334 lines
11 KiB
Go
334 lines
11 KiB
Go
// Copyright 2016 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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"bytes"
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"errors"
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"fmt"
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"log"
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"net/http"
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"net/http/httptest"
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"strings"
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"testing"
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"time"
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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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type errorCollector struct{}
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func (e errorCollector) Describe(ch chan<- *prometheus.Desc) {
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ch <- prometheus.NewDesc("invalid_metric", "not helpful", nil, nil)
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}
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func (e errorCollector) Collect(ch chan<- prometheus.Metric) {
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ch <- prometheus.NewInvalidMetric(
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prometheus.NewDesc("invalid_metric", "not helpful", nil, nil),
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errors.New("collect error"),
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)
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}
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type blockingCollector struct {
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CollectStarted, Block chan struct{}
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}
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func (b blockingCollector) Describe(ch chan<- *prometheus.Desc) {
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ch <- prometheus.NewDesc("dummy_desc", "not helpful", nil, nil)
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}
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func (b blockingCollector) Collect(ch chan<- prometheus.Metric) {
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select {
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case b.CollectStarted <- struct{}{}:
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default:
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}
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// Collects nothing, just waits for a channel receive.
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<-b.Block
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}
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type mockTransactionGatherer struct {
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g prometheus.Gatherer
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gatherInvoked int
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doneInvoked int
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}
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func (g *mockTransactionGatherer) Gather() (_ []*dto.MetricFamily, done func(), err error) {
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g.gatherInvoked++
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mfs, err := g.g.Gather()
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return mfs, func() { g.doneInvoked++ }, err
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}
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func TestHandlerErrorHandling(t *testing.T) {
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// Create a registry that collects a MetricFamily with two elements,
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// another with one, and reports an error. Further down, we'll use the
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// same registry in the HandlerOpts.
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reg := prometheus.NewRegistry()
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cnt := prometheus.NewCounter(prometheus.CounterOpts{
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Name: "the_count",
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Help: "Ah-ah-ah! Thunder and lightning!",
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})
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reg.MustRegister(cnt)
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cntVec := prometheus.NewCounterVec(
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prometheus.CounterOpts{
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Name: "name",
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Help: "docstring",
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ConstLabels: prometheus.Labels{"constname": "constvalue"},
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},
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[]string{"labelname"},
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)
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cntVec.WithLabelValues("val1").Inc()
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cntVec.WithLabelValues("val2").Inc()
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reg.MustRegister(cntVec)
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reg.MustRegister(errorCollector{})
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logBuf := &bytes.Buffer{}
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logger := log.New(logBuf, "", 0)
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writer := httptest.NewRecorder()
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request, _ := http.NewRequest("GET", "/", nil)
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request.Header.Add("Accept", "test/plain")
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mReg := &mockTransactionGatherer{g: reg}
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errorHandler := HandlerForTransactional(mReg, HandlerOpts{
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ErrorLog: logger,
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ErrorHandling: HTTPErrorOnError,
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Registry: reg,
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})
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continueHandler := HandlerForTransactional(mReg, HandlerOpts{
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ErrorLog: logger,
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ErrorHandling: ContinueOnError,
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Registry: reg,
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})
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panicHandler := HandlerForTransactional(mReg, HandlerOpts{
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ErrorLog: logger,
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ErrorHandling: PanicOnError,
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Registry: reg,
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})
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// Expect gatherer not touched.
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if got := mReg.gatherInvoked; got != 0 {
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t.Fatalf("unexpected number of gather invokes, want 0, got %d", got)
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}
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if got := mReg.doneInvoked; got != 0 {
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t.Fatalf("unexpected number of done invokes, want 0, got %d", got)
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}
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wantMsg := `error gathering metrics: error collecting metric Desc{fqName: "invalid_metric", help: "not helpful", constLabels: {}, variableLabels: {}}: collect error
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`
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wantErrorBody := `An error has occurred while serving metrics:
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error collecting metric Desc{fqName: "invalid_metric", help: "not helpful", constLabels: {}, variableLabels: {}}: collect error
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`
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wantOKBody1 := `# HELP name docstring
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# TYPE name counter
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name{constname="constvalue",labelname="val1"} 1
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name{constname="constvalue",labelname="val2"} 1
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# HELP promhttp_metric_handler_errors_total Total number of internal errors encountered by the promhttp metric handler.
