Extend dump backend to be able to write to a file

config.example.toml

@@ -141,4 +141,10 @@ client-secret = ""
 [service.dump]
 # This backend allows writing listens and loves as console output. Useful for
 # debugging the export from other services.
-backend = "dump"
+backend   = "dump"
+# Path to a file where the listens and loves are written to. If not set,
+# the output is written to stdout.
+file-path = ""
+# If true (default), new listens will be appended to the existing file. Set to
+# false to overwrite the file on every run.
+append    = true

internal/backends/dump/dump.go

@@ -17,25 +17,80 @@ Scotty. If not, see <https://www.gnu.org/licenses/>.
 package dump
 
 import (
+	"bytes"
 	"context"
 	"fmt"
+	"io"
+	"os"
+	"strings"
 
 	"go.uploadedlobster.com/scotty/internal/config"
+	"go.uploadedlobster.com/scotty/internal/i18n"
 	"go.uploadedlobster.com/scotty/internal/models"
 )
 
-type DumpBackend struct{}
+type DumpBackend struct {
+	buffer io.ReadWriter
+	print  bool // Whether to print the output to stdout
+}
 
 func (b *DumpBackend) Name() string { return "dump" }
 
-func (b *DumpBackend) Options() []models.BackendOption { return nil }
+func (b *DumpBackend) Options() []models.BackendOption {
+	return []models.BackendOption{{
+		Name:  "file-path",
+		Label: i18n.Tr("File path"),
+		Type:  models.String,
+	}, {
+		Name:    "append",
+		Label:   i18n.Tr("Append to file"),
+		Type:    models.Bool,
+		Default: "true",
+	}}
+}
 
 func (b *DumpBackend) InitConfig(config *config.ServiceConfig) error {
+	filePath := config.GetString("file-path")
+	append := config.GetBool("append", true)
+	if strings.TrimSpace(filePath) != "" {
+		mode := os.O_WRONLY | os.O_CREATE
+		if !append {
+			mode |= os.O_TRUNC // Truncate the file if not appending
+		}
+		f, err := os.OpenFile(filePath, mode, 0644)
+		if err != nil {
+			return err
+		}
+		b.buffer = f
+		b.print = false // If a file path is specified, we don't print to stdout
+	} else {
+		// If no file path is specified, use a bytes.Buffer for in-memory dumping
+		b.buffer = new(bytes.Buffer)
+		b.print = true // Print to stdout
+	}
 	return nil
 }
 
-func (b *DumpBackend) StartImport() error  { return nil }
-func (b *DumpBackend) FinishImport() error { return nil }
+func (b *DumpBackend) StartImport() error { return nil }
+
+func (b *DumpBackend) FinishImport() error {
+	if b.print {
+		out := new(strings.Builder)
+		_, err := io.Copy(out, b.buffer)
+		if err != nil {
+			return err
+		}
+		fmt.Println(out.String())
+	}
+
+	// Close the io writer if it is closable
+	if closer, ok := b.buffer.(io.Closer); ok {
+		if err := closer.Close(); err != nil {
+			return fmt.Errorf("failed to close output file: %w", err)
+		}
+	}
+	return nil
+}
 
 func (b *DumpBackend) ImportListens(ctx context.Context, export models.ListensResult, importResult models.ImportResult, progress chan models.TransferProgress) (models.ImportResult, error) {
 	for _, listen := range export.Items {
@@ -45,9 +100,11 @@ func (b *DumpBackend) ImportListens(ctx context.Context, export models.ListensRe
 
 		importResult.UpdateTimestamp(listen.ListenedAt)
 		importResult.ImportCount += 1
-		msg := fmt.Sprintf("🎶 %v: \"%v\" by %v (%v)",
+		_, err := fmt.Fprintf(b.buffer, "🎶 %v: \"%v\" by %v (%v)\n",
 			listen.ListenedAt, listen.TrackName, listen.ArtistName(), listen.RecordingMBID)
-		importResult.Log(models.Info, msg)
+		if err != nil {
+			return importResult, err
+		}
 		progress <- models.TransferProgress{}.FromImportResult(importResult, false)
 	}
 
@@ -62,9 +119,11 @@ func (b *DumpBackend) ImportLoves(ctx context.Context, export models.LovesResult
 
 		importResult.UpdateTimestamp(love.Created)
 		importResult.ImportCount += 1
-		msg := fmt.Sprintf("❤️ %v: \"%v\" by %v (%v)",
+		_, err := fmt.Fprintf(b.buffer, "❤️ %v: \"%v\" by %v (%v)\n",
 			love.Created, love.TrackName, love.ArtistName(), love.RecordingMBID)
-		importResult.Log(models.Info, msg)
+		if err != nil {
+			return importResult, err
+		}
 		progress <- models.TransferProgress{}.FromImportResult(importResult, false)
 	}