func (m *targetManager) AddTargetsFromConfig(config config.Config) {
	for _, job := range config.Jobs() {
		if job.SdName != nil {
			m.Lock()
			m.targetPoolForJob(job)
			m.Unlock()
			continue
		}

		for _, targetGroup := range job.TargetGroup {
			baseLabels := clientmodel.LabelSet{
				clientmodel.JobLabel: clientmodel.LabelValue(job.GetName()),
			}
			if targetGroup.Labels != nil {
				for _, label := range targetGroup.Labels.Label {
					baseLabels[clientmodel.LabelName(label.GetName())] = clientmodel.LabelValue(label.GetValue())
				}
			}

			for _, endpoint := range targetGroup.Target {
				target := NewTarget(endpoint, job.ScrapeTimeout(), baseLabels)
				m.AddTarget(job, target)
			}
		}
	}
}

func relabel(labels clientmodel.LabelSet, cfg *config.RelabelConfig) (clientmodel.LabelSet, error) {
	values := make([]string, 0, len(cfg.SourceLabels))
	for _, ln := range cfg.SourceLabels {
		values = append(values, string(labels[ln]))
	}
	val := strings.Join(values, cfg.Separator)

	switch cfg.Action {
	case config.RelabelDrop:
		if cfg.Regex.MatchString(val) {
			return nil, nil
		}
	case config.RelabelKeep:
		if !cfg.Regex.MatchString(val) {
			return nil, nil
		}
	case config.RelabelReplace:
		// If there is no match no replacement must take place.
		if !cfg.Regex.MatchString(val) {
			break
		}
		res := cfg.Regex.ReplaceAllString(val, cfg.Replacement)
		if res == "" {
			delete(labels, cfg.TargetLabel)
		} else {
			labels[cfg.TargetLabel] = clientmodel.LabelValue(res)
		}
	case config.RelabelHashMod:
		mod := sum64(md5.Sum([]byte(val))) % cfg.Modulus
		labels[cfg.TargetLabel] = clientmodel.LabelValue(fmt.Sprintf("%d", mod))
	default:
		panic(fmt.Errorf("retrieval.relabel: unknown relabel action type %q", cfg.Action))
	}
	return labels, nil
}

func (t *target) recordScrapeHealth(ingester extraction.Ingester, timestamp clientmodel.Timestamp, healthy bool, scrapeDuration time.Duration) {
	healthMetric := clientmodel.Metric{}
	durationMetric := clientmodel.Metric{}
	for label, value := range t.baseLabels {
		healthMetric[label] = value
		durationMetric[label] = value
	}
	healthMetric[clientmodel.MetricNameLabel] = clientmodel.LabelValue(scrapeHealthMetricName)
	durationMetric[clientmodel.MetricNameLabel] = clientmodel.LabelValue(scrapeDurationMetricName)
	healthMetric[InstanceLabel] = clientmodel.LabelValue(t.URL())
	durationMetric[InstanceLabel] = clientmodel.LabelValue(t.URL())

	healthValue := clientmodel.SampleValue(0)
	if healthy {
		healthValue = clientmodel.SampleValue(1)
	}

	healthSample := &clientmodel.Sample{
		Metric:    healthMetric,
		Timestamp: timestamp,
		Value:     healthValue,
	}
	durationSample := &clientmodel.Sample{
		Metric:    durationMetric,
		Timestamp: timestamp,
		Value:     clientmodel.SampleValue(float64(scrapeDuration) / float64(time.Second)),
	}

	ingester.Ingest(clientmodel.Samples{healthSample, durationSample})
}

func extractCounter(out Ingester, o *ProcessOptions, f *dto.MetricFamily) error {
	samples := make(model.Samples, 0, len(f.Metric))

	for _, m := range f.Metric {
		if m.Counter == nil {
			continue
		}

		sample := new(model.Sample)
		samples = append(samples, sample)

		if m.TimestampMs != nil {
			sample.Timestamp = model.TimestampFromUnix(*m.TimestampMs / 1000)
		} else {
			sample.Timestamp = o.Timestamp
		}
		sample.Metric = model.Metric{}
		metric := sample.Metric

