github.com/pingcap/tiflow@v0.0.0-20240520035814-5bf52d54e205/engine/pkg/rpcutil/checker.go (about)

     1  // Copyright 2022 PingCAP, Inc.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // See the License for the specific language governing permissions and
    12  // limitations under the License.
    13  
    14  package rpcutil
    15  
    16  // ForwardChecker is used for checking whether a request should be forwarded or not.
    17  type ForwardChecker[T any] interface {
    18  	// LeaderOnly returns whether the request is only allowed to handle by the leader.
    19  	LeaderOnly(method string) bool
    20  	// IsLeader returns whether the current node is the leader.
    21  	IsLeader() bool
    22  	// LeaderClient returns the leader client. If there is no leader, it should return
    23  	// nil and errors.ErrMasterNoLeader.
    24  	LeaderClient() (T, error)
    25  }
    26  
    27  // FeatureChecker defines an interface that checks whether a feature is available
    28  // or under degradation.
    29  type FeatureChecker interface {
    30  	Available(method string) bool
    31  }