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# TYPE promhttp_metric_handler_errors_total counter
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promhttp_metric_handler_errors_total{cause="encoding"} 0
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promhttp_metric_handler_errors_total{cause="gathering"} 1
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# HELP the_count Ah-ah-ah! Thunder and lightning!
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# TYPE the_count counter
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the_count 0
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`
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// It might happen that counting the gathering error makes it to the
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// promhttp_metric_handler_errors_total counter before it is gathered
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// itself. Thus, we have to bodies that are acceptable for the test.
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wantOKBody2 := `# HELP name docstring
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# TYPE name counter
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name{constname="constvalue",labelname="val1"} 1
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name{constname="constvalue",labelname="val2"} 1
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# HELP promhttp_metric_handler_errors_total Total number of internal errors encountered by the promhttp metric handler.
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# TYPE promhttp_metric_handler_errors_total counter
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promhttp_metric_handler_errors_total{cause="encoding"} 0
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promhttp_metric_handler_errors_total{cause="gathering"} 2
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# HELP the_count Ah-ah-ah! Thunder and lightning!
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# TYPE the_count counter
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the_count 0
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`
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errorHandler.ServeHTTP(writer, request)
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if got := mReg.gatherInvoked; got != 1 {
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t.Fatalf("unexpected number of gather invokes, want 1, got %d", got)
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}
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if got := mReg.doneInvoked; got != 1 {
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t.Fatalf("unexpected number of done invokes, want 1, got %d", got)
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}
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if got, want := writer.Code, http.StatusInternalServerError; got != want {
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t.Errorf("got HTTP status code %d, want %d", got, want)
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}
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if got, want := logBuf.String(), wantMsg; got != want {
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t.Errorf("got log buf %q, want %q", got, want)
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}
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if got, want := writer.Body.String(), wantErrorBody; got != want {
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t.Errorf("got body %q, want %q", got, want)
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}
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logBuf.Reset()
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writer.Body.Reset()
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writer.Code = http.StatusOK
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continueHandler.ServeHTTP(writer, request)
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if got := mReg.gatherInvoked; got != 2 {
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t.Fatalf("unexpected number of gather invokes, want 2, got %d", got)
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}
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if got := mReg.doneInvoked; got != 2 {
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t.Fatalf("unexpected number of done invokes, want 2, got %d", got)
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}
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if got, want := writer.Code, http.StatusOK; got != want {
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t.Errorf("got HTTP status code %d, want %d", got, want)
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}
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if got, want := logBuf.String(), wantMsg; got != want {
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t.Errorf("got log buf %q, want %q", got, want)
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}
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if got := writer.Body.String(); got != wantOKBody1 && got != wantOKBody2 {
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t.Errorf("got body %q, want either %q or %q", got, wantOKBody1, wantOKBody2)
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}
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defer func() {
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if err := recover(); err == nil {
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t.Error("expected panic from panicHandler")
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}
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if got := mReg.gatherInvoked; got != 3 {
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t.Fatalf("unexpected number of gather invokes, want 3, got %d", got)
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}
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if got := mReg.doneInvoked; got != 3 {
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t.Fatalf("unexpected number of done invokes, want 3, got %d", got)
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}
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}()
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panicHandler.ServeHTTP(writer, request)
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}
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func TestInstrumentMetricHandler(t *testing.T) {
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reg := prometheus.NewRegistry()
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mReg := &mockTransactionGatherer{g: reg}
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handler := InstrumentMetricHandler(reg, HandlerForTransactional(mReg, HandlerOpts{}))
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// Do it again to test idempotency.
