diff options
Diffstat (limited to 'kube2msb/src/vendor/github.com/prometheus/client_golang/prometheus/registry.go')
-rw-r--r-- | kube2msb/src/vendor/github.com/prometheus/client_golang/prometheus/registry.go | 726 |
1 files changed, 726 insertions, 0 deletions
diff --git a/kube2msb/src/vendor/github.com/prometheus/client_golang/prometheus/registry.go b/kube2msb/src/vendor/github.com/prometheus/client_golang/prometheus/registry.go new file mode 100644 index 0000000..5970aae --- /dev/null +++ b/kube2msb/src/vendor/github.com/prometheus/client_golang/prometheus/registry.go @@ -0,0 +1,726 @@ +// 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. + +// Copyright (c) 2013, The Prometheus Authors +// All rights reserved. +// +// Use of this source code is governed by a BSD-style license that can be found +// in the LICENSE file. + +package prometheus + +import ( + "bytes" + "compress/gzip" + "errors" + "fmt" + "hash/fnv" + "io" + "net/http" + "net/url" + "os" + "sort" + "strings" + "sync" + + "github.com/golang/protobuf/proto" + "github.com/prometheus/common/expfmt" + + dto "github.com/prometheus/client_model/go" +) + +var ( + defRegistry = newDefaultRegistry() + errAlreadyReg = errors.New("duplicate metrics collector registration attempted") +) + +// Constants relevant to the HTTP interface. +const ( + // APIVersion is the version of the format of the exported data. This + // will match this library's version, which subscribes to the Semantic + // Versioning scheme. + APIVersion = "0.0.4" + + // DelimitedTelemetryContentType is the content type set on telemetry + // data responses in delimited protobuf format. + DelimitedTelemetryContentType = `application/vnd.google.protobuf; proto=io.prometheus.client.MetricFamily; encoding=delimited` + // TextTelemetryContentType is the content type set on telemetry data + // responses in text format. + TextTelemetryContentType = `text/plain; version=` + APIVersion + // ProtoTextTelemetryContentType is the content type set on telemetry + // data responses in protobuf text format. (Only used for debugging.) + ProtoTextTelemetryContentType = `application/vnd.google.protobuf; proto=io.prometheus.client.MetricFamily; encoding=text` + // ProtoCompactTextTelemetryContentType is the content type set on + // telemetry data responses in protobuf compact text format. (Only used + // for debugging.) + ProtoCompactTextTelemetryContentType = `application/vnd.google.protobuf; proto=io.prometheus.client.MetricFamily; encoding=compact-text` + + // Constants for object pools. + numBufs = 4 + numMetricFamilies = 1000 + numMetrics = 10000 + + // Capacity for the channel to collect metrics and descriptors. + capMetricChan = 1000 + capDescChan = 10 + + contentTypeHeader = "Content-Type" + contentLengthHeader = "Content-Length" + contentEncodingHeader = "Content-Encoding" + + acceptEncodingHeader = "Accept-Encoding" + acceptHeader = "Accept" +) + +// Handler returns the HTTP handler for the global Prometheus registry. It is +// already instrumented with InstrumentHandler (using "prometheus" as handler +// name). Usually the handler is used to handle the "/metrics" endpoint. +func Handler() http.Handler { + return InstrumentHandler("prometheus", defRegistry) +} + +// UninstrumentedHandler works in the same way as Handler, but the returned HTTP +// handler is not instrumented. This is useful if no instrumentation is desired +// (for whatever reason) or if the instrumentation has to happen with a +// different handler name (or with a different instrumentation approach +// altogether). See the InstrumentHandler example. +func UninstrumentedHandler() http.Handler { + return defRegistry +} + +// 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 Desc +// documentation. +// +// Do not register the same Collector multiple times concurrently. (Registering +// the same Collector twice would result in an error anyway, but on top of that, +// it is not safe to do so concurrently.) +func Register(m Collector) error { + _, err := defRegistry.Register(m) + return err +} + +// MustRegister works like Register but panics where Register would have +// returned an error. +func MustRegister(m Collector) { + err := Register(m) + if err != nil { + panic(err) + } +} + +// RegisterOrGet works like Register but does not return an error if a Collector +// is registered that equals a previously registered Collector. (Two Collectors +// are considered equal if their Describe method yields the same set of +// descriptors.) Instead, the previously registered Collector is returned (which +// is helpful if the new and previously registered Collectors are equal but not +// identical, i.e. not pointers to the same object). +// +// As for Register, it is still not safe to call RegisterOrGet with the same +// Collector multiple times concurrently. +func RegisterOrGet(m Collector) (Collector, error) { + return defRegistry.RegisterOrGet(m) +} + +// MustRegisterOrGet works like Register but panics where RegisterOrGet