Golang expfmt.NewEncoder函数代码示例

func (r *registry) Push(job, instance, pushURL, method string) error {
	if !strings.Contains(pushURL, "://") {
		pushURL = "http://" + pushURL
	}
	pushURL = fmt.Sprintf("%s/metrics/jobs/%s", pushURL, url.QueryEscape(job))
	if instance != "" {
		pushURL += "/instances/" + url.QueryEscape(instance)
	}
	buf := r.getBuf()
	defer r.giveBuf(buf)
	if err := r.writePB(expfmt.NewEncoder(buf, expfmt.FmtProtoDelim)); err != nil {
		if r.panicOnCollectError {
			panic(err)
		}
		return err
	}
	req, err := http.NewRequest(method, pushURL, buf)
	if err != nil {
		return err
	}
	req.Header.Set(contentTypeHeader, DelimitedTelemetryContentType)
	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	if resp.StatusCode != 202 {
		return fmt.Errorf("unexpected status code %d while pushing to %s", resp.StatusCode, pushURL)
	}
	return nil
}

func (fed *Federation) ServeHTTP(w http.ResponseWriter, req *http.Request) {
	req.ParseForm()

	metrics := map[model.Fingerprint]metric.Metric{}

	for _, s := range req.Form["match[]"] {
		matchers, err := promql.ParseMetricSelector(s)
		if err != nil {
			http.Error(w, err.Error(), http.StatusBadRequest)
			return
		}
		for fp, met := range fed.Storage.MetricsForLabelMatchers(matchers...) {
			metrics[fp] = met
		}
	}

	format := expfmt.Negotiate(req.Header)
	w.Header().Set("Content-Type", string(format))

	enc := expfmt.NewEncoder(w, format)

	protMetric := &dto.Metric{
		Label:   []*dto.LabelPair{},
		Untyped: &dto.Untyped{},
	}
	protMetricFam := &dto.MetricFamily{
		Metric: []*dto.Metric{protMetric},
		Type:   dto.MetricType_UNTYPED.Enum(),
	}

	for fp, met := range metrics {
		sp := fed.Storage.LastSamplePairForFingerprint(fp)
		if sp == nil {
			continue
		}

		// Reset label slice.
		protMetric.Label = protMetric.Label[:0]

		for ln, lv := range met.Metric {
			if ln == model.MetricNameLabel {
				protMetricFam.Name = proto.String(string(lv))
				continue
			}
			protMetric.Label = append(protMetric.Label, &dto.LabelPair{
				Name:  proto.String(string(ln)),
				Value: proto.String(string(lv)),
			})
		}
		protMetric.TimestampMs = (*int64)(&sp.Timestamp)
		protMetric.Untyped.Value = (*float64)(&sp.Value)

		if err := enc.Encode(protMetricFam); err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return

		}
	}
}

func collect(c prometheus.Collector) ([]byte, error) {
	r := prometheus.NewRegistry()
	if err := r.Register(c); err != nil {
		return nil, err
	}
	m, err := r.Gather()
	if err != nil {
		return nil, err
	}
	var b bytes.Buffer
	enc := expfmt.NewEncoder(&b, expfmt.FmtText)
	for _, f := range m {
		if err := enc.Encode(f); err != nil {
			return nil, err
		}
	}
	return b.Bytes(), nil
}

func (r *registry) ServeHTTP(w http.ResponseWriter, req *http.Request) {
	contentType := expfmt.Negotiate(req.Header)
	buf := r.getBuf()
	defer r.giveBuf(buf)
	writer, encoding := decorateWriter(req, buf)
	if err := r.writePB(expfmt.NewEncoder(writer, contentType)); err != nil {
		if r.panicOnCollectError {
			panic(err)
		}
		http.Error(w, "An error has occurred:\n\n"+err.Error(), http.StatusInternalServerError)
		return
	}
	if closer, ok := writer.(io.Closer); ok {
		closer.Close()
	}
	header := w.Header()
	header.Set(contentTypeHeader, string(contentType))
	header.Set(contentLengthHeader, fmt.Sprint(buf.Len()))
	if encoding != "" {
		header.Set(contentEncodingHeader, encoding)
	}
	w.Write(buf.Bytes())
}

