Backend: Refactor gorm.DB connection provider in entity package

Signed-off-by: Michael Mayer <michael@photoprism.app>

internal/entity/db.go

@@ -0,0 +1,14 @@
+package entity
+
+import "github.com/jinzhu/gorm"
+
+// Db returns the default *gorm.DB connection.
+func Db() *gorm.DB {
+	return dbConn.Db()
+}
+
+// UnscopedDb returns an unscoped *gorm.DB connection
+// that returns all records including deleted records.
+func UnscopedDb() *gorm.DB {
+	return Db().Unscoped()
+}

internal/entity/db_conn.go

@@ -10,7 +10,7 @@ import (
 	_ "github.com/jinzhu/gorm/dialects/sqlite"
 )
 
-// SQL Databases.
+// Supported test databases.
 const (
 	MySQL           = "mysql"
 	SQLite3         = "sqlite3"
@@ -18,43 +18,16 @@ const (
 	SQLiteMemoryDSN = ":memory:"
 )
 
-var dbProvider DbProvider
+// dbConn is the global gorm.DB connection provider.
+var dbConn Gorm
 
-type DbProvider interface {
+// Gorm is a gorm.DB connection provider interface.
+type Gorm interface {
 	Db() *gorm.DB
 }
 
-// IsDialect returns true if the given sql dialect is used.
+// DbConn is a gorm.DB connection provider.
-func IsDialect(name string) bool {
+type DbConn struct {
-	return name == Db().Dialect().GetName()
-}
-
-// DbDialect returns the sql dialect name.
-func DbDialect() string {
-	return Db().Dialect().GetName()
-}
-
-// SetDbProvider sets the Gorm database connection provider.
-func SetDbProvider(provider DbProvider) {
-	dbProvider = provider
-}
-
-// HasDbProvider returns true if a db provider exists.
-func HasDbProvider() bool {
-	return dbProvider != nil
-}
-
-// Db returns the database connection.
-func Db() *gorm.DB {
-	return dbProvider.Db()
-}
-
-// UnscopedDb returns an unscoped database connection.
-func UnscopedDb() *gorm.DB {
-	return Db().Unscoped()
-}
-
-type Gorm struct {
 	Driver string
 	Dsn    string
 
@@ -63,8 +36,8 @@ type Gorm struct {
 }
 
 // Db returns the gorm db connection.
-func (g *Gorm) Db() *gorm.DB {
+func (g *DbConn) Db() *gorm.DB {
-	g.once.Do(g.Connect)
+	g.once.Do(g.Open)
 
 	if g.db == nil {
 		log.Fatal("migrate: database not connected")
@@ -73,8 +46,8 @@ func (g *Gorm) Db() *gorm.DB {
 	return g.db
 }
 
-// Connect creates a new gorm db connection.
+// Open creates a new gorm db connection.
-func (g *Gorm) Connect() {
+func (g *DbConn) Open() {
 	db, err := gorm.Open(g.Driver, g.Dsn)
 
 	if err != nil || db == nil {
@@ -104,7 +77,7 @@ func (g *Gorm) Connect() {
 }
 
 // Close closes the gorm db connection.
-func (g *Gorm) Close() {
+func (g *DbConn) Close() {
 	if g.db != nil {
 		if err := g.db.Close(); err != nil {
 			log.Fatal(err)
@@ -113,3 +86,23 @@ func (g *Gorm) Close() {
 		g.db = nil
 	}
 }
+
+// IsDialect returns true if the given sql dialect is used.
+func IsDialect(name string) bool {
+	return name == Db().Dialect().GetName()
+}
+
+// DbDialect returns the sql dialect name.
+func DbDialect() string {
+	return Db().Dialect().GetName()
+}
+
+// SetDbProvider sets the Gorm database connection provider.
+func SetDbProvider(conn Gorm) {
+	dbConn = conn
+}
+
+// HasDbProvider returns true if a db provider exists.
+func HasDbProvider() bool {
+	return dbConn != nil
+}

internal/entity/entity_init.go

@@ -43,7 +43,7 @@ func InitDb(dropDeprecated, runFailed bool, ids []string) {
 }
 
 // InitTestDb connects to and completely initializes the test database incl fixtures.
-func InitTestDb(driver, dsn string) *Gorm {
+func InitTestDb(driver, dsn string) *DbConn {
 	if HasDbProvider() {
 		return nil
 	}
@@ -68,13 +68,13 @@ func InitTestDb(driver, dsn string) *Gorm {
 
 	log.Infof("initializing %s test db in %s", driver, dsn)
 
-	// Create ORM instance.
+	// Create gorm.DB connection provider.
-	db := &Gorm{
+	db := &DbConn{
 		Driver: driver,
 		Dsn:    dsn,
 	}
 
-	// Insert test fixtures.
+	// Insert test fixtures into the database.
 	SetDbProvider(db)
 	ResetTestFixtures()
 	File{}.RegenerateIndex()