github.com/insionng/yougam@v0.0.0-20170714101924-2bc18d833463/libraries/rcrowley/go-metrics/exp/exp.go (about)

     1  // Hook go-metrics into expvar
     2  // on any /debug/metrics request, load all vars from the registry into expvar, and execute regular expvar handler
     3  package exp
     4  
     5  import (
     6  	"expvar"
     7  	"fmt"
     8  	"github.com/insionng/yougam/libraries/rcrowley/go-metrics"
     9  	"net/http"
    10  	"sync"
    11  )
    12  
    13  type exp struct {
    14  	expvarLock sync.Mutex // expvar panics if you try to register the same var twice, so we must probe it safely
    15  	registry   metrics.Registry
    16  }
    17  
    18  func (exp *exp) expHandler(w http.ResponseWriter, r *http.Request) {
    19  	// load our variables into expvar
    20  	exp.syncToExpvar()
    21  
    22  	// now just run the official expvar handler code (which is not publicly callable, so pasted inline)
    23  	w.Header().Set("Content-Type", "application/json; charset=utf-8")
    24  	fmt.Fprintf(w, "{\n")
    25  	first := true
    26  	expvar.Do(func(kv expvar.KeyValue) {
    27  		if !first {
    28  			fmt.Fprintf(w, ",\n")
    29  		}
    30  		first = false
    31  		fmt.Fprintf(w, "%q: %s", kv.Key, kv.Value)
    32  	})
    33  	fmt.Fprintf(w, "\n}\n")
    34  }
    35  
    36  func Exp(r metrics.Registry) {
    37  	e := exp{sync.Mutex{}, r}
    38  	// this would cause a panic:
    39  	// panic: http: multiple registrations for /debug/vars
    40  	// http.HandleFunc("/debug/vars", e.expHandler)
    41  	// haven't found an elegant way, so just use a different endpoint
    42  	http.HandleFunc("/debug/metrics", e.expHandler)
    43  }
    44  
    45  func (exp *exp) getInt(name string) *expvar.Int {
    46  	var v *expvar.Int
    47  	exp.expvarLock.Lock()
    48  	p := expvar.Get(name)
    49  	if p != nil {
    50  		v = p.(*expvar.Int)
    51  	} else {
    52  		v = new(expvar.Int)
    53  		expvar.Publish(name, v)
    54  	}
    55  	exp.expvarLock.Unlock()
    56  	return v
    57  }
    58  
    59  func (exp *exp) getFloat(name string) *expvar.Float {
    60  	var v *expvar.Float
    61  	exp.expvarLock.Lock()
    62  	p := expvar.Get(name)
    63  	if p != nil {
    64  		v = p.(*expvar.Float)
    65  	} else {
    66  		v = new(expvar.Float)
    67  		expvar.Publish(name, v)
    68  	}
    69  	exp.expvarLock.Unlock()
    70  	return v
    71  }
    72  
    73  func (exp *exp) publishCounter(name string, metric metrics.Counter) {
    74  	v := exp.getInt(name)
    75  	v.Set(metric.Count())
    76  }
    77  
    78  func (exp *exp) publishGauge(name string, metric metrics.Gauge) {
    79  	v := exp.getInt(name)
    80  	v.Set(metric.Value())
    81  }
    82  func (exp *exp) publishGaugeFloat64(name string, metric metrics.GaugeFloat64) {
    83  	exp.getFloat(name).Set(metric.Value())
    84  }
    85  
    86  func (exp *exp) publishHistogram(name string, metric metrics.Histogram) {
    87  	h := metric.Snapshot()
    88  	ps := h.Percentiles([]float64{0.5, 0.75, 0.95, 0.99, 0.999})
    89  	exp.getInt(name + ".count").Set(h.Count())
    90  	exp.getFloat(name + ".min").Set(float64(h.Min()))
    91  	exp.getFloat(name + ".max").Set(float64(h.Max()))
    92  	exp.getFloat(name + ".mean").Set(float64(h.Mean()))
    93  	exp.getFloat(name + ".std-dev").Set(float64(h.StdDev()))
    94  	exp.getFloat(name + ".50-percentile").Set(float64(ps[0]))
    95  	exp.getFloat(name + ".75-percentile").Set(float64(ps[1]))
    96  	exp.getFloat(name + ".95-percentile").Set(float64(ps[2]))
    97  	exp.getFloat(name + ".99-percentile").Set(float64(ps[3]))
    98  	exp.getFloat(name + ".999-percentile").Set(float64(ps[4]))
    99  }
   100  
   101  func (exp *exp) publishMeter(name string, metric metrics.Meter) {
   102  	m := metric.Snapshot()
   103  	exp.getInt(name + ".count").Set(m.Count())
   104  	exp.getFloat(name + ".one-minute").Set(float64(m.Rate1()))
   105  	exp.getFloat(name + ".five-minute").Set(float64(m.Rate5()))
   106  	exp.getFloat(name + ".fifteen-minute").Set(float64((m.Rate15())))
   107  	exp.getFloat(name + ".mean").Set(float64(m.RateMean()))
   108  }
   109  
   110  func (exp *exp) publishTimer(name string, metric metrics.Timer) {
   111  	t := metric.Snapshot()
   112  	ps := t.Percentiles([]float64{0.5, 0.75, 0.95, 0.99, 0.999})
   113  	exp.getInt(name + ".count").Set(t.Count())
   114  	exp.getFloat(name + ".min").Set(float64(t.Min()))
   115  	exp.getFloat(name + ".max").Set(float64(t.Max()))
   116  	exp.getFloat(name + ".mean").Set(float64(t.Mean()))
   117  	exp.getFloat(name + ".std-dev").Set(float64(t.StdDev()))
   118  	exp.getFloat(name + ".50-percentile").Set(float64(ps[0]))
   119  	exp.getFloat(name + ".75-percentile").Set(float64(ps[1]))
   120  	exp.getFloat(name + ".95-percentile").Set(float64(ps[2]))
   121  	exp.getFloat(name + ".99-percentile").Set(float64(ps[3]))
   122  	exp.getFloat(name + ".999-percentile").Set(float64(ps[4]))
   123  	exp.getFloat(name + ".one-minute").Set(float64(t.Rate1()))
   124  	exp.getFloat(name + ".five-minute").Set(float64(t.Rate5()))
   125  	exp.getFloat(name + ".fifteen-minute").Set(float64((t.Rate15())))
   126  	exp.getFloat(name + ".mean-rate").Set(float64(t.RateMean()))
   127  }
   128  
   129  func (exp *exp) syncToExpvar() {
   130  	exp.registry.Each(func(name string, i interface{}) {
   131  		switch i.(type) {
   132  		case metrics.Counter:
   133  			exp.publishCounter(name, i.(metrics.Counter))
   134  		case metrics.Gauge:
   135  			exp.publishGauge(name, i.(metrics.Gauge))
   136  		case metrics.GaugeFloat64:
   137  			exp.publishGaugeFloat64(name, i.(metrics.GaugeFloat64))
   138  		case metrics.Histogram:
   139  			exp.publishHistogram(name, i.(metrics.Histogram))
   140  		case metrics.Meter:
   141  			exp.publishMeter(name, i.(metrics.Meter))
   142  		case metrics.Timer:
   143  			exp.publishTimer(name, i.(metrics.Timer))
   144  		default:
   145  			panic(fmt.Sprintf("unsupported type for '%s': %T", name, i))
   146  		}
   147  	})
   148  }