121 lines
3.1 KiB
Go
121 lines
3.1 KiB
Go
/*
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Copyright 2014 CoreOS, Inc.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package stats
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import (
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"encoding/json"
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"log"
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"math"
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"sync"
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"time"
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)
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// LeaderStats is used by the leader in an etcd cluster, and encapsulates
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// statistics about communication with its followers
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type LeaderStats struct {
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// TODO(jonboulle): clarify that these are IDs, not names
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Leader string `json:"leader"`
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Followers map[string]*FollowerStats `json:"followers"`
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sync.Mutex
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}
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// NewLeaderStats generates a new LeaderStats with the given id as leader
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func NewLeaderStats(id string) *LeaderStats {
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return &LeaderStats{
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Leader: id,
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Followers: make(map[string]*FollowerStats),
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}
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}
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func (ls *LeaderStats) JSON() []byte {
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ls.Lock()
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stats := *ls
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ls.Unlock()
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b, err := json.Marshal(stats)
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// TODO(jonboulle): appropriate error handling?
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if err != nil {
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log.Printf("error marshalling leader stats: %v", err)
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}
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return b
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}
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func (ls *LeaderStats) Follower(name string) *FollowerStats {
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ls.Lock()
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defer ls.Unlock()
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fs, ok := ls.Followers[name]
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if !ok {
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fs = &FollowerStats{}
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fs.Latency.Minimum = 1 << 63
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ls.Followers[name] = fs
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}
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return fs
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}
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// FollowerStats encapsulates various statistics about a follower in an etcd cluster
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type FollowerStats struct {
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Latency struct {
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Current float64 `json:"current"`
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Average float64 `json:"average"`
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averageSquare float64
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StandardDeviation float64 `json:"standardDeviation"`
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Minimum float64 `json:"minimum"`
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Maximum float64 `json:"maximum"`
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} `json:"latency"`
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Counts struct {
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Fail uint64 `json:"fail"`
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Success uint64 `json:"success"`
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} `json:"counts"`
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sync.Mutex
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}
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// Succ updates the FollowerStats with a successful send
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func (fs *FollowerStats) Succ(d time.Duration) {
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fs.Lock()
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defer fs.Unlock()
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total := float64(fs.Counts.Success) * fs.Latency.Average
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totalSquare := float64(fs.Counts.Success) * fs.Latency.averageSquare
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fs.Counts.Success++
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fs.Latency.Current = float64(d) / (1000000.0)
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if fs.Latency.Current > fs.Latency.Maximum {
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fs.Latency.Maximum = fs.Latency.Current
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}
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if fs.Latency.Current < fs.Latency.Minimum {
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fs.Latency.Minimum = fs.Latency.Current
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}
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fs.Latency.Average = (total + fs.Latency.Current) / float64(fs.Counts.Success)
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fs.Latency.averageSquare = (totalSquare + fs.Latency.Current*fs.Latency.Current) / float64(fs.Counts.Success)
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// sdv = sqrt(avg(x^2) - avg(x)^2)
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fs.Latency.StandardDeviation = math.Sqrt(fs.Latency.averageSquare - fs.Latency.Average*fs.Latency.Average)
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}
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// Fail updates the FollowerStats with an unsuccessful send
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func (fs *FollowerStats) Fail() {
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fs.Lock()
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defer fs.Unlock()
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fs.Counts.Fail++
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}
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