aboutsummaryrefslogtreecommitdiffstats
path: root/metrics/exp/exp.go
blob: c19d00a94d6e804060722c5eb7568f40ca112970 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
// Hook go-metrics into expvar
// on any /debug/metrics request, load all vars from the registry into expvar, and execute regular expvar handler
package exp

import (
    "expvar"
    "fmt"
    "net/http"
    "sync"

    "github.com/ethereum/go-ethereum/metrics"
)

type exp struct {
    expvarLock sync.Mutex // expvar panics if you try to register the same var twice, so we must probe it safely
    registry   metrics.Registry
}

func (exp *exp) expHandler(w http.ResponseWriter, r *http.Request) {
    // load our variables into expvar
    exp.syncToExpvar()

    // now just run the official expvar handler code (which is not publicly callable, so pasted inline)
    w.Header().Set("Content-Type", "application/json; charset=utf-8")
    fmt.Fprintf(w, "{\n")
    first := true
    expvar.Do(func(kv expvar.KeyValue) {
        if !first {
            fmt.Fprintf(w, ",\n")
        }
        first = false
        fmt.Fprintf(w, "%q: %s", kv.Key, kv.Value)
    })
    fmt.Fprintf(w, "\n}\n")
}

// Exp will register an expvar powered metrics handler with http.DefaultServeMux on "/debug/vars"
func Exp(r metrics.Registry) {
    h := ExpHandler(r)
    // this would cause a panic:
    // panic: http: multiple registrations for /debug/vars
    // http.HandleFunc("/debug/vars", e.expHandler)
    // haven't found an elegant way, so just use a different endpoint
    http.Handle("/debug/metrics", h)
}

// ExpHandler will return an expvar powered metrics handler.
func ExpHandler(r metrics.Registry) http.Handler {
    e := exp{sync.Mutex{}, r}
    return http.HandlerFunc(e.expHandler)
}

func (exp *exp) getInt(name string) *expvar.Int {
    var v *expvar.Int
    exp.expvarLock.Lock()
    p := expvar.Get(name)
    if p != nil {
        v = p.(*expvar.Int)
    } else {
        v = new(expvar.Int)
        expvar.Publish(name, v)
    }
    exp.expvarLock.Unlock()
    return v
}

func (exp *exp) getFloat(name string) *expvar.Float {
    var v *expvar.Float
    exp.expvarLock.Lock()
    p := expvar.Get(name)
    if p != nil {
        v = p.(*expvar.Float)
    } else {
        v = new(expvar.Float)
        expvar.Publish(name, v)
    }
    exp.expvarLock.Unlock()
    return v
}

func (exp *exp) publishCounter(name string, metric metrics.Counter) {
    v := exp.getInt(name)
    v.Set(metric.Count())
}

func (exp *exp) publishGauge(name string, metric metrics.Gauge) {
    v := exp.getInt(name)
    v.Set(metric.Value())
}
func (exp *exp) publishGaugeFloat64(name string, metric metrics.GaugeFloat64) {
    exp.getFloat(name).Set(metric.Value())
}

func (exp *exp) publishHistogram(name string, metric metrics.Histogram) {
    h := metric.Snapshot()
    ps := h.Percentiles([]float64{0.5, 0.75, 0.95, 0.99, 0.999})
    exp.getInt(name + ".count").Set(h.Count())
    exp.getFloat(name + ".min").Set(float64(h.Min()))
    exp.getFloat(name + ".max").Set(float64(h.Max()))
    exp.getFloat(name + ".mean").Set(h.Mean())
    exp.getFloat(name + ".std-dev").Set(h.StdDev())
    exp.getFloat(name + ".50-percentile").Set(ps[0])
    exp.getFloat(name + ".75-percentile").Set(ps[1])
    exp.getFloat(name + ".95-percentile").Set(ps[2])
    exp.getFloat(name + ".99-percentile").Set(ps[3])
    exp.getFloat(name + ".999-percentile").Set(ps[4])
}

func (exp *exp) publishMeter(name string, metric metrics.Meter) {
    m := metric.Snapshot()
    exp.getInt(name + ".count").Set(m.Count())
    exp.getFloat(name + ".one-minute").Set(m.Rate1())
    exp.getFloat(name + ".five-minute").Set(m.Rate5())
    exp.getFloat(name + ".fifteen-minute").Set((m.Rate15()))
    exp.getFloat(name + ".mean").Set(m.RateMean())
}

func (exp *exp) publishTimer(name string, metric metrics.Timer) {
    t := metric.Snapshot()
    ps := t.Percentiles([]float64{0.5, 0.75, 0.95, 0.99, 0.999})
    exp.getInt(name + ".count").Set(t.Count())
    exp.getFloat(name + ".min").Set(float64(t.Min()))
    exp.getFloat(name + ".max").Set(float64(t.Max()))
    exp.getFloat(name + ".mean").Set(t.Mean())
    exp.getFloat(name + ".std-dev").Set(t.StdDev())
    exp.getFloat(name + ".50-percentile").Set(ps[0])
    exp.getFloat(name + ".75-percentile").Set(ps[1])
    exp.getFloat(name + ".95-percentile").Set(ps[2])
    exp.getFloat(name + ".99-percentile").Set(ps[3])
    exp.getFloat(name + ".999-percentile").Set(ps[4])
    exp.getFloat(name + ".one-minute").Set(t.Rate1())
    exp.getFloat(name + ".five-minute").Set(t.Rate5())
    exp.getFloat(name + ".fifteen-minute").Set(t.Rate15())
    exp.getFloat(name + ".mean-rate").Set(t.RateMean())
}

func (exp *exp) syncToExpvar() {
    exp.registry.Each(func(name string, i interface{}) {
        switch i.(type) {
        case metrics.Counter:
            exp.publishCounter(name, i.(metrics.Counter))
        case metrics.Gauge:
            exp.publishGauge(name, i.(metrics.Gauge))
        case metrics.GaugeFloat64:
            exp.publishGaugeFloat64(name, i.(metrics.GaugeFloat64))
        case metrics.Histogram:
            exp.publishHistogram(name, i.(metrics.Histogram))
        case metrics.Meter:
            exp.publishMeter(name, i.(metrics.Meter))
        case metrics.Timer:
            exp.publishTimer(name, i.(metrics.Timer))
        default:
            panic(fmt.Sprintf("unsupported type for '%s': %T", name, i))
        }
    })
}