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Author SHA1 Message Date
bwplotka db2636b0a3 Assure we exhaust bodies of all HTTP responses.
Signed-off-by: bwplotka <bwplotka@gmail.com>
2022-08-22 19:43:03 +02:00
5 changed files with 159 additions and 32 deletions

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@ -24,6 +24,8 @@ import (
"path"
"strings"
"time"
"github.com/prometheus/client_golang/internal/errcapture"
)
// DefaultRoundTripper is used if no RoundTripper is set in Config.
@ -118,39 +120,17 @@ func (c *httpClient) URL(ep string, args map[string]string) *url.URL {
return &u
}
func (c *httpClient) Do(ctx context.Context, req *http.Request) (*http.Response, []byte, error) {
func (c *httpClient) Do(ctx context.Context, req *http.Request) (_ *http.Response, _ []byte, err error) {
if ctx != nil {
req = req.WithContext(ctx)
}
resp, err := c.client.Do(req)
defer func() {
if resp != nil {
resp.Body.Close()
}
}()
if err != nil {
return nil, nil, err
}
defer errcapture.ExhaustClose(&err, resp.Body, "close response body")
var body []byte
done := make(chan struct{})
go func() {
var buf bytes.Buffer
_, err = buf.ReadFrom(resp.Body)
body = buf.Bytes()
close(done)
}()
select {
case <-ctx.Done():
<-done
err = resp.Body.Close()
if err == nil {
err = ctx.Err()
}
case <-done:
}
return resp, body, err
var buf bytes.Buffer
_, err = buf.ReadFrom(resp.Body)
return resp, buf.Bytes(), err
}

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@ -0,0 +1,61 @@
// Copyright 2014 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 errcapture
import (
"errors"
"fmt"
"io"
"io/ioutil"
"os"
"github.com/prometheus/client_golang/prometheus"
)
type doFunc func() error
// Do runs function and on error return error by argument including the given error (usually
// from caller function).
func Do(err *error, doer doFunc, format string, a ...interface{}) {
derr := doer()
if err == nil || derr == nil {
return
}
// For os closers, it's a common case to double close.
// From reliability purpose this is not a problem it may only indicate surprising execution path.
if errors.Is(derr, os.ErrClosed) {
return
}
errs := prometheus.MultiError{}
errs.Append(*err)
errs.Append(fmt.Errorf(format+": %w", append(a, derr)...))
*err = errs
}
// ExhaustClose closes the io.ReadCloser with error capture but exhausts the reader before.
func ExhaustClose(err *error, r io.ReadCloser, format string, a ...interface{}) {
_, copyErr := io.Copy(ioutil.Discard, r)
Do(err, r.Close, format, a...)
if copyErr == nil {
return
}
errs := prometheus.MultiError{}
errs.Append(copyErr)
errs.Append(*err)
*err = errs
}

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@ -0,0 +1,82 @@
// Copyright 2014 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 errcapture
import (
"errors"
"io"
"testing"
)
type testCloser struct {
err error
}
func (c testCloser) Close() error {
return c.err
}
func TestDo(t *testing.T) {
for _, tcase := range []struct {
err error
closer io.Closer
expectedErrStr string
}{
{
err: nil,
closer: testCloser{err: nil},
expectedErrStr: "",
},
{
err: errors.New("test"),
closer: testCloser{err: nil},
expectedErrStr: "test",
},
{
err: nil,
closer: testCloser{err: errors.New("test")},
expectedErrStr: "1 error(s) occurred:\n* close: test",
},
{
err: errors.New("test"),
closer: testCloser{err: errors.New("test")},
expectedErrStr: "2 error(s) occurred:\n* test\n* close: test",
},
} {
if ok := t.Run("", func(t *testing.T) {
ret := tcase.err
Do(&ret, tcase.closer.Close, "close")
if tcase.expectedErrStr == "" {
if ret != nil {
t.Error("Expected error to be nil")
t.Fail()
}
} else {
if ret == nil {
t.Error("Expected error to be not nil")
t.Fail()
}
if tcase.expectedErrStr != ret.Error() {
t.Errorf("%s != %s", tcase.expectedErrStr, ret.Error())
t.Fail()
}
}
}); !ok {
return
}
}
}

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@ -48,6 +48,7 @@ import (
"github.com/prometheus/common/expfmt"
"github.com/prometheus/common/model"
"github.com/prometheus/client_golang/internal/errcapture"
"github.com/prometheus/client_golang/prometheus"
)
@ -228,7 +229,7 @@ func (p *Pusher) Format(format expfmt.Format) *Pusher {
//
// Delete returns the first error encountered by any method call (including this
// one) in the lifetime of the Pusher.
func (p *Pusher) Delete() error {
func (p *Pusher) Delete() (err error) {
if p.error != nil {
return p.error
}
@ -243,7 +244,8 @@ func (p *Pusher) Delete() error {
if err != nil {
return err
}
defer resp.Body.Close()
defer errcapture.ExhaustClose(&err, resp.Body, "close response body")
if resp.StatusCode != http.StatusAccepted {
body, _ := io.ReadAll(resp.Body) // Ignore any further error as this is for an error message only.
return fmt.Errorf("unexpected status code %d while deleting %s: %s", resp.StatusCode, p.fullURL(), body)
@ -294,7 +296,8 @@ func (p *Pusher) push(ctx context.Context, method string) error {
if err != nil {
return err
}
defer resp.Body.Close()
defer errcapture.ExhaustClose(&err, resp.Body, "close response body")
// Depending on version and configuration of the PGW, StatusOK or StatusAccepted may be returned.
if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusAccepted {
body, _ := io.ReadAll(resp.Body) // Ignore any further error as this is for an error message only.

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@ -48,6 +48,7 @@ import (
dto "github.com/prometheus/client_model/go"
"github.com/prometheus/common/expfmt"
"github.com/prometheus/client_golang/internal/errcapture"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/internal"
)
@ -158,12 +159,12 @@ func GatherAndCount(g prometheus.Gatherer, metricNames ...string) (int, error) {
// ScrapeAndCompare calls a remote exporter's endpoint which is expected to return some metrics in
// plain text format. Then it compares it with the results that the `expected` would return.
// If the `metricNames` is not empty it would filter the comparison only to the given metric names.
func ScrapeAndCompare(url string, expected io.Reader, metricNames ...string) error {
func ScrapeAndCompare(url string, expected io.Reader, metricNames ...string) (err error) {
resp, err := http.Get(url)
if err != nil {
return fmt.Errorf("scraping metrics failed: %w", err)
}
defer resp.Body.Close()
defer errcapture.ExhaustClose(&err, resp.Body, "close response body")
if resp.StatusCode != http.StatusOK {
return fmt.Errorf("the scraping target returned a status code other than 200: %d",