go.etcd.io/etcd@v3.3.27+incompatible/clientv3/example_metrics_test.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 clientv3_test
    16  
    17  import (
    18  	"context"
    19  	"fmt"
    20  	"io/ioutil"
    21  	"log"
    22  	"net"
    23  	"net/http"
    24  	"strings"
    25  
    26  	"github.com/coreos/etcd/clientv3"
    27  
    28  	grpcprom "github.com/grpc-ecosystem/go-grpc-prometheus"
    29  	"github.com/prometheus/client_golang/prometheus/promhttp"
    30  	"google.golang.org/grpc"
    31  )
    32  
    33  func ExampleClient_metrics() {
    34  	cli, err := clientv3.New(clientv3.Config{
    35  		Endpoints: endpoints,
    36  		DialOptions: []grpc.DialOption{
    37  			grpc.WithUnaryInterceptor(grpcprom.UnaryClientInterceptor),
    38  			grpc.WithStreamInterceptor(grpcprom.StreamClientInterceptor),
    39  		},
    40  	})
    41  	if err != nil {
    42  		log.Fatal(err)
    43  	}
    44  	defer cli.Close()
    45  
    46  	// get a key so it shows up in the metrics as a range RPC
    47  	cli.Get(context.TODO(), "test_key")
    48  
    49  	// listen for all Prometheus metrics
    50  	ln, err := net.Listen("tcp", ":0")
    51  	if err != nil {
    52  		log.Fatal(err)
    53  	}
    54  	donec := make(chan struct{})
    55  	go func() {
    56  		defer close(donec)
    57  		http.Serve(ln, promhttp.Handler())
    58  	}()
    59  	defer func() {
    60  		ln.Close()
    61  		<-donec
    62  	}()
    63  
    64  	// make an http request to fetch all Prometheus metrics
    65  	url := "http://" + ln.Addr().String() + "/metrics"
    66  	resp, err := http.Get(url)
    67  	if err != nil {
    68  		log.Fatalf("fetch error: %v", err)
    69  	}
    70  	b, err := ioutil.ReadAll(resp.Body)
    71  	resp.Body.Close()
    72  	if err != nil {
    73  		log.Fatalf("fetch error: reading %s: %v", url, err)
    74  	}
    75  
    76  	// confirm range request in metrics
    77  	for _, l := range strings.Split(string(b), "\n") {
    78  		if strings.Contains(l, `grpc_client_started_total{grpc_method="Range"`) {
    79  			fmt.Println(l)
    80  			break
    81  		}
    82  	}
    83  	// Output:
    84  	//	grpc_client_started_total{grpc_method="Range",grpc_service="etcdserverpb.KV",grpc_type="unary"} 1
    85  }