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Added Transactional Gatherer allowed cached solutions (#989) 

* Added cached collector.

Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>

update.

Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>

Attempt 2

Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>

Added blocking registry, with raw collector and transactional handler.

Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>

Added fast path to normal (empty) registry to save 8 allocs and 3K5B per Gather.

Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>

Simplified API, added tests.

Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>

Fix.

Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>

Simplified implementation.

Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>

Added benchmark.

Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>

Optimized.

Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>

* Optimization attempt.

Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>

* Revert "Optimization attempt."

This reverts commit 2fcaf51be9.

Optimization was not worth it:

 benchstat v1.txt v2.txt
name                                                           old time/op    new time/op    delta
CachedTGatherer_Update/Update_of_one_element_without_reset-12    2.64µs ± 0%    4.05µs ± 0%   ~     (p=1.000 n=1+1)
CachedTGatherer_Update/Update_of_all_elements_with_reset-12       701ms ± 0%     358ms ± 0%   ~     (p=1.000 n=1+1)
CachedTGatherer_Update/Gather-12                                  535µs ± 0%  703934µs ± 0%   ~     (p=1.000 n=1+1)

name                                                           old alloc/op   new alloc/op   delta
CachedTGatherer_Update/Update_of_one_element_without_reset-12      208B ± 0%      208B ± 0%   ~     (all equal)
CachedTGatherer_Update/Update_of_all_elements_with_reset-12      40.2MB ± 0%    41.1MB ± 0%   ~     (p=1.000 n=1+1)
CachedTGatherer_Update/Gather-12                                 48.6kB ± 0%    84.3kB ± 0%   ~     (p=1.000 n=1+1)

name                                                           old allocs/op  new allocs/op  delta
CachedTGatherer_Update/Update_of_one_element_without_reset-12      3.00 ± 0%      3.00 ± 0%   ~     (all equal)
CachedTGatherer_Update/Update_of_all_elements_with_reset-12        6.00 ± 0%   4003.00 ± 0%   ~     (p=1.000 n=1+1)
CachedTGatherer_Update/Gather-12                                  1.00k ± 0%     2.01k ± 0%   ~     (p=1.000 n=1+1)

* nit.

Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>

* Another optimization attempt.

Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>

* rename and further optimization.

Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>

* Hopefully final optimization.

benchstat -delta-test=none v6.txt v9.txt
name                                                           old time/op    new time/op    delta
CachedTGatherer_Update/Update_of_one_element_without_reset-12    13.1ms ± 0%     0.0ms ± 0%  -99.81%
CachedTGatherer_Update/Update_of_all_elements_with_reset-12       309ms ± 0%     282ms ± 0%   -8.77%
CachedTGatherer_Update/Gather-12                                  422ms ± 0%       0ms ± 0%  -99.95%

name                                                           old alloc/op   new alloc/op   delta
CachedTGatherer_Update/Update_of_one_element_without_reset-12      208B ± 0%      208B ± 0%    0.00%
CachedTGatherer_Update/Update_of_all_elements_with_reset-12      2.47kB ± 0%    1.67kB ± 0%  -32.56%
CachedTGatherer_Update/Gather-12                                 52.8kB ± 0%    24.6kB ± 0%  -53.34%

name                                                           old allocs/op  new allocs/op  delta
CachedTGatherer_Update/Update_of_one_element_without_reset-12      3.00 ± 0%      3.00 ± 0%    0.00%
CachedTGatherer_Update/Update_of_all_elements_with_reset-12        0.00           0.00         0.00%
CachedTGatherer_Update/Gather-12                                  1.00k ± 0%     0.00k ± 0%  -99.60%

Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>

* Removed obsolete comment

Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>

* Fixed tests.

Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>

* Removed cache.

Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>

* Fixed tests.

Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>

* Re-add cache.

Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>

* Removed cache.

Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>
This commit is contained in:
Bartlomiej Plotka 2022-02-23 12:22:52 +01:00 committed by GitHub
parent f3021b0b81
commit 1f81b3e913
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
10 changed files with 340 additions and 64 deletions
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4
prometheus/desc.go
View File

@ -20,6 +20,8 @@ import (
"strings"
"github.com/cespare/xxhash/v2"
"github.com/prometheus/client_golang/prometheus/internal"
//nolint:staticcheck // Ignore SA1019. Need to keep deprecated package for compatibility.
"github.com/golang/protobuf/proto"
"github.com/prometheus/common/model"
@ -154,7 +156,7 @@ func NewDesc(fqName, help string, variableLabels []string, constLabels Labels) *
Value: proto.String(v),
})
}
sort.Sort(labelPairSorter(d.constLabelPairs))
sort.Sort(internal.LabelPairSorter(d.constLabelPairs))
return d
}

28
prometheus/internal/metric.go
View File

@ -19,18 +19,34 @@ import (
dto "github.com/prometheus/client_model/go"
)
// metricSorter is a sortable slice of *dto.Metric.
type metricSorter []*dto.Metric
// LabelPairSorter implements sort.Interface. It is used to sort a slice of
// dto.LabelPair pointers.
type LabelPairSorter []*dto.LabelPair
func (s metricSorter) Len() int {
func (s LabelPairSorter) Len() int {
return len(s)
}
func (s metricSorter) Swap(i, j int) {
func (s LabelPairSorter) Swap(i, j int) {
s[i], s[j] = s[j], s[i]
}
func (s metricSorter) Less(i, j int) bool {
func (s LabelPairSorter) Less(i, j int) bool {
return s[i].GetName() < s[j].GetName()
}
// MetricSorter is a sortable slice of *dto.Metric.
type MetricSorter []*dto.Metric
func (s MetricSorter) Len() int {
return len(s)
}
func (s MetricSorter) Swap(i, j int) {
s[i], s[j] = s[j], s[i]
}
func (s MetricSorter) Less(i, j int) bool {
if len(s[i].Label) != len(s[j].Label) {
// This should not happen. The metrics are
// inconsistent. However, we have to deal with the fact, as
@ -68,7 +84,7 @@ func (s metricSorter) Less(i, j int) bool {
// the slice, with the contained Metrics sorted within each MetricFamily.
func NormalizeMetricFamilies(metricFamiliesByName map[string]*dto.MetricFamily) []*dto.MetricFamily {
for _, mf := range metricFamiliesByName {
sort.Sort(metricSorter(mf.Metric))
sort.Sort(MetricSorter(mf.Metric))
}
names := make([]string, 0, len(metricFamiliesByName))
for name, mf := range metricFamiliesByName {

16
prometheus/metric.go
View File

@ -115,22 +115,6 @@ func BuildFQName(namespace, subsystem, name string) string {
return name
}
// labelPairSorter implements sort.Interface. It is used to sort a slice of
// dto.LabelPair pointers.
type labelPairSorter []*dto.LabelPair
func (s labelPairSorter) Len() int {
return len(s)
}
func (s labelPairSorter) Swap(i, j int) {
s[i], s[j] = s[j], s[i]
}
func (s labelPairSorter) Less(i, j int) bool {
return s[i].GetName() < s[j].GetName()
}
type invalidMetric struct {
desc *Desc
err error

10
prometheus/promhttp/http.go
View File

@ -84,6 +84,13 @@ func Handler() http.Handler {
// instrumentation. Use the InstrumentMetricHandler function to apply the same
// kind of instrumentation as it is used by the Handler function.
func HandlerFor(reg prometheus.Gatherer, opts HandlerOpts) http.Handler {
return HandlerForTransactional(prometheus.ToTransactionalGatherer(reg), opts)
}
// HandlerForTransactional is like HandlerFor, but it uses transactional gather, which
// can safely change in-place returned *dto.MetricFamily before call to `Gather` and after
// call to `done` of that `Gather`.
func HandlerForTransactional(reg prometheus.TransactionalGatherer, opts HandlerOpts) http.Handler {
var (
inFlightSem chan struct{}
errCnt = prometheus.NewCounterVec(
@ -123,7 +130,8 @@ func HandlerFor(reg prometheus.Gatherer, opts HandlerOpts) http.Handler {
return
}
}
mfs, err := reg.Gather()
mfs, done, err := reg.Gather()
defer done()
if err != nil {
if opts.ErrorLog != nil {
opts.ErrorLog.Println("error gathering metrics:", err)