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InstrumentMetricHandler(reg, HandlerForTransactional(mReg, HandlerOpts{}))
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writer := httptest.NewRecorder()
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request, _ := http.NewRequest("GET", "/", nil)
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request.Header.Add("Accept", "test/plain")
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handler.ServeHTTP(writer, request)
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if got := mReg.gatherInvoked; got != 1 {
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t.Fatalf("unexpected number of gather invokes, want 1, got %d", got)
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}
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if got := mReg.doneInvoked; got != 1 {
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t.Fatalf("unexpected number of done invokes, want 1, got %d", got)
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}
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if got, want := writer.Code, http.StatusOK; got != want {
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t.Errorf("got HTTP status code %d, want %d", got, want)
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}
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want := "promhttp_metric_handler_requests_in_flight 1\n"
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if got := writer.Body.String(); !strings.Contains(got, want) {
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t.Errorf("got body %q, does not contain %q", got, want)
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}
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want = "promhttp_metric_handler_requests_total{code=\"200\"} 0\n"
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if got := writer.Body.String(); !strings.Contains(got, want) {
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t.Errorf("got body %q, does not contain %q", got, want)
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}
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for i := 0; i < 100; i++ {
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writer.Body.Reset()
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handler.ServeHTTP(writer, request)
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if got, want := mReg.gatherInvoked, i+2; got != want {
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t.Fatalf("unexpected number of gather invokes, want %d, got %d", want, got)
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}
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if got, want := mReg.doneInvoked, i+2; got != want {
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t.Fatalf("unexpected number of done invokes, want %d, got %d", want, got)
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}
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if got, want := writer.Code, http.StatusOK; got != want {
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t.Errorf("got HTTP status code %d, want %d", got, want)
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}
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want := "promhttp_metric_handler_requests_in_flight 1\n"
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if got := writer.Body.String(); !strings.Contains(got, want) {
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t.Errorf("got body %q, does not contain %q", got, want)
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}
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want = fmt.Sprintf("promhttp_metric_handler_requests_total{code=\"200\"} %d\n", i+1)
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if got := writer.Body.String(); !strings.Contains(got, want) {
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t.Errorf("got body %q, does not contain %q", got, want)
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}
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}
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}
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func TestHandlerMaxRequestsInFlight(t *testing.T) {
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reg := prometheus.NewRegistry()
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handler := HandlerFor(reg, HandlerOpts{MaxRequestsInFlight: 1})
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w1 := httptest.NewRecorder()
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w2 := httptest.NewRecorder()
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w3 := httptest.NewRecorder()
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request, _ := http.NewRequest("GET", "/", nil)
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request.Header.Add("Accept", "test/plain")
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c := blockingCollector{Block: make(chan struct{}), CollectStarted: make(chan struct{}, 1)}
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reg.MustRegister(c)
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rq1Done := make(chan struct{})
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go func() {
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handler.ServeHTTP(w1, request)
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close(rq1Done)
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}()
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<-c.CollectStarted
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handler.ServeHTTP(w2, request)
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if got, want := w2.Code, http.StatusServiceUnavailable; got != want {
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t.Errorf("got HTTP status code %d, want %d", got, want)
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}
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if got, want := w2.Body.String(), "Limit of concurrent requests reached (1), try again later.\n"; got != want {
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t.Errorf("got body %q, want %q", got, want)
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}
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close(c.Block)
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<-rq1Done
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handler.ServeHTTP(w3, request)
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if got, want := w3.Code, http.StatusOK; got != want {
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t.Errorf("got HTTP status code %d, want %d", got, want)
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}
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}
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func TestHandlerTimeout(t *testing.T) {
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reg := prometheus.NewRegistry()
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handler := HandlerFor(reg, HandlerOpts{Timeout: time.Millisecond})
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w := httptest.NewRecorder()
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request, _ := http.NewRequest("GET", "/", nil)
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request.Header.Add("Accept", "test/plain")
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c := blockingCollector{Block: make(chan struct{}), CollectStarted: make(chan struct{}, 1)}
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reg.MustRegister(c)
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handler.ServeHTTP(w, request)
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if got, want := w.Code, http.StatusServiceUnavailable; got != want {
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t.Errorf("got HTTP status code %d, want %d", got, want)
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}
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if got, want := w.Body.String(), "Exceeded configured timeout of 1ms.\n"; got != want {
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t.Errorf("got body %q, want %q", got, want)
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}
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close(c.Block) // To not leak a goroutine.
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}
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