Add wrapping of Registerers with labels and prefix
Essentially middleware for Registerers! Signed-off-by: beorn7 <beorn@soundcloud.com>
This commit is contained in:
beorn7
parent
7858729281
commit
84d7aa0cd9
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@ -17,7 +17,7 @@ import (
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"strings"
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"time"
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"github.com/gogo/protobuf/proto"
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"github.com/golang/protobuf/proto"
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dto "github.com/prometheus/client_model/go"
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)
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@ -539,6 +539,11 @@ func processMetric(
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registeredDescIDs map[uint64]struct{},
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) error {
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desc := metric.Desc()
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// Wrapped metrics collected by an unchecked Collector can have an
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// invalid Desc.
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if desc.err != nil {
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return desc.err
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}
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dtoMetric := &dto.Metric{}
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if err := metric.Write(dtoMetric); err != nil {
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return fmt.Errorf("error collecting metric %v: %s", desc, err)
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@ -17,9 +17,9 @@ import (
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"fmt"
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"sort"
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dto "github.com/prometheus/client_model/go"
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"github.com/golang/protobuf/proto"
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dto "github.com/prometheus/client_model/go"
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)
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// ValueType is an enumeration of metric types that represent a simple value.
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@ -0,0 +1,170 @@
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// Copyright 2018 The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package prometheus
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import (
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"fmt"
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"sort"
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"github.com/golang/protobuf/proto"
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dto "github.com/prometheus/client_model/go"
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)
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// WrapWith returns a Registerer wrapping the provided Registerer. Collectors
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// registered with the returned Registerer will be registered with the wrapped
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// Registerer in a modified way. The modified Collector adds the provided Labels
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// to all Metrics it collects (as ConstLabels). The Metrics collected by the
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// unmodified Collector must not duplicate any of those labels.
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//
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// WrapWith provides a way to add fixed labels to a subset of Collectors. It
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// should not be used to add fixed labels to all metrics exposed.
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func WrapWith(labels Labels, reg Registerer) Registerer {
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return &wrappingRegisterer{
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wrappedRegisterer: reg,
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labels: labels,
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}
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}
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// WrapWithPrefix returns a Registerer wrapping the provided Registerer. Collectors
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// registered with the returned Registerer will be registered with the wrapped
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// Registerer in a modified way. The modified Collector adds the provided prefix
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// to the name of all Metrics it collects.
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//
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// WrapWithPrefix is useful to have one place to prefix all metrics of a
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// sub-system. To make this work, register metrics of the sub-system with the
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// wrapping Registerer returned by WrapWithPrefix.
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func WrapWithPrefix(prefix string, reg Registerer) Registerer {
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return &wrappingRegisterer{
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wrappedRegisterer: reg,
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prefix: prefix,
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}
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}
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type wrappingRegisterer struct {
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wrappedRegisterer Registerer
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prefix string
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labels Labels
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}
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func (r *wrappingRegisterer) Register(c Collector) error {
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return r.wrappedRegisterer.Register(&wrappingCollector{
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wrappedCollector: c,
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prefix: r.prefix,
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labels: r.labels,
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})
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}
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func (r *wrappingRegisterer) MustRegister(cs ...Collector) {
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for _, c := range cs {
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if err := r.Register(c); err != nil {
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panic(err)
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}
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}
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}
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func (r *wrappingRegisterer) Unregister(c Collector) bool {
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return r.wrappedRegisterer.Unregister(&wrappingCollector{
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wrappedCollector: c,
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prefix: r.prefix,
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labels: r.labels,
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})
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}
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type wrappingCollector struct {
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wrappedCollector Collector
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prefix string
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labels Labels
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}
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func (c *wrappingCollector) Collect(ch chan<- Metric) {
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wrappedCh := make(chan Metric)
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go func() {
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c.wrappedCollector.Collect(wrappedCh)
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close(wrappedCh)
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}()
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for m := range wrappedCh {
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ch <- &wrappingMetric{
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wrappedMetric: m,
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prefix: c.prefix,
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labels: c.labels,
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}
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}
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}
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func (c *wrappingCollector) Describe(ch chan<- *Desc) {
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wrappedCh := make(chan *Desc)
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go func() {
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c.wrappedCollector.Describe(wrappedCh)
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close(wrappedCh)
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}()
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for desc := range wrappedCh {
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ch <- wrapDesc(desc, c.prefix, c.labels)
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}
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}
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type wrappingMetric struct {
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wrappedMetric Metric
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prefix string
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labels Labels
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}
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func (m *wrappingMetric) Desc() *Desc {
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return wrapDesc(m.wrappedMetric.Desc(), m.prefix, m.labels)
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}
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func (m *wrappingMetric) Write(out *dto.Metric) error {
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if err := m.wrappedMetric.Write(out); err != nil {
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return err
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}
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if len(m.labels) == 0 {
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// No wrapping labels.