107
prometheus/promhttp/http_test.go
View File

@ -16,6 +16,7 @@ package promhttp
import (
"bytes"
"errors"
"fmt"
"log"
"net/http"
"net/http/httptest"
@ -24,6 +25,7 @@ import (
"time"
"github.com/prometheus/client_golang/prometheus"
dto "github.com/prometheus/client_model/go"
)
type errorCollector struct{}
@ -56,8 +58,19 @@ func (b blockingCollector) Collect(ch chan<- prometheus.Metric) {
<-b.Block
}
func TestHandlerErrorHandling(t *testing.T) {
type mockTransactionGatherer struct {
g prometheus.Gatherer
gatherInvoked int
doneInvoked int
}
func (g *mockTransactionGatherer) Gather() (_ []*dto.MetricFamily, done func(), err error) {
g.gatherInvoked++
mfs, err := g.g.Gather()
return mfs, func() { g.doneInvoked++ }, err
}
func TestHandlerErrorHandling(t *testing.T) {
// Create a registry that collects a MetricFamily with two elements,
// another with one, and reports an error. Further down, we'll use the
// same registry in the HandlerOpts.
@ -90,21 +103,30 @@ func TestHandlerErrorHandling(t *testing.T) {
request, _ := http.NewRequest("GET", "/", nil)
request.Header.Add("Accept", "test/plain")
errorHandler := HandlerFor(reg, HandlerOpts{
mReg := &mockTransactionGatherer{g: reg}
errorHandler := HandlerForTransactional(mReg, HandlerOpts{
ErrorLog: logger,
ErrorHandling: HTTPErrorOnError,
Registry: reg,
})
continueHandler := HandlerFor(reg, HandlerOpts{
continueHandler := HandlerForTransactional(mReg, HandlerOpts{
ErrorLog: logger,
ErrorHandling: ContinueOnError,
Registry: reg,
})
panicHandler := HandlerFor(reg, HandlerOpts{
panicHandler := HandlerForTransactional(mReg, HandlerOpts{
ErrorLog: logger,
ErrorHandling: PanicOnError,
Registry: reg,
})
// Expect gatherer not touched.
if got := mReg.gatherInvoked; got != 0 {
t.Fatalf("unexpected number of gather invokes, want 0, got %d", got)
}
if got := mReg.doneInvoked; got != 0 {
t.Fatalf("unexpected number of done invokes, want 0, got %d", got)
}
wantMsg := `error gathering metrics: error collecting metric Desc{fqName: "invalid_metric", help: "not helpful", constLabels: {}, variableLabels: []}: collect error
`
wantErrorBody := `An error has occurred while serving metrics:
@ -140,25 +162,39 @@ the_count 0
`
errorHandler.ServeHTTP(writer, request)
if got := mReg.gatherInvoked; got != 1 {
t.Fatalf("unexpected number of gather invokes, want 1, got %d", got)
}
if got := mReg.doneInvoked; got != 1 {
t.Fatalf("unexpected number of done invokes, want 1, got %d", got)
}
if got, want := writer.Code, http.StatusInternalServerError; got != want {
t.Errorf("got HTTP status code %d, want %d", got, want)
}
if got := logBuf.String(); got != wantMsg {
t.Errorf("got log message:\n%s\nwant log message:\n%s\n", got, wantMsg)
if got, want := logBuf.String(), wantMsg; got != want {
t.Errorf("got log buf %q, want %q", got, want)
}
if got := writer.Body.String(); got != wantErrorBody {
t.Errorf("got body:\n%s\nwant body:\n%s\n", got, wantErrorBody)
if got, want := writer.Body.String(), wantErrorBody; got != want {
t.Errorf("got body %q, want %q", got, want)
}
logBuf.Reset()
writer.Body.Reset()
writer.Code = http.StatusOK
continueHandler.ServeHTTP(writer, request)
if got := mReg.gatherInvoked; got != 2 {
t.Fatalf("unexpected number of gather invokes, want 2, got %d", got)
}
if got := mReg.doneInvoked; got != 2 {
t.Fatalf("unexpected number of done invokes, want 2, got %d", got)
