prometheus/retrieval/scrape_test.go
Brian Brazil b87d3ca9ea Create stale markers when a target is stopped.
When a target is no longer returned from SD stop()
is called. However it may be recreated before the
next scrape interval happens. So we wait to set stalemarkers
until the scrape of the new target would have happened
and been ingested, which is 2 scrape intervals.

If we're shutting down the context will be cancelled,
so return immediately rather than holding things up for potentially
minutes waiting to safely set stalemarkers no newer than now.
If the server starts immediately back up again all is well.
If not, we're missing some stale markers.
2017-05-16 18:33:51 +01:00

899 lines
23 KiB
Go

// 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 retrieval
import (
"bytes"
"fmt"
"io"
"io/ioutil"
"math"
"net/http"
"net/http/httptest"
"net/url"
"reflect"
"strings"
"sync"
"testing"
"time"
"github.com/prometheus/common/model"
"github.com/stretchr/testify/require"
"golang.org/x/net/context"
"github.com/prometheus/prometheus/config"
"github.com/prometheus/prometheus/pkg/labels"
"github.com/prometheus/prometheus/pkg/timestamp"
"github.com/prometheus/prometheus/pkg/value"
"github.com/prometheus/prometheus/storage"
)
func TestNewScrapePool(t *testing.T) {
var (
app = &nopAppendable{}
cfg = &config.ScrapeConfig{}
sp = newScrapePool(context.Background(), cfg, app)
)
if a, ok := sp.appendable.(*nopAppendable); !ok || a != app {
t.Fatalf("Wrong sample appender")
}
if sp.config != cfg {
t.Fatalf("Wrong scrape config")
}
if sp.newLoop == nil {
t.Fatalf("newLoop function not initialized")
}
}
type testLoop struct {
startFunc func(interval, timeout time.Duration, errc chan<- error)
stopFunc func()
}
func (l *testLoop) run(interval, timeout time.Duration, errc chan<- error) {
l.startFunc(interval, timeout, errc)
}
func (l *testLoop) stop() {
l.stopFunc()
}
func TestScrapePoolStop(t *testing.T) {
sp := &scrapePool{
targets: map[uint64]*Target{},
loops: map[uint64]loop{},
}
var mtx sync.Mutex
stopped := map[uint64]bool{}
numTargets := 20
// Stopping the scrape pool must call stop() on all scrape loops,
// clean them and the respective targets up. It must wait until each loop's
// stop function returned before returning itself.
for i := 0; i < numTargets; i++ {
t := &Target{
labels: labels.FromStrings(model.AddressLabel, fmt.Sprintf("example.com:%d", i)),
}
l := &testLoop{}
l.stopFunc = func() {
time.Sleep(time.Duration(i*20) * time.Millisecond)
mtx.Lock()
stopped[t.hash()] = true
mtx.Unlock()
}
sp.targets[t.hash()] = t
sp.loops[t.hash()] = l
}
done := make(chan struct{})
stopTime := time.Now()
go func() {
sp.stop()
close(done)
}()
select {
case <-time.After(5 * time.Second):
t.Fatalf("scrapeLoop.stop() did not return as expected")
case <-done:
// This should have taken at least as long as the last target slept.
if time.Since(stopTime) < time.Duration(numTargets*20)*time.Millisecond {
t.Fatalf("scrapeLoop.stop() exited before all targets stopped")
}
}
mtx.Lock()
if len(stopped) != numTargets {
t.Fatalf("Expected 20 stopped loops, got %d", len(stopped))
}
mtx.Unlock()
if len(sp.targets) > 0 {
t.Fatalf("Targets were not cleared on stopping: %d left", len(sp.targets))
}
if len(sp.loops) > 0 {
t.Fatalf("Loops were not cleared on stopping: %d left", len(sp.loops))
}
}
func TestScrapePoolReload(t *testing.T) {
var mtx sync.Mutex
numTargets := 20
stopped := map[uint64]bool{}
reloadCfg := &config.ScrapeConfig{
ScrapeInterval: model.Duration(3 * time.Second),
ScrapeTimeout: model.Duration(2 * time.Second),
}
// On starting to run, new loops created on reload check whether their preceding
// equivalents have been stopped.
