Make the storage backend modular

cmd/yans/main.go

@@ -30,11 +30,11 @@ func main() {
 	log.Printf("Starting %s...", common.ServerName)
 	ns, err := server.NewNNTPServer(cfg)
 	if err != nil {
-		log.Fatal(err)
+		log.Fatalf("Error occurred while starting the server: %s", err)
 	}
 
 	if err := ns.Start(); err != nil {
-		log.Fatal(err)
+		log.Fatalf("Error occurred while starting the server: %s", err)
 	}
 	log.Printf("%s has been successfully started!", common.ServerName)
 	log.Printf("Version: %s", common.ServerVersion)

config.sample.toml

@@ -0,0 +1,6 @@
+address = "localhost"
+port = 1119
+backend_type = "sqlite"
+
+[sqlite]
+path = "yans.db"

internal/backend/sqlite/sqlite.go

@@ -0,0 +1,47 @@
+package sqlite
+
+import (
+	"embed"
+	"github.com/ChronosX88/yans/internal/config"
+	"github.com/ChronosX88/yans/internal/models"
+	"github.com/jmoiron/sqlx"
+	_ "github.com/mattn/go-sqlite3"
+	"github.com/pressly/goose/v3"
+)
+
+//go:embed migrations/*.sql
+var migrations embed.FS
+
+type SQLiteBackend struct {
+	db *sqlx.DB
+}
+
+func NewSQLiteBackend(cfg config.SQLiteBackendConfig) (*SQLiteBackend, error) {
+	db, err := sqlx.Open("sqlite3", cfg.Path)
+	if err != nil {
+		return nil, err
+	}
+	goose.SetBaseFS(migrations)
+
+	if err := goose.SetDialect("sqlite3"); err != nil {
+		return nil, err
+	}
+
+	if err := goose.Up(db.DB, "migrations"); err != nil {
+		return nil, err
+	}
+
+	return &SQLiteBackend{
+		db: db,
+	}, nil
+}
+
+func (sb *SQLiteBackend) ListGroups() ([]models.Group, error) {
+	var groups []models.Group
+	return groups, sb.db.Select(&groups, "SELECT * FROM groups")
+}
+
+func (sb *SQLiteBackend) GetArticlesCount(g models.Group) (int, error) {
+	var count int
+	return count, sb.db.Select(&count, "SELECT COUNT(*) FROM articles_to_groups WHERE group_id = ?", g.ID)
+}

internal/backend/storage_backend.go

@@ -0,0 +1,12 @@
+package backend
+
+import "github.com/ChronosX88/yans/internal/models"
+
+const (
+	SupportedBackendList = "sqlite"
+)
+
+type StorageBackend interface {
+	ListGroups() ([]models.Group, error)
+	GetArticlesCount(g models.Group) (int, error)
+}

internal/config/config.go

@@ -5,9 +5,19 @@ import (
 	"os"
 )
 
+const (
+	SQLiteBackendType = "sqlite"
+)
+
 type Config struct {
-	Port         int
-	DatabasePath string
+	Address     string              `toml:"address"`
+	Port        int                 `toml:"port"`
+	BackendType string              `toml:"backend_type"`
+	SQLite      SQLiteBackendConfig `toml:"sqlite"`
+}
+
+type SQLiteBackendConfig struct {
+	Path string `toml:"path"`
 }
 
 func ParseConfig(path string) (Config, error) {

internal/migrations.go

@@ -1,6 +0,0 @@
-package internal
-
-import "embed"
-
-//go:embed migrations/*.sql
-var Migrations embed.FS

internal/server/handler.go

@@ -2,21 +2,20 @@ package server
 
 import (
 	"fmt"
-	"github.com/ChronosX88/yans/internal/models"
+	"github.com/ChronosX88/yans/internal/backend"
 	"github.com/ChronosX88/yans/internal/protocol"
-	"github.com/jmoiron/sqlx"
 	"strings"
 	"time"
 )
 
 type Handler struct {
 	handlers map[string]func(s *Session, arguments []string) error
-	db       *sqlx.DB
+	backend  backend.StorageBackend
 }
 
