refactor pooler faces

Author: maxim-konovalov

pool/pooler.go

@@ -1,15 +1,21 @@
 package pool
 
 import (
+	"context"
 	"time"
 
 	"github.com/tarantool/go-tarantool/v2"
 )
 
 // Pooler is the interface that must be implemented by a connection pool.
 type Pooler interface {
+	PoolerTopology
+
 	ConnectedNow(mode Mode) (bool, error)
 	Close() []error
+	// CloseGraceful closes connections in the ConnectionPool gracefully. It waits
+	// for all requests to complete.
+	CloseGraceful() []error
 	ConfiguredTimeout(mode Mode) (time.Duration, error)
 	NewPrepared(expr string, mode Mode) (*tarantool.Prepared, error)
 	NewStream(mode Mode) (*tarantool.Stream, error)
@@ -155,3 +161,9 @@ type Pooler interface {
 	ExecuteAsync(expr string, args interface{},
 		mode Mode) *tarantool.Future
 }
+
+// PoolerTopology is the interface that must be implemented by a connection pool and describe topology methods.
+type PoolerTopology interface {
+	Add(ctx context.Context, instance Instance) error
+	Remove(name string) error
+}