newLoop := func(ctx context.Context, s scraper, app, reportApp func() storage.Appender) loop {
l := &testLoop{}
l.startFunc = func(interval, timeout time.Duration, errc chan<- error) {
if interval != 3*time.Second {
t.Errorf("Expected scrape interval %d but got %d", 3*time.Second, interval)
}
if timeout != 2*time.Second {
t.Errorf("Expected scrape timeout %d but got %d", 2*time.Second, timeout)
}
mtx.Lock()
if !stopped[s.(*targetScraper).hash()] {
t.Errorf("Scrape loop for %v not stopped yet", s.(*targetScraper))
}
mtx.Unlock()
}
return l
}
sp := &scrapePool{
appendable: &nopAppendable{},
targets: map[uint64]*Target{},
loops: map[uint64]loop{},
newLoop: newLoop,
}
// Reloading a scrape pool with a new scrape configuration must stop all scrape
// loops and start new ones. A new loop must not be started before the preceding
// one terminated.
for i := 0; i < numTargets; i++ {
t := &Target{
labels: labels.FromStrings(model.AddressLabel, fmt.Sprintf("example.com:%d", i)),
}
l := &testLoop{}
l.stopFunc = func() {
time.Sleep(time.Duration(i*20) * time.Millisecond)
mtx.Lock()
stopped[t.hash()] = true
mtx.Unlock()
}
sp.targets[t.hash()] = t
sp.loops[t.hash()] = l
}
done := make(chan struct{})
beforeTargets := map[uint64]*Target{}
for h, t := range sp.targets {
beforeTargets[h] = t
}
reloadTime := time.Now()
go func() {
sp.reload(reloadCfg)
close(done)
}()
select {
case <-time.After(5 * time.Second):
t.Fatalf("scrapeLoop.reload() did not return as expected")
case <-done:
// This should have taken at least as long as the last target slept.
if time.Since(reloadTime) < time.Duration(numTargets*20)*time.Millisecond {
t.Fatalf("scrapeLoop.stop() exited before all targets stopped")
}
}
mtx.Lock()
if len(stopped) != numTargets {
t.Fatalf("Expected 20 stopped loops, got %d", len(stopped))
}
mtx.Unlock()
if !reflect.DeepEqual(sp.targets, beforeTargets) {
t.Fatalf("Reloading affected target states unexpectedly")
}
if len(sp.loops) != numTargets {
t.Fatalf("Expected %d loops after reload but got %d", numTargets, len(sp.loops))
}
}
func TestScrapePoolReportAppender(t *testing.T) {
cfg := &config.ScrapeConfig{
MetricRelabelConfigs: []*config.RelabelConfig{
{}, {}, {},
},
}
target := newTestTarget("example.com:80", 10*time.Millisecond, nil)
app := &nopAppendable{}
sp := newScrapePool(context.Background(), cfg, app)
cfg.HonorLabels = false
wrapped := sp.reportAppender(target)
rl, ok := wrapped.(ruleLabelsAppender)
if !ok {
t.Fatalf("Expected ruleLabelsAppender but got %T", wrapped)
}
if _, ok := rl.Appender.(nopAppender); !ok {
t.Fatalf("Expected base appender but got %T", rl.Appender)
}
cfg.HonorLabels = true
wrapped = sp.reportAppender(target)
hl, ok := wrapped.(ruleLabelsAppender)
if !ok {
t.Fatalf("Expected ruleLabelsAppender but got %T", wrapped)
}
if _, ok := rl.Appender.(nopAppender); !ok {
t.Fatalf("Expected base appender but got %T", hl.Appender)
}
}
func TestScrapePoolSampleAppender(t *testing.T) {
cfg := &config.ScrapeConfig{
MetricRelabelConfigs: []*config.RelabelConfig{
{}, {}, {},
},
}
target := newTestTarget("example.com:80", 10*time.Millisecond, nil)
app := &nopAppendable{}
sp := newScrapePool(context.Background(), cfg, app)
cfg.HonorLabels = false
wrapped := sp.sampleAppender(target)
rl, ok := wrapped.(ruleLabelsAppender)
if !ok {
t.Fatalf("Expected ruleLabelsAppender but got %T", wrapped)
}
re, ok := rl.Appender.(relabelAppender)
if !ok {
t.Fatalf("Expected relabelAppender but got %T", rl.Appender)
}
if _, ok := re.Appender.(nopAppender); !ok {
t.Fatalf("Expected base appender but got %T", re.Appender)
}
cfg.HonorLabels = true
cfg.SampleLimit = 100
wrapped = sp.sampleAppender(target)
hl, ok := wrapped.(honorLabelsAppender)
if !ok {
t.Fatalf("Expected honorLabelsAppender but got %T", wrapped)
}
re, ok = hl.Appender.(relabelAppender)
if !ok {
t.Fatalf("Expected relabelAppender but got %T", hl.Appender)
}
lm, ok := re.Appender.(*limitAppender)
if !ok {
t.Fatalf("Expected limitAppender but got %T", lm.Appender)
}
if _, ok := lm.Appender.(nopAppender); !ok {
t.Fatalf("Expected base appender but got %T", re.Appender)
}
}
func TestScrapeLoopStopBeforeRun(t *testing.T) {
scraper := &testScraper{}
sl := newScrapeLoop(context.Background(), scraper, nil, nil)
// The scrape pool synchronizes on stopping scrape loops. However, new scrape
// loops are started asynchronously. Thus it's possible, that a loop is stopped
// again before having started properly.
