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402 lines
11 KiB
402 lines
11 KiB
// Copyright 2017 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 promhttp
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import (
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"io"
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"log"
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"net/http"
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"net/http/httptest"
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"testing"
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"github.com/prometheus/client_golang/prometheus"
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)
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func TestLabelCheck(t *testing.T) {
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scenarios := map[string]struct {
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varLabels []string
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constLabels []string
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curriedLabels []string
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ok bool
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}{
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"empty": {
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varLabels: []string{},
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constLabels: []string{},
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curriedLabels: []string{},
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ok: true,
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},
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"code as single var label": {
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varLabels: []string{"code"},
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constLabels: []string{},
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curriedLabels: []string{},
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ok: true,
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},
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"method as single var label": {
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varLabels: []string{"method"},
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constLabels: []string{},
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curriedLabels: []string{},
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ok: true,
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},
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"cade and method as var labels": {
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varLabels: []string{"method", "code"},
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constLabels: []string{},
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curriedLabels: []string{},
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ok: true,
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},
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"valid case with all labels used": {
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varLabels: []string{"code", "method"},
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constLabels: []string{"foo", "bar"},
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curriedLabels: []string{"dings", "bums"},
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ok: true,
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},
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"unsupported var label": {
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varLabels: []string{"foo"},
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constLabels: []string{},
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curriedLabels: []string{},
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ok: false,
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},
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"mixed var labels": {
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varLabels: []string{"method", "foo", "code"},
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constLabels: []string{},
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curriedLabels: []string{},
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ok: false,
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},
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"unsupported var label but curried": {
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varLabels: []string{},
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constLabels: []string{},
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curriedLabels: []string{"foo"},
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ok: true,
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},
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"mixed var labels but unsupported curried": {
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varLabels: []string{"code", "method"},
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constLabels: []string{},
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curriedLabels: []string{"foo"},
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ok: true,
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},
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"supported label as const and curry": {
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varLabels: []string{},
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constLabels: []string{"code"},
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curriedLabels: []string{"method"},
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ok: true,
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},
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"supported label as const and curry with unsupported as var": {
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varLabels: []string{"foo"},
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constLabels: []string{"code"},
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curriedLabels: []string{"method"},
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ok: false,
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},
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}
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for name, sc := range scenarios {
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t.Run(name, func(t *testing.T) {
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constLabels := prometheus.Labels{}
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for _, l := range sc.constLabels {
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constLabels[l] = "dummy"
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}
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c := prometheus.NewCounterVec(
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prometheus.CounterOpts{
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Name: "c",
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Help: "c help",
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ConstLabels: constLabels,
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},
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append(sc.varLabels, sc.curriedLabels...),
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)
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o := prometheus.ObserverVec(prometheus.NewHistogramVec(
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prometheus.HistogramOpts{
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Name: "c",
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Help: "c help",
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ConstLabels: constLabels,
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},
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append(sc.varLabels, sc.curriedLabels...),
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))
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for _, l := range sc.curriedLabels {
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c = c.MustCurryWith(prometheus.Labels{l: "dummy"})
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o = o.MustCurryWith(prometheus.Labels{l: "dummy"})
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}
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func() {
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defer func() {
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if err := recover(); err != nil {
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if sc.ok {
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t.Error("unexpected panic:", err)
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}
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} else if !sc.ok {
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t.Error("expected panic")
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}
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}()
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InstrumentHandlerCounter(c, nil)
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}()
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func() {
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defer func() {
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if err := recover(); err != nil {
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if sc.ok {
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t.Error("unexpected panic:", err)
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}
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} else if !sc.ok {
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t.Error("expected panic")
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}
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}()
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InstrumentHandlerDuration(o, nil)
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}()
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if sc.ok {
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// Test if wantCode and wantMethod were detected correctly.