}
if got, want := writer.Code, http.StatusOK; got != want {
t.Errorf("got HTTP status code %d, want %d", got, want)
}
if got := logBuf.String(); got != wantMsg {
t.Errorf("got log message %q, want %q", got, wantMsg)
if got, want := logBuf.String(), wantMsg; got != want {
t.Errorf("got log buf %q, want %q", got, want)
}
if got := writer.Body.String(); got != wantOKBody1 && got != wantOKBody2 {
t.Errorf("got body %q, want either %q or %q", got, wantOKBody1, wantOKBody2)
@ -168,20 +204,34 @@ the_count 0
if err := recover(); err == nil {
t.Error("expected panic from panicHandler")
}
if got := mReg.gatherInvoked; got != 3 {
t.Fatalf("unexpected number of gather invokes, want 3, got %d", got)
}
if got := mReg.doneInvoked; got != 3 {
t.Fatalf("unexpected number of done invokes, want 3, got %d", got)
}
}()
panicHandler.ServeHTTP(writer, request)
}
func TestInstrumentMetricHandler(t *testing.T) {
reg := prometheus.NewRegistry()
handler := InstrumentMetricHandler(reg, HandlerFor(reg, HandlerOpts{}))
mReg := &mockTransactionGatherer{g: reg}
handler := InstrumentMetricHandler(reg, HandlerForTransactional(mReg, HandlerOpts{}))
// Do it again to test idempotency.
InstrumentMetricHandler(reg, HandlerFor(reg, HandlerOpts{}))
InstrumentMetricHandler(reg, HandlerForTransactional(mReg, HandlerOpts{}))
writer := httptest.NewRecorder()
request, _ := http.NewRequest("GET", "/", nil)
request.Header.Add("Accept", "test/plain")
handler.ServeHTTP(writer, request)
if got := mReg.gatherInvoked; got != 1 {
t.Fatalf("unexpected number of gather invokes, want 1, got %d", got)
}
if got := mReg.doneInvoked; got != 1 {
t.Fatalf("unexpected number of done invokes, want 1, got %d", got)
}
if got, want := writer.Code, http.StatusOK; got != want {
t.Errorf("got HTTP status code %d, want %d", got, want)
}
@ -195,19 +245,28 @@ func TestInstrumentMetricHandler(t *testing.T) {
t.Errorf("got body %q, does not contain %q", got, want)
}
writer.Body.Reset()
handler.ServeHTTP(writer, request)
if got, want := writer.Code, http.StatusOK; got != want {
t.Errorf("got HTTP status code %d, want %d", got, want)
}
for i := 0; i < 100; i++ {
writer.Body.Reset()
handler.ServeHTTP(writer, request)
want = "promhttp_metric_handler_requests_in_flight 1\n"
if got := writer.Body.String(); !strings.Contains(got, want) {
t.Errorf("got body %q, does not contain %q", got, want)
}
want = "promhttp_metric_handler_requests_total{code=\"200\"} 1\n"
if got := writer.Body.String(); !strings.Contains(got, want) {
t.Errorf("got body %q, does not contain %q", got, want)
if got, want := mReg.gatherInvoked, i+2; got != want {
t.Fatalf("unexpected number of gather invokes, want %d, got %d", want, got)
}
if got, want := mReg.doneInvoked, i+2; got != want {
t.Fatalf("unexpected number of done invokes, want %d, got %d", want, got)
}
if got, want := writer.Code, http.StatusOK; got != want {
t.Errorf("got HTTP status code %d, want %d", got, want)
}
want := "promhttp_metric_handler_requests_in_flight 1\n"
if got := writer.Body.String(); !strings.Contains(got, want) {
t.Errorf("got body %q, does not contain %q", got, want)
}
want = fmt.Sprintf("promhttp_metric_handler_requests_total{code=\"200\"} %d\n", i+1)
if got := writer.Body.String(); !strings.Contains(got, want) {
t.Errorf("got body %q, does not contain %q", got, want)
}
}
}