// Stopping not-yet-started loops must block until the run method was called and exited.
// The run method must exit immediately.
stopDone := make(chan struct{})
go func() {
sl.stop()
close(stopDone)
}()
select {
case <-stopDone:
t.Fatalf("Stopping terminated before run exited successfully")
case <-time.After(500 * time.Millisecond):
}
// Running the scrape loop must exit before calling the scraper even once.
scraper.scrapeFunc = func(context.Context, io.Writer) error {
t.Fatalf("scraper was called for terminated scrape loop")
return nil
}
runDone := make(chan struct{})
go func() {
sl.run(1, 0, nil)
close(runDone)
}()
select {
case <-runDone:
case <-time.After(1 * time.Second):
t.Fatalf("Running terminated scrape loop did not exit")
}
select {
case <-stopDone:
case <-time.After(1 * time.Second):
t.Fatalf("Stopping did not terminate after running exited")
}
}
func TestScrapeLoopStop(t *testing.T) {
appender := &collectResultAppender{}
var (
signal = make(chan struct{})
scraper = &testScraper{}
app = func() storage.Appender { return appender }
reportApp = func() storage.Appender { return &nopAppender{} }
numScrapes = 0
)
defer close(signal)
sl := newScrapeLoop(context.Background(), scraper, app, reportApp)
// Succeed once, several failures, then stop.
scraper.scrapeFunc = func(ctx context.Context, w io.Writer) error {
numScrapes += 1
if numScrapes == 2 {
go func() {
sl.stop()
}()
}
w.Write([]byte("metric_a 42\n"))
return nil
}
go func() {
sl.run(10*time.Millisecond, time.Hour, nil)
signal <- struct{}{}
}()
select {
case <-signal:
case <-time.After(5 * time.Second):
t.Fatalf("Scrape wasn't stopped.")
}
if len(appender.result) < 2 {
t.Fatalf("Appended samples not as expected. Wanted: at least %d samples Got: %d", 2, len(appender.result))
}
if !value.IsStaleNaN(appender.result[len(appender.result)-1].v) {
t.Fatalf("Appended last sample not as expected. Wanted: stale NaN Got: %x", math.Float64bits(appender.result[len(appender.result)].v))
}
}
func TestScrapeLoopRun(t *testing.T) {
var (
signal = make(chan struct{})
errc = make(chan error)
scraper = &testScraper{}
app = func() storage.Appender { return &nopAppender{} }
reportApp = func() storage.Appender { return &nopAppender{} }
)
defer close(signal)
ctx, cancel := context.WithCancel(context.Background())
sl := newScrapeLoop(ctx, scraper, app, reportApp)
// The loop must terminate during the initial offset if the context
// is canceled.
scraper.offsetDur = time.Hour
go func() {
sl.run(time.Second, time.Hour, errc)
signal <- struct{}{}
}()
// Wait to make sure we are actually waiting on the offset.
time.Sleep(1 * time.Second)
cancel()
select {
case <-signal:
case <-time.After(5 * time.Second):
t.Fatalf("Cancelation during initial offset failed")
case err := <-errc:
t.Fatalf("Unexpected error: %s", err)
}
// The provided timeout must cause cancelation of the context passed down to the
// scraper. The scraper has to respect the context.
scraper.offsetDur = 0
block := make(chan struct{})
scraper.scrapeFunc = func(ctx context.Context, _ io.Writer) error {
select {
case <-block:
case <-ctx.Done():
return ctx.Err()
}
return nil
}
ctx, cancel = context.WithCancel(context.Background())
sl = newScrapeLoop(ctx, scraper, app, reportApp)
go func() {
sl.run(time.Second, 100*time.Millisecond, errc)
signal <- struct{}{}
}()
select {
case err := <-errc:
if err != context.DeadlineExceeded {
t.Fatalf("Expected timeout error but got: %s", err)
}
case <-time.After(3 * time.Second):
t.Fatalf("Expected timeout error but got none")
}
// We already caught the timeout error and are certainly in the loop.
