From ed8bc523fd0d1a66acf3fa449c453508035efdfc Mon Sep 17 00:00:00 2001 From: Kevin Lyda Date: Sun, 12 Feb 2017 14:38:12 +0000 Subject: Initial pass at prometheus support. (#56) --- .../client_golang/prometheus/registry.go | 755 +++++++++++++++++++++ 1 file changed, 755 insertions(+) create mode 100644 vendor/github.com/prometheus/client_golang/prometheus/registry.go (limited to 'vendor/github.com/prometheus/client_golang/prometheus/registry.go') diff --git a/vendor/github.com/prometheus/client_golang/prometheus/registry.go b/vendor/github.com/prometheus/client_golang/prometheus/registry.go new file mode 100644 index 0000000..78d5f19 --- /dev/null +++ b/vendor/github.com/prometheus/client_golang/prometheus/registry.go @@ -0,0 +1,755 @@ +// Copyright 2014 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 ( + "bytes" + "errors" + "fmt" + "os" + "sort" + "sync" + + "github.com/golang/protobuf/proto" + + dto "github.com/prometheus/client_model/go" +) + +const ( + // Capacity for the channel to collect metrics and descriptors. + capMetricChan = 1000 + capDescChan = 10 +) + +// DefaultRegisterer and DefaultGatherer are the implementations of the +// Registerer and Gatherer interface a number of convenience functions in this +// package act on. Initially, both variables point to the same Registry, which +// has a process collector (see NewProcessCollector) and a Go collector (see +// NewGoCollector) already registered. This approach to keep default instances +// as global state mirrors the approach of other packages in the Go standard +// library. Note that there are caveats. Change the variables with caution and +// only if you understand the consequences. Users who want to avoid global state +// altogether should not use the convenience function and act on custom +// instances instead. +var ( + defaultRegistry = NewRegistry() + DefaultRegisterer Registerer = defaultRegistry + DefaultGatherer Gatherer = defaultRegistry +) + +func init() { + MustRegister(NewProcessCollector(os.Getpid(), "")) + MustRegister(NewGoCollector()) +} + +// NewRegistry creates a new vanilla Registry without any Collectors +// pre-registered. +func NewRegistry() *Registry { + return &Registry{ + collectorsByID: map[uint64]Collector{}, + descIDs: map[uint64]struct{}{}, + dimHashesByName: map[string]uint64{}, + } +} + +// NewPedanticRegistry returns a registry that checks during collection if each +// collected Metric is consistent with its reported Desc, and if the Desc has +// actually been registered with the registry. +// +// Usually, a Registry will be happy as long as the union of all collected +// Metrics is consistent and valid even if some metrics are not consistent with +// their own Desc or a Desc provided by their registered Collector. Well-behaved +// Collectors and Metrics will only provide consistent Descs. This Registry is +// useful to test the implementation of Collectors and Metrics. +func NewPedanticRegistry() *Registry { + r := NewRegistry() + r.pedanticChecksEnabled = true + return r +} + +// Registerer is the interface for the part of a registry in charge of +// registering and unregistering. Users of custom registries should use +// Registerer as type for registration purposes (rather then the Registry type +// directly). In that way, they are free to use custom Registerer implementation +// (e.g. for testing purposes). +type Registerer interface { + // Register registers a new Collector to be included in metrics + // collection. It returns an error if the descriptors provided by the + // Collector are invalid or if they — in combination with descriptors of + // already registered Collectors — do not fulfill the consistency and + // uniqueness criteria described in the documentation of metric.Desc. + // + // If the provided Collector is equal to a Collector already registered + // (which includes the case of re-registering the same Collector), the + // returned error is an instance of AlreadyRegisteredError, which + // contains the previously registered Collector. + // + // It is in general not safe to register the same Collector multiple + // times concurrently. + Register(Collector) error + // MustRegister works like Register