pool: add comments for balancer factory

Author: Maksim Konovalov

pool/balancer.go

@@ -2,15 +2,34 @@ package pool
 
 import "github.com/tarantool/go-tarantool/v2"
 
+// BalancerFactory is an interface for creating a balancing pool of connections.
 type BalancerFactory interface {
+	// Create initializes a new BalancingPool with the specified size.
+	// The size parameter indicates the intended number of connections to manage within the pool.
 	Create(size int) BalancingPool
 }
 
+// BalancingPool represents a connection pool with load balancing.
 type BalancingPool interface {
+	// GetConnection returns the connection associated with the specified identifier.
+	// If no connection with the given identifier is found, it returns nil.
 	GetConnection(string) *tarantool.Connection
+
+	// DeleteConnection removes the connection with the specified identifier from the pool
+	// and returns the removed connection. If no connection is found, it returns nil.
 	DeleteConnection(string) *tarantool.Connection
+
+	// AddConnection adds a new connection to the pool under the specified identifier.
+	// If a connection with that identifier already exists, the behavior may depend
+	// on the implementation (e.g., it may overwrite the existing connection).
 	AddConnection(id string, conn *tarantool.Connection)
+
+	// GetNextConnection returns the next available connection from the pool.
+	// The implementation may use load balancing algorithms to select the connection.
 	GetNextConnection() *tarantool.Connection
+
+	// GetConnections returns the current map of all connections in the pool,
+	// where the key is the connection identifier and the value is a pointer to the connection object.
 	GetConnections() map[string]*tarantool.Connection
 }