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return nil
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}
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for ln, lv := range m.labels {
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out.Label = append(out.Label, &dto.LabelPair{
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Name: proto.String(ln),
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Value: proto.String(lv),
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})
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}
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sort.Sort(labelPairSorter(out.Label))
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return nil
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}
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func wrapDesc(desc *Desc, prefix string, labels Labels) *Desc {
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constLabels := Labels{}
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for _, lp := range desc.constLabelPairs {
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constLabels[*lp.Name] = *lp.Value
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}
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for ln, lv := range labels {
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if _, alreadyUsed := constLabels[ln]; alreadyUsed {
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return &Desc{
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fqName: desc.fqName,
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help: desc.help,
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variableLabels: desc.variableLabels,
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constLabelPairs: desc.constLabelPairs,
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err: fmt.Errorf("attempted wrapping with already existing label name %q", ln),
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}
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}
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constLabels[ln] = lv
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}
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// NewDesc will do remaining validations.
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newDesc := NewDesc(prefix+desc.fqName, desc.help, desc.variableLabels, constLabels)
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// Propagate errors if there was any. This will override any errer
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// created by NewDesc above, i.e. earlier errors get precedence.
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if desc.err != nil {
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newDesc.err = desc.err
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}
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return newDesc
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}
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@ -0,0 +1,322 @@
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// Copyright 2018 The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package prometheus
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import (
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"fmt"
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"reflect"
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"strings"
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"testing"
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"github.com/gogo/protobuf/proto"
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dto "github.com/prometheus/client_model/go"
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)
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// uncheckedCollector wraps a Collector but its Describe method yields no Desc.
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type uncheckedCollector struct {
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c Collector
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}
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func (u uncheckedCollector) Describe(_ chan<- *Desc) {}
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func (u uncheckedCollector) Collect(c chan<- Metric) {
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u.c.Collect(c)
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}
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func toMetricFamilies(cs ...Collector) []*dto.MetricFamily {
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reg := NewRegistry()
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reg.MustRegister(cs...)
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out, err := reg.Gather()
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if err != nil {
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panic(err)
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}
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return out
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}
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func TestWrap(t *testing.T) {
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simpleCnt := NewCounter(CounterOpts{
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Name: "simpleCnt",
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Help: "helpSimpleCnt",
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})
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simpleCnt.Inc()
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simpleGge := NewGauge(GaugeOpts{
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Name: "simpleGge",
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Help: "helpSimpleGge",
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})
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simpleGge.Set(3.14)
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preCnt := NewCounter(CounterOpts{
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Name: "pre_simpleCnt",
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Help: "helpSimpleCnt",
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})
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preCnt.Inc()
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barLabeledCnt := NewCounter(CounterOpts{
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Name: "simpleCnt",
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Help: "helpSimpleCnt",
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ConstLabels: Labels{"foo": "bar"},
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})
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barLabeledCnt.Inc()
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bazLabeledCnt := NewCounter(CounterOpts{
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Name: "simpleCnt",
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Help: "helpSimpleCnt",
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ConstLabels: Labels{"foo": "baz"},
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})
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bazLabeledCnt.Inc()
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labeledPreCnt := NewCounter(CounterOpts{
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Name: "pre_simpleCnt",
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Help: "helpSimpleCnt",
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ConstLabels: Labels{"foo": "bar"},
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})
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labeledPreCnt.Inc()
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twiceLabeledPreCnt := NewCounter(CounterOpts{
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Name: "pre_simpleCnt",
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Help: "helpSimpleCnt",
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ConstLabels: Labels{"foo": "bar", "dings": "bums"},
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})
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twiceLabeledPreCnt.Inc()
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barLabeledUncheckedCollector := uncheckedCollector{barLabeledCnt}
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scenarios := map[string]struct {
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prefix string // First wrap with this prefix.
