client_golang/prometheus/wrap.go

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// Copyright 2018 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 prometheus
import (
"fmt"
"sort"
//nolint:staticcheck // Ignore SA1019. Need to keep deprecated package for compatibility.
"github.com/golang/protobuf/proto"
dto "github.com/prometheus/client_model/go"
"github.com/prometheus/client_golang/prometheus/internal"
)
// WrapRegistererWith returns a Registerer wrapping the provided
// Registerer. Collectors registered with the returned Registerer will be
// registered with the wrapped Registerer in a modified way. The modified
// Collector adds the provided Labels to all Metrics it collects (as
// ConstLabels). The Metrics collected by the unmodified Collector must not
// duplicate any of those labels. Wrapping a nil value is valid, resulting
// in a no-op Registerer.
//
// WrapRegistererWith provides a way to add fixed labels to a subset of
// Collectors. It should not be used to add fixed labels to all metrics
// exposed. See also
// https://prometheus.io/docs/instrumenting/writing_exporters/#target-labels-not-static-scraped-labels
//
// Conflicts between Collectors registered through the original Registerer with
// Collectors registered through the wrapping Registerer will still be
// detected. Any AlreadyRegisteredError returned by the Register method of
// either Registerer will contain the ExistingCollector in the form it was
// provided to the respective registry.
//
// The Collector example demonstrates a use of WrapRegistererWith.
func WrapRegistererWith(labels Labels, reg Registerer) Registerer {
return &wrappingRegisterer{
wrappedRegisterer: reg,
labels: labels,
}
}
// WrapRegistererWithPrefix returns a Registerer wrapping the provided
// Registerer. Collectors registered with the returned Registerer will be
// registered with the wrapped Registerer in a modified way. The modified
// Collector adds the provided prefix to the name of all Metrics it collects.
// Wrapping a nil value is valid, resulting in a no-op Registerer.
//
// WrapRegistererWithPrefix is useful to have one place to prefix all metrics of
// a sub-system. To make this work, register metrics of the sub-system with the
// wrapping Registerer returned by WrapRegistererWithPrefix. It is rarely useful
// to use the same prefix for all metrics exposed. In particular, do not prefix
// metric names that are standardized across applications, as that would break
// horizontal monitoring, for example the metrics provided by the Go collector
// (see NewGoCollector) and the process collector (see NewProcessCollector). (In
// fact, those metrics are already prefixed with “go_” or “process_”,
// respectively.)
//
// Conflicts between Collectors registered through the original Registerer with
// Collectors registered through the wrapping Registerer will still be
// detected. Any AlreadyRegisteredError returned by the Register method of
// either Registerer will contain the ExistingCollector in the form it was
// provided to the respective registry.
func WrapRegistererWithPrefix(prefix string, reg Registerer) Registerer {
return &wrappingRegisterer{
wrappedRegisterer: reg,
prefix: prefix,
}
}
type wrappingRegisterer struct {
wrappedRegisterer Registerer
prefix string
labels Labels
}
func (r *wrappingRegisterer) Register(c Collector) error {
if r.wrappedRegisterer == nil {
return nil
}
return r.wrappedRegisterer.Register(&wrappingCollector{
wrappedCollector: c,
prefix: r.prefix,
labels: r.labels,
})
}
func (r *wrappingRegisterer) MustRegister(cs ...Collector) {
if r.wrappedRegisterer == nil {
return
}
for _, c := range cs {
if err := r.Register(c); err != nil {
panic(err)
}
}
}
func (r *wrappingRegisterer) Unregister(c Collector) bool {
if r.wrappedRegisterer == nil {
return false
}
return r.wrappedRegisterer.Unregister(&wrappingCollector{
wrappedCollector: c,
prefix: r.prefix,
labels: r.labels,
})
}
type wrappingCollector struct {
wrappedCollector Collector
prefix string
labels Labels
}
func (c *wrappingCollector) Collect(ch chan<- Metric) {
wrappedCh := make(chan Metric)
go func() {
c.wrappedCollector.Collect(wrappedCh)
close(wrappedCh)
}()
for m := range wrappedCh {
ch <- &wrappingMetric{
wrappedMetric: m,
prefix: c.prefix,
labels: c.labels,
}
}
}
func (c *wrappingCollector) Describe(ch chan<- *Desc) {
wrappedCh := make(chan *Desc)
go func() {
c.wrappedCollector.Describe(wrappedCh)
close(wrappedCh)
}()
for desc := range wrappedCh {
ch <- wrapDesc(desc, c.prefix, c.labels)
}
}
func (c *wrappingCollector) unwrapRecursively() Collector {
switch wc := c.wrappedCollector.(type) {
case *wrappingCollector:
return wc.unwrapRecursively()
default:
return wc
}
}
type wrappingMetric struct {
wrappedMetric Metric
prefix string
labels Labels
}
func (m *wrappingMetric) Desc() *Desc {
return wrapDesc(m.wrappedMetric.Desc(), m.prefix, m.labels)
}
func (m *wrappingMetric) Write(out *dto.Metric) error {
if err := m.wrappedMetric.Write(out); err != nil {
return err
}
if len(m.labels) == 0 {
// No wrapping labels.
return nil
}
for ln, lv := range m.labels {
out.Label = append(out.Label, &dto.LabelPair{
Name: proto.String(ln),
Value: proto.String(lv),
})
}
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 2fcaf51be9a12b4b95413b6b3e0c13fabfaaf73f. 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>
2022-02-23 14:22:52 +03:00
sort.Sort(internal.LabelPairSorter(out.Label))
return nil
}
func wrapDesc(desc *Desc, prefix string, labels Labels) *Desc {
constLabels := Labels{}
for _, lp := range desc.constLabelPairs {
constLabels[*lp.Name] = *lp.Value
}
for ln, lv := range labels {
if _, alreadyUsed := constLabels[ln]; alreadyUsed {
return &Desc{
fqName: desc.fqName,
help: desc.help,
variableLabels: desc.variableLabels,
constLabelPairs: desc.constLabelPairs,
err: fmt.Errorf("attempted wrapping with already existing label name %q", ln),
}
}
constLabels[ln] = lv
}
// NewDesc will do remaining validations.
newDesc := NewDesc(prefix+desc.fqName, desc.help, desc.variableLabels, constLabels)
// Propagate errors if there was any. This will override any errer
// created by NewDesc above, i.e. earlier errors get precedence.
if desc.err != nil {
newDesc.err = desc.err
}
return newDesc
}