metrics.go

Documentation: go.etcd.io/etcd/server/v3/proxy/grpcproxy

     1  // Copyright 2016 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 grpcproxy
    16  
    17  import (
    18  	"fmt"
    19  	"io/ioutil"
    20  	"math/rand"
    21  	"net/http"
    22  	"strings"
    23  	"time"
    24  
    25  	"github.com/prometheus/client_golang/prometheus"
    26  	"github.com/prometheus/client_golang/prometheus/promhttp"
    27  	"go.etcd.io/etcd/server/v3/etcdserver/api/etcdhttp"
    28  )
    29  
    30  var (
    31  	watchersCoalescing = prometheus.NewGauge(prometheus.GaugeOpts{
    32  		Namespace: "etcd",
    33  		Subsystem: "grpc_proxy",
    34  		Name:      "watchers_coalescing_total",
    35  		Help:      "Total number of current watchers coalescing",
    36  	})
    37  	eventsCoalescing = prometheus.NewCounter(prometheus.CounterOpts{
    38  		Namespace: "etcd",
    39  		Subsystem: "grpc_proxy",
    40  		Name:      "events_coalescing_total",
    41  		Help:      "Total number of events coalescing",
    42  	})
    43  	cacheKeys = prometheus.NewGauge(prometheus.GaugeOpts{
    44  		Namespace: "etcd",
    45  		Subsystem: "grpc_proxy",
    46  		Name:      "cache_keys_total",
    47  		Help:      "Total number of keys/ranges cached",
    48  	})
    49  	cacheHits = prometheus.NewGauge(prometheus.GaugeOpts{
    50  		Namespace: "etcd",
    51  		Subsystem: "grpc_proxy",
    52  		Name:      "cache_hits_total",
    53  		Help:      "Total number of cache hits",
    54  	})
    55  	cachedMisses = prometheus.NewGauge(prometheus.GaugeOpts{
    56  		Namespace: "etcd",
    57  		Subsystem: "grpc_proxy",
    58  		Name:      "cache_misses_total",
    59  		Help:      "Total number of cache misses",
    60  	})
    61  )
    62  
    63  func init() {
    64  	prometheus.MustRegister(watchersCoalescing)
    65  	prometheus.MustRegister(eventsCoalescing)
    66  	prometheus.MustRegister(cacheKeys)
    67  	prometheus.MustRegister(cacheHits)
    68  	prometheus.MustRegister(cachedMisses)
    69  }
    70  
    71  // HandleMetrics performs a GET request against etcd endpoint and returns '/metrics'.
    72  func HandleMetrics(mux *http.ServeMux, c *http.Client, eps []string) {
    73  	// random shuffle endpoints
    74  	r := rand.New(rand.NewSource(int64(time.Now().Nanosecond())))
    75  	if len(eps) > 1 {
    76  		eps = shuffleEndpoints(r, eps)
    77  	}
    78  
    79  	pathMetrics := etcdhttp.PathMetrics
    80  	mux.HandleFunc(pathMetrics, func(w http.ResponseWriter, r *http.Request) {
    81  		target := fmt.Sprintf("%s%s", eps[0], pathMetrics)
    82  		if !strings.HasPrefix(target, "http") {
    83  			scheme := "http"
    84  			if r.TLS != nil {
    85  				scheme = "https"
    86  			}
    87  			target = fmt.Sprintf("%s://%s", scheme, target)
    88  		}
    89  
    90  		resp, err := c.Get(target)
    91  		if err != nil {
    92  			http.Error(w, "Internal server error", http.StatusInternalServerError)
    93  			return
    94  		}
    95  		defer resp.Body.Close()
    96  		w.Header().Set("Content-Type", "text/plain; version=0.0.4")
    97  		body, _ := ioutil.ReadAll(resp.Body)
    98  		fmt.Fprintf(w, "%s", body)
    99  	})
   100  }
   101  
   102  // HandleProxyMetrics registers metrics handler on '/proxy/metrics'.
   103  func HandleProxyMetrics(mux *http.ServeMux) {
   104  	mux.Handle(etcdhttp.PathProxyMetrics, promhttp.Handler())
   105  }
   106  
   107  func shuffleEndpoints(r *rand.Rand, eps []string) []string {
   108  	// copied from Go 1.9<= rand.Rand.Perm
   109  	n := len(eps)
   110  	p := make([]int, n)
   111  	for i := 0; i < n; i++ {
   112  		j := r.Intn(i + 1)
   113  		p[i] = p[j]
   114  		p[j] = i
   115  	}
   116  	neps := make([]string, n)
   117  	for i, k := range p {
   118  		neps[i] = eps[k]
   119  	}
   120  	return neps
   121  }
   122
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