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labels Labels // Then wrap the result with these labels.
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labels2 Labels // If any, wrap the prefix-wrapped one again.
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preRegister []Collector
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toRegister []struct { // If there are any labels2, register every other with that one.
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collector Collector
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registrationFails bool
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}
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gatherFails bool
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output []Collector
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}{
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"wrap nothing": {
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prefix: "pre_",
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labels: Labels{"foo": "bar"},
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},
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"wrap with nothing": {
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preRegister: []Collector{simpleGge},
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toRegister: []struct {
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collector Collector
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registrationFails bool
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}{{simpleCnt, false}},
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output: []Collector{simpleGge, simpleCnt},
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},
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"wrap counter with prefix": {
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prefix: "pre_",
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preRegister: []Collector{simpleGge},
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toRegister: []struct {
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collector Collector
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registrationFails bool
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}{{simpleCnt, false}},
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output: []Collector{simpleGge, preCnt},
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},
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"wrap counter with label pair": {
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labels: Labels{"foo": "bar"},
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preRegister: []Collector{simpleGge},
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toRegister: []struct {
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collector Collector
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registrationFails bool
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}{{simpleCnt, false}},
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output: []Collector{simpleGge, barLabeledCnt},
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},
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"wrap counter with label pair and prefix": {
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prefix: "pre_",
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labels: Labels{"foo": "bar"},
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preRegister: []Collector{simpleGge},
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toRegister: []struct {
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collector Collector
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registrationFails bool
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}{{simpleCnt, false}},
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output: []Collector{simpleGge, labeledPreCnt},
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},
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"wrap counter with invalid prefix": {
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prefix: "1+1",
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preRegister: []Collector{simpleGge},
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toRegister: []struct {
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collector Collector
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registrationFails bool
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}{{simpleCnt, true}},
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output: []Collector{simpleGge},
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},
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"wrap counter with invalid label": {
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preRegister: []Collector{simpleGge},
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labels: Labels{"42": "bar"},
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toRegister: []struct {
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collector Collector
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registrationFails bool
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}{{simpleCnt, true}},
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output: []Collector{simpleGge},
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},
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"counter registered twice but wrapped with different label values": {
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labels: Labels{"foo": "bar"},
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labels2: Labels{"foo": "baz"},
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toRegister: []struct {
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collector Collector
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registrationFails bool
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}{{simpleCnt, false}, {simpleCnt, false}},
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output: []Collector{barLabeledCnt, bazLabeledCnt},
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},
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"counter registered twice but wrapped with different inconsistent label values": {
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labels: Labels{"foo": "bar"},
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labels2: Labels{"bar": "baz"},
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toRegister: []struct {
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collector Collector
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registrationFails bool
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}{{simpleCnt, false}, {simpleCnt, true}},
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output: []Collector{barLabeledCnt},
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},
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"wrap counter with prefix and two labels": {
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prefix: "pre_",
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labels: Labels{"foo": "bar", "dings": "bums"},
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preRegister: []Collector{simpleGge},
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toRegister: []struct {
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collector Collector
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registrationFails bool
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}{{simpleCnt, false}},
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output: []Collector{simpleGge, twiceLabeledPreCnt},
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},
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"wrap labeled counter with prefix and another label": {
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prefix: "pre_",
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labels: Labels{"dings": "bums"},
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preRegister: []Collector{simpleGge},
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toRegister: []struct {
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collector Collector
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registrationFails bool
