Move setup of executable workers to function

- Fix startup crash if no site_info row was found

api/graphql/models/site_info.go

@@ -4,7 +4,7 @@ import (
 	"database/sql"
 )
 
-func InitializeSiteInfoRow(db *sql.DB) error {
+func initializeSiteInfoRow(db *sql.DB) error {
 	_, err := db.Exec("INSERT INTO site_info (initial_setup) VALUES (true)")
 	if err != nil {
 		return err
@@ -25,7 +25,7 @@ func GetSiteInfo(db *sql.DB) (*SiteInfo, error) {
 
 	if !rows.Next() {
 		// Entry does not exist
-		if err := InitializeSiteInfoRow(db); err != nil {
+		if err := initializeSiteInfoRow(db); err != nil {
 			return nil, err
 		}
 		initialSetup = true

api/scanner/executable_worker.go

@@ -10,8 +10,13 @@ import (
 	"github.com/pkg/errors"
 )
 
-var DarktableCli = newDarktableWorker()
-var FfmpegCli = newFfmpegWorker()
+func InitializeExecutableWorkers() {
+	DarktableCli = newDarktableWorker()
+	FfmpegCli = newFfmpegWorker()
+}
+
+var DarktableCli *DarktableWorker = nil
+var FfmpegCli *FfmpegWorker = nil
 
 type ExecutableWorker interface {
 	Path() string
@@ -25,38 +30,42 @@ type FfmpegWorker struct {
 	path string
 }
 
-func newDarktableWorker() DarktableWorker {
+func newDarktableWorker() *DarktableWorker {
 	path, err := exec.LookPath("darktable-cli")
 	if err != nil {
 		log.Println("Executable worker not found: darktable")
 	} else {
 		log.Println("Found executable worker: darktable")
+
+		return &DarktableWorker{
+			path: path,
+		}
 	}
 
-	return DarktableWorker{
-		path: path,
-	}
+	return nil
 }
 
-func newFfmpegWorker() FfmpegWorker {
+func newFfmpegWorker() *FfmpegWorker {
 	path, err := exec.LookPath("ffmpeg")
 	if err != nil {
 		log.Println("Executable worker not found: ffmpeg")
 	} else {
 		log.Println("Found executable worker: ffmpeg")
+
+		return &FfmpegWorker{
+			path: path,
+		}
 	}
 
-	return FfmpegWorker{
-		path: path,
-	}
+	return nil
 }
 
 func (worker *DarktableWorker) IsInstalled() bool {
-	return worker.path != ""
+	return worker != nil
 }
 
 func (worker *FfmpegWorker) IsInstalled() bool {
-	return worker.path != ""
+	return worker != nil
 }
 
 func (worker *DarktableWorker) EncodeJpeg(inputPath string, outputPath string, jpegQuality int) error {

api/scanner/queue.go

@@ -40,9 +40,12 @@ var global_scanner_queue ScannerQueue
 func InitializeScannerQueue(db *sql.DB) error {
 
 	var concurrentWorkers int
-	row := db.QueryRow("SELECT concurrent_workers FROM site_info")
-	if err := row.Scan(&concurrentWorkers); err != nil {
-		return errors.Wrap(err, "get current workers from database")
+	{
+		site_info, err := models.GetSiteInfo(db)
+		if err != nil {
+			return errors.Wrap(err, "get current workers from database")
+		}
+		concurrentWorkers = site_info.ConcurrentWorkers
 	}
 
 	global_scanner_queue = ScannerQueue{

api/server.go

@@ -49,6 +49,8 @@ func main() {
 		log.Panicf("Could not initialize periodic scanner: %s", err)
 	}
 
+	scanner.InitializeExecutableWorkers()
+
 	rootRouter := mux.NewRouter()
 
 	rootRouter.Use(auth.Middleware(db))