fix: use shared cache for sqlite in-memory mode (#129)

database/database.go

@@ -109,7 +109,7 @@ type InMemoryDatabase struct {
 func NewInMemory(logger *slog.Logger) (*InMemoryDatabase, error) {
 	// Open sqlite DB
 	metadataDb, err := gorm.Open(
-		sqlite.Open(":memory:"),
+		sqlite.Open("file::memory:?cache=shared"),
 		&gorm.Config{
 			Logger: gormlogger.Discard,
 		},

database/database_test.go

@@ -0,0 +1,62 @@
+// Copyright 2024 Blink Labs Software
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package database_test
+
+import (
+	"testing"
+	"time"
+
+	"github.com/blinklabs-io/node/database"
+	"gorm.io/gorm"
+)
+
+type TestTable struct {
+	gorm.Model
+}
+
+// TestInMemorySqliteMultipleTransaction tests that our sqlite connection allows multiple
+// concurrent transactions when using in-memory mode. This requires special URI flags, and
+// this is mostly making sure that we don't lose them
+func TestInMemorySqliteMultipleTransaction(t *testing.T) {
+	var db database.Database
+	doQuery := func(sleep time.Duration) error {
+		txn := db.Metadata().Begin()
+		if result := txn.First(&TestTable{}); result.Error != nil {
+			return result.Error
+		}
+		time.Sleep(sleep)
+		if result := txn.Commit(); result.Error != nil {
+			return result.Error
+		}
+		return nil
+	}
+	db, err := database.NewInMemory(nil)
+	if err != nil {
+		t.Fatalf("unexpected error: %s", err)
+	}
+	if err := db.Metadata().AutoMigrate(&TestTable{}); err != nil {
+		t.Fatalf("unexpected error: %s", err)
+	}
+	if result := db.Metadata().Create(&TestTable{}); result.Error != nil {
+		t.Fatalf("unexpected error: %s", result.Error)
+	}
+	// The linter calls us on the lack of error checking, but it's a goroutine...
+	//nolint:errcheck
+	go doQuery(5 * time.Second)
+	time.Sleep(1 * time.Second)
+	if err := doQuery(0); err != nil {
+		t.Fatalf("unexpected error: %s", err)
+	}
+}