225 lines
6.1 KiB
Go
225 lines
6.1 KiB
Go
// Copyright 2016 Google Inc. All Rights Reserved.
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//
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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 collector
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import (
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"fmt"
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"io/ioutil"
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"net"
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"net/http"
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"net/http/httptest"
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"os"
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"os/exec"
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"strings"
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"testing"
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"time"
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"github.com/miekg/dns"
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"github.com/prometheus/client_golang/prometheus"
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"github.com/prometheus/client_golang/prometheus/promhttp"
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)
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func TestDnsmasqExporter(t *testing.T) {
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// NOTE(stapelberg): dnsmasq disables DNS operation upon --port=0 (as
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// opposed to picking a free port). Hence, we must pick one. This is
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// inherently prone to race conditions: another process could grab the port
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// between our ln.Close() and dnsmasq’s bind(). Ideally, dnsmasq would
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// support grabbing a free port and announcing it, or inheriting a listening
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// socket à la systemd socket activation.
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ln, err := net.Listen("tcp", "localhost:0")
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if err != nil {
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t.Fatal(err)
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}
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_, port, err := net.SplitHostPort(ln.Addr().String())
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if err != nil {
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t.Fatal(err)
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}
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ln.Close()
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dnsmasq := exec.Command(
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"dnsmasq",
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"--port="+port,
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"--no-daemon",
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"--cache-size=666",
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"--bind-interfaces",
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"--interface=lo")
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dnsmasq.Stderr = os.Stderr
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fmt.Printf("starting %v\n", dnsmasq.Args)
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if err := dnsmasq.Start(); err != nil {
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t.Fatal(err)
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}
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defer dnsmasq.Process.Kill()
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// Wait until dnsmasq started up
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resolver := &dns.Client{}
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for {
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// Cause a cache miss (dnsmasq must forward this query)
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var m dns.Msg
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m.SetQuestion("localhost.", dns.TypeA)
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if _, _, err := resolver.Exchange(&m, "localhost:"+port); err == nil {
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break
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}
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time.Sleep(10 * time.Millisecond) // do not hog the CPU
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}
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testDataFilePath := os.Getenv("TESTDATA_FILE_PATH")
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if testDataFilePath == "" {
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testDataFilePath = "./testdata/dnsmasq.leases"
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}
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cfg := Config{
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DnsClient: &dns.Client{
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SingleInflight: true,
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},
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DnsmasqAddr: "localhost:" + port,
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LeasesPath: testDataFilePath,
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ExposeLeases: false,
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}
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c := New(cfg)
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t.Run("first", func(t *testing.T) {
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metrics := fetchMetrics(t, c)
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want := map[string]string{
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"dnsmasq_leases": "2",
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"dnsmasq_cachesize": "666",
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"dnsmasq_hits": "5",
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"dnsmasq_misses": "0",
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}
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for key, val := range want {
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if got, want := metrics[key], val; got != want {
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t.Errorf("metric %q: got %q, want %q", key, got, want)
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}
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}
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})
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t.Run("second", func(t *testing.T) {
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metrics := fetchMetrics(t, c)
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want := map[string]string{
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"dnsmasq_leases": "2",
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"dnsmasq_cachesize": "666",
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"dnsmasq_hits": "12",
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"dnsmasq_misses": "0",
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}
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for key, val := range want {
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if got, want := metrics[key], val; got != want {
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t.Errorf("metric %q: got %q, want %q", key, got, want)
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}
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}
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})
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// Cause a cache miss (dnsmasq must forward this query)
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var m dns.Msg
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m.SetQuestion("no.such.domain.invalid.", dns.TypeA)
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if _, _, err := resolver.Exchange(&m, "localhost:"+port); err != nil {
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t.Fatal(err)
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}
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t.Run("after query", func(t *testing.T) {
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metrics := fetchMetrics(t, c)
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want := map[string]string{
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"dnsmasq_leases": "2",
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"dnsmasq_cachesize": "666",
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"dnsmasq_hits": "19",
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"dnsmasq_misses": "1",
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}
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for key, val := range want {
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if got, want := metrics[key], val; got != want {
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t.Errorf("metric %q: got %q, want %q", key, got, want)
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}
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}
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})
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t.Run("should not expose lease information when disabled", func(t *testing.T) {
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metrics := fetchMetrics(t, c)
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for key, _ := range metrics {
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if strings.Contains(key, "dnsmasq_lease_expiry") {
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t.Errorf("lease information should not be exposed when disabled: %v", key)
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}
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}
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})
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c.cfg.ExposeLeases = true
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t.Run("with high-cardinality lease metrics enabled", func(t *testing.T) {
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metrics := fetchMetrics(t, c)
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want := map[string]string{
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"dnsmasq_leases": "2",
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"dnsmasq_cachesize": "666",
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"dnsmasq_hits": "33",
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"dnsmasq_misses": "1",
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"dnsmasq_lease_expiry{client_id=\"00:00:00:00:00:00\",computer_name=\"host-1\",ip_addr=\"10.10.10.10\",mac_addr=\"00:00:00:00:00:00\"}": "1.625595932e+09",
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"dnsmasq_lease_expiry{client_id=\"00:00:00:00:00:01\",computer_name=\"host-2\",ip_addr=\"10.10.10.11\",mac_addr=\"00:00:00:00:00:01\"}": "0",
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}
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for key, val := range want {
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if got, want := metrics[key], val; got != want {
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t.Errorf("metric %q: got %q, want %q", key, got, want)
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}
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}
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})
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c.cfg.LeasesPath = "testdata/dnsmasq.leases.does.not.exists"
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t.Run("without leases file", func(t *testing.T) {
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metrics := fetchMetrics(t, c)
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want := map[string]string{
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"dnsmasq_leases": "0",
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"dnsmasq_cachesize": "666",
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"dnsmasq_hits": "40",
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"dnsmasq_misses": "1",
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}
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for key, val := range want {
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if got, want := metrics[key], val; got != want {
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t.Errorf("metric %q: got %q, want %q", key, got, want)
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}
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}
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})
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}
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func fetchMetrics(t *testing.T, c *Collector) map[string]string {
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reg := prometheus.NewRegistry()
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reg.MustRegister(c)
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handler := promhttp.HandlerFor(reg, promhttp.HandlerOpts{})
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rec := httptest.NewRecorder()
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handler.ServeHTTP(rec, httptest.NewRequest("GET", "/metrics", nil))
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resp := rec.Result()
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if got, want := resp.StatusCode, http.StatusOK; got != want {
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b, _ := ioutil.ReadAll(resp.Body)
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t.Fatalf("unexpected HTTP status: got %v (%v), want %v", resp.Status, string(b), want)
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}
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body, err := ioutil.ReadAll(resp.Body)
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if err != nil {
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t.Fatal(err)
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}
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metrics := make(map[string]string)
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for _, line := range strings.Split(strings.TrimSpace(string(body)), "\n") {
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if strings.HasPrefix(line, "#") {
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continue
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}
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parts := strings.Split(line, " ")
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if len(parts) < 2 {
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continue
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}
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if !strings.HasPrefix(parts[0], "dnsmasq_") {
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continue
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}
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metrics[parts[0]] = parts[1]
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}
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return metrics
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}
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