// UninstrumentedHandler returns an HTTP handler for the DefaultGatherer.
//
// Deprecated: Use promhttp.Handler instead. See there for further documentation.
func UninstrumentedHandler() http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		mfs, err := DefaultGatherer.Gather()
		if err != nil {
			http.Error(w, "An error has occurred during metrics collection:\n\n"+err.Error(), http.StatusInternalServerError)
			return
		}

		contentType := expfmt.Negotiate(req.Header)
		buf := getBuf()
		defer giveBuf(buf)
		writer, encoding := decorateWriter(req, buf)
		enc := expfmt.NewEncoder(writer, contentType)
		var lastErr error
		for _, mf := range mfs {
			if err := enc.Encode(mf); err != nil {
				lastErr = err
				http.Error(w, "An error has occurred during metrics encoding:\n\n"+err.Error(), http.StatusInternalServerError)
				return
			}
		}
		if closer, ok := writer.(io.Closer); ok {
			closer.Close()
		}
		if lastErr != nil && buf.Len() == 0 {
			http.Error(w, "No metrics encoded, last error:\n\n"+err.Error(), http.StatusInternalServerError)
			return
		}
		header := w.Header()
		header.Set(contentTypeHeader, string(contentType))
		header.Set(contentLengthHeader, fmt.Sprint(buf.Len()))
		if encoding != "" {
			header.Set(contentEncodingHeader, encoding)
		}
		w.Write(buf.Bytes())
	})
}

func TestPush(t *testing.T) {

	var (
		lastMethod string
		lastBody   []byte
		lastPath   string
	)

	host, err := os.Hostname()
	if err != nil {
		t.Error(err)
	}

	// Fake a Pushgateway that always responds with 202.
	pgwOK := httptest.NewServer(
		http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			lastMethod = r.Method
			var err error
			lastBody, err = ioutil.ReadAll(r.Body)
			if err != nil {
				t.Fatal(err)
			}
			lastPath = r.URL.EscapedPath()
			w.Header().Set("Content-Type", `text/plain; charset=utf-8`)
			w.WriteHeader(http.StatusAccepted)
		}),
	)
	defer pgwOK.Close()

	// Fake a Pushgateway that always responds with 500.
	pgwErr := httptest.NewServer(
		http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			http.Error(w, "fake error", http.StatusInternalServerError)
		}),
	)
	defer pgwErr.Close()

	metric1 := prometheus.NewCounter(prometheus.CounterOpts{
		Name: "testname1",
		Help: "testhelp1",
	})
	metric2 := prometheus.NewGauge(prometheus.GaugeOpts{
		Name:        "testname2",
		Help:        "testhelp2",
		ConstLabels: prometheus.Labels{"foo": "bar", "dings": "bums"},
	})

	reg := prometheus.NewRegistry()
	reg.MustRegister(metric1)
	reg.MustRegister(metric2)

	mfs, err := reg.Gather()
	if err != nil {
		t.Fatal(err)
	}

	buf := &bytes.Buffer{}
	enc := expfmt.NewEncoder(buf, expfmt.FmtProtoDelim)

	for _, mf := range mfs {
		if err := enc.Encode(mf); err != nil {
			t.Fatal(err)
		}
	}
	wantBody := buf.Bytes()

	// PushCollectors, all good.
	if err := Collectors("testjob", HostnameGroupingKey(), pgwOK.URL, metric1, metric2); err != nil {
		t.Fatal(err)
	}
	if lastMethod != "PUT" {
		t.Error("want method PUT for PushCollectors, got", lastMethod)
	}
	if bytes.Compare(lastBody, wantBody) != 0 {
		t.Errorf("got body %v, want %v", lastBody, wantBody)
	}
	if lastPath != "/metrics/job/testjob/instance/"+host {
		t.Error("unexpected path:", lastPath)
	}

