Added exemplar support to http middleware. (#1055)
* Added exemplar support to http middlewares. Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com> * Small fix. Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com> * Fixed test. Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com> * Added tests and options for RT. Signed-off-by: bwplotka <bwplotka@gmail.com> * goimports. Signed-off-by: bwplotka <bwplotka@gmail.com>
This commit is contained in:
parent
3faf3bae70
commit
c7488be2e4
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@ -38,11 +38,11 @@ func (rt RoundTripperFunc) RoundTrip(r *http.Request) (*http.Response, error) {
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//
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// See the example for ExampleInstrumentRoundTripperDuration for example usage.
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func InstrumentRoundTripperInFlight(gauge prometheus.Gauge, next http.RoundTripper) RoundTripperFunc {
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return RoundTripperFunc(func(r *http.Request) (*http.Response, error) {
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return func(r *http.Request) (*http.Response, error) {
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gauge.Inc()
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defer gauge.Dec()
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return next.RoundTrip(r)
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})
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}
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}
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// InstrumentRoundTripperCounter is a middleware that wraps the provided
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@ -59,22 +59,29 @@ func InstrumentRoundTripperInFlight(gauge prometheus.Gauge, next http.RoundTripp
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// If the wrapped RoundTripper panics or returns a non-nil error, the Counter
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// is not incremented.
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//
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// Use with WithExemplarFromContext to instrument the exemplars on the counter of requests.
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//
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// See the example for ExampleInstrumentRoundTripperDuration for example usage.
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func InstrumentRoundTripperCounter(counter *prometheus.CounterVec, next http.RoundTripper, opts ...Option) RoundTripperFunc {
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rtOpts := &option{}
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rtOpts := defaultOptions()
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for _, o := range opts {
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o(rtOpts)
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o.apply(rtOpts)
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}
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code, method := checkLabels(counter)
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return RoundTripperFunc(func(r *http.Request) (*http.Response, error) {
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return func(r *http.Request) (*http.Response, error) {
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resp, err := next.RoundTrip(r)
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if err == nil {
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exemplarAdd(
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counter.With(labels(code, method, r.Method, resp.StatusCode, rtOpts.extraMethods...)),
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1,
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rtOpts.getExemplarFn(r.Context()),
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)
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counter.With(labels(code, method, r.Method, resp.StatusCode, rtOpts.extraMethods...)).Inc()
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}
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return resp, err
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})
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}
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}
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// InstrumentRoundTripperDuration is a middleware that wraps the provided
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@ -94,24 +101,30 @@ func InstrumentRoundTripperCounter(counter *prometheus.CounterVec, next http.Rou
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// If the wrapped RoundTripper panics or returns a non-nil error, no values are
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// reported.
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//
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// Use with WithExemplarFromContext to instrument the exemplars on the duration histograms.
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//
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// Note that this method is only guaranteed to never observe negative durations
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// if used with Go1.9+.
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func InstrumentRoundTripperDuration(obs prometheus.ObserverVec, next http.RoundTripper, opts ...Option) RoundTripperFunc {
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rtOpts := &option{}
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rtOpts := defaultOptions()
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for _, o := range opts {
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o(rtOpts)
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o.apply(rtOpts)
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}
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code, method := checkLabels(obs)
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return RoundTripperFunc(func(r *http.Request) (*http.Response, error) {
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return func(r *http.Request) (*http.Response, error) {
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start := time.Now()
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resp, err := next.RoundTrip(r)
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if err == nil {
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obs.With(labels(code, method, r.Method, resp.StatusCode, rtOpts.extraMethods...)).Observe(time.Since(start).Seconds())
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exemplarObserve(
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obs.With(labels(code, method, r.Method, resp.StatusCode, rtOpts.extraMethods...)),
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time.Since(start).Seconds(),
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rtOpts.getExemplarFn(r.Context()),
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)
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}
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return resp, err
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})
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}
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}
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// InstrumentTrace is used to offer flexibility in instrumenting the available
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@ -149,7 +162,7 @@ type InstrumentTrace struct {
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//
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// See the example for ExampleInstrumentRoundTripperDuration for example usage.
