renamed exaples to playground, edited README

pool.go

@@ -24,40 +24,45 @@ var (
 		},
 	}
 
-	ErrInitTX   = errors.New("failed to init db.tx")
-	ErrCommitTX = errors.New("failed to commit db.tx")
-	ErrNoRows   = errors.New("no data found")
+	ErrConnStringMissing = errors.New("connection string is empty")
+	ErrInitTX            = errors.New("failed to init db.tx")
+	ErrCommitTX          = errors.New("failed to commit db.tx")
+	ErrNoRows            = errors.New("no data found")
 )
 
 type Config struct {
+	ConnString      string
 	MaxConns        int32
 	MinConns        int32
 	MaxConnLifetime time.Duration
 	MaxConnIdleTime time.Duration
 }
 
-func Init(connString string, conf *Config) {
-	cfg, err := pgxpool.ParseConfig(connString)
+// InitPool will create new pgxpool.Pool and will keep it for its working
+func InitPool(conf Config) {
+	if conf.ConnString == "" {
+		panic(ErrConnStringMissing)
+	}
+
+	cfg, err := pgxpool.ParseConfig(conf.ConnString)
 	if err != nil {
 		panic(err)
 	}
 
-	if conf != nil {
-		if conf.MaxConns > 0 {
-			cfg.MaxConns = conf.MaxConns // 100
-		}
+	if conf.MaxConns > 0 {
+		cfg.MaxConns = conf.MaxConns // 100
+	}
 
-		if conf.MinConns > 0 {
-			cfg.MinConns = conf.MaxConns // 5
-		}
+	if conf.MinConns > 0 {
+		cfg.MinConns = conf.MaxConns // 5
+	}
 
-		if conf.MaxConnLifetime > 0 {
-			cfg.MaxConnLifetime = conf.MaxConnLifetime // time.Minute * 10
-		}
+	if conf.MaxConnLifetime > 0 {
+		cfg.MaxConnLifetime = conf.MaxConnLifetime // time.Minute * 10
+	}
 
-		if conf.MaxConnIdleTime > 0 {
-			cfg.MaxConnIdleTime = conf.MaxConnIdleTime // time.Minute * 5
-		}
+	if conf.MaxConnIdleTime > 0 {
+		cfg.MaxConnIdleTime = conf.MaxConnIdleTime // time.Minute * 5
 	}
 
 	p, err := pgxpool.NewWithConfig(context.Background(), cfg)
@@ -72,10 +77,22 @@ func Init(connString string, conf *Config) {
 	poolPGX.Store(p)
 }
 
+// GetPool instance
 func GetPool() *pgxpool.Pool {
 	return poolPGX.Load()
 }
 
+// BeginTx begins a pgx poll transaction
+func BeginTx(ctx context.Context) (pgx.Tx, error) {
+	tx, err := poolPGX.Load().Begin(ctx)
+	if err != nil {
+		slog.Error(err.Error())
+		return nil, errors.New("failed to open db tx")
+	}
+
+	return tx, err
+}
+
 // get string builder from pool
 func getSB() *strings.Builder {
 	return poolStringBuilder.Get().(*strings.Builder)
@@ -86,13 +103,3 @@ func putSB(sb *strings.Builder) {
 	sb.Reset()
 	poolStringBuilder.Put(sb)
 }
-
-func BeginTx(ctx context.Context) (pgx.Tx, error) {
-	tx, err := poolPGX.Load().Begin(ctx)
-	if err != nil {
-		slog.Error(err.Error())
-		return nil, errors.New("failed to open db tx")
-	}
-
-	return tx, err
-}