	// PushAddCollectors, with nil grouping, all good.
	if err := AddCollectors("testjob", nil, pgwOK.URL, metric1, metric2); err != nil {
		t.Fatal(err)
	}
	if lastMethod != "POST" {
		t.Error("want method POST for PushAddCollectors, got", lastMethod)
	}
	if bytes.Compare(lastBody, wantBody) != 0 {
		t.Errorf("got body %v, want %v", lastBody, wantBody)
	}
	if lastPath != "/metrics/job/testjob" {
		t.Error("unexpected path:", lastPath)
	}

	// PushCollectors with a broken PGW.
	if err := Collectors("testjob", nil, pgwErr.URL, metric1, metric2); err == nil {
		t.Error("push to broken Pushgateway succeeded")
	} else {
		if got, want := err.Error(), "unexpected status code 500 while pushing to "+pgwErr.URL+"/metrics/job/testjob: fake error\n"; got != want {
			t.Errorf("got error %q, want %q", got, want)
//.........这里部分代码省略.........

func (h *Handler) federation(w http.ResponseWriter, req *http.Request) {
	h.mtx.RLock()
	defer h.mtx.RUnlock()

	req.ParseForm()

	var matcherSets []metric.LabelMatchers
	for _, s := range req.Form["match[]"] {
		matchers, err := promql.ParseMetricSelector(s)
		if err != nil {
			http.Error(w, err.Error(), http.StatusBadRequest)
			return
		}
		matcherSets = append(matcherSets, matchers)
	}

	var (
		minTimestamp = h.now().Add(-promql.StalenessDelta)
		format       = expfmt.Negotiate(req.Header)
		enc          = expfmt.NewEncoder(w, format)
	)
	w.Header().Set("Content-Type", string(format))

	q, err := h.storage.Querier()
	if err != nil {
		federationErrors.Inc()
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	defer q.Close()

	vector, err := q.LastSampleForLabelMatchers(h.context, minTimestamp, matcherSets...)
	if err != nil {
		federationErrors.Inc()
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	sort.Sort(byName(vector))

	var (
		lastMetricName model.LabelValue
		protMetricFam  *dto.MetricFamily
	)
	for _, s := range vector {
		nameSeen := false
		globalUsed := map[model.LabelName]struct{}{}
		protMetric := &dto.Metric{
			Untyped: &dto.Untyped{},
		}

		for ln, lv := range s.Metric {
			if lv == "" {
				// No value means unset. Never consider those labels.
				// This is also important to protect against nameless metrics.
				continue
			}
			if ln == model.MetricNameLabel {
				nameSeen = true
				if lv == lastMetricName {
					// We already have the name in the current MetricFamily,
					// and we ignore nameless metrics.
					continue
				}
				// Need to start a new MetricFamily. Ship off the old one (if any) before
				// creating the new one.
				if protMetricFam != nil {
					if err := enc.Encode(protMetricFam); err != nil {
						federationErrors.Inc()
						log.With("err", err).Error("federation failed")
						return
					}
				}
				protMetricFam = &dto.MetricFamily{
					Type: dto.MetricType_UNTYPED.Enum(),
					Name: proto.String(string(lv)),
				}
				lastMetricName = lv
				continue
			}
			protMetric.Label = append(protMetric.Label, &dto.LabelPair{
				Name:  proto.String(string(ln)),
				Value: proto.String(string(lv)),
			})
			if _, ok := h.externalLabels[ln]; ok {
				globalUsed[ln] = struct{}{}
			}
		}
		if !nameSeen {
			log.With("metric", s.Metric).Warn("Ignoring nameless metric during federation.")
			continue
		}
		// Attach global labels if they do not exist yet.
		for ln, lv := range h.externalLabels {
			if _, ok := globalUsed[ln]; !ok {
				protMetric.Label = append(protMetric.Label, &dto.LabelPair{
					Name:  proto.String(string(ln)),
					Value: proto.String(string(lv)),
				})
			}
		}
//.........这里部分代码省略.........