101
prometheus/registry.go
View File

@ -407,6 +407,14 @@ func (r *Registry) MustRegister(cs ...Collector) {
// Gather implements Gatherer.
func (r *Registry) Gather() ([]*dto.MetricFamily, error) {
r.mtx.RLock()
if len(r.collectorsByID) == 0 && len(r.uncheckedCollectors) == 0 {
// Fast path.
r.mtx.RUnlock()
return nil, nil
}
var (
checkedMetricChan = make(chan Metric, capMetricChan)
uncheckedMetricChan = make(chan Metric, capMetricChan)
@ -416,7 +424,6 @@ func (r *Registry) Gather() ([]*dto.MetricFamily, error) {
registeredDescIDs map[uint64]struct{} // Only used for pedantic checks
)
r.mtx.RLock()
goroutineBudget := len(r.collectorsByID) + len(r.uncheckedCollectors)
metricFamiliesByName := make(map[string]*dto.MetricFamily, len(r.dimHashesByName))
checkedCollectors := make(chan Collector, len(r.collectorsByID))
@ -884,11 +891,11 @@ func checkMetricConsistency(
h.Write(separatorByteSlice)
// Make sure label pairs are sorted. We depend on it for the consistency
// check.
if !sort.IsSorted(labelPairSorter(dtoMetric.Label)) {
if !sort.IsSorted(internal.LabelPairSorter(dtoMetric.Label)) {
// We cannot sort dtoMetric.Label in place as it is immutable by contract.
copiedLabels := make([]*dto.LabelPair, len(dtoMetric.Label))
copy(copiedLabels, dtoMetric.Label)
sort.Sort(labelPairSorter(copiedLabels))
sort.Sort(internal.LabelPairSorter(copiedLabels))
dtoMetric.Label = copiedLabels
}
for _, lp := range dtoMetric.Label {
@ -935,7 +942,7 @@ func checkDescConsistency(
metricFamily.GetName(), dtoMetric, desc,
)
}
sort.Sort(labelPairSorter(lpsFromDesc))
sort.Sort(internal.LabelPairSorter(lpsFromDesc))
for i, lpFromDesc := range lpsFromDesc {
lpFromMetric := dtoMetric.Label[i]
if lpFromDesc.GetName() != lpFromMetric.GetName() ||
@ -948,3 +955,89 @@ func checkDescConsistency(
}
return nil
}
var _ TransactionalGatherer = &MultiTRegistry{}
// MultiTRegistry is a TransactionalGatherer that joins gathered metrics from multiple
// transactional gatherers.
//
// It is caller responsibility to ensure two registries have mutually exclusive metric families,
// no deduplication will happen.
type MultiTRegistry struct {
tGatherers []TransactionalGatherer
}
// NewMultiTRegistry creates MultiTRegistry.
func NewMultiTRegistry(tGatherers ...TransactionalGatherer) *MultiTRegistry {
return &MultiTRegistry{
tGatherers: tGatherers,
}
}
// Gather implements TransactionalGatherer interface.
func (r *MultiTRegistry) Gather() (mfs []*dto.MetricFamily, done func(), err error) {
errs := MultiError{}
dFns := make([]func(), 0, len(r.tGatherers))
// TODO(bwplotka): Implement concurrency for those?
for _, g := range r.tGatherers {
// TODO(bwplotka): Check for duplicates?
m, d, err := g.Gather()
errs.Append(err)
mfs = append(mfs, m...)
dFns = append(dFns, d)
}
// TODO(bwplotka): Consider sort in place, given metric family in gather is sorted already.
sort.Slice(mfs, func(i, j int) bool {
return *mfs[i].Name < *mfs[j].Name
})
return mfs, func() {
for _, d := range dFns {
d()
}
}, errs.MaybeUnwrap()
}
// TransactionalGatherer represents transactional gatherer that can be triggered to notify gatherer that memory
// used by metric family is no longer used by a caller. This allows implementations with cache.
type TransactionalGatherer interface {
// Gather returns metrics in a lexicographically sorted slice
// of uniquely named MetricFamily protobufs. Gather ensures that the
// returned slice is valid and self-consistent so that it can be used
// for valid exposition. As an exception to the strict consistency
// requirements described for metric.Desc, Gather will tolerate
// different sets of label names for metrics of the same metric family.
//
// Even if an error occurs, Gather attempts to gather as many metrics as
// possible. Hence, if a non-nil error is returned, the returned
// MetricFamily slice could be nil (in case of a fatal error that
// prevented any meaningful metric collection) or contain a number of
// MetricFamily protobufs, some of which might be incomplete, and some
// might be missing altogether. The returned error (which might be a
// MultiError) explains the details. Note that this is mostly useful for
// debugging purposes. If the gathered protobufs are to be used for
// exposition in actual monitoring, it is almost always better to not
// expose an incomplete result and instead disregard the returned
// MetricFamily protobufs in case the returned error is non-nil.
//
// Important: done is expected to be triggered (even if the error occurs!)
// once caller does not need returned slice of dto.MetricFamily.
Gather() (_ []*dto.MetricFamily, done func(), err error)
}
// ToTransactionalGatherer transforms Gatherer to transactional one with noop as done function.
func ToTransactionalGatherer(g Gatherer) TransactionalGatherer {
return &noTransactionGatherer{g: g}
}
type noTransactionGatherer struct {
g Gatherer
}
// Gather implements TransactionalGatherer interface.
func (g *noTransactionGatherer) Gather() (_ []*dto.MetricFamily, done func(), err error) {
mfs, err := g.g.Gather()
return mfs, func() {}, err
}

