apply postgresql(with bun orm)

db/main.go

@@ -0,0 +1,35 @@
+package db
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"database/sql"
+
+	"github.com/uptrace/bun"
+	"github.com/uptrace/bun/dialect/pgdialect"
+	"github.com/uptrace/bun/driver/pgdriver"
+)
+
+func GetDB(pgDsn string) (*bun.DB, error) {
+	if pgDsn == "" {
+		return nil, fmt.Errorf("pg_dsn is required")
+	}
+
+	sqlConnection := sql.OpenDB(pgdriver.NewConnector(
+		pgdriver.WithDSN(pgDsn),
+	))
+
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	if err := sqlConnection.PingContext(ctx); err != nil {
+		_ = sqlConnection.Close()
+		return nil, fmt.Errorf("failed to connect to database: %w", err)
+	}
+
+	db := bun.NewDB(sqlConnection, pgdialect.New())
+
+	return db, nil
+}