func testHandler(t testing.TB) {

	metricVec := prometheus.NewCounterVec(
		prometheus.CounterOpts{
			Name:        "name",
			Help:        "docstring",
			ConstLabels: prometheus.Labels{"constname": "constvalue"},
		},
		[]string{"labelname"},
	)

	metricVec.WithLabelValues("val1").Inc()
	metricVec.WithLabelValues("val2").Inc()

	externalMetricFamily := &dto.MetricFamily{
		Name: proto.String("externalname"),
		Help: proto.String("externaldocstring"),
		Type: dto.MetricType_COUNTER.Enum(),
		Metric: []*dto.Metric{
			{
				Label: []*dto.LabelPair{
					{
						Name:  proto.String("externalconstname"),
						Value: proto.String("externalconstvalue"),
					},
					{
						Name:  proto.String("externallabelname"),
						Value: proto.String("externalval1"),
					},
				},
				Counter: &dto.Counter{
					Value: proto.Float64(1),
				},
			},
		},
	}
	externalBuf := &bytes.Buffer{}
	enc := expfmt.NewEncoder(externalBuf, expfmt.FmtProtoDelim)
	if err := enc.Encode(externalMetricFamily); err != nil {
		t.Fatal(err)
	}
	externalMetricFamilyAsBytes := externalBuf.Bytes()
	externalMetricFamilyAsText := []byte(`# HELP externalname externaldocstring
# TYPE externalname counter
externalname{externalconstname="externalconstvalue",externallabelname="externalval1"} 1
`)
	externalMetricFamilyAsProtoText := []byte(`name: "externalname"
help: "externaldocstring"
type: COUNTER
metric: <
  label: <
    name: "externalconstname"
    value: "externalconstvalue"
  >
  label: <
    name: "externallabelname"
    value: "externalval1"
  >
  counter: <
    value: 1
  >
>

`)
	externalMetricFamilyAsProtoCompactText := []byte(`name:"externalname" help:"externaldocstring" type:COUNTER metric:<label:<name:"externalconstname" value:"externalconstvalue" > label:<name:"externallabelname" value:"externalval1" > counter:<value:1 > > 
`)

	expectedMetricFamily := &dto.MetricFamily{
		Name: proto.String("name"),
		Help: proto.String("docstring"),
		Type: dto.MetricType_COUNTER.Enum(),
		Metric: []*dto.Metric{
			{
				Label: []*dto.LabelPair{
					{
						Name:  proto.String("constname"),
						Value: proto.String("constvalue"),
					},
					{
						Name:  proto.String("labelname"),
						Value: proto.String("val1"),
					},
				},
				Counter: &dto.Counter{
					Value: proto.Float64(1),
				},
			},
			{
				Label: []*dto.LabelPair{
					{
						Name:  proto.String("constname"),
						Value: proto.String("constvalue"),
					},
					{
						Name:  proto.String("labelname"),
						Value: proto.String("val2"),
					},
				},
				Counter: &dto.Counter{
					Value: proto.Float64(1),
//.........这里部分代码省略.........

func (h *Handler) federation(w http.ResponseWriter, req *http.Request) {
	h.mtx.RLock()
	defer h.mtx.RUnlock()

	req.ParseForm()

	metrics := map[model.Fingerprint]metric.Metric{}

	for _, s := range req.Form["match[]"] {
		matchers, err := promql.ParseMetricSelector(s)
		if err != nil {
			http.Error(w, err.Error(), http.StatusBadRequest)
			return
		}
		for fp, met := range h.storage.MetricsForLabelMatchers(matchers...) {
			metrics[fp] = met
		}
	}

	format := expfmt.Negotiate(req.Header)
	w.Header().Set("Content-Type", string(format))

	enc := expfmt.NewEncoder(w, format)

	protMetric := &dto.Metric{
		Label:   []*dto.LabelPair{},
		Untyped: &dto.Untyped{},
	}
	protMetricFam := &dto.MetricFamily{
		Metric: []*dto.Metric{protMetric},
		Type:   dto.MetricType_UNTYPED.Enum(),
	}

	for fp, met := range metrics {
		globalUsed := map[model.LabelName]struct{}{}

		sp := h.storage.LastSamplePairForFingerprint(fp)
		if sp == nil {
			continue
		}