		for _, p := range m.Label {
			metric[model.LabelName(p.GetName())] = model.LabelValue(p.GetValue())
		}

		metric[model.MetricNameLabel] = model.LabelValue(f.GetName())

		sample.Value = model.SampleValue(m.Counter.GetValue())
	}

	return out.Ingest(&Result{Samples: samples})
}

// watchServices retrieves updates from Consul's services endpoint and sends
// potential updates to the update channel.
func (cd *ConsulDiscovery) watchServices(update chan<- *consulService) {
	var lastIndex uint64
	for {
		catalog := cd.client.Catalog()
		srvs, meta, err := catalog.Services(&consul.QueryOptions{
			WaitIndex: lastIndex,
			WaitTime:  consulWatchTimeout,
		})
		if err != nil {
			log.Errorf("Error refreshing service list: %s", err)
			<-time.After(consulRetryInterval)
			continue
		}
		// If the index equals the previous one, the watch timed out with no update.
		if meta.LastIndex == lastIndex {
			continue
		}
		lastIndex = meta.LastIndex

		cd.mu.Lock()
		select {
		case <-cd.srvsDone:
			cd.mu.Unlock()
			return
		default:
			// Continue.
		}
		// Check for new services.
		for name := range srvs {
			if _, ok := cd.scrapedServices[name]; !ok {
				continue
			}
			srv, ok := cd.services[name]
			if !ok {
				srv = &consulService{
					name:   name,
					tgroup: &config.TargetGroup{},
					done:   make(chan struct{}, 1),
				}
				srv.tgroup.Source = consulSourcePrefix + ":" + name
				cd.services[name] = srv
			}
			srv.tgroup.Labels = clientmodel.LabelSet{
				ConsulServiceLabel: clientmodel.LabelValue(name),
				ConsulDCLabel:      clientmodel.LabelValue(cd.clientConf.Datacenter),
			}
			update <- srv
		}
		// Check for removed services.
		for name, srv := range cd.services {
			if _, ok := srvs[name]; !ok {
				srv.removed = true
				update <- srv
				srv.done <- struct{}{}
				delete(cd.services, name)
			}
		}
		cd.mu.Unlock()
	}
}

func extractUntyped(out Ingester, o *ProcessOptions, f *dto.MetricFamily) error {
	samples := make(model.Samples, 0, len(f.Metric))

	for _, m := range f.Metric {
		if m.Untyped == nil {
			continue
		}

		sample := &model.Sample{
			Metric: model.Metric{},
			Value:  model.SampleValue(m.Untyped.GetValue()),
		}
		samples = append(samples, sample)

		if m.TimestampMs != nil {
			sample.Timestamp = model.TimestampFromUnixNano(*m.TimestampMs * 1000000)
		} else {
			sample.Timestamp = o.Timestamp
		}

		metric := sample.Metric
		for _, p := range m.Label {
			metric[model.LabelName(p.GetName())] = model.LabelValue(p.GetValue())
		}
		metric[model.MetricNameLabel] = model.LabelValue(f.GetName())
	}

	return out.Ingest(samples)
}

func (dd *DNSDiscovery) refresh(name string, ch chan<- *config.TargetGroup) error {
	response, err := lookupSRV(name)
	dnsSDLookupsCount.Inc()
	if err != nil {
		dnsSDLookupFailuresCount.Inc()
		return err
	}

	tg := &config.TargetGroup{}
	for _, record := range response.Answer {
		addr, ok := record.(*dns.SRV)
		if !ok {
			log.Warnf("%q is not a valid SRV record", record)
			continue
		}
		// Remove the final dot from rooted DNS names to make them look more usual.
		addr.Target = strings.TrimRight(addr.Target, ".")