but registers any number of + // Collectors and panics upon the first registration that causes an + // error. + MustRegister(...Collector) + // Unregister unregisters the Collector that equals the Collector passed + // in as an argument. (Two Collectors are considered equal if their + // Describe method yields the same set of descriptors.) The function + // returns whether a Collector was unregistered. + // + // Note that even after unregistering, it will not be possible to + // register a new Collector that is inconsistent with the unregistered + // Collector, e.g. a Collector collecting metrics with the same name but + // a different help string. The rationale here is that the same registry + // instance must only collect consistent metrics throughout its + // lifetime. + Unregister(Collector) bool +} + +// Gatherer is the interface for the part of a registry in charge of gathering +// the collected metrics into a number of MetricFamilies. The Gatherer interface +// comes with the same general implication as described for the Registerer +// interface. +type Gatherer interface { + // Gather calls the Collect method of the registered Collectors and then + // gathers the collected metrics into a lexicographically sorted slice + // of MetricFamily protobufs. 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. In scenarios + // where complete collection is critical, the returned MetricFamily + // protobufs should be disregarded if the returned error is non-nil. + Gather() ([]*dto.MetricFamily, error) +} + +// Register registers the provided Collector with the DefaultRegisterer. +// +// Register is a shortcut for DefaultRegisterer.Register(c). See there for more +// details. +func Register(c Collector) error { + return DefaultRegisterer.Register(c) +} + +// MustRegister registers the provided Collectors with the DefaultRegisterer and +// panics if any error occurs. +// +// MustRegister is a shortcut for DefaultRegisterer.MustRegister(cs...). See +// there for more details. +func MustRegister(cs ...Collector) { + DefaultRegisterer.MustRegister(cs...) +} + +// Unregister removes the registration of the provided Collector from the +// DefaultRegisterer. +// +// Unregister is a shortcut for DefaultRegisterer.Unregister(c). See there for +// more details. +func Unregister(c Collector) bool { + return DefaultRegisterer.Unregister(c) +} + +// GathererFunc turns a function into a Gatherer. +type GathererFunc func() ([]*dto.MetricFamily, error) + +// Gather implements Gatherer. +func (gf GathererFunc) Gather() ([]*dto.MetricFamily, error) { + return gf() +} + +// AlreadyRegisteredError is returned by the Register method if the Collector to +// be registered has already been registered before, or a different Collector +// that collects the same metrics has been registered before. Registration fails +// in that case, but you can detect from the kind of error what has +// happened. The error contains fields for the existing Collector and the +// (rejected) new Collector that equals the existing one. This can be used to +// find out if an equal Collector has been registered before and switch over to +// using the old one, as demonstrated in the example. +type AlreadyRegisteredError struct { + ExistingCollector, NewCollector Collector +} + +func (err AlreadyRegisteredError) Error() string { + return "duplicate metrics collector registration attempted" +} + +// MultiError is a slice of errors implementing the error interface. It is used +// by a Gatherer to report multiple errors during MetricFamily gathering. +type MultiError []error + +func (errs MultiError) Error() string { + if len(errs) == 0 { + return "" + } + buf := &bytes.Buffer{} + fmt.Fprintf(buf, "%d error(s) occurred:", len(errs)) + for _, err := range errs { + fmt.Fprintf(buf, "\n* %s", err) + } + return buf.String() +} + +// MaybeUnwrap returns nil if len(errs) is 0. It returns the first and only +// contained error as error if len(errs is 1). In all other cases, it returns +// the MultiError directly. This is helpful for returning a MultiError in a way +// that only uses the MultiError if needed. +func (errs MultiError) MaybeUnwrap() error { + switch len(errs) { + case 0: + return nil + case 1: + return errs[0] + default: + return errs + } +} + +// Registry registers Prometheus collectors, collects their metrics, and gathers +// them into MetricFamilies for exposition. It implements both Registerer and +// Gatherer. The zero value is not usable. Create instances with NewRegistry or +// NewPedanticRegistry. +type Registry struct { + mtx sync.RWMutex + collectorsByID map[uint64]Collector // ID is a hash of the descIDs. + descIDs map[uint64]struct{} + dimHashesByName map[string]uint64 + pedanticChecksEnabled bool +} + +// Register implements Registerer. +func (r *Registry) Register(c Collector) error { + var ( + descChan = make(chan *Desc, capDescChan) + newDescIDs = map[uint64]struct{}{} + newDimHashesByName = map[string]uint64{} + collectorID uint64 // Just a sum of all desc IDs. + duplicateDescErr error + ) + go func() { + c.Describe(descChan) + close(descChan) + }() + r.mtx.Lock() + defer r.mtx.Unlock() + // Coduct various tests... + for desc := range descChan { + + // Is the descriptor valid at all? + if desc.err != nil { + return fmt.Errorf("descriptor %s is invalid: %s", desc, desc.err) + } + + // Is the descID unique? + // (In other words: Is the fqName + constLabel combination unique?) + if _, exists := r.descIDs[desc.id]; exists { + duplicateDescErr = fmt.Errorf("descriptor %s already exists with the same fully-qualified name and const label values", desc) + } + // If it is not a duplicate desc in this collector, add it to + // the collectorID. (We allow duplicate descs within the same + // collector, but their existence must be a no-op.) + if _, exists := newDescIDs[desc.id]; !exists { + newDescIDs[desc.id] = struct{}{} + collectorID += desc.id + } + + // Are all the label names and the help string consistent with + // previous descriptors of the same name? + // First check existing descriptors... + if dimHash, exists := r.dimHashesByName[desc.fqName]; exists { + if dimHash != desc.dimHash { + return fmt.Errorf("a previously registered descriptor with the same fully-qualified name as %s has different label names or a different help string", desc) + } + } else { + // ...then check the new descriptors already seen. + if dimHash, exists := newDimHashesByName[desc.fqName]; exists { + if dimHash != desc.dimHash { + return fmt.Errorf("descriptors reported by collector have inconsistent label names or help strings for the same fully-qualified name, offender is %s", desc) + } + } else { + newDimHashesByName[desc.fqName] = desc.dimHash + } + } + } + // Did anything happen at all? + if len(newDescIDs) == 0 { + return errors.New("collector has no descriptors") + } + if existing, exists := r.collectorsByID[collectorID]; exists { + return AlreadyRegisteredError{ + ExistingCollector: existing, + NewCollector: c, + } + } + // If the collectorID is new, but at least one of the descs existed + // before, we are in trouble. + if duplicateDescErr != nil { + return duplicateDescErr + } + + // Only after all tests have passed, actually register. + r.collectorsByID[collectorID] = c + for hash := range newDescIDs { + r.descIDs[hash] = struct{}{} + } + for name, dimHash := range newDimHashesByName { + r.dimHashesByName[name] = dimHash + } + return nil +} + +// Unregister implements Registerer. +func (r *Registry) Unregister(c Collector) bool { + var ( + descChan = make(chan *Desc, capDescChan) + descIDs = map[uint64]struct{}{} + collectorID uint64 // Just a sum of the desc IDs. + ) + go func() { + c.Describe(descChan) + close(descChan) + }() + for desc := range descChan { + if _, exists := descIDs[desc.id]; !exists { + collectorID += desc.id + descIDs[desc.id] = struct{}{} + } + } + + r.mtx.RLock() + if _, exists := r.collectorsByID[collectorID]; !exists { + r.mtx.RUnlock() + return false + } + r.mtx.RUnlock() + + r.mtx.Lock() + defer r.mtx.Unlock() + + delete(r.collectorsByID, collectorID) + for id := range descIDs { + delete(r.descIDs, id) + } + // dimHashesByName is left untouched as those must be consistent + // throughout the lifetime of a program. + return true +} + +// MustRegister implements Registerer. +func (r *Registry) MustRegister(cs ...Collector) { + for _, c := range cs { + if err := r.Register(c); err != nil { + panic(err) + } + } +} + +// Gather implements Gatherer. +func (r *Registry) Gather() ([]*dto.MetricFamily, error) { + var ( + metricChan = make(chan Metric, capMetricChan) + metricHashes = map[uint64]struct{}{} + dimHashes = map[string]uint64{} + wg sync.WaitGroup + errs MultiError // The collected errors to return in the end. + registeredDescIDs map[uint64]struct{} // Only used for pedantic checks + ) + + r.mtx.RLock() + metricFamiliesByName := make(map[string]*dto.MetricFamily, len(r.dimHashesByName)) + + // Scatter. + // (Collectors could be complex and slow, so we call them all at once.) + wg.Add(len(r.collectorsByID)) + go func() { + wg.Wait() + close(metricChan) + }() + for _, collector := range r.collectorsByID { + go func(collector Collector) { + defer wg.Done() + collector.Collect(metricChan) + }(collector) + } + + // In case pedantic checks are enabled, we have to copy the map before + // giving up the RLock. + if r.pedanticChecksEnabled { + registeredDescIDs = make(map[uint64]struct{}, len(r.descIDs)) + for id := range r.descIDs { + registeredDescIDs[id] = struct{}{} + } + } + + r.mtx.RUnlock() + + // Drain metricChan in case of premature return. + defer func() { + for range metricChan { + } + }() + + // Gather. + for metric := range metricChan { + // This could be done concurrently, too, but it required locking + // of metricFamiliesByName (and of metricHashes if checks are + // enabled). Most likely not worth it. + desc := metric.Desc() + dtoMetric := &dto.Metric{} + if err := metric.Write(dtoMetric); err != nil { + errs = append(errs, fmt.Errorf( + "error collecting metric %v: %s", desc, err, + )) + continue + } + metricFamily, ok := metricFamiliesByName[desc.fqName] + if ok { + if metricFamily.GetHelp() != desc.help { + errs = append(errs, fmt.Errorf( + "collected metric %s %s has help %q but should have %q", + desc.fqName, dtoMetric, desc.help, metricFamily.GetHelp(), + )) + continue + } + // TODO(beorn7): Simplify switch once Desc has type. + switch metricFamily.GetType() { + case dto.MetricType_COUNTER: + if dtoMetric.Counter == nil { + errs = append(errs, fmt.Errorf( + "collected metric %s %s should be a Counter", + desc.fqName, dtoMetric, + )) + continue + } + case dto.MetricType_GAUGE: + if dtoMetric.Gauge == nil { + errs = append(errs, fmt.Errorf( + "collected metric %s %s should be a Gauge", + desc.fqName, dtoMetric, + )) + continue + } + case dto.MetricType_SUMMARY: + if dtoMetric.Summary == nil { + errs = append(errs, fmt.Errorf( + "collected metric %s %s should be a Summary", + desc.fqName, dtoMetric, + )) + continue + } + case dto.MetricType_UNTYPED: + if dtoMetric.Untyped == nil { + errs = append(errs, fmt.Errorf( + "collected metric %s %s should be Untyped", + desc.fqName, dtoMetric, + )) + continue + } + case dto.MetricType_HISTOGRAM: + if dtoMetric.Histogram == nil { + errs = append(errs, fmt.Errorf( + "collected metric %s %s should be a Histogram", + desc.fqName, dtoMetric, + )) + continue + } + default: + panic("encountered MetricFamily with invalid type") + } + } else { + metricFamily = &dto.MetricFamily{} + metricFamily.Name = proto.String(desc.fqName) + metricFamily.Help = proto.String(desc.help) + // TODO(beorn7): Simplify switch once Desc has type. + switch { + case dtoMetric.Gauge != nil: + metricFamily.Type = dto.MetricType_GAUGE.Enum() + case dtoMetric.Counter != nil: + metricFamily.Type = dto.MetricType_COUNTER.Enum() + case dtoMetric.Summary != nil: + metricFamily.Type = dto.MetricType_SUMMARY.Enum() + case dtoMetric.Untyped != nil: + metricFamily.Type = dto.MetricType_UNTYPED.Enum() + case dtoMetric.Histogram != nil: + metricFamily.Type = dto.MetricType_HISTOGRAM.Enum() + default: + errs = append(errs, fmt.Errorf( + "empty metric collected: %s", dtoMetric, + )) + continue + } + metricFamiliesByName[desc.fqName] = metricFamily + } + if err := checkMetricConsistency(metricFamily, dtoMetric, metricHashes, dimHashes); err != nil { + errs = append(errs, err) + continue + } + if r.pedanticChecksEnabled { + // Is the desc registered at all? + if _, exist := registeredDescIDs[desc.id]; !exist { + errs = append(errs, fmt.Errorf( + "collected metric %s %s with