refactor:

pkg/external/postgres/postgres.go

@@ -0,0 +1,30 @@
+package postgres
+
+import (
+	"github.com/jmoiron/sqlx"
+	"time"
+)
+
+const (
+	maxOpenConns    = 60
+	connMaxLifetime = 120
+	maxIdleConns    = 30
+	connMaxIdleTime = 20
+)
+
+func NewPostgresDB(dsn string) (*sqlx.DB, error) {
+	db, err := sqlx.Open("pgx", dsn)
+	if err != nil {
+		return nil, err
+	}
+
+	db.SetMaxOpenConns(maxOpenConns)
+	db.SetConnMaxLifetime(connMaxLifetime * time.Second)
+	db.SetMaxIdleConns(maxIdleConns)
+	db.SetConnMaxIdleTime(connMaxIdleTime * time.Second)
+	if err = db.Ping(); err != nil {
+		return nil, err
+	}
+
+	return db, nil
+}