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func InstrumentRoundTripperTrace(it *InstrumentTrace, next http.RoundTripper) RoundTripperFunc {
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return RoundTripperFunc(func(r *http.Request) (*http.Response, error) {
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return func(r *http.Request) (*http.Response, error) {
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start := time.Now()
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trace := &httptrace.ClientTrace{
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@ -231,5 +244,5 @@ func InstrumentRoundTripperTrace(it *InstrumentTrace, next http.RoundTripper) Ro
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r = r.WithContext(httptrace.WithClientTrace(r.Context(), trace))
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return next.RoundTrip(r)
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})
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}
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}
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@ -18,14 +18,19 @@ import (
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"log"
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"net/http"
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"net/http/httptest"
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"reflect"
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"sort"
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"strings"
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"testing"
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"time"
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"github.com/prometheus/client_golang/prometheus"
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dto "github.com/prometheus/client_model/go"
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"google.golang.org/protobuf/proto"
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)
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func makeInstrumentedClient() (*http.Client, *prometheus.Registry) {
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func makeInstrumentedClient(opts ...Option) (*http.Client, *prometheus.Registry) {
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client := http.DefaultClient
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client.Timeout = 1 * time.Second
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@ -91,13 +96,91 @@ func makeInstrumentedClient() (*http.Client, *prometheus.Registry) {
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client.Transport = InstrumentRoundTripperInFlight(inFlightGauge,
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InstrumentRoundTripperCounter(counter,
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InstrumentRoundTripperTrace(trace,
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InstrumentRoundTripperDuration(histVec, http.DefaultTransport),
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InstrumentRoundTripperDuration(histVec, http.DefaultTransport, opts...),
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),
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),
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opts...),
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)
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return client, reg
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}
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func labelsToLabelPair(l prometheus.Labels) []*dto.LabelPair {
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ret := make([]*dto.LabelPair, 0, len(l))
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for k, v := range l {
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ret = append(ret, &dto.LabelPair{Name: proto.String(k), Value: proto.String(v)})
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}
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sort.Slice(ret, func(i, j int) bool {
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return *ret[i].Name < *ret[j].Name
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})
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return ret
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}
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func assetMetricAndExemplars(
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t *testing.T,
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reg *prometheus.Registry,
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expectedNumMetrics int,
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expectedExemplar []*dto.LabelPair,
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) {
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t.Helper()
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mfs, err := reg.Gather()
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if err != nil {
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t.Fatal(err)
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}
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if want, got := expectedNumMetrics, len(mfs); want != got {
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t.Fatalf("unexpected number of metric families gathered, want %d, got %d", want, got)
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}
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for _, mf := range mfs {
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if len(mf.Metric) == 0 {
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t.Errorf("metric family %s must not be empty", mf.GetName())
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}
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for _, m := range mf.GetMetric() {
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if c := m.GetCounter(); c != nil {
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if len(expectedExemplar) == 0 {
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if c.Exemplar != nil {
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t.Errorf("expected no exemplar on the counter %v%v, got %v", mf.GetName(), m.Label, c.Exemplar.String())
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}
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continue
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}
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if c.Exemplar == nil {
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t.Errorf("expected exemplar %v on the counter %v%v, got none", expectedExemplar, mf.GetName(), m.Label)
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continue
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}
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if got := c.Exemplar.Label; !reflect.DeepEqual(expectedExemplar, got) {
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t.Errorf("expected exemplar %v on the counter %v%v, got %v", expectedExemplar, mf.GetName(), m.Label, got)
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}
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continue
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}
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if h := m.GetHistogram(); h != nil {
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found := false
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for _, b := range h.GetBucket() {