unregistered descriptor %s", + metricFamily.GetName(), dtoMetric, desc, + )) + continue + } + if err := checkDescConsistency(metricFamily, dtoMetric, desc); err != nil { + errs = append(errs, err) + continue + } + } + metricFamily.Metric = append(metricFamily.Metric, dtoMetric) + } + return normalizeMetricFamilies(metricFamiliesByName), errs.MaybeUnwrap() +} + +// Gatherers is a slice of Gatherer instances that implements the Gatherer +// interface itself. Its Gather method calls Gather on all Gatherers in the +// slice in order and returns the merged results. Errors returned from the +// Gather calles are all returned in a flattened MultiError. Duplicate and +// inconsistent Metrics are skipped (first occurrence in slice order wins) and +// reported in the returned error. +// +// Gatherers can be used to merge the Gather results from multiple +// Registries. It also provides a way to directly inject existing MetricFamily +// protobufs into the gathering by creating a custom Gatherer with a Gather +// method that simply returns the existing MetricFamily protobufs. Note that no +// registration is involved (in contrast to Collector registration), so +// obviously registration-time checks cannot happen. Any inconsistencies between +// the gathered MetricFamilies are reported as errors by the Gather method, and +// inconsistent Metrics are dropped. Invalid parts of the MetricFamilies +// (e.g. syntactically invalid metric or label names) will go undetected. +type Gatherers []Gatherer + +// Gather implements Gatherer. +func (gs Gatherers) Gather() ([]*dto.MetricFamily, error) { + var ( + metricFamiliesByName = map[string]*dto.MetricFamily{} + metricHashes = map[uint64]struct{}{} + dimHashes = map[string]uint64{} + errs MultiError // The collected errors to return in the end. + ) + + for i, g := range gs { + mfs, err := g.Gather() + if err != nil { + if multiErr, ok := err.(MultiError); ok { + for _, err := range multiErr { + errs = append(errs, fmt.Errorf("[from Gatherer #%d] %s", i+1, err)) + } + } else { + errs = append(errs, fmt.Errorf("[from Gatherer #%d] %s", i+1, err)) + } + } + for _, mf := range mfs { + existingMF, exists := metricFamiliesByName[mf.GetName()] + if exists { + if existingMF.GetHelp() != mf.GetHelp() { + errs = append(errs, fmt.Errorf( + "gathered metric family %s has help %q but should have %q", + mf.GetName(), mf.GetHelp(), existingMF.GetHelp(), + )) + continue + } + if existingMF.GetType() != mf.GetType() { + errs = append(errs, fmt.Errorf( + "gathered metric family %s has type %s but should have %s", + mf.GetName(), mf.GetType(), existingMF.GetType(), + )) + continue + } + } else { + existingMF = &dto.MetricFamily{} + existingMF.Name = mf.Name + existingMF.Help = mf.Help + existingMF.Type = mf.Type + metricFamiliesByName[mf.GetName()] = existingMF + } + for _, m := range mf.Metric { + if err := checkMetricConsistency(existingMF, m, metricHashes, dimHashes); err != nil { + errs = append(errs, err) + continue + } + existingMF.Metric = append(existingMF.Metric, m) + } + } + } + return normalizeMetricFamilies(metricFamiliesByName), errs.MaybeUnwrap() +} + +// 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 + // people might use custom collectors or metric family injection + // to create inconsistent metrics. So let's simply compare the + // number of labels in this case. That will still yield + // reproducible sorting. + return len(s[i].Label) < len(s[j].Label) + } + for n, lp := range s[i].Label { + vi := lp.GetValue() + vj := s[j].Label[n].GetValue() + if vi != vj { + return vi < vj + } + } + + // We should never arrive here. Multiple metrics with the same + // label set in the same scrape will lead to undefined ingestion + // behavior. However, as above, we have to provide stable sorting + // here, even for inconsistent metrics. So sort equal metrics + // by their timestamp, with missing timestamps (implying "now") + // coming last. + if s[i].TimestampMs == nil { + return false + } + if s[j].TimestampMs == nil { + return true + } + return s[i].GetTimestampMs() < s[j].GetTimestampMs() +} + +// normalizeMetricFamilies returns a MetricFamily slice with empty +// MetricFamilies pruned and the remaining