80
prometheus/registry_test.go
View File

@ -21,6 +21,7 @@ package prometheus_test
import (
"bytes"
"errors"
"fmt"
"io/ioutil"
"math/rand"
@ -1175,3 +1176,82 @@ func TestAlreadyRegisteredCollision(t *testing.T) {
}
}
}
type tGatherer struct {
done bool
err error
}
func (g *tGatherer) Gather() (_ []*dto.MetricFamily, done func(), err error) {
name := "g1"
val := 1.0
return []*dto.MetricFamily{
{Name: &name, Metric: []*dto.Metric{{Gauge: &dto.Gauge{Value: &val}}}},
}, func() { g.done = true }, g.err
}
func TestNewMultiTRegistry(t *testing.T) {
treg := &tGatherer{}
t.Run("one registry", func(t *testing.T) {
m := prometheus.NewMultiTRegistry(treg)
ret, done, err := m.Gather()
if err != nil {
t.Error("gather failed:", err)
}
done()
if len(ret) != 1 {
t.Error("unexpected number of metric families, expected 1, got", ret)
}
if !treg.done {
t.Error("inner transactional registry not marked as done")
}
})
reg := prometheus.NewRegistry()
if err := reg.Register(prometheus.NewCounter(prometheus.CounterOpts{Name: "c1", Help: "help c1"})); err != nil {
t.Error("registration failed:", err)
}
// Note on purpose two registries will have exactly same metric family name (but with different string).
// This behaviour is undefined at the moment.
if err := reg.Register(prometheus.NewGauge(prometheus.GaugeOpts{Name: "g1", Help: "help g1"})); err != nil {
t.Error("registration failed:", err)
}
treg.done = false
t.Run("two registries", func(t *testing.T) {
m := prometheus.NewMultiTRegistry(prometheus.ToTransactionalGatherer(reg), treg)
ret, done, err := m.Gather()
if err != nil {
t.Error("gather failed:", err)
}
done()
if len(ret) != 3 {
t.Error("unexpected number of metric families, expected 3, got", ret)
}
if !treg.done {
t.Error("inner transactional registry not marked as done")
}
})
treg.done = false
// Inject error.
treg.err = errors.New("test err")
t.Run("two registries, one with error", func(t *testing.T) {
m := prometheus.NewMultiTRegistry(prometheus.ToTransactionalGatherer(reg), treg)
ret, done, err := m.Gather()
if err != treg.err {
t.Error("unexpected error:", err)
}
done()
if len(ret) != 3 {
t.Error("unexpected number of metric families, expected 3, got", ret)
}
// Still on error, we expect done to be triggered.
if !treg.done {
t.Error("inner transactional registry not marked as done")
}
})
}