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if len(expectedExemplar) == 0 {
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if b.Exemplar != nil {
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t.Errorf("expected no exemplar on histogram %v%v bkt %v, got %v", mf.GetName(), m.Label, b.GetUpperBound(), b.Exemplar.String())
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}
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continue
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}
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if b.Exemplar == nil {
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continue
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}
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if got := b.Exemplar.Label; !reflect.DeepEqual(expectedExemplar, got) {
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t.Errorf("expected exemplar %v on the histogram %v%v on bkt %v, got %v", expectedExemplar, mf.GetName(), m.Label, b.GetUpperBound(), got)
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continue
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}
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found = true
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break
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}
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if len(expectedExemplar) > 0 && !found {
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t.Errorf("expected exemplar %v on at least one bucket of the histogram %v%v, got none", expectedExemplar, mf.GetName(), m.Label)
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}
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}
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}
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}
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}
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func TestClientMiddlewareAPI(t *testing.T) {
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client, reg := makeInstrumentedClient()
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backend := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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@ -111,21 +194,28 @@ func TestClientMiddlewareAPI(t *testing.T) {
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}
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defer resp.Body.Close()
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mfs, err := reg.Gather()
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assetMetricAndExemplars(t, reg, 3, nil)
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}
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func TestClientMiddlewareAPI_WithExemplars(t *testing.T) {
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exemplar := prometheus.Labels{"traceID": "example situation observed by this metric"}
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client, reg := makeInstrumentedClient(WithExemplarFromContext(func(_ context.Context) prometheus.Labels { return exemplar }))
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backend := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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w.WriteHeader(http.StatusOK)
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}))
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defer backend.Close()
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resp, err := client.Get(backend.URL)
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if err != nil {
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t.Fatal(err)
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}
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if want, got := 3, len(mfs); want != got {
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t.Fatalf("unexpected number of metric families gathered, want %d, got %d", want, got)
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}
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for _, mf := range mfs {
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if len(mf.Metric) == 0 {
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t.Errorf("metric family %s must not be empty", mf.GetName())
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}
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}
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defer resp.Body.Close()
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assetMetricAndExemplars(t, reg, 3, labelsToLabelPair(exemplar))
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}
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func TestClientMiddlewareAPIWithRequestContext(t *testing.T) {
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func TestClientMiddlewareAPI_WithRequestContext(t *testing.T) {
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client, reg := makeInstrumentedClient()
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backend := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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w.WriteHeader(http.StatusOK)
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@ -28,6 +28,22 @@ import (
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// magicString is used for the hacky label test in checkLabels. Remove once fixed.
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const magicString = "zZgWfBxLqvG8kc8IMv3POi2Bb0tZI3vAnBx+gBaFi9FyPzB/CzKUer1yufDa"
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func exemplarObserve(obs prometheus.Observer, val float64, labels map[string]string) {
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if labels == nil {
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obs.Observe(val)
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return
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}
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obs.(prometheus.ExemplarObserver).ObserveWithExemplar(val, labels)
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}
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func exemplarAdd(obs prometheus.Counter, val float64, labels map[string]string) {
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if labels == nil {
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obs.Add(val)
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return
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}
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obs.(prometheus.ExemplarAdder).AddWithExemplar(val, labels)
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}
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// InstrumentHandlerInFlight is a middleware that wraps the provided
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// http.Handler. It sets the provided prometheus.Gauge to the number of
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// requests currently handled by the wrapped http.Handler.
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@ -62,28 +78,37 @@ func InstrumentHandlerInFlight(g prometheus.Gauge, next http.Handler) http.Handl
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// Note that this method is only guaranteed to never observe negative durations
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// if used with Go1.9+.
