node_exporter/node_exporter_test.go

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// Copyright 2017 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 main
import (
"fmt"
"io/ioutil"
"net/http"
"os"
"os/exec"
"path/filepath"
"testing"
"time"
"github.com/prometheus/procfs"
)
var (
binary = filepath.Join(os.Getenv("GOPATH"), "bin/node_exporter")
)
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const (
address = "localhost:19100"
)
func TestFileDescriptorLeak(t *testing.T) {
if _, err := os.Stat(binary); err != nil {
t.Skipf("node_exporter binary not available, try to run `make build` first: %s", err)
}
fs, err := procfs.NewDefaultFS()
if err != nil {
t.Skipf("proc filesystem is not available, but currently required to read number of open file descriptors: %s", err)
}
if _, err := fs.Stat(); err != nil {
t.Errorf("unable to read process stats: %s", err)
}
exporter := exec.Command(binary, "--web.listen-address", address)
test := func(pid int) error {
if err := queryExporter(address); err != nil {
return err
}
proc, err := procfs.NewProc(pid)
if err != nil {
return err
}
fdsBefore, err := proc.FileDescriptors()
if err != nil {
return err
}
for i := 0; i < 5; i++ {
if err := queryExporter(address); err != nil {
return err
}
}
fdsAfter, err := proc.FileDescriptors()
if err != nil {
return err
}
if want, have := len(fdsBefore), len(fdsAfter); want != have {
return fmt.Errorf("want %d open file descriptors after metrics scrape, have %d", want, have)
}
return nil
}
if err := runCommandAndTests(exporter, address, test); err != nil {
t.Error(err)
}
}
func TestHandlingOfDuplicatedMetrics(t *testing.T) {
if _, err := os.Stat(binary); err != nil {
t.Skipf("node_exporter binary not available, try to run `make build` first: %s", err)
}
dir, err := ioutil.TempDir("", "node-exporter")
if err != nil {
t.Fatal(err)
}
defer os.RemoveAll(dir)
content := []byte("dummy_metric 1\n")
if err := ioutil.WriteFile(filepath.Join(dir, "a.prom"), content, 0600); err != nil {
t.Fatal(err)
}
if err := ioutil.WriteFile(filepath.Join(dir, "b.prom"), content, 0600); err != nil {
t.Fatal(err)
}
exporter := exec.Command(binary, "--web.listen-address", address, "--collector.textfile.directory", dir)
test := func(_ int) error {
return queryExporter(address)
}
if err := runCommandAndTests(exporter, address, test); err != nil {
t.Error(err)
}
}
func queryExporter(address string) error {
resp, err := http.Get(fmt.Sprintf("http://%s/metrics", address))
if err != nil {
return err
}
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b, err := ioutil.ReadAll(resp.Body)
if err != nil {
return err
}
if err := resp.Body.Close(); err != nil {
return err
}
if want, have := http.StatusOK, resp.StatusCode; want != have {
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return fmt.Errorf("want /metrics status code %d, have %d. Body:\n%s", want, have, b)
}
return nil
}
func runCommandAndTests(cmd *exec.Cmd, address string, fn func(pid int) error) error {
if err := cmd.Start(); err != nil {
return fmt.Errorf("failed to start command: %s", err)
}
time.Sleep(50 * time.Millisecond)
for i := 0; i < 10; i++ {
if err := queryExporter(address); err == nil {
break
}
time.Sleep(500 * time.Millisecond)
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if cmd.Process == nil || i == 9 {
return fmt.Errorf("can't start command")
}
}
errc := make(chan error)
go func(pid int) {
errc <- fn(pid)
}(cmd.Process.Pid)
err := <-errc
if cmd.Process != nil {
cmd.Process.Kill()
}
return err
}