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// Copyright 2016 The etcd Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package grpcproxy
import (
"fmt"
"io/ioutil"
"math/rand"
"net/http"
"strings"
"time"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/promhttp"
"go.etcd.io/etcd/server/v3/etcdserver/api/etcdhttp"
)
var (
watchersCoalescing = prometheus.NewGauge(prometheus.GaugeOpts{
Namespace: "etcd",
Subsystem: "grpc_proxy",
Name: "watchers_coalescing_total",
Help: "Total number of current watchers coalescing",
})
eventsCoalescing = prometheus.NewCounter(prometheus.CounterOpts{
Namespace: "etcd",
Subsystem: "grpc_proxy",
Name: "events_coalescing_total",
Help: "Total number of events coalescing",
})
cacheKeys = prometheus.NewGauge(prometheus.GaugeOpts{
Namespace: "etcd",
Subsystem: "grpc_proxy",
Name: "cache_keys_total",
Help: "Total number of keys/ranges cached",
})
cacheHits = prometheus.NewGauge(prometheus.GaugeOpts{
Namespace: "etcd",
Subsystem: "grpc_proxy",
Name: "cache_hits_total",
Help: "Total number of cache hits",
})
cachedMisses = prometheus.NewGauge(prometheus.GaugeOpts{
Namespace: "etcd",
Subsystem: "grpc_proxy",
Name: "cache_misses_total",
Help: "Total number of cache misses",
})
)
func init() {
prometheus.MustRegister(watchersCoalescing)
prometheus.MustRegister(eventsCoalescing)
prometheus.MustRegister(cacheKeys)
prometheus.MustRegister(cacheHits)
prometheus.MustRegister(cachedMisses)
}
// HandleMetrics performs a GET request against etcd endpoint and returns '/metrics'.
func HandleMetrics(mux *http.ServeMux, c *http.Client, eps []string) {
// random shuffle endpoints
r := rand.New(rand.NewSource(int64(time.Now().Nanosecond())))
if len(eps) > 1 {
eps = shuffleEndpoints(r, eps)
}
pathMetrics := etcdhttp.PathMetrics
mux.HandleFunc(pathMetrics, func(w http.ResponseWriter, r *http.Request) {
target := fmt.Sprintf("%s%s", eps[0], pathMetrics)
if !strings.HasPrefix(target, "http") {
scheme := "http"
if r.TLS != nil {
scheme = "https"
}
target = fmt.Sprintf("%s://%s", scheme, target)
}
resp, err := c.Get(target)
if err != nil {
http.Error(w, "Internal server error", http.StatusInternalServerError)
return
}
defer resp.Body.Close()
w.Header().Set("Content-Type", "text/plain; version=0.0.4")
body, _ := ioutil.ReadAll(resp.Body)
fmt.Fprintf(w, "%s", body)
})
}
// HandleProxyMetrics registers metrics handler on '/proxy/metrics'.
func HandleProxyMetrics(mux *http.ServeMux) {
mux.Handle(etcdhttp.PathProxyMetrics, promhttp.Handler())
}
func shuffleEndpoints(r *rand.Rand, eps []string) []string {
// copied from Go 1.9<= rand.Rand.Perm
n := len(eps)
p := make([]int, n)
for i := 0; i < n; i++ {
j := r.Intn(i + 1)
p[i] = p[j]
p[j] = i
}
neps := make([]string, n)
for i, k := range p {
neps[i] = eps[k]
}
return neps
}
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