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func InstrumentHandlerDuration(obs prometheus.ObserverVec, next http.Handler, opts ...Option) http.HandlerFunc {
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mwOpts := &option{}
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hOpts := defaultOptions()
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for _, o := range opts {
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o(mwOpts)
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o.apply(hOpts)
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}
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code, method := checkLabels(obs)
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if code {
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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return func(w http.ResponseWriter, r *http.Request) {
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now := time.Now()
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d := newDelegator(w, nil)
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next.ServeHTTP(d, r)
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obs.With(labels(code, method, r.Method, d.Status(), mwOpts.extraMethods...)).Observe(time.Since(now).Seconds())
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})
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exemplarObserve(
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obs.With(labels(code, method, r.Method, d.Status(), hOpts.extraMethods...)),
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time.Since(now).Seconds(),
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hOpts.getExemplarFn(r.Context()),
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)
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}
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}
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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return func(w http.ResponseWriter, r *http.Request) {
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now := time.Now()
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next.ServeHTTP(w, r)
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obs.With(labels(code, method, r.Method, 0, mwOpts.extraMethods...)).Observe(time.Since(now).Seconds())
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})
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exemplarObserve(
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obs.With(labels(code, method, r.Method, 0, hOpts.extraMethods...)),
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time.Since(now).Seconds(),
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hOpts.getExemplarFn(r.Context()),
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)
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}
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}
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// InstrumentHandlerCounter is a middleware that wraps the provided http.Handler
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@ -104,25 +129,34 @@ func InstrumentHandlerDuration(obs prometheus.ObserverVec, next http.Handler, op
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//
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// See the example for InstrumentHandlerDuration for example usage.
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func InstrumentHandlerCounter(counter *prometheus.CounterVec, next http.Handler, opts ...Option) http.HandlerFunc {
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mwOpts := &option{}
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hOpts := defaultOptions()
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for _, o := range opts {
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o(mwOpts)
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o.apply(hOpts)
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}
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code, method := checkLabels(counter)
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if code {
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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return func(w http.ResponseWriter, r *http.Request) {
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d := newDelegator(w, nil)
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next.ServeHTTP(d, r)
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counter.With(labels(code, method, r.Method, d.Status(), mwOpts.extraMethods...)).Inc()
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})
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exemplarAdd(
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counter.With(labels(code, method, r.Method, d.Status(), hOpts.extraMethods...)),
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1,
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hOpts.getExemplarFn(r.Context()),
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)
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}
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}
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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return func(w http.ResponseWriter, r *http.Request) {
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next.ServeHTTP(w, r)
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counter.With(labels(code, method, r.Method, 0, mwOpts.extraMethods...)).Inc()
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})
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exemplarAdd(
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counter.With(labels(code, method, r.Method, 0, hOpts.extraMethods...)),
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1,
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hOpts.getExemplarFn(r.Context()),
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)
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}
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}
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// InstrumentHandlerTimeToWriteHeader is a middleware that wraps the provided
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@ -148,20 +182,24 @@ func InstrumentHandlerCounter(counter *prometheus.CounterVec, next http.Handler,
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//
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// See the example for InstrumentHandlerDuration for example usage.
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func InstrumentHandlerTimeToWriteHeader(obs prometheus.ObserverVec, next http.Handler, opts ...Option) http.HandlerFunc {
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mwOpts := &option{}
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hOpts := defaultOptions()
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for _, o := range opts {
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o(mwOpts)
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o.apply(hOpts)
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}
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code, method := checkLabels(obs)
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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return func(w http.ResponseWriter, r *http.Request) {
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now := time.Now()
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d := newDelegator(w, func(status int) {
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obs.With(labels(code, method, r.Method, status, mwOpts.extraMethods...)).Observe(time.Since(now).Seconds())
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exemplarObserve(
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obs.With(labels(code, method, r.Method, status, hOpts.extraMethods...)),
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time.Since(now).Seconds(),
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hOpts.getExemplarFn(r.Context()),
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)
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})
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next.ServeHTTP(d, r)
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})
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}
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}
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// InstrumentHandlerRequestSize is a middleware that wraps the provided
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@ -184,27 +222,34 @@ func InstrumentHandlerTimeToWriteHeader(obs prometheus.ObserverVec, next http.Ha
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//
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// See the example for InstrumentHandlerDuration for example usage.
