start implementing db interface

internal/db/service.go

@@ -0,0 +1,67 @@
+/*
+   GoToSocial
+   Copyright (C) 2021 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package db
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/go-fed/activity/pub"
+)
+
+const dbTypePostgres string = "POSTGRES"
+
+// Service provides methods for interacting with an underlying database (for now, just postgres).
+// The function mapping lines up with the Database interface described in go-fed.
+// See here: https://github.com/go-fed/activity/blob/master/pub/database.go
+type Service interface {
+	/*
+		GO-FED DATABASE FUNCTIONS
+	*/
+	pub.Database
+
+	/*
+		ANY ADDITIONAL DESIRED FUNCTIONS
+	*/
+
+	// Ready indicates whether the database is ready to handle queries and whatnot.
+	Ready() bool
+}
+
+// Config provides configuration options for the database connection
+type Config struct {
+	Type            string
+	Address         string
+	Port            int
+	User            string
+	Password        string
+	Database        string
+	ApplicationName string
+}
+
+// NewService returns a new database service that satisfies the Service interface and, by extension,
+// the go-fed database interface described here: https://github.com/go-fed/activity/blob/master/pub/database.go
+func NewService(config *Config) (Service, error) {
+	switch strings.ToUpper(config.Type) {
+	case dbTypePostgres:
+		return newPostgresService(config)
+	default:
+		return nil, fmt.Errorf("database type %s not supported", config.Type)
+	}
+}