		// Reset label slice.
		protMetric.Label = protMetric.Label[:0]

		for ln, lv := range met.Metric {
			if ln == model.MetricNameLabel {
				protMetricFam.Name = proto.String(string(lv))
				continue
			}
			protMetric.Label = append(protMetric.Label, &dto.LabelPair{
				Name:  proto.String(string(ln)),
				Value: proto.String(string(lv)),
			})
			if _, ok := h.globalLabels[ln]; ok {
				globalUsed[ln] = struct{}{}
			}
		}

		// Attach global labels if they do not exist yet.
		for ln, lv := range h.globalLabels {
			if _, ok := globalUsed[ln]; !ok {
				protMetric.Label = append(protMetric.Label, &dto.LabelPair{
					Name:  proto.String(string(ln)),
					Value: proto.String(string(lv)),
				})
			}
		}

		protMetric.TimestampMs = (*int64)(&sp.Timestamp)
		protMetric.Untyped.Value = (*float64)(&sp.Value)

		if err := enc.Encode(protMetricFam); err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}
	}
}

func (h *Handler) federation(w http.ResponseWriter, req *http.Request) {
	h.mtx.RLock()
	defer h.mtx.RUnlock()

	req.ParseForm()

	fps := map[model.Fingerprint]struct{}{}

	for _, s := range req.Form["match[]"] {
		matchers, err := promql.ParseMetricSelector(s)
		if err != nil {
			http.Error(w, err.Error(), http.StatusBadRequest)
			return
		}
		for fp := range h.storage.MetricsForLabelMatchers(
			model.Now().Add(-promql.StalenessDelta), model.Latest,
			matchers...,
		) {
			fps[fp] = struct{}{}
		}
	}

	var (
		minTimestamp = model.Now().Add(-promql.StalenessDelta)
		format       = expfmt.Negotiate(req.Header)
		enc          = expfmt.NewEncoder(w, format)
	)
	w.Header().Set("Content-Type", string(format))

	protMetric := &dto.Metric{
		Label:   []*dto.LabelPair{},
		Untyped: &dto.Untyped{},
	}
	protMetricFam := &dto.MetricFamily{
		Metric: []*dto.Metric{protMetric},
		Type:   dto.MetricType_UNTYPED.Enum(),
	}

	for fp := range fps {
		globalUsed := map[model.LabelName]struct{}{}

		s := h.storage.LastSampleForFingerprint(fp)
		// Discard if sample does not exist or lays before the staleness interval.
		if s.Timestamp.Before(minTimestamp) {
			continue
		}

		// Reset label slice.
		protMetric.Label = protMetric.Label[:0]

		for ln, lv := range s.Metric {
			if ln == model.MetricNameLabel {
				protMetricFam.Name = proto.String(string(lv))
				continue
			}
			protMetric.Label = append(protMetric.Label, &dto.LabelPair{
				Name:  proto.String(string(ln)),
				Value: proto.String(string(lv)),
			})
			if _, ok := h.externalLabels[ln]; ok {
				globalUsed[ln] = struct{}{}
			}
		}

		// Attach global labels if they do not exist yet.
		for ln, lv := range h.externalLabels {
			if _, ok := globalUsed[ln]; !ok {
				protMetric.Label = append(protMetric.Label, &dto.LabelPair{
					Name:  proto.String(string(ln)),
					Value: proto.String(string(lv)),
				})
			}
		}

		protMetric.TimestampMs = proto.Int64(int64(s.Timestamp))
		protMetric.Untyped.Value = proto.Float64(float64(s.Value))

		if err := enc.Encode(protMetricFam); err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}
	}
}

func push(job string, grouping map[string]string, pushURL string, g prometheus.Gatherer, method string) error {
	if !strings.Contains(pushURL, "://") {
		pushURL = "http://" + pushURL
	}
	if strings.HasSuffix(pushURL, "/") {
		pushURL = pushURL[:len(pushURL)-1]
	}

