k8s.io/apiserver@v0.29.3/pkg/storage/etcd3/latency_tracker.go (about)

     1  /*
     2  Copyright 2022 The Kubernetes Authors.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8      http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package etcd3
    18  
    19  import (
    20  	"context"
    21  	"time"
    22  
    23  	clientv3 "go.etcd.io/etcd/client/v3"
    24  	endpointsrequest "k8s.io/apiserver/pkg/endpoints/request"
    25  )
    26  
    27  // NewETCDLatencyTracker returns an implementation of
    28  // clientv3.KV that times the calls from the specified
    29  // 'delegate' KV instance in order to track latency incurred.
    30  func NewETCDLatencyTracker(delegate clientv3.KV) clientv3.KV {
    31  	return &clientV3KVLatencyTracker{KV: delegate}
    32  }
    33  
    34  // clientV3KVLatencyTracker decorates a clientv3.KV instance and times
    35  // each call so we can track the latency an API request incurs in etcd
    36  // round trips (the time it takes to send data to etcd and get the
    37  // complete response back)
    38  //
    39  // If an API request involves N (N>=1) round trips to etcd, then we will sum
    40  // up the latenciy incurred in each roundtrip.
    41  
    42  // It uses the context associated with the request in flight, so there
    43  // are no states shared among the requests in flight, and so there is no
    44  // concurrency overhead.
    45  // If the goroutine executing the request handler makes concurrent calls
    46  // to the underlying storage layer, that is protected since the latency
    47  // tracking function TrackStorageLatency is thread safe.
    48  //
    49  // NOTE: Compact is an asynchronous process and is not associated with
    50  // any request, so we will not be tracking its latency.
    51  type clientV3KVLatencyTracker struct {
    52  	clientv3.KV
    53  }
    54  
    55  func (c *clientV3KVLatencyTracker) Put(ctx context.Context, key, val string, opts ...clientv3.OpOption) (*clientv3.PutResponse, error) {
    56  	startedAt := time.Now()
    57  	defer func() {
    58  		endpointsrequest.TrackStorageLatency(ctx, time.Since(startedAt))
    59  	}()
    60  
    61  	return c.KV.Put(ctx, key, val, opts...)
    62  }
    63  
    64  func (c *clientV3KVLatencyTracker) Get(ctx context.Context, key string, opts ...clientv3.OpOption) (*clientv3.GetResponse, error) {
    65  	startedAt := time.Now()
    66  	defer func() {
    67  		endpointsrequest.TrackStorageLatency(ctx, time.Since(startedAt))
    68  	}()
    69  
    70  	return c.KV.Get(ctx, key, opts...)
    71  }
    72  
    73  func (c *clientV3KVLatencyTracker) Delete(ctx context.Context, key string, opts ...clientv3.OpOption) (*clientv3.DeleteResponse, error) {
    74  	startedAt := time.Now()
    75  	defer func() {
    76  		endpointsrequest.TrackStorageLatency(ctx, time.Since(startedAt))
    77  	}()
    78  
    79  	return c.KV.Delete(ctx, key, opts...)
    80  }
    81  
    82  func (c *clientV3KVLatencyTracker) Do(ctx context.Context, op clientv3.Op) (clientv3.OpResponse, error) {
    83  	startedAt := time.Now()
    84  	defer func() {
    85  		endpointsrequest.TrackStorageLatency(ctx, time.Since(startedAt))
    86  	}()
    87  
    88  	return c.KV.Do(ctx, op)
    89  }
    90  
    91  func (c *clientV3KVLatencyTracker) Txn(ctx context.Context) clientv3.Txn {
    92  	return &clientV3TxnTracker{ctx: ctx, Txn: c.KV.Txn(ctx)}
    93  }
    94  
    95  type clientV3TxnTracker struct {
    96  	ctx context.Context
    97  	clientv3.Txn
    98  }
    99  
   100  func (t *clientV3TxnTracker) Commit() (*clientv3.TxnResponse, error) {
   101  	startedAt := time.Now()
   102  	defer func() {
   103  		endpointsrequest.TrackStorageLatency(t.ctx, time.Since(startedAt))
   104  	}()
   105  
   106  	return t.Txn.Commit()
   107  }