Make database optional (#72)

messenger.go

@@ -230,22 +230,25 @@ func NewMessenger(
 		}
 	}
 
+	var err error
+
 	// Configure the database.
 	database := c.db
-	if c.db == nil && c.dbConfig == (dbConfig{}) {
-		return nil, errors.New("database instance or database path needs to be provided")
-	}
-	if c.db == nil {
+	if database == nil && c.dbConfig != (dbConfig{}) {
 		logger.Info("opening a database", zap.String("dbPath", c.dbConfig.dbPath))
-		var err error
 		database, err = sqlite.Open(c.dbConfig.dbPath, c.dbConfig.dbKey)
 		if err != nil {
 			return nil, errors.Wrap(err, "failed to initialize database from the db config")
 		}
+	} else {
+		logger.Info("using in-memory database")
+		database, err = sqlite.Open(":memory:", "")
+		if err != nil {
+			return nil, errors.Wrap(err, "failed to initialize in-memory database")
+		}
 	}
-
 	// Apply migrations for all components.
-	err := sqlite.Migrate(database)
+	err = sqlite.Migrate(database)
 	if err != nil {
 		return nil, errors.Wrap(err, "failed to apply migrations")
 	}

messenger_test.go

@@ -100,6 +100,28 @@ func (s *MessengerSuite) TearDownTest() {
 	_ = s.logger.Sync()
 }
 
+func (s *MessengerSuite) TestInMemoryDatabase() {
+	key, err := crypto.GenerateKey()
+	s.Require().NoError(err)
+	m, err := NewMessenger(
+		key,
+		s.shh,
+		"installation-1",
+	)
+	s.Require().NoError(err)
+	// Verify the in-memory database works.
+	err = m.persistence.SaveChat(Chat{
+		ID:       "abc",
+		Name:     "abc",
+		Active:   true,
+		ChatType: ChatTypePublic,
+	})
+	s.Require().NoError(err)
+	result, err := m.persistence.Chats()
+	s.Require().NoError(err)
+	s.Require().Len(result, 1)
+}
+
 func (s *MessengerSuite) TestInit() {
 	testCases := []struct {
 		Name         string