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}{{barLabeledCnt, false}},
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output: []Collector{simpleGge, twiceLabeledPreCnt},
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},
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"wrap labeled counter with prefix and inconsistent label": {
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prefix: "pre_",
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labels: Labels{"foo": "bums"},
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preRegister: []Collector{simpleGge},
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toRegister: []struct {
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collector Collector
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registrationFails bool
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}{{barLabeledCnt, true}},
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output: []Collector{simpleGge},
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},
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"wrap labeled counter with prefix and the same label again": {
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prefix: "pre_",
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labels: Labels{"foo": "bar"},
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preRegister: []Collector{simpleGge},
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toRegister: []struct {
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collector Collector
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registrationFails bool
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}{{barLabeledCnt, true}},
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output: []Collector{simpleGge},
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},
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"wrap labeled unchecked collector with prefix and another label": {
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prefix: "pre_",
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labels: Labels{"dings": "bums"},
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preRegister: []Collector{simpleGge},
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toRegister: []struct {
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collector Collector
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registrationFails bool
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}{{barLabeledUncheckedCollector, false}},
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output: []Collector{simpleGge, twiceLabeledPreCnt},
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},
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"wrap labeled unchecked collector with prefix and inconsistent label": {
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prefix: "pre_",
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labels: Labels{"foo": "bums"},
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preRegister: []Collector{simpleGge},
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toRegister: []struct {
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collector Collector
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registrationFails bool
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}{{barLabeledUncheckedCollector, false}},
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gatherFails: true,
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output: []Collector{simpleGge},
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},
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"wrap labeled unchecked collector with prefix and the same label again": {
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prefix: "pre_",
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labels: Labels{"foo": "bar"},
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preRegister: []Collector{simpleGge},
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toRegister: []struct {
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collector Collector
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registrationFails bool
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}{{barLabeledUncheckedCollector, false}},
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gatherFails: true,
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output: []Collector{simpleGge},
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},
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"wrap labeled unchecked collector with prefix and another label resulting in collision with pre-registered counter": {
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prefix: "pre_",
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labels: Labels{"dings": "bums"},
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preRegister: []Collector{twiceLabeledPreCnt},
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toRegister: []struct {
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collector Collector
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registrationFails bool
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}{{barLabeledUncheckedCollector, false}},
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gatherFails: true,
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output: []Collector{twiceLabeledPreCnt},
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},
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}
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for n, s := range scenarios {
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t.Run(n, func(t *testing.T) {
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reg := NewPedanticRegistry()
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for _, c := range s.preRegister {
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if err := reg.Register(c); err != nil {
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t.Fatal("error registering with unwrapped registry:", err)
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}
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}
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preReg := WrapWithPrefix(s.prefix, reg)
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lReg := WrapWith(s.labels, preReg)
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l2Reg := WrapWith(s.labels2, preReg)
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for i, tr := range s.toRegister {
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var err error
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if i%2 != 0 && len(s.labels2) != 0 {
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err = l2Reg.Register(tr.collector)
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} else {
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err = lReg.Register(tr.collector)
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}
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if tr.registrationFails && err == nil {
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t.Fatalf("registration with wrapping registry unexpectedly succeded for collector #%d", i)
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}
|
||||
if !tr.registrationFails && err != nil {
|
||||
t.Fatalf("registration with wrapping registry failed for collector #%d: %s", i, err)
|
||||
}
|
||||
}
|
||||
wantMF := toMetricFamilies(s.output...)
|
||||
gotMF, err := reg.Gather()
|
||||
if s.gatherFails && err == nil {
|
||||
t.Fatal("gathering unexpectedly succeded")
|
||||
}
|
||||
if !s.gatherFails && err != nil {
|
||||
t.Fatal("gathering failed:", err)
|
||||
}
|
||||
if !reflect.DeepEqual(gotMF, wantMF) {
|
||||
var want, got []string
|
||||
|
||||
for i, mf := range wantMF {
|
||||
want = append(want, fmt.Sprintf("%3d: %s", i, proto.MarshalTextString(mf)))
|
||||
}
|
||||
for i, mf := range gotMF {
|
||||
got = append(got, fmt.Sprintf("%3d: %s", i, proto.MarshalTextString(mf)))
|
||||
}
|
||||
|
||||
t.Fatalf(
|
||||
"unexpected output of gathering:\n\nWANT:\n%s\n\nGOT:\n%s\n",
|
||||
strings.Join(want, "\n"),
|
||||
strings.Join(got, "\n"),
|
||||
)
|
||||
}
|
||||
})
|
||||
}
|
||||
|
||||
}
|
||||
Loading…
Reference in New Issue