go.etcd.io/etcd@v3.3.27+incompatible/clientv3/ordering/util.go (about)

     1  // Copyright 2017 The etcd Authors
     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  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package ordering
    16  
    17  import (
    18  	"errors"
    19  	"sync"
    20  	"time"
    21  
    22  	"github.com/coreos/etcd/clientv3"
    23  )
    24  
    25  type OrderViolationFunc func(op clientv3.Op, resp clientv3.OpResponse, prevRev int64) error
    26  
    27  var ErrNoGreaterRev = errors.New("etcdclient: no cluster members have a revision higher than the previously received revision")
    28  
    29  func NewOrderViolationSwitchEndpointClosure(c clientv3.Client) OrderViolationFunc {
    30  	var mu sync.Mutex
    31  	violationCount := 0
    32  	return func(op clientv3.Op, resp clientv3.OpResponse, prevRev int64) error {
    33  		if violationCount > len(c.Endpoints()) {
    34  			return ErrNoGreaterRev
    35  		}
    36  		mu.Lock()
    37  		defer mu.Unlock()
    38  		eps := c.Endpoints()
    39  		// force client to connect to given endpoint by limiting to a single endpoint
    40  		c.SetEndpoints(eps[violationCount%len(eps)])
    41  		// give enough time for operation
    42  		time.Sleep(1 * time.Second)
    43  		// set available endpoints back to all endpoints in to ensure
    44  		// the client has access to all the endpoints.
    45  		c.SetEndpoints(eps...)
    46  		violationCount++
    47  		return nil
    48  	}
    49  }