		target := clientmodel.LabelValue(fmt.Sprintf("%s:%d", addr.Target, addr.Port))
		tg.Targets = append(tg.Targets, clientmodel.LabelSet{
			clientmodel.AddressLabel: target,
			DNSNameLabel:             clientmodel.LabelValue(name),
		})
	}

	tg.Source = dnsSourcePrefix + ":" + name
	ch <- tg

	return nil
}

// fullLabels returns the base labels plus internal labels defining the target.
func (t *Target) fullLabels() clientmodel.LabelSet {
	t.RLock()
	defer t.RUnlock()
	lset := make(clientmodel.LabelSet, len(t.baseLabels)+2)
	for ln, lv := range t.baseLabels {
		lset[ln] = lv
	}
	lset[clientmodel.MetricsPathLabel] = clientmodel.LabelValue(t.url.Path)
	lset[clientmodel.AddressLabel] = clientmodel.LabelValue(t.url.Host)
	return lset
}

func targetsForApp(app *App) []clientmodel.LabelSet {
	targets := make([]clientmodel.LabelSet, 0, len(app.Tasks))
	for _, t := range app.Tasks {
		target := targetForTask(&t)
		targets = append(targets, clientmodel.LabelSet{
			clientmodel.AddressLabel: clientmodel.LabelValue(target),
			taskLabel:                clientmodel.LabelValue(t.ID),
		})
	}
	return targets
}

func relabel(labels clientmodel.LabelSet, cfg *config.RelabelConfig) (clientmodel.LabelSet, error) {
	values := make([]string, 0, len(cfg.SourceLabels))
	for _, ln := range cfg.SourceLabels {
		values = append(values, string(labels[ln]))
	}
	val := strings.Join(values, cfg.Separator)

	switch cfg.Action {
	case config.RelabelDrop:
		if cfg.Regex.MatchString(val) {
			return nil, nil
		}
	case config.RelabelKeep:
		if !cfg.Regex.MatchString(val) {
			return nil, nil
		}
	case config.RelabelReplace:
		indexes := cfg.Regex.FindStringSubmatchIndex(val)
		// If there is no match no replacement must take place.
		if indexes == nil {
			break
		}
		res := cfg.Regex.ExpandString([]byte{}, cfg.Replacement, val, indexes)
		if len(res) == 0 {
			delete(labels, cfg.TargetLabel)
		} else {
			labels[cfg.TargetLabel] = clientmodel.LabelValue(res)
		}
	case config.RelabelHashMod:
		mod := sum64(md5.Sum([]byte(val))) % cfg.Modulus
		labels[cfg.TargetLabel] = clientmodel.LabelValue(fmt.Sprintf("%d", mod))
	case config.RelabelLabelMap:
		out := make(clientmodel.LabelSet, len(labels))
		// Take a copy to avoid infinite loops.
		for ln, lv := range labels {
			out[ln] = lv
		}
		for ln, lv := range labels {
			if cfg.Regex.MatchString(string(ln)) {
				res := cfg.Regex.ReplaceAllString(string(ln), cfg.Replacement)
				out[clientmodel.LabelName(res)] = lv
			}
		}
		labels = out
	default:
		panic(fmt.Errorf("retrieval.relabel: unknown relabel action type %q", cfg.Action))
	}
	return labels, nil
}

func BenchmarkGetFingerprintsForNotEqualMatcher1000(b *testing.B) {
	numSeries := 1000
	samples := make(clientmodel.Samples, 0, numSeries)
	for i := 0; i < numSeries; i++ {
		samples = append(samples, &clientmodel.Sample{
			Metric: clientmodel.Metric{
				clientmodel.MetricNameLabel: "testmetric",
				"instance":                  clientmodel.LabelValue(fmt.Sprint("instance_", i)),
			},
			Value:     1,
			Timestamp: clientmodel.TimestampFromTime(time.Date(2000, 0, 0, 0, 0, 0, 0, time.UTC)),
		})
	}

	s := NewMemorySeriesStorage(MemorySeriesOptions{})
	if err := s.AppendSamples(samples); err != nil {
		b.Fatal(err)
	}

	m, err := metric.NewLabelMatcher(metric.NotEqual, "instance", "foo")
	if err != nil {
		b.Fatal(err)
	}