-func NewHandler(db *sqlx.DB) *Handler {
+func NewHandler(b backend.StorageBackend) *Handler {
 	h := &Handler{}
-	h.db = db
+	h.backend = b
 	h.handlers = map[string]func(s *Session, arguments []string) error{
 		protocol.CommandCapabilities: h.handleCapabilities,
 		protocol.CommandDate:         h.handleDate,
@@ -54,7 +53,7 @@ func (h *Handler) handleList(s *Session, arguments []string) error {
 		fallthrough
 	case "ACTIVE":
 		{
-			groups, err := h.listGroups()
+			groups, err := h.backend.ListGroups()
 			if err != nil {
 				return err
 			}
@@ -66,7 +65,7 @@ func (h *Handler) handleList(s *Session, arguments []string) error {
 		}
 	case "NEWSGROUPS":
 		{
-			groups, err := h.listGroups()
+			groups, err := h.backend.ListGroups()
 			if err != nil {
 				return err
 			}
@@ -117,14 +116,3 @@ func (h *Handler) Handle(s *Session, message string) error {
 	}
 	return handler(s, splittedMessage[1:])
 }
-
-// TODO Refactor to "storage backend" entity
-func (h *Handler) listGroups() ([]models.Group, error) {
-	var groups []models.Group
-	return groups, h.db.Select(&groups, "SELECT * FROM groups")
-}
-
-func (h *Handler) getArticlesCount(g models.Group) (int, error) {
-	var count int
-	return count, h.db.Select(&count, "SELECT COUNT(*) FROM articles_to_groups WHERE group_id = ?", g.ID)
-}

internal/server/nntp_server.go

@@ -3,14 +3,12 @@ package server
 import (
 	"context"
 	"fmt"
-	"github.com/ChronosX88/yans/internal"
+	"github.com/ChronosX88/yans/internal/backend"
+	"github.com/ChronosX88/yans/internal/backend/sqlite"
 	"github.com/ChronosX88/yans/internal/common"
 	"github.com/ChronosX88/yans/internal/config"
 	"github.com/ChronosX88/yans/internal/protocol"
 	"github.com/google/uuid"
-	"github.com/jmoiron/sqlx"
-	_ "github.com/mattn/go-sqlite3"
-	"github.com/pressly/goose/v3"
 	"log"
 	"net"
 	"sync"
@@ -29,46 +27,60 @@ type NNTPServer struct {
 	cancelFunc context.CancelFunc
 
 	ln  net.Listener
-	port int
+	cfg config.Config
 
-	db *sqlx.DB
+	backend backend.StorageBackend
 
 	sessionPool      map[string]*Session
 	sessionPoolMutex sync.Mutex
 }
 
 func NewNNTPServer(cfg config.Config) (*NNTPServer, error) {
-	db, err := sqlx.Open("sqlite3", cfg.DatabasePath)
+	b, err := initBackend(cfg)
 	if err != nil {
 		return nil, err
 	}
-	goose.SetBaseFS(internal.Migrations)
-
-	if err := goose.SetDialect("sqlite3"); err != nil {
-		return nil, err
-	}
-
-	if err := goose.Up(db.DB, "migrations"); err != nil {
-		return nil, err
-	}
 
 	ctx, cancel := context.WithCancel(context.Background())
 	ns := &NNTPServer{
 		ctx:         ctx,
 		cancelFunc:  cancel,
-		port:        cfg.Port,
-		db:          db,
+		cfg:         cfg,
+		backend:     b,
 		sessionPool: map[string]*Session{},
 	}
 	return ns, nil
 }
 
+func initBackend(cfg config.Config) (backend.StorageBackend, error) {
+	var sb backend.StorageBackend
+
+	switch cfg.BackendType {
+	case config.SQLiteBackendType:
+		{
+			sqliteBackend, err := sqlite.NewSQLiteBackend(cfg.SQLite)
+			if err != nil {
+				return nil, err
+			}
+			sb = sqliteBackend
+		}
+	default:
+		{
+			return nil, fmt.Errorf("invalid backend type, supported backends: %s", backend.SupportedBackendList)
+		}
+	}
+	return sb, nil
+}
+
 func (ns *NNTPServer) Start() error {
-	ln, err := net.Listen("tcp", fmt.Sprintf(":%d", ns.port))
+	address := fmt.Sprintf("%s:%d", ns.cfg.Address, ns.cfg.Port)
+	ln, err := net.Listen("tcp", address)
 	if err != nil {
 		return err
 	}
 
+	log.Printf("Listening on %s...", address)
+
 	go func(ctx context.Context) {
 		for {
 			select {
@@ -84,7 +96,7 @@ func (ns *NNTPServer) Start() error {
 
 					id, _ := uuid.NewUUID()
 					closed := make(chan bool)
-					session, err := NewSession(ctx, conn, Capabilities, id.String(), closed, NewHandler(ns.db))
+					session, err := NewSession(ctx, conn, Capabilities, id.String(), closed, NewHandler(ns.backend))
 					ns.sessionPoolMutex.Lock()
 					ns.sessionPool[id.String()] = session
 					ns.sessionPoolMutex.Unlock()