11
prometheus/testutil/testutil.go
View File

@ -167,7 +167,16 @@ func CollectAndCompare(c prometheus.Collector, expected io.Reader, metricNames .
// exposition format. If any metricNames are provided, only metrics with those
// names are compared.
func GatherAndCompare(g prometheus.Gatherer, expected io.Reader, metricNames ...string) error {
got, err := g.Gather()
return TransactionalGatherAndCompare(prometheus.ToTransactionalGatherer(g), expected, metricNames...)
}
// TransactionalGatherAndCompare gathers all metrics from the provided Gatherer and compares
// it to an expected output read from the provided Reader in the Prometheus text
// exposition format. If any metricNames are provided, only metrics with those
// names are compared.
func TransactionalGatherAndCompare(g prometheus.TransactionalGatherer, expected io.Reader, metricNames ...string) error {
got, done, err := g.Gather()
defer done()
if err != nil {
return fmt.Errorf("gathering metrics failed: %s", err)
}

44
prometheus/value.go
View File

@ -21,6 +21,7 @@ import (
//nolint:staticcheck // Ignore SA1019. Need to keep deprecated package for compatibility.
"github.com/golang/protobuf/proto"
"github.com/prometheus/client_golang/prometheus/internal"
"google.golang.org/protobuf/types/known/timestamppb"
dto "github.com/prometheus/client_model/go"
@ -38,6 +39,23 @@ const (
UntypedValue
)
var (
CounterMetricTypePtr = func() *dto.MetricType { d := dto.MetricType_COUNTER; return &d }()
GaugeMetricTypePtr = func() *dto.MetricType { d := dto.MetricType_GAUGE; return &d }()
UntypedMetricTypePtr = func() *dto.MetricType { d := dto.MetricType_UNTYPED; return &d }()
)
func (v ValueType) ToDTO() *dto.MetricType {
switch v {
case CounterValue:
return CounterMetricTypePtr
case GaugeValue:
return GaugeMetricTypePtr
default:
return UntypedMetricTypePtr
}
}
// valueFunc is a generic metric for simple values retrieved on collect time
// from a function. It implements Metric and Collector. Its effective type is
// determined by ValueType. This is a low-level building block used by the
@ -91,11 +109,15 @@ func NewConstMetric(desc *Desc, valueType ValueType, value float64, labelValues
if err := validateLabelValues(labelValues, len(desc.variableLabels)); err != nil {
return nil, err
}
metric := &dto.Metric{}
if err := populateMetric(valueType, value, MakeLabelPairs(desc, labelValues), nil, metric); err != nil {
return nil, err
}
return &constMetric{
desc: desc,
valType: valueType,
val: value,
labelPairs: MakeLabelPairs(desc, labelValues),
desc: desc,
metric: metric,
}, nil
}
@ -110,10 +132,8 @@ func MustNewConstMetric(desc *Desc, valueType ValueType, value float64, labelVal
}
type constMetric struct {
desc *Desc
valType ValueType
val float64
labelPairs []*dto.LabelPair
desc *Desc
metric *dto.Metric
}
func (m *constMetric) Desc() *Desc {
@ -121,7 +141,11 @@ func (m *constMetric) Desc() *Desc {
}
func (m *constMetric) Write(out *dto.Metric) error {
return populateMetric(m.valType, m.val, m.labelPairs, nil, out)
out.Label = m.metric.Label
out.Counter = m.metric.Counter
out.Gauge = m.metric.Gauge
out.Untyped = m.metric.Untyped
return nil
}
func populateMetric(
@ -170,7 +194,7 @@ func MakeLabelPairs(desc *Desc, labelValues []string) []*dto.LabelPair {
})
}
labelPairs = append(labelPairs, desc.constLabelPairs...)
sort.Sort(labelPairSorter(labelPairs))
sort.Sort(internal.LabelPairSorter(labelPairs))
return labelPairs
}

3
prometheus/wrap.go
View File

@ -20,6 +20,7 @@ import (
//nolint:staticcheck // Ignore SA1019. Need to keep deprecated package for compatibility.
"github.com/golang/protobuf/proto"
"github.com/prometheus/client_golang/prometheus/internal"
dto "github.com/prometheus/client_model/go"
)
@ -182,7 +183,7 @@ func (m *wrappingMetric) Write(out *dto.Metric) error {
Value: proto.String(lv),
})
}
sort.Sort(labelPairSorter(out.Label))
sort.Sort(internal.LabelPairSorter(out.Label))
return nil
}