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Added tests and options for RT.
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Signed-off-by: bwplotka <bwplotka@gmail.com>
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@bwplotka
bwplotka committed Aug 2, 2022
1 parent a5b3380 commit e29b75f
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Showing 5 changed files with 218 additions and 76 deletions.
39 changes: 26 additions & 13 deletions prometheus/promhttp/instrument_client.go
View file
Expand Up @@ -38,11 +38,11 @@ func (rt RoundTripperFunc) RoundTrip(r *http.Request) (*http.Response, error) {
//
// See the example for ExampleInstrumentRoundTripperDuration for example usage.
func InstrumentRoundTripperInFlight(gauge prometheus.Gauge, next http.RoundTripper) RoundTripperFunc {
return RoundTripperFunc(func(r *http.Request) (*http.Response, error) {
return func(r *http.Request) (*http.Response, error) {
gauge.Inc()
defer gauge.Dec()
return next.RoundTrip(r)
})
}
}

// InstrumentRoundTripperCounter is a middleware that wraps the provided
Expand All @@ -59,22 +59,29 @@ func InstrumentRoundTripperInFlight(gauge prometheus.Gauge, next http.RoundTripp
// If the wrapped RoundTripper panics or returns a non-nil error, the Counter
// is not incremented.
//
// Use with WithExemplarFromContext to instrument the exemplars on the counter of requests.
//
// See the example for ExampleInstrumentRoundTripperDuration for example usage.
func InstrumentRoundTripperCounter(counter *prometheus.CounterVec, next http.RoundTripper, opts ...Option) RoundTripperFunc {
rtOpts := &option{}
rtOpts := defaultOptions()
for _, o := range opts {
o(rtOpts)
o.apply(rtOpts)
}

code, method := checkLabels(counter)

return RoundTripperFunc(func(r *http.Request) (*http.Response, error) {
return func(r *http.Request) (*http.Response, error) {
resp, err := next.RoundTrip(r)
if err == nil {
exemplarAdd(
counter.With(labels(code, method, r.Method, resp.StatusCode, rtOpts.extraMethods...)),
1,
rtOpts.getExemplarFn(r.Context()),
)
counter.With(labels(code, method, r.Method, resp.StatusCode, rtOpts.extraMethods...)).Inc()
}
return resp, err
})
}
}

// InstrumentRoundTripperDuration is a middleware that wraps the provided
Expand All @@ -94,24 +101,30 @@ func InstrumentRoundTripperCounter(counter *prometheus.CounterVec, next http.Rou
// If the wrapped RoundTripper panics or returns a non-nil error, no values are
// reported.
//
// Use with WithExemplarFromContext to instrument the exemplars on the duration histograms.
//
// Note that this method is only guaranteed to never observe negative durations
// if used with Go1.9+.
func InstrumentRoundTripperDuration(obs prometheus.ObserverVec, next http.RoundTripper, opts ...Option) RoundTripperFunc {
rtOpts := &option{}
rtOpts := defaultOptions()
for _, o := range opts {
o(rtOpts)
o.apply(rtOpts)
}

code, method := checkLabels(obs)

return RoundTripperFunc(func(r *http.Request) (*http.Response, error) {
return func(r *http.Request) (*http.Response, error) {
start := time.Now()
resp, err := next.RoundTrip(r)
if err == nil {
obs.With(labels(code, method, r.Method, resp.StatusCode, rtOpts.extraMethods...)).Observe(time.Since(start).Seconds())
exemplarObserve(
obs.With(labels(code, method, r.Method, resp.StatusCode, rtOpts.extraMethods...)),
time.Since(start).Seconds(),
rtOpts.getExemplarFn(r.Context()),
)
}
return resp, err
})
}
}

// InstrumentTrace is used to offer flexibility in instrumenting the available
Expand Down Expand Up @@ -149,7 +162,7 @@ type InstrumentTrace struct {
//
// See the example for ExampleInstrumentRoundTripperDuration for example usage.
func InstrumentRoundTripperTrace(it *InstrumentTrace, next http.RoundTripper) RoundTripperFunc {
return RoundTripperFunc(func(r *http.Request) (*http.Response, error) {
return func(r *http.Request) (*http.Response, error) {
start := time.Now()

trace := &httptrace.ClientTrace{
Expand Down Expand Up @@ -231,5 +244,5 @@ func InstrumentRoundTripperTrace(it *InstrumentTrace, next http.RoundTripper) Ro
r = r.WithContext(httptrace.WithClientTrace(r.Context(), trace))

return next.RoundTrip(r)
})
}
}
115 changes: 102 additions & 13 deletions prometheus/promhttp/instrument_client_test.go
View file
Expand Up @@ -18,14 +18,18 @@ import (
"log"
"net/http"
"net/http/httptest"
"reflect"
"sort"
"strings"
"testing"
"time"