	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		s.GetFingerprintsForLabelMatchers(metric.LabelMatchers{m})
	}
}

func (m *ruleManager) queueAlertNotifications(rule *AlertingRule) {
	activeAlerts := rule.ActiveAlerts()
	if len(activeAlerts) == 0 {
		return
	}

	notifications := make(notification.NotificationReqs, 0, len(activeAlerts))
	for _, aa := range activeAlerts {
		if aa.State != FIRING {
			// BUG: In the future, make AlertManager support pending alerts?
			continue
		}

		notifications = append(notifications, &notification.NotificationReq{
			Summary:     rule.Summary,
			Description: rule.Description,
			Labels: aa.Labels.Merge(clientmodel.LabelSet{
				AlertNameLabel: clientmodel.LabelValue(rule.Name()),
			}),
			Value:        aa.Value,
			ActiveSince:  aa.ActiveSince.Time(),
			RuleString:   rule.String(),
			GeneratorUrl: m.prometheusUrl + ConsoleLinkForExpression(rule.vector.String()),
		})
	}
	m.notifications <- notifications
}

func createTargetGroup(app *App) *config.TargetGroup {
	var (
		targets = targetsForApp(app)
		source  = targetGroupName(app)
		appName = clientmodel.LabelValue(sanitizeName(app.ID))
		image   = clientmodel.LabelValue(imageName(app))
	)
	return &config.TargetGroup{
		Targets: targets,
		Labels: clientmodel.LabelSet{
			AppLabel:   appName,
			ImageLabel: image,
		},
		Source: source,
	}
}

func AppendSampleAsPureSparseAppendTests(p metric.Persistence, t test.Tester) {
	appendSample := func(x int) (success bool) {
		v := clientmodel.SampleValue(x)
		ts := clientmodel.TimestampFromUnix(int64(x))
		labelName := clientmodel.LabelName(x)
		labelValue := clientmodel.LabelValue(x)
		l := clientmodel.Metric{labelName: labelValue}

		sample := &clientmodel.Sample{
			Value:     v,
			Timestamp: ts,
			Metric:    l,
		}

		err := p.AppendSamples(clientmodel.Samples{sample})

		success = err == nil
		if !success {
			t.Error(err)
		}

		return
	}

	if err := quick.Check(appendSample, nil); err != nil {
		t.Error(err)
	}
}

// readFile reads a JSON or YAML list of targets groups from the file, depending on its
// file extension. It returns full configuration target groups.
func readFile(filename string) ([]*config.TargetGroup, error) {
	content, err := ioutil.ReadFile(filename)
	if err != nil {
		return nil, err
	}

	var targetGroups []*config.TargetGroup

	switch ext := filepath.Ext(filename); strings.ToLower(ext) {
	case ".json":
		if err := json.Unmarshal(content, &targetGroups); err != nil {
			return nil, err
		}
	case ".yml", ".yaml":
		if err := yaml.Unmarshal(content, &targetGroups); err != nil {
			return nil, err
		}
	default:
		panic(fmt.Errorf("retrieval.FileDiscovery.readFile: unhandled file extension %q", ext))
	}

	for i, tg := range targetGroups {
		tg.Source = fileSource(filename, i)
		if tg.Labels == nil {
			tg.Labels = clientmodel.LabelSet{}
		}
		tg.Labels[FileSDFilepathLabel] = clientmodel.LabelValue(filename)
	}
	return targetGroups, nil
}

func (s *testNotificationScenario) test(i int, t *testing.T) {
	notifications := make(chan NotificationReqs)
	defer close(notifications)
	h := NewNotificationHandler("alertmanager_url", notifications)

	receivedPost := make(chan bool, 1)
	poster := testHttpPoster{receivedPost: receivedPost}
	h.httpClient = &poster

	go h.Run()

	notifications <- NotificationReqs{
		{
			Summary:     s.summary,
			Description: s.description,
			Labels: clientmodel.LabelSet{
				clientmodel.LabelName("instance"): clientmodel.LabelValue("testinstance"),
			},
			Value:        clientmodel.SampleValue(1.0 / 3.0),
			ActiveSince:  time.Time{},
			RuleString:   "Test rule string",
			GeneratorUrl: "prometheus_url",
		},
	}

	<-receivedPost
	if poster.message != s.message {
		t.Fatalf("%d. Expected '%s', received '%s'", i, s.message, poster.message)
	}
}

