revision.go

Documentation: go.etcd.io/etcd/server/v3/etcdserver/api/v3compactor

     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 v3compactor
    16  
    17  import (
    18  	"context"
    19  	"sync"
    20  	"time"
    21  
    22  	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
    23  	"go.etcd.io/etcd/server/v3/mvcc"
    24  
    25  	"github.com/jonboulle/clockwork"
    26  	"go.uber.org/zap"
    27  )
    28  
    29  // Revision compacts the log by purging revisions older than
    30  // the configured reivison number. Compaction happens every 5 minutes.
    31  type Revision struct {
    32  	lg *zap.Logger
    33  
    34  	clock     clockwork.Clock
    35  	retention int64
    36  
    37  	rg RevGetter
    38  	c  Compactable
    39  
    40  	ctx    context.Context
    41  	cancel context.CancelFunc
    42  
    43  	mu     sync.Mutex
    44  	paused bool
    45  }
    46  
    47  // newRevision creates a new instance of Revisonal compactor that purges
    48  // the log older than retention revisions from the current revision.
    49  func newRevision(lg *zap.Logger, clock clockwork.Clock, retention int64, rg RevGetter, c Compactable) *Revision {
    50  	rc := &Revision{
    51  		lg:        lg,
    52  		clock:     clock,
    53  		retention: retention,
    54  		rg:        rg,
    55  		c:         c,
    56  	}
    57  	rc.ctx, rc.cancel = context.WithCancel(context.Background())
    58  	return rc
    59  }
    60  
    61  const revInterval = 5 * time.Minute
    62  
    63  // Run runs revision-based compactor.
    64  func (rc *Revision) Run() {
    65  	prev := int64(0)
    66  	go func() {
    67  		for {
    68  			select {
    69  			case <-rc.ctx.Done():
    70  				return
    71  			case <-rc.clock.After(revInterval):
    72  				rc.mu.Lock()
    73  				p := rc.paused
    74  				rc.mu.Unlock()
    75  				if p {
    76  					continue
    77  				}
    78  			}
    79  
    80  			rev := rc.rg.Rev() - rc.retention
    81  			if rev <= 0 || rev == prev {
    82  				continue
    83  			}
    84  
    85  			now := time.Now()
    86  			rc.lg.Info(
    87  				"starting auto revision compaction",
    88  				zap.Int64("revision", rev),
    89  				zap.Int64("revision-compaction-retention", rc.retention),
    90  			)
    91  			_, err := rc.c.Compact(rc.ctx, &pb.CompactionRequest{Revision: rev})
    92  			if err == nil || err == mvcc.ErrCompacted {
    93  				prev = rev
    94  				rc.lg.Info(
    95  					"completed auto revision compaction",
    96  					zap.Int64("revision", rev),
    97  					zap.Int64("revision-compaction-retention", rc.retention),
    98  					zap.Duration("took", time.Since(now)),
    99  				)
   100  			} else {
   101  				rc.lg.Warn(
   102  					"failed auto revision compaction",
   103  					zap.Int64("revision", rev),
   104  					zap.Int64("revision-compaction-retention", rc.retention),
   105  					zap.Duration("retry-interval", revInterval),
   106  					zap.Error(err),
   107  				)
   108  			}
   109  		}
   110  	}()
   111  }
   112  
   113  // Stop stops revision-based compactor.
   114  func (rc *Revision) Stop() {
   115  	rc.cancel()
   116  }
   117  
   118  // Pause pauses revision-based compactor.
   119  func (rc *Revision) Pause() {
   120  	rc.mu.Lock()
   121  	rc.paused = true
   122  	rc.mu.Unlock()
   123  }
   124  
   125  // Resume resumes revision-based compactor.
   126  func (rc *Revision) Resume() {
   127  	rc.mu.Lock()
   128  	rc.paused = false
   129  	rc.mu.Unlock()
   130  }
   131
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