Merge b38f14bfbd21d77faea7ac9b052faed8898d93ee into 0e22837c043e3f3405020fbb11ed4115accb5aaf

README.md

@@ -106,6 +106,10 @@ db, err := gorm.Open("postgres", "user=gorm dbname=gorm sslmode=disable")
 // db, err := gorm.Open("mysql", "user:password@/dbname?charset=utf8&parseTime=True")
 // db, err := gorm.Open("sqlite3", "/tmp/gorm.db")
 
+// You can also use an existing database connection handle
+// dbSql, _ := sql.Open("postgres", "user=gorm dbname=gorm sslmode=disable")
+// db := gorm.Open("postgres", dbSql)
+
 // Get database connection handle [*sql.DB](http://golang.org/pkg/database/sql/#DB)
 db.DB()
 

main.go

@@ -35,28 +35,41 @@ type DB struct {
 	values        map[string]interface{}
 }
 
-func Open(dialect string, drivesources ...string) (DB, error) {
+func Open(dialect string, args ...interface{}) (DB, error) {
 	var db DB
 	var err error
-	var driver = dialect
 	var source string
+	var dbSql sqlCommon
 
-	if len(drivesources) == 0 {
+	if len(args) == 0 {
 		err = errors.New("invalid database source")
+	}
+
+	switch value := args[0].(type) {
+	case string:
+		var driver = dialect
+		if len(args) == 1 {
+			source = value
+		} else if len(args) >= 2 {
+			driver = value
+			source = args[1].(string)
+		}
+		dbSql, err = sql.Open(driver, source)
+	case sqlCommon:
+		if reflect.TypeOf(value).Kind() == reflect.Ptr {
+			source = reflect.ValueOf(value).Elem().FieldByName("dsn").String()
 		} else {
-		if len(drivesources) == 1 {
-			source = drivesources[0]
-		} else if len(drivesources) >= 2 {
-			driver = drivesources[0]
-			source = drivesources[1]
+			source = reflect.ValueOf(value).FieldByName("dsn").String()
+		}
+		dbSql = value
 	}
 
 	db = DB{dialect: NewDialect(dialect), tagIdentifier: "sql",
 		logger: defaultLogger, callback: DefaultCallback, source: source,
 		values: map[string]interface{}{}}
-		db.db, err = sql.Open(driver, source)
+	db.db = dbSql
 	db.parent = &db
-	}
+
 	return db, err
 }
 

main_test.go

@@ -554,6 +554,22 @@ func TestCompatibilityMode(t *testing.T) {
 	}
 }
 
+func TestOpenExistingDB(t *testing.T) {
+	DB.Save(&User{Name: "jnfeinstein"})
+	dialect := os.Getenv("GORM_DIALECT")
+
+	db, err := gorm.Open(dialect, DB.DB())
+	if err != nil {
+		t.Errorf("Should have wrapped the existing DB connection")
+	}
+
+	var user User
+	if db.Where("name = ?", "jnfeinstein").First(&user).Error == gorm.RecordNotFound {
+		t.Errorf("Should have found existing record")
+	}
+
+}
+
 func BenchmarkGorm(b *testing.B) {
 	b.N = 2000
 	for x := 0; x < b.N; x++ {