// Update overwrites settings in the target that are derived from the job config
// it belongs to.
func (t *Target) Update(cfg *config.ScrapeConfig, baseLabels, metaLabels clientmodel.LabelSet) {
	t.Lock()
	defer t.Unlock()

	t.url.Scheme = cfg.Scheme
	t.url.Path = string(baseLabels[clientmodel.MetricsPathLabel])
	if cfg.BasicAuth != nil {
		t.url.User = url.UserPassword(cfg.BasicAuth.Username, cfg.BasicAuth.Password)
	}
	t.url.RawQuery = cfg.Params.Encode()

	t.scrapeInterval = time.Duration(cfg.ScrapeInterval)
	t.deadline = time.Duration(cfg.ScrapeTimeout)
	t.httpClient = httputil.NewDeadlineClient(time.Duration(cfg.ScrapeTimeout))

	t.honorLabels = cfg.HonorLabels
	t.metaLabels = metaLabels
	t.baseLabels = clientmodel.LabelSet{}
	// All remaining internal labels will not be part of the label set.
	for name, val := range baseLabels {
		if !strings.HasPrefix(string(name), clientmodel.ReservedLabelPrefix) {
			t.baseLabels[name] = val
		}
	}
	if _, ok := t.baseLabels[clientmodel.InstanceLabel]; !ok {
		t.baseLabels[clientmodel.InstanceLabel] = clientmodel.LabelValue(t.InstanceIdentifier())
	}
	t.metricRelabelConfigs = cfg.MetricRelabelConfigs
}

// sample returns a Sample suitable for recording the alert.
func (a Alert) sample(timestamp clientmodel.Timestamp, value clientmodel.SampleValue) *clientmodel.Sample {
	recordedMetric := clientmodel.Metric{}
	for label, value := range a.Labels {
		recordedMetric[label] = value
	}

	recordedMetric[clientmodel.MetricNameLabel] = AlertMetricName
	recordedMetric[AlertNameLabel] = clientmodel.LabelValue(a.Name)
	recordedMetric[AlertStateLabel] = clientmodel.LabelValue(a.State.String())

	return &clientmodel.Sample{
		Metric:    recordedMetric,
		Value:     value,
		Timestamp: timestamp,
	}
}

func newTestTarget(targetURL string, deadline time.Duration, baseLabels clientmodel.LabelSet) *Target {
	cfg := &config.ScrapeConfig{
		ScrapeTimeout: config.Duration(deadline),
	}
	c, _ := newHTTPClient(cfg)
	t := &Target{
		url: &url.URL{
			Scheme: "http",
			Host:   strings.TrimLeft(targetURL, "http://"),
			Path:   "/metrics",
		},
		deadline:        deadline,
		status:          &TargetStatus{},
		scrapeInterval:  1 * time.Millisecond,
		httpClient:      c,
		scraperStopping: make(chan struct{}),
		scraperStopped:  make(chan struct{}),
	}
	t.baseLabels = clientmodel.LabelSet{
		clientmodel.InstanceLabel: clientmodel.LabelValue(t.InstanceIdentifier()),
	}
	for baseLabel, baseValue := range baseLabels {
		t.baseLabels[baseLabel] = baseValue
	}
	return t
}

func (s *testNotificationScenario) test(i int, t *testing.T) {
	h := NewNotificationHandler(&NotificationHandlerOptions{
		AlertmanagerURL: "alertmanager_url",
		QueueCapacity:   0,
		Deadline:        10 * time.Second,
	})
	defer h.Stop()

	receivedPost := make(chan bool, 1)
	poster := testHTTPPoster{receivedPost: receivedPost}
	h.httpClient = &poster

	go h.Run()

	h.SubmitReqs(NotificationReqs{
		{
			Summary:     s.summary,
			Description: s.description,
			Labels: clientmodel.LabelSet{
				clientmodel.LabelName("instance"): clientmodel.LabelValue("testinstance"),
			},
			Value:        clientmodel.SampleValue(1.0 / 3.0),
			ActiveSince:  time.Time{},
			RuleString:   "Test rule string",
			GeneratorURL: "prometheus_url",
		},
	})

	<-receivedPost
	if poster.message != s.message {
		t.Fatalf("%d. Expected '%s', received '%s'", i, s.message, poster.message)
	}
}