go.etcd.io/etcd@v3.3.27+incompatible/functional/runner/lock_racer_command.go (about)

     1  // Copyright 2016 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 runner
    16  
    17  import (
    18  	"context"
    19  	"errors"
    20  	"fmt"
    21  	"sync"
    22  
    23  	"github.com/coreos/etcd/clientv3/concurrency"
    24  
    25  	"github.com/spf13/cobra"
    26  )
    27  
    28  // NewLockRacerCommand returns the cobra command for "lock-racer runner".
    29  func NewLockRacerCommand() *cobra.Command {
    30  	cmd := &cobra.Command{
    31  		Use:   "lock-racer [name of lock (defaults to 'racers')]",
    32  		Short: "Performs lock race operation",
    33  		Run:   runRacerFunc,
    34  	}
    35  	cmd.Flags().IntVar(&totalClientConnections, "total-client-connections", 10, "total number of client connections")
    36  	return cmd
    37  }
    38  
    39  func runRacerFunc(cmd *cobra.Command, args []string) {
    40  	racers := "racers"
    41  	if len(args) == 1 {
    42  		racers = args[0]
    43  	}
    44  
    45  	if len(args) > 1 {
    46  		ExitWithError(ExitBadArgs, errors.New("lock-racer takes at most one argument"))
    47  	}
    48  
    49  	rcs := make([]roundClient, totalClientConnections)
    50  	ctx := context.Background()
    51  	// mu ensures validate and release funcs are atomic.
    52  	var mu sync.Mutex
    53  	cnt := 0
    54  
    55  	eps := endpointsFromFlag(cmd)
    56  
    57  	for i := range rcs {
    58  		var (
    59  			s   *concurrency.Session
    60  			err error
    61  		)
    62  
    63  		rcs[i].c = newClient(eps, dialTimeout)
    64  
    65  		for {
    66  			s, err = concurrency.NewSession(rcs[i].c)
    67  			if err == nil {
    68  				break
    69  			}
    70  		}
    71  		m := concurrency.NewMutex(s, racers)
    72  		rcs[i].acquire = func() error { return m.Lock(ctx) }
    73  		rcs[i].validate = func() error {
    74  			mu.Lock()
    75  			defer mu.Unlock()
    76  			if cnt++; cnt != 1 {
    77  				return fmt.Errorf("bad lock; count: %d", cnt)
    78  			}
    79  			return nil
    80  		}
    81  		rcs[i].release = func() error {
    82  			mu.Lock()
    83  			defer mu.Unlock()
    84  			if err := m.Unlock(ctx); err != nil {
    85  				return err
    86  			}
    87  			cnt = 0
    88  			return nil
    89  		}
    90  	}
    91  	// each client creates 1 key from NewMutex() and delete it from Unlock()
    92  	// a round involves in 2*len(rcs) requests.
    93  	doRounds(rcs, rounds, 2*len(rcs))
    94  }