"github.com/golang/protobuf/proto"
"github.com/prometheus/client_golang/prometheus"
dto "github.com/prometheus/client_model/go"
)

func makeInstrumentedClient() (*http.Client, *prometheus.Registry) {
func makeInstrumentedClient(opts ...Option) (*http.Client, *prometheus.Registry) {
client := http.DefaultClient
client.Timeout = 1 * time.Second

Expand Down Expand Up @@ -91,13 +95,91 @@ func makeInstrumentedClient() (*http.Client, *prometheus.Registry) {
client.Transport = InstrumentRoundTripperInFlight(inFlightGauge,
InstrumentRoundTripperCounter(counter,
InstrumentRoundTripperTrace(trace,
InstrumentRoundTripperDuration(histVec, http.DefaultTransport),
InstrumentRoundTripperDuration(histVec, http.DefaultTransport, opts...),
),
),
opts...),
)
return client, reg
}

func labelsToLabelPair(l prometheus.Labels) []*dto.LabelPair {
ret := make([]*dto.LabelPair, 0, len(l))
for k, v := range l {
ret = append(ret, &dto.LabelPair{Name: proto.String(k), Value: proto.String(v)})
}
sort.Slice(ret, func(i, j int) bool {
return *ret[i].Name < *ret[j].Name
})
return ret
}

func assetMetricAndExemplars(
t *testing.T,
reg *prometheus.Registry,
expectedNumMetrics int,
expectedExemplar []*dto.LabelPair,
) {
t.Helper()

mfs, err := reg.Gather()
if err != nil {
t.Fatal(err)
}
if want, got := expectedNumMetrics, len(mfs); want != got {
t.Fatalf("unexpected number of metric families gathered, want %d, got %d", want, got)
}

for _, mf := range mfs {
if len(mf.Metric) == 0 {
t.Errorf("metric family %s must not be empty", mf.GetName())
}
for _, m := range mf.GetMetric() {
if c := m.GetCounter(); c != nil {
if len(expectedExemplar) == 0 {
if c.Exemplar != nil {
t.Errorf("expected no exemplar on the counter %v%v, got %v", mf.GetName(), m.Label, c.Exemplar.String())
}
continue
}

if c.Exemplar == nil {
t.Errorf("expected exemplar %v on the counter %v%v, got none", expectedExemplar, mf.GetName(), m.Label)
continue
}
if got := c.Exemplar.Label; !reflect.DeepEqual(expectedExemplar, got) {
t.Errorf("expected exemplar %v on the counter %v%v, got %v", expectedExemplar, mf.GetName(), m.Label, got)
}
continue
}
if h := m.GetHistogram(); h != nil {
found := false
for _, b := range h.GetBucket() {
if len(expectedExemplar) == 0 {
if b.Exemplar != nil {
t.Errorf("expected no exemplar on histogram %v%v bkt %v, got %v", mf.GetName(), m.Label, b.GetUpperBound(), b.Exemplar.String())
}
continue
}

if b.Exemplar == nil {
continue
}
if got := b.Exemplar.Label; !reflect.DeepEqual(expectedExemplar, got) {
t.Errorf("expected exemplar %v on the histogram %v%v on bkt %v, got %v", expectedExemplar, mf.GetName(), m.Label, b.GetUpperBound(), got)
continue
}
found = true
break
}

if len(expectedExemplar) > 0 && !found {
t.Errorf("expected exemplar %v on at least one bucket of the histogram %v%v, got none", expectedExemplar, mf.GetName(), m.Label)
}
}
}
}
}

func TestClientMiddlewareAPI(t *testing.T) {
client, reg := makeInstrumentedClient()
backend := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
Expand All @@ -111,21 +193,28 @@ func TestClientMiddlewareAPI(t *testing.T) {
}
defer resp.Body.Close()

mfs, err := reg.Gather()
assetMetricAndExemplars(t, reg, 3, nil)
}

func TestClientMiddlewareAPI_WithExemplars(t *testing.T) {
exemplar := prometheus.Labels{"traceID": "example situation observed by this metric"}

client, reg := makeInstrumentedClient(WithExemplarFromContext(func(_ context.Context) prometheus.Labels { return exemplar }))
backend := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
w.WriteHeader(http.StatusOK)
}))
defer backend.Close()

resp, err := client.Get(backend.URL)
if err != nil {
t.Fatal(err)
}
if want, got := 3, len(mfs); want != got {
t.Fatalf("unexpected number of metric families gathered, want %d, got %d", want, got)
}
for _, mf := range mfs {
if len(mf.Metric) == 0 {
t.Errorf("metric family %s must not be empty", mf.GetName())
}
}
defer resp.Body.Close()

assetMetricAndExemplars(t, reg, 3, labelsToLabelPair(exemplar))
}

func TestClientMiddlewareAPIWithRequestContext(t *testing.T) {
func TestClientMiddlewareAPI_WithRequestContext(t *testing.T) {
client, reg := makeInstrumentedClient()
backend := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
w.WriteHeader(http.StatusOK)
Expand Down

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