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func InstrumentHandlerRequestSize(obs prometheus.ObserverVec, next http.Handler, opts ...Option) http.HandlerFunc {
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mwOpts := &option{}
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hOpts := defaultOptions()
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for _, o := range opts {
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o(mwOpts)
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o.apply(hOpts)
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}
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code, method := checkLabels(obs)
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if code {
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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return func(w http.ResponseWriter, r *http.Request) {
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d := newDelegator(w, nil)
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next.ServeHTTP(d, r)
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size := computeApproximateRequestSize(r)
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obs.With(labels(code, method, r.Method, d.Status(), mwOpts.extraMethods...)).Observe(float64(size))
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})
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exemplarObserve(
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obs.With(labels(code, method, r.Method, d.Status(), hOpts.extraMethods...)),
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float64(size),
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hOpts.getExemplarFn(r.Context()),
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)
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}
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}
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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return func(w http.ResponseWriter, r *http.Request) {
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next.ServeHTTP(w, r)
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size := computeApproximateRequestSize(r)
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obs.With(labels(code, method, r.Method, 0, mwOpts.extraMethods...)).Observe(float64(size))
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})
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exemplarObserve(
|
||||
obs.With(labels(code, method, r.Method, 0, hOpts.extraMethods...)),
|
||||
float64(size),
|
||||
hOpts.getExemplarFn(r.Context()),
|
||||
)
|
||||
}
|
||||
}
|
||||
|
||||
// InstrumentHandlerResponseSize is a middleware that wraps the provided
|
||||
|
@ -227,9 +272,9 @@ func InstrumentHandlerRequestSize(obs prometheus.ObserverVec, next http.Handler,
|
|||
//
|
||||
// See the example for InstrumentHandlerDuration for example usage.
|
||||
func InstrumentHandlerResponseSize(obs prometheus.ObserverVec, next http.Handler, opts ...Option) http.Handler {
|
||||
mwOpts := &option{}
|
||||
hOpts := defaultOptions()
|
||||
for _, o := range opts {
|
||||
o(mwOpts)
|
||||
o.apply(hOpts)
|
||||
}
|
||||
|
||||
code, method := checkLabels(obs)
|
||||
|
@ -237,7 +282,11 @@ func InstrumentHandlerResponseSize(obs prometheus.ObserverVec, next http.Handler
|
|||
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
|
||||
d := newDelegator(w, nil)
|
||||
next.ServeHTTP(d, r)
|
||||
obs.With(labels(code, method, r.Method, d.Status(), mwOpts.extraMethods...)).Observe(float64(d.Written()))
|
||||
exemplarObserve(
|
||||
obs.With(labels(code, method, r.Method, d.Status(), hOpts.extraMethods...)),
|
||||
float64(d.Written()),
|
||||
hOpts.getExemplarFn(r.Context()),
|
||||
)
|
||||
})
|
||||
}
|
||||
|
||||
|
|
|
@ -14,6 +14,7 @@
|
|||
package promhttp
|
||||
|
||||
import (
|
||||
"context"
|
||||
"io"
|
||||
"log"
|
||||
"net/http"
|
||||
|
@ -321,7 +322,7 @@ func TestLabels(t *testing.T) {
|
|||
}
|
||||
}
|
||||
|
||||
func TestMiddlewareAPI(t *testing.T) {
|
||||
