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// Copyright 2016 The Prometheus 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 promhttp
import (
"bytes"
"errors"
"log"
"net/http"
"net/http/httptest"
"strings"
"testing"
"time"
"github.com/prometheus/client_golang/prometheus"
)
type errorCollector struct{}
func (e errorCollector) Describe(ch chan<- *prometheus.Desc) {
ch <- prometheus.NewDesc("invalid_metric", "not helpful", nil, nil)
}
func (e errorCollector) Collect(ch chan<- prometheus.Metric) {
ch <- prometheus.NewInvalidMetric(
prometheus.NewDesc("invalid_metric", "not helpful", nil, nil),
errors.New("collect error"),
)
}
type blockingCollector struct {
CollectStarted, Block chan struct{}
}
func (b blockingCollector) Describe(ch chan<- *prometheus.Desc) {
ch <- prometheus.NewDesc("dummy_desc", "not helpful", nil, nil)
}
func (b blockingCollector) Collect(ch chan<- prometheus.Metric) {
select {
case b.CollectStarted <- struct{}{}:
default:
}
// Collects nothing, just waits for a channel receive.
<-b.Block
}
func TestHandlerErrorHandling(t *testing.T) {
// Create a registry that collects a MetricFamily with two elements,
// another with one, and reports an error.
reg := prometheus.NewRegistry()
cnt := prometheus.NewCounter(prometheus.CounterOpts{
Name: "the_count",
Help: "Ah-ah-ah! Thunder and lightning!",
})
reg.MustRegister(cnt)
cntVec := prometheus.NewCounterVec(
prometheus.CounterOpts{
Name: "name",
Help: "docstring",
ConstLabels: prometheus.Labels{"constname": "constvalue"},
},
[]string{"labelname"},
)
cntVec.WithLabelValues("val1").Inc()
cntVec.WithLabelValues("val2").Inc()
reg.MustRegister(cntVec)
reg.MustRegister(errorCollector{})
logBuf := &bytes.Buffer{}
logger := log.New(logBuf, "", 0)
writer := httptest.NewRecorder()
request, _ := http.NewRequest("GET", "/", nil)
request.Header.Add("Accept", "test/plain")
errorHandler := HandlerFor(reg, HandlerOpts{
ErrorLog: logger,
ErrorHandling: HTTPErrorOnError,
})
continueHandler := HandlerFor(reg, HandlerOpts{
ErrorLog: logger,
ErrorHandling: ContinueOnError,
})
panicHandler := HandlerFor(reg, HandlerOpts{
ErrorLog: logger,
ErrorHandling: PanicOnError,
})
wantMsg := `error gathering metrics: error collecting metric Desc{fqName: "invalid_metric", help: "not helpful", constLabels: {}, variableLabels: []}: collect error
`
wantErrorBody := `An error has occurred during metrics gathering:
error collecting metric Desc{fqName: "invalid_metric", help: "not helpful", constLabels: {}, variableLabels: []}: collect error
`
wantOKBody := `# HELP name docstring
# TYPE name counter
name{constname="constvalue",labelname="val1"} 1
name{constname="constvalue",labelname="val2"} 1
# HELP the_count Ah-ah-ah! Thunder and lightning!
# TYPE the_count counter
the_count 0
`
errorHandler.ServeHTTP(writer, request)
if got, want := writer.Code, http.StatusInternalServerError; got != want {
t.Errorf("got HTTP status code %d, want %d", got, want)
}
if got := logBuf.String(); got != wantMsg {
t.Errorf("got log message:\n%s\nwant log mesage:\n%s\n", got, wantMsg)
}
if got := writer.Body.String(); got != wantErrorBody {
t.Errorf("got body:\n%s\nwant body:\n%s\n", got, wantErrorBody)
}
logBuf.Reset()
writer.Body.Reset()
writer.Code = http.StatusOK
continueHandler.ServeHTTP(writer, request)
if got, want := writer.Code, http.StatusOK; got != want {
t.Errorf("got HTTP status code %d, want %d", got, want)
}
if got := logBuf.String(); got != wantMsg {
t.Errorf("got log message %q, want %q", got, wantMsg)
}
if got := writer.Body.String(); got != wantOKBody {
t.Errorf("got body %q, want %q", got, wantOKBody)
}
defer func() {
if err := recover(); err == nil {
t.Error("expected panic from panicHandler")
}
}()
panicHandler.ServeHTTP(writer, request)
}
func TestInstrumentMetricHandler(t *testing.T) {
reg := prometheus.NewRegistry()
handler := InstrumentMetricHandler(reg, HandlerFor(reg, HandlerOpts{}))
// Do it again to test idempotency.