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var wantCode, wantMethod bool
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for _, l := range sc.varLabels {
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if l == "code" {
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wantCode = true
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}
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if l == "method" {
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wantMethod = true
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}
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}
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gotCode, gotMethod := checkLabels(c)
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if gotCode != wantCode {
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t.Errorf("wanted code=%t for counter, got code=%t", wantCode, gotCode)
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}
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if gotMethod != wantMethod {
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t.Errorf("wanted method=%t for counter, got method=%t", wantMethod, gotMethod)
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}
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gotCode, gotMethod = checkLabels(o)
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if gotCode != wantCode {
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t.Errorf("wanted code=%t for observer, got code=%t", wantCode, gotCode)
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}
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if gotMethod != wantMethod {
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t.Errorf("wanted method=%t for observer, got method=%t", wantMethod, gotMethod)
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}
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}
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})
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}
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}
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func TestMiddlewareAPI(t *testing.T) {
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reg := prometheus.NewRegistry()
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inFlightGauge := prometheus.NewGauge(prometheus.GaugeOpts{
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Name: "in_flight_requests",
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Help: "A gauge of requests currently being served by the wrapped handler.",
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})
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counter := prometheus.NewCounterVec(
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prometheus.CounterOpts{
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Name: "api_requests_total",
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Help: "A counter for requests to the wrapped handler.",
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},
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[]string{"code", "method"},
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)
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histVec := prometheus.NewHistogramVec(
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prometheus.HistogramOpts{
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Name: "response_duration_seconds",
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Help: "A histogram of request latencies.",
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Buckets: prometheus.DefBuckets,
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ConstLabels: prometheus.Labels{"handler": "api"},
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},
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[]string{"method"},
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)
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writeHeaderVec := prometheus.NewHistogramVec(
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prometheus.HistogramOpts{
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Name: "write_header_duration_seconds",
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Help: "A histogram of time to first write latencies.",
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Buckets: prometheus.DefBuckets,
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ConstLabels: prometheus.Labels{"handler": "api"},
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},
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[]string{},
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)
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responseSize := prometheus.NewHistogramVec(
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prometheus.HistogramOpts{
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Name: "push_request_size_bytes",
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Help: "A histogram of request sizes for requests.",
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Buckets: []float64{200, 500, 900, 1500},
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},
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[]string{},
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)
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handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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w.Write([]byte("OK"))
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})
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reg.MustRegister(inFlightGauge, counter, histVec, responseSize, writeHeaderVec)
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chain := InstrumentHandlerInFlight(inFlightGauge,
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InstrumentHandlerCounter(counter,
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InstrumentHandlerDuration(histVec,
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InstrumentHandlerTimeToWriteHeader(writeHeaderVec,
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InstrumentHandlerResponseSize(responseSize, handler),
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),
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),
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),
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)
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r, _ := http.NewRequest("GET", "www.example.com", nil)
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w := httptest.NewRecorder()
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chain.ServeHTTP(w, r)
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}
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func TestInstrumentTimeToFirstWrite(t *testing.T) {
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var i int
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dobs := &responseWriterDelegator{
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ResponseWriter: httptest.NewRecorder(),
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observeWriteHeader: func(status int) {
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i = status
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},
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}
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d := newDelegator(dobs, nil)
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d.WriteHeader(http.StatusOK)
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if i != http.StatusOK {
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t.Fatalf("failed to execute observeWriteHeader")
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}
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}
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// testResponseWriter is an http.ResponseWriter that also implements
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// http.CloseNotifier, http.Flusher, and io.ReaderFrom.
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type testResponseWriter struct {
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closeNotifyCalled, flushCalled, readFromCalled bool
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}
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func (t *testResponseWriter) Header() http.Header { return nil }
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func (t *testResponseWriter) Write([]byte) (int, error) { return 0, nil }
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func (t *testResponseWriter) WriteHeader(int) {}
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func (t *testResponseWriter) CloseNotify() <-chan bool {
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t.closeNotifyCalled = true
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return nil
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}
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func (t *testResponseWriter) Flush() { t.flushCalled = true }
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func (t *testResponseWriter) ReadFrom(io.Reader) (int64, error) {
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t.readFromCalled = true
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return 0, nil
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}
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// testFlusher is an http.ResponseWriter that also implements http.Flusher.