// Let the scrapes returns immediately to cause no further timeout errors
// and check whether canceling the parent context terminates the loop.
close(block)
cancel()
select {
case <-signal:
// Loop terminated as expected.
case err := <-errc:
t.Fatalf("Unexpected error: %s", err)
case <-time.After(3 * time.Second):
t.Fatalf("Loop did not terminate on context cancelation")
}
}
func TestScrapeLoopRunCreatesStaleMarkersOnFailedScrape(t *testing.T) {
appender := &collectResultAppender{}
var (
signal = make(chan struct{})
scraper = &testScraper{}
app = func() storage.Appender { return appender }
reportApp = func() storage.Appender { return &nopAppender{} }
numScrapes = 0
)
defer close(signal)
ctx, cancel := context.WithCancel(context.Background())
sl := newScrapeLoop(ctx, scraper, app, reportApp)
// Succeed once, several failures, then stop.
scraper.scrapeFunc = func(ctx context.Context, w io.Writer) error {
numScrapes += 1
if numScrapes == 1 {
w.Write([]byte("metric_a 42\n"))
return nil
} else if numScrapes == 5 {
cancel()
}
return fmt.Errorf("Scrape failed.")
}
go func() {
sl.run(10*time.Millisecond, time.Hour, nil)
signal <- struct{}{}
}()
select {
case <-signal:
case <-time.After(5 * time.Second):
t.Fatalf("Scrape wasn't stopped.")
}
if len(appender.result) != 2 {
t.Fatalf("Appended samples not as expected. Wanted: %d samples Got: %d", 2, len(appender.result))
}
if appender.result[0].v != 42.0 {
t.Fatalf("Appended first sample not as expected. Wanted: %f Got: %f", appender.result[0], 42)
}
if !value.IsStaleNaN(appender.result[1].v) {
t.Fatalf("Appended second sample not as expected. Wanted: stale NaN Got: %x", math.Float64bits(appender.result[1].v))
}
}
func TestScrapeLoopRunCreatesStaleMarkersOnParseFailure(t *testing.T) {
appender := &collectResultAppender{}
var (
signal = make(chan struct{})
scraper = &testScraper{}
app = func() storage.Appender { return appender }
reportApp = func() storage.Appender { return &nopAppender{} }
numScrapes = 0
)
defer close(signal)
ctx, cancel := context.WithCancel(context.Background())
sl := newScrapeLoop(ctx, scraper, app, reportApp)
// Succeed once, several failures, then stop.
scraper.scrapeFunc = func(ctx context.Context, w io.Writer) error {
numScrapes += 1
if numScrapes == 1 {
w.Write([]byte("metric_a 42\n"))
return nil
} else if numScrapes == 2 {
w.Write([]byte("7&-\n"))
return nil
} else if numScrapes == 3 {
cancel()
}
return fmt.Errorf("Scrape failed.")
}
go func() {
sl.run(10*time.Millisecond, time.Hour, nil)
signal <- struct{}{}
}()
select {
case <-signal:
case <-time.After(5 * time.Second):
t.Fatalf("Scrape wasn't stopped.")
}
if len(appender.result) != 2 {
t.Fatalf("Appended samples not as expected. Wanted: %d samples Got: %d", 2, len(appender.result))
}
if appender.result[0].v != 42.0 {
t.Fatalf("Appended first sample not as expected. Wanted: %f Got: %f", appender.result[0], 42)
}
if !value.IsStaleNaN(appender.result[1].v) {
t.Fatalf("Appended second sample not as expected. Wanted: stale NaN Got: %x", math.Float64bits(appender.result[1].v))
}
}
func TestScrapeLoopAppend(t *testing.T) {
app := &collectResultAppender{}
sl := &scrapeLoop{
appender: func() storage.Appender { return app },
reportAppender: func() storage.Appender { return nopAppender{} },
refCache: map[string]uint64{},
lsetCache: map[uint64]lsetCacheEntry{},
}
now := time.Now()
_, _, err := sl.append([]byte("metric_a 1\nmetric_b NaN\n"), now)
if err != nil {
t.Fatalf("Unexpected append error: %s", err)
}
ingestedNaN := math.Float64bits(app.result[1].v)
if ingestedNaN != value.NormalNaN {
t.Fatalf("Appended NaN samples wasn't as expected. Wanted: %x Got: %x", value.NormalNaN, ingestedNaN)
}
// DeepEqual will report NaNs as being different, so replace with a different value.
