feat: statefile versioning

cmd/mcbdd/mailcow.go

@@ -36,7 +36,7 @@ func (d *Daemon) getUserPass(ctx context.Context, username string) (string, erro
 	slog.InfoContext(ctx, "created new app password", "user", username)
 	d.userTokensLock.Lock()
 	d.userTokens[username] = pass
-	d.userTokensUnsaved = true
+	d.stateUnsaved = true
 	d.userTokensLock.Unlock()
 	return pass, nil
 }

cmd/mcbdd/main.go

@@ -24,13 +24,13 @@ var (
 )
 
 type Daemon struct {
-	userTokens        map[string]string
-	userTokensLock    *sync.RWMutex
-	userTokensUnsaved bool
-	httpClient        *http.Client
-	baseURL           string
-	mailcowClient     mailcow.Client
-	statefile         string
+	httpClient     *http.Client
+	baseURL        string
+	mailcowClient  mailcow.Client
+	userTokens     map[string]string
+	userTokensLock *sync.RWMutex
+	stateFilepath  string
+	stateUnsaved   bool
 }
 
 func main() {
@@ -46,22 +46,22 @@ func run() error {
 		userTokens:     make(map[string]string),
 		userTokensLock: &sync.RWMutex{},
 		baseURL:        os.Getenv("MAILCOW_BASE"),
-		statefile:      os.Getenv("STATEFILE"),
+		stateFilepath:  os.Getenv("STATEFILE"),
 		httpClient: &http.Client{
 			Transport: &http.Transport{
 				Proxy: http.ProxyFromEnvironment,
 			},
 		},
 	}
-	if len(d.statefile) == 0 {
-		d.statefile = "state.json"
+	if len(d.stateFilepath) == 0 {
+		d.stateFilepath = "state.json"
 	}
 	d.mailcowClient = mailcow.New(
 		d.httpClient,
 		d.baseURL,
 		os.Getenv("MAILCOW_APIKEY"),
 	)
-	if err := d.LoadFromDisk(); err != nil {
+	if err := d.loadState(); err != nil {
 		return err
 	}
 	d.daemonLoop()
@@ -92,12 +92,12 @@ func (d *Daemon) daemonRun() error {
 		})
 	}
 	eg.Wait()
-	if d.userTokensUnsaved {
+	if d.stateUnsaved {
 		slog.Info("saving tokens to disk", "count", len(d.userTokens))
-		if err := d.SaveToDisk(); err != nil {
+		if err := d.saveState(); err != nil {
 			return err
 		}
-		d.userTokensUnsaved = false
+		d.stateUnsaved = false
 	}
 	return nil
 }

cmd/mcbdd/persist.go

@@ -1,13 +1,64 @@
 package main
 
 import (
+	"encoding/base64"
 	"encoding/json"
 	"errors"
+	"fmt"
+	"log/slog"
 	"os"
 )
 
-func (d *Daemon) LoadFromDisk() error {
-	f, err := os.OpenFile(d.statefile, os.O_RDONLY, 0o660)
+func (d *Daemon) loadState() error {
+	stateVer := struct {
+		Version int `json:"version"`
+	}{}
+	if err := d.loadFromDisk(&stateVer); err != nil {
+		return fmt.Errorf("cant detect state version: %w", err)
+	}
+	switch stateVer.Version {
+	case 0:
+		slog.Warn("loading old state version", "stateVer", stateVer.Version)
+		if err := d.loadFromDisk(&d.userTokens); err != nil {
+			return fmt.Errorf("cant load state v%d: %w", stateVer.Version, err)
+		}
+		d.stateUnsaved = true
+	case 1:
+		state := struct {
+			Version    int               `json:"version"`
+			UserTokens map[string]string `json:"userTokens"`
+		}{}
+		if err := d.loadFromDisk(&state); err != nil {
+			return fmt.Errorf("cant load state v%d: %w", stateVer.Version, err)
+		}
+		for k, v := range state.UserTokens {
+			dec, err := base64.StdEncoding.DecodeString(v)
+			if err != nil {
+				return fmt.Errorf("cant decode pass from %s: %w", k, err)
+			}
+			d.userTokens[k] = string(dec)
+		}
+	}
+	return nil
+}
+
+func (d *Daemon) saveState() error {
+	encTokens := make(map[string]string, len(d.userTokens))
+	for k, v := range d.userTokens {
+		encTokens[k] = base64.StdEncoding.EncodeToString([]byte(v))
+	}
+	state := struct {
+		Version    int               `json:"version"`
+		UserTokens map[string]string `json:"userTokens"`
+	}{
+		Version:    1,
+		UserTokens: encTokens,
+	}
+	return d.saveToDisk(state)
+}
+
+func (d *Daemon) loadFromDisk(state any) error {
+	f, err := os.OpenFile(d.stateFilepath, os.O_RDONLY, 0o660)
 	if err != nil {
 		if errors.Is(err, os.ErrNotExist) {
 			return nil
@@ -15,14 +66,14 @@ func (d *Daemon) LoadFromDisk() error {
 		return err
 	}
 	defer f.Close()
-	return json.NewDecoder(f).Decode(&d.userTokens)
+	return json.NewDecoder(f).Decode(state)
 }
 
-func (d *Daemon) SaveToDisk() error {
-	f, err := os.OpenFile(d.statefile, os.O_CREATE|os.O_WRONLY, 0o660)
+func (d *Daemon) saveToDisk(state any) error {
+	f, err := os.OpenFile(d.stateFilepath, os.O_CREATE|os.O_WRONLY, 0o660)
 	if err != nil {
 		return err
 	}
 	defer f.Close()
-	return json.NewEncoder(f).Encode(d.userTokens)
+	return json.NewEncoder(f).Encode(state)
 }