go.etcd.io/etcd@v3.3.27+incompatible/proxy/grpcproxy/metrics.go (about) 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/coreos/etcd/etcdserver/api/etcdhttp" 26 "github.com/prometheus/client_golang/prometheus" 27 ) 28 29 var ( 30 watchersCoalescing = prometheus.NewGauge(prometheus.GaugeOpts{ 31 Namespace: "etcd", 32 Subsystem: "grpc_proxy", 33 Name: "watchers_coalescing_total", 34 Help: "Total number of current watchers coalescing", 35 }) 36 eventsCoalescing = prometheus.NewCounter(prometheus.CounterOpts{ 37 Namespace: "etcd", 38 Subsystem: "grpc_proxy", 39 Name: "events_coalescing_total", 40 Help: "Total number of events coalescing", 41 }) 42 cacheKeys = prometheus.NewGauge(prometheus.GaugeOpts{ 43 Namespace: "etcd", 44 Subsystem: "grpc_proxy", 45 Name: "cache_keys_total", 46 Help: "Total number of keys/ranges cached", 47 }) 48 cacheHits = prometheus.NewGauge(prometheus.GaugeOpts{ 49 Namespace: "etcd", 50 Subsystem: "grpc_proxy", 51 Name: "cache_hits_total", 52 Help: "Total number of cache hits", 53 }) 54 cachedMisses = prometheus.NewGauge(prometheus.GaugeOpts{ 55 Namespace: "etcd", 56 Subsystem: "grpc_proxy", 57 Name: "cache_misses_total", 58 Help: "Total number of cache misses", 59 }) 60 ) 61 62 func init() { 63 prometheus.MustRegister(watchersCoalescing) 64 prometheus.MustRegister(eventsCoalescing) 65 prometheus.MustRegister(cacheKeys) 66 prometheus.MustRegister(cacheHits) 67 prometheus.MustRegister(cachedMisses) 68 } 69 70 // HandleMetrics performs a GET request against etcd endpoint and returns '/metrics'. 71 func HandleMetrics(mux *http.ServeMux, c *http.Client, eps []string) { 72 // random shuffle endpoints 73 r := rand.New(rand.NewSource(int64(time.Now().Nanosecond()))) 74 if len(eps) > 1 { 75 eps = shuffleEndpoints(r, eps) 76 } 77 78 pathMetrics := etcdhttp.PathMetrics 79 mux.HandleFunc(pathMetrics, func(w http.ResponseWriter, r *http.Request) { 80 target := fmt.Sprintf("%s%s", eps[0], pathMetrics) 81 if !strings.HasPrefix(target, "http") { 82 scheme := "http" 83 if r.TLS != nil { 84 scheme = "https" 85 } 86 target = fmt.Sprintf("%s://%s", scheme, target) 87 } 88 89 resp, err := c.Get(target) 90 if err != nil { 91 http.Error(w, "Internal server error", http.StatusInternalServerError) 92 return 93 } 94 defer resp.Body.Close() 95 w.Header().Set("Content-Type", "text/plain; version=0.0.4") 96 body, _ := ioutil.ReadAll(resp.Body) 97 fmt.Fprintf(w, "%s", body) 98 }) 99 } 100 101 func shuffleEndpoints(r *rand.Rand, eps []string) []string { 102 // copied from Go 1.9<= rand.Rand.Perm 103 n := len(eps) 104 p := make([]int, n) 105 for i := 0; i < n; i++ { 106 j := r.Intn(i + 1) 107 p[i] = p[j] 108 p[j] = i 109 } 110 neps := make([]string, n) 111 for i, k := range p { 112 neps[i] = eps[k] 113 } 114 return neps 115 }