app.result[1].v = 42
want := []sample{
{
metric: labels.FromStrings(model.MetricNameLabel, "metric_a"),
t: timestamp.FromTime(now),
v: 1,
},
{
metric: labels.FromStrings(model.MetricNameLabel, "metric_b"),
t: timestamp.FromTime(now),
v: 42,
},
}
if !reflect.DeepEqual(want, app.result) {
t.Fatalf("Appended samples not as expected. Wanted: %+v Got: %+v", want, app.result)
}
}
func TestScrapeLoopAppendStaleness(t *testing.T) {
app := &collectResultAppender{}
sl := &scrapeLoop{
appender: func() storage.Appender { return app },
reportAppender: func() storage.Appender { return nopAppender{} },
refCache: map[string]uint64{},
lsetCache: map[uint64]lsetCacheEntry{},
}
now := time.Now()
_, _, err := sl.append([]byte("metric_a 1\n"), now)
if err != nil {
t.Fatalf("Unexpected append error: %s", err)
}
_, _, err = sl.append([]byte(""), now.Add(time.Second))
if err != nil {
t.Fatalf("Unexpected append error: %s", err)
}
ingestedNaN := math.Float64bits(app.result[1].v)
if ingestedNaN != value.StaleNaN {
t.Fatalf("Appended stale sample wasn't as expected. Wanted: %x Got: %x", value.StaleNaN, ingestedNaN)
}
// DeepEqual will report NaNs as being different, so replace with a different value.
app.result[1].v = 42
want := []sample{
{
metric: labels.FromStrings(model.MetricNameLabel, "metric_a"),
t: timestamp.FromTime(now),
v: 1,
},
{
metric: labels.FromStrings(model.MetricNameLabel, "metric_a"),
t: timestamp.FromTime(now.Add(time.Second)),
v: 42,
},
}
if !reflect.DeepEqual(want, app.result) {
t.Fatalf("Appended samples not as expected. Wanted: %+v Got: %+v", want, app.result)
}
}
func TestScrapeLoopAppendNoStalenessIfTimestamp(t *testing.T) {
app := &collectResultAppender{}
sl := &scrapeLoop{
appender: func() storage.Appender { return app },
reportAppender: func() storage.Appender { return nopAppender{} },
refCache: map[string]uint64{},
lsetCache: map[uint64]lsetCacheEntry{},
}
now := time.Now()
_, _, err := sl.append([]byte("metric_a 1 1000\n"), now)
if err != nil {
t.Fatalf("Unexpected append error: %s", err)
}
_, _, err = sl.append([]byte(""), now.Add(time.Second))
if err != nil {
t.Fatalf("Unexpected append error: %s", err)
}
want := []sample{
{
metric: labels.FromStrings(model.MetricNameLabel, "metric_a"),
t: 1000,
v: 1,
},
}
if !reflect.DeepEqual(want, app.result) {
t.Fatalf("Appended samples not as expected. Wanted: %+v Got: %+v", want, app.result)
}
}
type errorAppender struct {
collectResultAppender
}
func (app *errorAppender) Add(lset labels.Labels, t int64, v float64) (uint64, error) {
if lset.Get(model.MetricNameLabel) == "out_of_order" {
return 0, storage.ErrOutOfOrderSample
} else if lset.Get(model.MetricNameLabel) == "amend" {
return 0, storage.ErrDuplicateSampleForTimestamp
}
return app.collectResultAppender.Add(lset, t, v)
}
func (app *errorAppender) AddFast(ref uint64, t int64, v float64) error {
return app.collectResultAppender.AddFast(ref, t, v)
}
func TestScrapeLoopAppendGracefullyIfAmendOrOutOfOrder(t *testing.T) {
app := &errorAppender{}
sl := &scrapeLoop{
appender: func() storage.Appender { return app },
reportAppender: func() storage.Appender { return nopAppender{} },
refCache: map[string]uint64{},
lsetCache: map[uint64]lsetCacheEntry{},
}
now := time.Unix(1, 0)
_, _, err := sl.append([]byte("out_of_order 1\namend 1\nnormal 1\n"), now)
if err != nil {
t.Fatalf("Unexpected append error: %s", err)
}
want := []sample{
{
metric: labels.FromStrings(model.MetricNameLabel, "normal"),
t: timestamp.FromTime(now),
v: 1,
},
}
if !reflect.DeepEqual(want, app.result) {
