	"cloudsave/pkg/tools/id"
-	"crypto/md5"
-	"encoding/hex"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
-	"io/fs"
 	"os"
 	"path/filepath"
 	"time"
+
+	"github.com/google/uuid"
 )
 
 type (
@@ -21,6 +22,13 @@ type (
 		Version int       `json:"version"`
 		Date    time.Time `json:"date"`
 	}
+
+	Backup struct {
+		CreatedAt   time.Time `json:"created_at"`
+		MD5         string    `json:"md5"`
+		UUID        string    `json:"uuid"`
+		ArchivePath string    `json:"-"`
+	}
 )
 
 var (
@@ -142,46 +150,20 @@ func Archive(gameID string) error {
 	// open old
 	f, err := os.OpenFile(path, os.O_RDONLY, 0)
 	if err != nil {
+		if errors.Is(err, os.ErrNotExist) {
+			return nil
+		}
 		return fmt.Errorf("failed to open old file: %w", err)
 	}
 	defer f.Close()
 
-	histDirPath := filepath.Join(datastorepath, gameID, "hist")
+	histDirPath := filepath.Join(datastorepath, gameID, "hist", uuid.NewString())
 	if err := os.MkdirAll(histDirPath, 0740); err != nil {
-		return fmt.Errorf("failed to make 'hist' directory")
+		return fmt.Errorf("failed to make directory: %w", err)
-	}
-
-	d, err := os.ReadDir(histDirPath)
-	if err != nil {
-		return fmt.Errorf("failed to open 'hist' directory")
-	}
-
-	// keep the dir under 6 files
-	if len(d) > 5 {
-		var oldest *fs.FileInfo
-		for _, hfile := range d {
-			finfo, err := hfile.Info()
-			if err != nil {
-				return fmt.Errorf("failed to read backup file: %w", err)
-			}
-
-			if oldest == nil {
-				oldest = &finfo
-				continue
-			}
-
-			if finfo.ModTime().Before((*oldest).ModTime()) {
-				oldest = &finfo
-			}
-		}
-
-		if err := os.Remove((*oldest).Name()); err != nil {
-			return fmt.Errorf("failed to remove the oldest backup file: %w", err)
-		}
 	}
 
 	// open new
-	nf, err := os.OpenFile(filepath.Join(datastorepath, gameID, "hist", time.Now().Format("2006-01-02T15-04-05Z07-00")+".data.tar.gz"), os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0740)
+	nf, err := os.OpenFile(filepath.Join(histDirPath, "data.tar.gz"), os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0740)
 	if err != nil {
 		return fmt.Errorf("failed to open new file: %w", err)
 	}
@@ -195,6 +177,43 @@ func Archive(gameID string) error {
 	return nil
 }
 
+func Archives(gameID string) ([]Backup, error) {
+	histDirPath := filepath.Join(datastorepath, gameID, "hist")
+	if err := os.MkdirAll(histDirPath, 0740); err != nil {
+		return nil, fmt.Errorf("failed to make 'hist' directory")
+	}
+
+	d, err := os.ReadDir(histDirPath)
+	if err != nil {
+		return nil, fmt.Errorf("failed to open 'hist' directory")
+	}
+
+	var res []Backup
+	for _, f := range d {
+		finfo, err := f.Info()
+		if err != nil {
+			return nil, fmt.Errorf("corrupted datastore: %w", err)
+		}
+		path := filepath.Join(histDirPath, finfo.Name())
+		archivePath := filepath.Join(path, "data.tar.gz")
+
+		h, err := hash.FileMD5(archivePath)
+		if err != nil {
+			return nil, fmt.Errorf("failed to calculate md5 hash: %w", err)
+		}
+
+		b := Backup{
+			CreatedAt:   finfo.ModTime(),
+			UUID:        filepath.Base(finfo.Name()),
+			MD5:         h,
+			ArchivePath: archivePath,
+		}
+
+		res = append(res, b)
+	}
+	return res, nil
+}
+
 func DatastorePath() string {
 	return datastorepath
 }
@@ -210,18 +229,7 @@ func Remove(gameID string) error {
 func Hash(gameID string) (string, error) {
 	path := filepath.Join(datastorepath, gameID, "data.tar.gz")
 
-	f, err := os.OpenFile(path, os.O_RDONLY, 0)
+	return hash.FileMD5(path)
-	if err != nil {
-		return "", err
-	}
-	defer f.Close()
-
-	hasher := md5.New()
-	if _, err := io.Copy(hasher, f); err != nil {
-		return "", err
-	}
-	sum := hasher.Sum(nil)
-	return hex.EncodeToString(sum), nil
 }
 
 func Version(gameID string) (int, error) {

pkg/tools/archive/archive.go

@@ -73,7 +73,7 @@ func Untar(file io.Reader, path string) error {
 	}
 }
 
-func Tar(file io.Writer, path string) error {
+func Tar(file io.Writer, root string) error {
 	gw := gzip.NewWriter(file)
 	defer gw.Close()
 
@@ -81,26 +81,31 @@ func Tar(file io.Writer, path string) error {
 	defer tw.Close()
 
 	// Walk again to add files
-	err := filepath.Walk(path, func(path string, info os.FileInfo, walkErr error) error {
+	err := filepath.Walk(root, func(path string, info os.FileInfo, walkErr error) error {
 		if walkErr != nil {
 			return walkErr
 		}
+
+		path, err := filepath.Rel(root, path)
+		if err != nil {
+			return err
+		}
+
 		// Create tar header
 		header, err := tar.FileInfoHeader(info, path)
 		if err != nil {
 			return err
 		}
-		// Preserve directory structure relative to srcDir
+		header.Name = path
-		relPath, err := filepath.Rel(filepath.Dir(path), path)
-		if err != nil {
-			return err
-		}
-		header.Name = relPath
 
 		if err := tw.WriteHeader(header); err != nil {
 			return err
 		}
-		if info.Mode().IsRegular() {
+
+		if !info.Mode().IsRegular() {
+			return nil
+		}
+
 		file, err := os.Open(path)
 		if err != nil {
 			return err
@@ -109,7 +114,6 @@ func Tar(file io.Writer, path string) error {
 		if _, err := io.Copy(tw, file); err != nil {
 			return err
 		}
-		}
 		return nil
 	})
 	if err != nil {

pkg/tools/hash/hash.go

@@ -0,0 +1,23 @@
+package hash
+
+import (
+	"crypto/md5"
+	"encoding/hex"
+	"io"
+	"os"
+)
+
+func FileMD5(fp string) (string, error) {
+	f, err := os.OpenFile(fp, os.O_RDONLY, 0)
+	if err != nil {
+		return "", err
+	}
+	defer f.Close()
+
+	hasher := md5.New()
+	if _, err := io.Copy(hasher, f); err != nil {
+		return "", err
+	}
+	sum := hasher.Sum(nil)
+	return hex.EncodeToString(sum), nil
+}