prometheus/storage/remote/write_handler.go

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// Copyright 2021 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package remote
import (
"context"
"errors"
"fmt"
"net/http"
"github.com/go-kit/log"
"github.com/go-kit/log/level"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/prometheus/model/exemplar"
"github.com/prometheus/prometheus/prompb"
"github.com/prometheus/prometheus/storage"
)
type writeHandler struct {
logger log.Logger
appendable storage.Appendable
samplesWithInvalidLabelsTotal prometheus.Counter
}
// NewWriteHandler creates a http.Handler that accepts remote write requests and
// writes them to the provided appendable.
func NewWriteHandler(logger log.Logger, reg prometheus.Registerer, appendable storage.Appendable) http.Handler {
h := &writeHandler{
logger: logger,
appendable: appendable,
samplesWithInvalidLabelsTotal: prometheus.NewCounter(prometheus.CounterOpts{
Namespace: "prometheus",
Subsystem: "api",
Name: "remote_write_invalid_labels_samples_total",
Help: "The total number of remote write samples which contains invalid labels.",
}),
}
if reg != nil {
reg.MustRegister(h.samplesWithInvalidLabelsTotal)
}
return h
}
func (h *writeHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
req, err := DecodeWriteRequest(r.Body)
if err != nil {
level.Error(h.logger).Log("msg", "Error decoding remote write request", "err", err.Error())
http.Error(w, err.Error(), http.StatusBadRequest)
return
}
err = h.write(r.Context(), req)
switch err {
case nil:
case storage.ErrOutOfOrderSample, storage.ErrOutOfBounds, storage.ErrDuplicateSampleForTimestamp:
// Indicated an out of order sample is a bad request to prevent retries.
http.Error(w, err.Error(), http.StatusBadRequest)
return
default:
level.Error(h.logger).Log("msg", "Error appending remote write", "err", err.Error())
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
w.WriteHeader(http.StatusNoContent)
}
// checkAppendExemplarError modifies the AppendExamplar's returned error based on the error cause.
func (h *writeHandler) checkAppendExemplarError(err error, e exemplar.Exemplar, outOfOrderErrs *int) error {
unwrappedErr := errors.Unwrap(err)
if unwrappedErr == nil {
unwrappedErr = err
}
switch {
case errors.Is(unwrappedErr, storage.ErrNotFound):
return storage.ErrNotFound
case errors.Is(unwrappedErr, storage.ErrOutOfOrderExemplar):
*outOfOrderErrs++
level.Debug(h.logger).Log("msg", "Out of order exemplar", "exemplar", fmt.Sprintf("%+v", e))
return nil
default:
return err
}
}
func (h *writeHandler) write(ctx context.Context, req *prompb.WriteRequest) (err error) {
outOfOrderExemplarErrs := 0
samplesWithInvalidLabels := 0
app := h.appendable.Appender(ctx)
defer func() {
if err != nil {
_ = app.Rollback()
return
}
err = app.Commit()
}()
var exemplarErr error
for _, ts := range req.Timeseries {
labels := labelProtosToLabels(ts.Labels)
if !labels.IsValid() {
level.Warn(h.logger).Log("msg", "Invalid metric names or labels", "got", labels.String())
samplesWithInvalidLabels++
continue
}
for _, s := range ts.Samples {
_, err = app.Append(0, labels, s.Timestamp, s.Value)
if err != nil {
unwrappedErr := errors.Unwrap(err)
if unwrappedErr == nil {
unwrappedErr = err
}
if errors.Is(err, storage.ErrOutOfOrderSample) || errors.Is(unwrappedErr, storage.ErrOutOfBounds) || errors.Is(unwrappedErr, storage.ErrDuplicateSampleForTimestamp) {
level.Error(h.logger).Log("msg", "Out of order sample from remote write", "err", err.Error(), "series", labels.String(), "timestamp", s.Timestamp)
}
return err
}
}
for _, ep := range ts.Exemplars {
e := exemplarProtoToExemplar(ep)
_, exemplarErr = app.AppendExemplar(0, labels, e)
exemplarErr = h.checkAppendExemplarError(exemplarErr, e, &outOfOrderExemplarErrs)
if exemplarErr != nil {
// Since exemplar storage is still experimental, we don't fail the request on ingestion errors.
level.Debug(h.logger).Log("msg", "Error while adding exemplar in AddExemplar", "exemplar", fmt.Sprintf("%+v", e), "err", exemplarErr)
}
}
for _, hp := range ts.Histograms {
if hp.IsFloatHistogram() {
fhs := FloatHistogramProtoToFloatHistogram(hp)
_, err = app.AppendHistogram(0, labels, hp.Timestamp, nil, fhs)
} else {
hs := HistogramProtoToHistogram(hp)
_, err = app.AppendHistogram(0, labels, hp.Timestamp, hs, nil)
}
if err != nil {
unwrappedErr := errors.Unwrap(err)
if unwrappedErr == nil {
unwrappedErr = err
}
// Although AppendHistogram does not currently return ErrDuplicateSampleForTimestamp there is
// a note indicating its inclusion in the future.
if errors.Is(unwrappedErr, storage.ErrOutOfOrderSample) || errors.Is(unwrappedErr, storage.ErrOutOfBounds) || errors.Is(unwrappedErr, storage.ErrDuplicateSampleForTimestamp) {
level.Error(h.logger).Log("msg", "Out of order histogram from remote write", "err", err.Error(), "series", labels.String(), "timestamp", hp.Timestamp)
}
return err
}
}
}
if outOfOrderExemplarErrs > 0 {
_ = level.Warn(h.logger).Log("msg", "Error on ingesting out-of-order exemplars", "num_dropped", outOfOrderExemplarErrs)
}
if samplesWithInvalidLabels > 0 {
h.samplesWithInvalidLabelsTotal.Add(float64(samplesWithInvalidLabels))
}
return nil
}