	if strings.Contains(job, "/") {
		return fmt.Errorf("job contains '/': %s", job)
	}
	urlComponents := []string{url.QueryEscape(job)}
	for ln, lv := range grouping {
		if !model.LabelNameRE.MatchString(ln) {
			return fmt.Errorf("grouping label has invalid name: %s", ln)
		}
		if strings.Contains(lv, "/") {
			return fmt.Errorf("value of grouping label %s contains '/': %s", ln, lv)
		}
		urlComponents = append(urlComponents, ln, lv)
	}
	pushURL = fmt.Sprintf("%s/metrics/job/%s", pushURL, strings.Join(urlComponents, "/"))

	mfs, err := g.Gather()
	if err != nil {
		return err
	}
	buf := &bytes.Buffer{}
	enc := expfmt.NewEncoder(buf, expfmt.FmtProtoDelim)
	// Check for pre-existing grouping labels:
	for _, mf := range mfs {
		for _, m := range mf.GetMetric() {
			for _, l := range m.GetLabel() {
				if l.GetName() == "job" {
					return fmt.Errorf("pushed metric %s (%s) already contains a job label", mf.GetName(), m)
				}
				if _, ok := grouping[l.GetName()]; ok {
					return fmt.Errorf(
						"pushed metric %s (%s) already contains grouping label %s",
						mf.GetName(), m, l.GetName(),
					)
				}
			}
		}
		enc.Encode(mf)
	}
	req, err := http.NewRequest(method, pushURL, buf)
	if err != nil {
		return err
	}
	req.Header.Set(contentTypeHeader, string(expfmt.FmtProtoDelim))
	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	if resp.StatusCode != 202 {
		body, _ := ioutil.ReadAll(resp.Body) // Ignore any further error as this is for an error message only.
		return fmt.Errorf("unexpected status code %d while pushing to %s: %s", resp.StatusCode, pushURL, body)
	}
	return nil
}

// HandlerFor returns an http.Handler for the provided Gatherer. The behavior
// of the Handler is defined by the provided HandlerOpts.
func HandlerFor(reg prometheus.Gatherer, opts HandlerOpts) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		mfs, err := reg.Gather()
		if err != nil {
			if opts.ErrorLog != nil {
				opts.ErrorLog.Println("error gathering metrics:", err)
			}
			switch opts.ErrorHandling {
			case PanicOnError:
				panic(err)
			case ContinueOnError:
				if len(mfs) == 0 {
					http.Error(w, "No metrics gathered, last error:\n\n"+err.Error(), http.StatusInternalServerError)
					return
				}
			case HTTPErrorOnError:
				http.Error(w, "An error has occurred during metrics gathering:\n\n"+err.Error(), http.StatusInternalServerError)
				return
			}
		}

		contentType := expfmt.Negotiate(req.Header)
		buf := getBuf()
		defer giveBuf(buf)
		writer, encoding := decorateWriter(req, buf, opts.DisableCompression)
		enc := expfmt.NewEncoder(writer, contentType)
		var lastErr error
		for _, mf := range mfs {
			if err := enc.Encode(mf); err != nil {
				lastErr = err
				if opts.ErrorLog != nil {
					opts.ErrorLog.Println("error encoding metric family:", err)
				}
				switch opts.ErrorHandling {
				case PanicOnError:
					panic(err)
				case ContinueOnError:
					// Handled later.
				case HTTPErrorOnError:
					http.Error(w, "An error has occurred during metrics encoding:\n\n"+err.Error(), http.StatusInternalServerError)
					return
				}
			}
		}
		if closer, ok := writer.(io.Closer); ok {
			closer.Close()
		}
		if lastErr != nil && buf.Len() == 0 {
			http.Error(w, "No metrics encoded, last error:\n\n"+err.Error(), http.StatusInternalServerError)
			return
		}
		header := w.Header()
		header.Set(contentTypeHeader, string(contentType))
		header.Set(contentLengthHeader, fmt.Sprint(buf.Len()))
		if encoding != "" {
			header.Set(contentEncodingHeader, encoding)
		}
		w.Write(buf.Bytes())
		// TODO(beorn7): Consider streaming serving of metrics.
	})
}