MetricFamilies sorted by name within +// 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)) + } + names := make([]string, 0, len(metricFamiliesByName)) + for name, mf := range metricFamiliesByName { + if len(mf.Metric) > 0 { + names = append(names, name) + } + } + sort.Strings(names) + result := make([]*dto.MetricFamily, 0, len(names)) + for _, name := range names { + result = append(result, metricFamiliesByName[name]) + } + return result +} + +// checkMetricConsistency checks if the provided Metric is consistent with the +// provided MetricFamily. It also hashed the Metric labels and the MetricFamily +// name. If the resulting hash is alread in the provided metricHashes, an error +// is returned. If not, it is added to metricHashes. The provided dimHashes maps +// MetricFamily names to their dimHash (hashed sorted label names). If dimHashes +// doesn't yet contain a hash for the provided MetricFamily, it is +// added. Otherwise, an error is returned if the existing dimHashes in not equal +// the calculated dimHash. +func checkMetricConsistency( + metricFamily *dto.MetricFamily, + dtoMetric *dto.Metric, + metricHashes map[uint64]struct{}, + dimHashes map[string]uint64, +) error { + // Type consistency with metric family. + if metricFamily.GetType() == dto.MetricType_GAUGE && dtoMetric.Gauge == nil || + metricFamily.GetType() == dto.MetricType_COUNTER && dtoMetric.Counter == nil || + metricFamily.GetType() == dto.MetricType_SUMMARY && dtoMetric.Summary == nil || + metricFamily.GetType() == dto.MetricType_HISTOGRAM && dtoMetric.Histogram == nil || + metricFamily.GetType() == dto.MetricType_UNTYPED && dtoMetric.Untyped == nil { + return fmt.Errorf( + "collected metric %s %s is not a %s", + metricFamily.GetName(), dtoMetric, metricFamily.GetType(), + ) + } + + // Is the metric unique (i.e. no other metric with the same name and the same label values)? + h := hashNew() + h = hashAdd(h, metricFamily.GetName()) + h = hashAddByte(h, separatorByte) + dh := hashNew() + // Make sure label pairs are sorted. We depend on it for the consistency + // check. + sort.Sort(LabelPairSorter(dtoMetric.Label)) + for _, lp := range dtoMetric.Label { + h = hashAdd(h, lp.GetValue()) + h = hashAddByte(h, separatorByte) + dh = hashAdd(dh, lp.GetName()) + dh = hashAddByte(dh, separatorByte) + } + if _, exists := metricHashes[h]; exists { + return fmt.Errorf( + "collected metric %s %s was collected before with the same name and label values", + metricFamily.GetName(), dtoMetric, + ) + } + if dimHash, ok := dimHashes[metricFamily.GetName()]; ok { + if dimHash != dh { + return fmt.Errorf( + "collected metric %s %s has label dimensions inconsistent with previously collected metrics in the same metric family", + metricFamily.GetName(), dtoMetric, + ) + } + } else { + dimHashes[metricFamily.GetName()] = dh + } + metricHashes[h] = struct{}{} + return nil +} + +func checkDescConsistency( + metricFamily *dto.MetricFamily, + dtoMetric *dto.Metric, + desc *Desc, +) error { + // Desc help consistency with metric family help. + if metricFamily.GetHelp() != desc.help { + return fmt.Errorf( + "collected metric %s %s has help %q but should have %q", + metricFamily.GetName(), dtoMetric, metricFamily.GetHelp(), desc.help, + ) + } + + // Is the desc consistent with the content of the metric? + lpsFromDesc := make([]*dto.LabelPair, 0, len(dtoMetric.Label)) + lpsFromDesc = append(lpsFromDesc, desc.constLabelPairs...) + for _, l := range desc.variableLabels { + lpsFromDesc = append(lpsFromDesc, &dto.LabelPair{ + Name: proto.String(l), + }) + } + if len(lpsFromDesc) != len(dtoMetric.Label) { + return fmt.Errorf( + "labels in collected metric %s %s are inconsistent with descriptor %s", + metricFamily.GetName(), dtoMetric, desc, + ) + } + sort.Sort(LabelPairSorter(lpsFromDesc)) + for i, lpFromDesc := range lpsFromDesc { + lpFromMetric := dtoMetric.Label[i] + if lpFromDesc.GetName() != lpFromMetric.GetName() || + lpFromDesc.Value != nil && lpFromDesc.GetValue() != lpFromMetric.GetValue() { + return fmt.Errorf( + "labels in collected metric %s %s are inconsistent with descriptor %s", + metricFamily.GetName(), dtoMetric, desc, + ) + } + } + return nil +} -- cgit v1.2.3