khenaidoo | 2672188 | 2021-08-11 17:42:52 -0400 | [diff] [blame] | 1 | // Copyright 2015 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 stats |
| 16 | |
| 17 | import ( |
| 18 | "encoding/json" |
| 19 | "math" |
| 20 | "sync" |
| 21 | "time" |
| 22 | ) |
| 23 | |
| 24 | // LeaderStats is used by the leader in an etcd cluster, and encapsulates |
| 25 | // statistics about communication with its followers |
| 26 | type LeaderStats struct { |
| 27 | leaderStats |
| 28 | sync.Mutex |
| 29 | } |
| 30 | |
| 31 | type leaderStats struct { |
| 32 | // Leader is the ID of the leader in the etcd cluster. |
| 33 | // TODO(jonboulle): clarify that these are IDs, not names |
| 34 | Leader string `json:"leader"` |
| 35 | Followers map[string]*FollowerStats `json:"followers"` |
| 36 | } |
| 37 | |
| 38 | // NewLeaderStats generates a new LeaderStats with the given id as leader |
| 39 | func NewLeaderStats(id string) *LeaderStats { |
| 40 | return &LeaderStats{ |
| 41 | leaderStats: leaderStats{ |
| 42 | Leader: id, |
| 43 | Followers: make(map[string]*FollowerStats), |
| 44 | }, |
| 45 | } |
| 46 | } |
| 47 | |
| 48 | func (ls *LeaderStats) JSON() []byte { |
| 49 | ls.Lock() |
| 50 | stats := ls.leaderStats |
| 51 | ls.Unlock() |
| 52 | b, err := json.Marshal(stats) |
| 53 | // TODO(jonboulle): appropriate error handling? |
| 54 | if err != nil { |
| 55 | plog.Errorf("error marshalling leader stats (%v)", err) |
| 56 | } |
| 57 | return b |
| 58 | } |
| 59 | |
| 60 | func (ls *LeaderStats) Follower(name string) *FollowerStats { |
| 61 | ls.Lock() |
| 62 | defer ls.Unlock() |
| 63 | fs, ok := ls.Followers[name] |
| 64 | if !ok { |
| 65 | fs = &FollowerStats{} |
| 66 | fs.Latency.Minimum = 1 << 63 |
| 67 | ls.Followers[name] = fs |
| 68 | } |
| 69 | return fs |
| 70 | } |
| 71 | |
| 72 | // FollowerStats encapsulates various statistics about a follower in an etcd cluster |
| 73 | type FollowerStats struct { |
| 74 | Latency LatencyStats `json:"latency"` |
| 75 | Counts CountsStats `json:"counts"` |
| 76 | |
| 77 | sync.Mutex |
| 78 | } |
| 79 | |
| 80 | // LatencyStats encapsulates latency statistics. |
| 81 | type LatencyStats struct { |
| 82 | Current float64 `json:"current"` |
| 83 | Average float64 `json:"average"` |
| 84 | averageSquare float64 |
| 85 | StandardDeviation float64 `json:"standardDeviation"` |
| 86 | Minimum float64 `json:"minimum"` |
| 87 | Maximum float64 `json:"maximum"` |
| 88 | } |
| 89 | |
| 90 | // CountsStats encapsulates raft statistics. |
| 91 | type CountsStats struct { |
| 92 | Fail uint64 `json:"fail"` |
| 93 | Success uint64 `json:"success"` |
| 94 | } |
| 95 | |
| 96 | // Succ updates the FollowerStats with a successful send |
| 97 | func (fs *FollowerStats) Succ(d time.Duration) { |
| 98 | fs.Lock() |
| 99 | defer fs.Unlock() |
| 100 | |
| 101 | total := float64(fs.Counts.Success) * fs.Latency.Average |
| 102 | totalSquare := float64(fs.Counts.Success) * fs.Latency.averageSquare |
| 103 | |
| 104 | fs.Counts.Success++ |
| 105 | |
| 106 | fs.Latency.Current = float64(d) / (1000000.0) |
| 107 | |
| 108 | if fs.Latency.Current > fs.Latency.Maximum { |
| 109 | fs.Latency.Maximum = fs.Latency.Current |
| 110 | } |
| 111 | |
| 112 | if fs.Latency.Current < fs.Latency.Minimum { |
| 113 | fs.Latency.Minimum = fs.Latency.Current |
| 114 | } |
| 115 | |
| 116 | fs.Latency.Average = (total + fs.Latency.Current) / float64(fs.Counts.Success) |
| 117 | fs.Latency.averageSquare = (totalSquare + fs.Latency.Current*fs.Latency.Current) / float64(fs.Counts.Success) |
| 118 | |
| 119 | // sdv = sqrt(avg(x^2) - avg(x)^2) |
| 120 | fs.Latency.StandardDeviation = math.Sqrt(fs.Latency.averageSquare - fs.Latency.Average*fs.Latency.Average) |
| 121 | } |
| 122 | |
| 123 | // Fail updates the FollowerStats with an unsuccessful send |
| 124 | func (fs *FollowerStats) Fail() { |
| 125 | fs.Lock() |
| 126 | defer fs.Unlock() |
| 127 | fs.Counts.Fail++ |
| 128 | } |