t.Fatalf("Appended samples not as expected. Wanted: %+v Got: %+v", want, app.result)
}
}
func TestTargetScraperScrapeOK(t *testing.T) {
const (
configTimeout = 1500 * time.Millisecond
expectedTimeout = "1.500000"
)
server := httptest.NewServer(
http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
timeout := r.Header.Get("X-Prometheus-Scrape-Timeout-Seconds")
if timeout != expectedTimeout {
t.Errorf("Scrape timeout did not match expected timeout")
t.Errorf("Expected: %v", expectedTimeout)
t.Fatalf("Got: %v", timeout)
}
w.Header().Set("Content-Type", `text/plain; version=0.0.4`)
w.Write([]byte("metric_a 1\nmetric_b 2\n"))
}),
)
defer server.Close()
serverURL, err := url.Parse(server.URL)
if err != nil {
panic(err)
}
ts := &targetScraper{
Target: &Target{
labels: labels.FromStrings(
model.SchemeLabel, serverURL.Scheme,
model.AddressLabel, serverURL.Host,
),
},
client: http.DefaultClient,
timeout: configTimeout,
}
var buf bytes.Buffer
if err := ts.scrape(context.Background(), &buf); err != nil {
t.Fatalf("Unexpected scrape error: %s", err)
}
require.Equal(t, "metric_a 1\nmetric_b 2\n", buf.String())
}
func TestTargetScrapeScrapeCancel(t *testing.T) {
block := make(chan struct{})
server := httptest.NewServer(
http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
<-block
}),
)
defer server.Close()
serverURL, err := url.Parse(server.URL)
if err != nil {
panic(err)
}
ts := &targetScraper{
Target: &Target{
labels: labels.FromStrings(
model.SchemeLabel, serverURL.Scheme,
model.AddressLabel, serverURL.Host,
),
},
client: http.DefaultClient,
}
ctx, cancel := context.WithCancel(context.Background())
errc := make(chan error)
go func() {
time.Sleep(1 * time.Second)
cancel()
}()
go func() {
if err := ts.scrape(ctx, ioutil.Discard); err != context.Canceled {
errc <- fmt.Errorf("Expected context cancelation error but got: %s", err)
}
close(errc)
}()
select {
case <-time.After(5 * time.Second):
t.Fatalf("Scrape function did not return unexpectedly")
case err := <-errc:
if err != nil {
t.Fatalf(err.Error())
}
}
// If this is closed in a defer above the function the test server
// does not terminate and the test doens't complete.
close(block)
}
func TestTargetScrapeScrapeNotFound(t *testing.T) {
server := httptest.NewServer(
http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
w.WriteHeader(http.StatusNotFound)
}),
)
defer server.Close()
serverURL, err := url.Parse(server.URL)
if err != nil {
panic(err)
}
ts := &targetScraper{
Target: &Target{
labels: labels.FromStrings(
model.SchemeLabel, serverURL.Scheme,
model.AddressLabel, serverURL.Host,
),
},
client: http.DefaultClient,
}
if err := ts.scrape(context.Background(), ioutil.Discard); !strings.Contains(err.Error(), "404") {
t.Fatalf("Expected \"404 NotFound\" error but got: %s", err)
}
}
// testScraper implements the scraper interface and allows setting values
// returned by its methods. It also allows setting a custom scrape function.
type testScraper struct {
offsetDur time.Duration
lastStart time.Time
lastDuration time.Duration
lastError error
scrapeErr error
scrapeFunc func(context.Context, io.Writer) error
}
func (ts *testScraper) offset(interval time.Duration) time.Duration {
return ts.offsetDur
}
func (ts *testScraper) report(start time.Time, duration time.Duration, err error) {
ts.lastStart = start
ts.lastDuration = duration
ts.lastError = err
}
func (ts *testScraper) scrape(ctx context.Context, w io.Writer) error {
if ts.scrapeFunc != nil {
return ts.scrapeFunc(ctx, w)
}
return ts.scrapeErr
}