func makeInstrumentedHandler(handler http.HandlerFunc, opts ...Option) (http.Handler, *prometheus.Registry) {
|
||||
reg := prometheus.NewRegistry()
|
||||
|
||||
inFlightGauge := prometheus.NewGauge(prometheus.GaugeOpts{
|
||||
|
@ -366,25 +367,43 @@ func TestMiddlewareAPI(t *testing.T) {
|
|||
[]string{},
|
||||
)
|
||||
|
||||
handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
|
||||
w.Write([]byte("OK"))
|
||||
})
|
||||
|
||||
reg.MustRegister(inFlightGauge, counter, histVec, responseSize, writeHeaderVec)
|
||||
|
||||
chain := InstrumentHandlerInFlight(inFlightGauge,
|
||||
return InstrumentHandlerInFlight(inFlightGauge,
|
||||
InstrumentHandlerCounter(counter,
|
||||
InstrumentHandlerDuration(histVec,
|
||||
InstrumentHandlerTimeToWriteHeader(writeHeaderVec,
|
||||
InstrumentHandlerResponseSize(responseSize, handler),
|
||||
),
|
||||
),
|
||||
),
|
||||
)
|
||||
InstrumentHandlerResponseSize(responseSize, handler, opts...),
|
||||
opts...),
|
||||
opts...),
|
||||
opts...),
|
||||
), reg
|
||||
}
|
||||
|
||||
func TestMiddlewareAPI(t *testing.T) {
|
||||
chain, reg := makeInstrumentedHandler(func(w http.ResponseWriter, r *http.Request) {
|
||||
_, _ = w.Write([]byte("OK"))
|
||||
})
|
||||
|
||||
r, _ := http.NewRequest("GET", "www.example.com", nil)
|
||||
w := httptest.NewRecorder()
|
||||
chain.ServeHTTP(w, r)
|
||||
|
||||
assetMetricAndExemplars(t, reg, 5, nil)
|
||||
}
|
||||
|
||||
func TestMiddlewareAPI_WithExemplars(t *testing.T) {
|
||||
exemplar := prometheus.Labels{"traceID": "example situation observed by this metric"}
|
||||
|
||||
chain, reg := makeInstrumentedHandler(func(w http.ResponseWriter, r *http.Request) {
|
||||
_, _ = w.Write([]byte("OK"))
|
||||
}, WithExemplarFromContext(func(_ context.Context) prometheus.Labels { return exemplar }))
|
||||
|
||||
r, _ := http.NewRequest("GET", "www.example.com", nil)
|
||||
w := httptest.NewRecorder()
|
||||
chain.ServeHTTP(w, r)
|
||||
|
||||
assetMetricAndExemplars(t, reg, 5, labelsToLabelPair(exemplar))
|
||||
}
|
||||
|
||||
func TestInstrumentTimeToFirstWrite(t *testing.T) {
|
||||
|
|
|
@ -13,19 +13,46 @@
|
|||
|
||||
package promhttp
|
||||
|
||||
// Option are used to configure a middleware or round tripper..
|
||||
type Option func(*option)
|
||||
import (
|
||||
"context"
|
||||
|
||||
type option struct {
|
||||
extraMethods []string
|
||||
"github.com/prometheus/client_golang/prometheus"
|
||||
)
|
||||
|
||||
// Option are used to configure both handler (middleware) or round tripper.
|
||||
type Option interface {
|
||||
apply(*options)
|
||||
}
|
||||
|
||||
// options store options for both a handler or round tripper.
|
||||
type options struct {
|
||||
extraMethods []string
|
||||
getExemplarFn func(requestCtx context.Context) prometheus.Labels
|
||||
}
|
||||
|
||||
func defaultOptions() *options {
|
||||
return &options{getExemplarFn: func(ctx context.Context) prometheus.Labels { return nil }}
|
||||
}
|
||||
|
||||
type optionApplyFunc func(*options)
|
||||
|
||||
func (o optionApplyFunc) apply(opt *options) { o(opt) }
|
||||
|
||||
// WithExtraMethods adds additional HTTP methods to the list of allowed methods.
|
||||
// See https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods for the default list.
|
||||
//
|
||||
// See the example for ExampleInstrumentHandlerWithExtraMethods for example usage.
|
||||
func WithExtraMethods(methods ...string) Option {
|
||||
return func(o *option) {
|
||||
return optionApplyFunc(func(o *options) {
|
||||
o.extraMethods = methods
|
||||
}
|
||||
})
|
||||
}
|
||||
|
||||
// WithExemplarFromContext adds allows to put a hook to all counter and histogram metrics.
|
||||
// If the hook function returns non-nil labels, exemplars will be added for that request, otherwise metric
|
||||
// will get instrumented without exemplar.
|
||||
func WithExemplarFromContext(getExemplarFn func(requestCtx context.Context) prometheus.Labels) Option {
|
||||
return optionApplyFunc(func(o *options) {
|
||||
o.getExemplarFn = getExemplarFn
|
||||
})
|
||||
}
|
||||
|
|
Loading…
Reference in New Issue