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type testFlusher struct {
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flushCalled bool
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}
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func (t *testFlusher) Header() http.Header { return nil }
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func (t *testFlusher) Write([]byte) (int, error) { return 0, nil }
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func (t *testFlusher) WriteHeader(int) {}
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func (t *testFlusher) Flush() { t.flushCalled = true }
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func TestInterfaceUpgrade(t *testing.T) {
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w := &testResponseWriter{}
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d := newDelegator(w, nil)
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d.(http.CloseNotifier).CloseNotify()
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if !w.closeNotifyCalled {
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t.Error("CloseNotify not called")
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}
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d.(http.Flusher).Flush()
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if !w.flushCalled {
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t.Error("Flush not called")
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}
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d.(io.ReaderFrom).ReadFrom(nil)
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if !w.readFromCalled {
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t.Error("ReadFrom not called")
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}
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if _, ok := d.(http.Hijacker); ok {
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t.Error("delegator unexpectedly implements http.Hijacker")
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}
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f := &testFlusher{}
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d = newDelegator(f, nil)
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if _, ok := d.(http.CloseNotifier); ok {
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t.Error("delegator unexpectedly implements http.CloseNotifier")
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}
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d.(http.Flusher).Flush()
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if !w.flushCalled {
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t.Error("Flush not called")
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}
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if _, ok := d.(io.ReaderFrom); ok {
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t.Error("delegator unexpectedly implements io.ReaderFrom")
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}
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if _, ok := d.(http.Hijacker); ok {
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t.Error("delegator unexpectedly implements http.Hijacker")
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}
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}
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func ExampleInstrumentHandlerDuration() {
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inFlightGauge := prometheus.NewGauge(prometheus.GaugeOpts{
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Name: "in_flight_requests",
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Help: "A gauge of requests currently being served by the wrapped handler.",
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})
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counter := prometheus.NewCounterVec(
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prometheus.CounterOpts{
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Name: "api_requests_total",
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Help: "A counter for requests to the wrapped handler.",
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},
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[]string{"code", "method"},
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)
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// duration is partitioned by the HTTP method and handler. It uses custom
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// buckets based on the expected request duration.
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duration := prometheus.NewHistogramVec(
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prometheus.HistogramOpts{
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Name: "request_duration_seconds",
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Help: "A histogram of latencies for requests.",
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Buckets: []float64{.25, .5, 1, 2.5, 5, 10},
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},
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[]string{"handler", "method"},
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)
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// responseSize has no labels, making it a zero-dimensional
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// ObserverVec.
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responseSize := prometheus.NewHistogramVec(
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prometheus.HistogramOpts{
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Name: "response_size_bytes",
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Help: "A histogram of response sizes for requests.",
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Buckets: []float64{200, 500, 900, 1500},
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},
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[]string{},
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)
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// Create the handlers that will be wrapped by the middleware.
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pushHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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w.Write([]byte("Push"))
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})
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pullHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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w.Write([]byte("Pull"))
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})
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// Register all of the metrics in the standard registry.
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prometheus.MustRegister(inFlightGauge, counter, duration, responseSize)
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// Instrument the handlers with all the metrics, injecting the "handler"
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// label by currying.
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pushChain := InstrumentHandlerInFlight(inFlightGauge,
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InstrumentHandlerDuration(duration.MustCurryWith(prometheus.Labels{"handler": "push"}),
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InstrumentHandlerCounter(counter,
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InstrumentHandlerResponseSize(responseSize, pushHandler),
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),
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),
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)
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pullChain := InstrumentHandlerInFlight(inFlightGauge,
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InstrumentHandlerDuration(duration.MustCurryWith(prometheus.Labels{"handler": "pull"}),
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InstrumentHandlerCounter(counter,
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InstrumentHandlerResponseSize(responseSize, pullHandler),
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),
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),
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)
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http.Handle("/metrics", Handler())
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http.Handle("/push", pushChain)
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http.Handle("/pull", pullChain)
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if err := http.ListenAndServe(":3000", nil); err != nil {
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log.Fatal(err)
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}
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}
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