InstrumentMetricHandler(reg, HandlerFor(reg, HandlerOpts{}))
writer := httptest.NewRecorder()
request, _ := http.NewRequest("GET", "/", nil)
request.Header.Add("Accept", "test/plain")
handler.ServeHTTP(writer, request)
if got, want := writer.Code, http.StatusOK; got != want {
t.Errorf("got HTTP status code %d, want %d", got, want)
}
want := "promhttp_metric_handler_requests_in_flight 1\n"
if got := writer.Body.String(); !strings.Contains(got, want) {
t.Errorf("got body %q, does not contain %q", got, want)
}
want = "promhttp_metric_handler_requests_total{code=\"200\"} 0\n"
if got := writer.Body.String(); !strings.Contains(got, want) {
t.Errorf("got body %q, does not contain %q", got, want)
}
writer.Body.Reset()
handler.ServeHTTP(writer, request)
if got, want := writer.Code, http.StatusOK; got != want {
t.Errorf("got HTTP status code %d, want %d", got, want)
}
want = "promhttp_metric_handler_requests_in_flight 1\n"
if got := writer.Body.String(); !strings.Contains(got, want) {
t.Errorf("got body %q, does not contain %q", got, want)
}
want = "promhttp_metric_handler_requests_total{code=\"200\"} 1\n"
if got := writer.Body.String(); !strings.Contains(got, want) {
t.Errorf("got body %q, does not contain %q", got, want)
}
}
func TestHandlerMaxRequestsInFlight(t *testing.T) {
reg := prometheus.NewRegistry()
handler := HandlerFor(reg, HandlerOpts{MaxRequestsInFlight: 1})
w1 := httptest.NewRecorder()
w2 := httptest.NewRecorder()
w3 := httptest.NewRecorder()
request, _ := http.NewRequest("GET", "/", nil)
request.Header.Add("Accept", "test/plain")
c := blockingCollector{Block: make(chan struct{}), CollectStarted: make(chan struct{}, 1)}
reg.MustRegister(c)
rq1Done := make(chan struct{})
go func() {
handler.ServeHTTP(w1, request)
close(rq1Done)
}()
<-c.CollectStarted
handler.ServeHTTP(w2, request)
if got, want := w2.Code, http.StatusServiceUnavailable; got != want {
t.Errorf("got HTTP status code %d, want %d", got, want)
}
if got, want := w2.Body.String(), "Limit of concurrent requests reached (1), try again later.\n"; got != want {
t.Errorf("got body %q, want %q", got, want)
}
close(c.Block)
<-rq1Done
handler.ServeHTTP(w3, request)
if got, want := w3.Code, http.StatusOK; got != want {
t.Errorf("got HTTP status code %d, want %d", got, want)
}
}
func TestHandlerTimeout(t *testing.T) {
reg := prometheus.NewRegistry()
handler := HandlerFor(reg, HandlerOpts{Timeout: time.Millisecond})
w := httptest.NewRecorder()
request, _ := http.NewRequest("GET", "/", nil)
request.Header.Add("Accept", "test/plain")
c := blockingCollector{Block: make(chan struct{}), CollectStarted: make(chan struct{}, 1)}
reg.MustRegister(c)
handler.ServeHTTP(w, request)
if got, want := w.Code, http.StatusServiceUnavailable; got != want {
t.Errorf("got HTTP status code %d, want %d", got, want)
}
if got, want := w.Body.String(), "Exceeded configured timeout of 1ms.\n"; got != want {
t.Errorf("got body %q, want %q", got, want)
}
close(c.Block) // To not leak a goroutine.
}
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