98 lines
3.3 KiB
Go
98 lines
3.3 KiB
Go
// Copyright 2014 The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package prometheus_test
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import (
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"expvar"
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"fmt"
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"sort"
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"strings"
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dto "github.com/prometheus/client_model/go"
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"github.com/prometheus/client_golang/prometheus"
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)
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func ExampleExpvarCollector() {
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expvarCollector := prometheus.NewExpvarCollector(map[string]*prometheus.Desc{
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"memstats": prometheus.NewDesc(
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"expvar_memstats",
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"All numeric memstats as one metric family. Not a good role-model, actually... ;-)",
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[]string{"type"}, nil,
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),
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"lone-int": prometheus.NewDesc(
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"expvar_lone_int",
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"Just an expvar int as an example.",
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nil, nil,
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),
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"http-request-map": prometheus.NewDesc(
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"expvar_http_request_total",
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"How many http requests processed, partitioned by status code and http method.",
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[]string{"code", "method"}, nil,
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),
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})
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prometheus.MustRegister(expvarCollector)
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// The Prometheus part is done here. But to show that this example is
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// doing anything, we have to manually export something via expvar. In
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// real-life use-cases, some library would already have exported via
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// expvar what we want to re-export as Prometheus metrics.
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expvar.NewInt("lone-int").Set(42)
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expvarMap := expvar.NewMap("http-request-map")
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var (
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expvarMap1, expvarMap2 expvar.Map
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expvarInt11, expvarInt12, expvarInt21, expvarInt22 expvar.Int
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)
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expvarMap1.Init()
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expvarMap2.Init()
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expvarInt11.Set(3)
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expvarInt12.Set(13)
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expvarInt21.Set(11)
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expvarInt22.Set(212)
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expvarMap1.Set("POST", &expvarInt11)
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expvarMap1.Set("GET", &expvarInt12)
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expvarMap2.Set("POST", &expvarInt21)
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expvarMap2.Set("GET", &expvarInt22)
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expvarMap.Set("404", &expvarMap1)
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expvarMap.Set("200", &expvarMap2)
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// Results in the following expvar map:
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// "http-request-count": {"200": {"POST": 11, "GET": 212}, "404": {"POST": 3, "GET": 13}}
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// Let's see what the scrape would yield, but exclude the memstats metrics.
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metricStrings := []string{}
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metric := dto.Metric{}
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metricChan := make(chan prometheus.Metric)
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go func() {
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expvarCollector.Collect(metricChan)
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close(metricChan)
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}()
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for m := range metricChan {
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if strings.Index(m.Desc().String(), "expvar_memstats") == -1 {
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metric.Reset()
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m.Write(&metric)
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metricStrings = append(metricStrings, metric.String())
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}
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}
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sort.Strings(metricStrings)
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for _, s := range metricStrings {
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fmt.Println(strings.TrimRight(s, " "))
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}
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// Output:
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// label:<name:"code" value:"200" > label:<name:"method" value:"GET" > untyped:<value:212 >
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// label:<name:"code" value:"200" > label:<name:"method" value:"POST" > untyped:<value:11 >
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// label:<name:"code" value:"404" > label:<name:"method" value:"GET" > untyped:<value:13 >
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// label:<name:"code" value:"404" > label:<name:"method" value:"POST" > untyped:<value:3 >
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// untyped:<value:42 >
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}
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