would +// have returned an error. +func MustRegisterOrGet(m Collector) Collector { + existing, err := RegisterOrGet(m) + if err != nil { + panic(err) + } + return existing +} + +// 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. +func Unregister(c Collector) bool { + return defRegistry.Unregister(c) +} + +// SetMetricFamilyInjectionHook sets a function that is called whenever metrics +// are collected. The hook function must be set before metrics collection begins +// (i.e. call SetMetricFamilyInjectionHook before setting the HTTP handler.) The +// MetricFamily protobufs returned by the hook function are merged with the +// metrics collected in the usual way. +// +// This is a way to directly inject MetricFamily protobufs managed and owned by +// the caller. The caller has full responsibility. As no registration of the +// injected metrics has happened, there is no descriptor to check against, and +// there are no registration-time checks. If collect-time checks are disabled +// (see function EnableCollectChecks), no sanity checks are performed on the +// returned protobufs at all. If collect-checks are enabled, type and uniqueness +// checks are performed, but no further consistency checks (which would require +// knowledge of a metric descriptor). +// +// Sorting concerns: The caller is responsible for sorting the label pairs in +// each metric. However, the order of metrics will be sorted by the registry as +// it is required anyway after merging with the metric families collected +// conventionally. +// +// The function must be callable at any time and concurrently. +func SetMetricFamilyInjectionHook(hook func() []*dto.MetricFamily) { + defRegistry.metricFamilyInjectionHook = hook +} + +// PanicOnCollectError sets the behavior whether a panic is caused upon an error +// while metrics are collected and served to the HTTP endpoint. By default, an +// internal server error (status code 500) is served with an error message. +func PanicOnCollectError(b bool) { + defRegistry.panicOnCollectError = b +} + +// EnableCollectChecks enables (or disables) additional consistency checks +// during metrics collection. These additional checks are not enabled by default +// because they inflict a performance penalty and the errors they check for can +// only happen if the used Metric and Collector types have internal programming +// errors. It can be helpful to enable these checks while working with custom +// Collectors or Metrics whose correctness is not well established yet. +func EnableCollectChecks(b bool) { + defRegistry.collectChecksEnabled = b +} + +// encoder is a function that writes a dto.MetricFamily to an io.Writer in a +// certain encoding. It returns the number of bytes written and any error +// encountered. Note that pbutil.WriteDelimited and pbutil.MetricFamilyToText +// are encoders. +type encoder func(io.Writer, *dto.MetricFamily) (int, error) + +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 + bufPool chan *bytes.Buffer + metricFamilyPool chan *dto.MetricFamily + metricPool chan *dto.Metric + metricFamilyInjectionHook func() []*dto.MetricFamily + + panicOnCollectError, collectChecksEnabled bool +} + +func (r *registry) Register(c Collector) (Collector, error) { + descChan := make(chan *Desc, capDescChan) + go func() { + c.Describe(descChan) + close(descChan) + }() + + newDescIDs := map[uint64]struct{}{} + newDimHashesByName := map[string]uint64{} + var collectorID uint64 // Just a sum of all desc IDs. + var duplicateDescErr error + + 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 c, 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 nil, 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 nil, 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 nil, errors.New("collector has no descriptors") + } + if existing, exists := r.collectorsByID[collectorID]; exists { + return existing, errAlreadyReg + } + // If the collectorID is new, but at least one of the descs existed + // before, we are in trouble. + if duplicateDescErr != nil { + return nil, 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 c, nil +} + +func (r *registry) RegisterOrGet(m Collector) (Collector, error) { + existing, err := r.Register(m) + if err != nil && err != errAlreadyReg { + return nil, err + } + return existing, nil +} + +func (r *registry) Unregister(c Collector) bool { + descChan := make(chan *Desc, capDescChan) + go func() { + c.Describe(descChan) + close(descChan) + }() + + descIDs := map[uint64]struct{}{} + var collectorID uint64 // Just a sum of the desc IDs. + 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 +} + +func (r *registry) Push(job, instance, pushURL, method string) error { + if !strings.Contains(pushURL, "://") { + pushURL = "http://" + pushURL + } + pushURL = fmt.Sprintf("%s/metrics/jobs/%s", pushURL, url.QueryEscape(job)) + if instance != "" { + pushURL += "/instances/" + url.QueryEscape(instance) + } + buf := r.getBuf() + defer r.giveBuf(buf) + if err := r.writePB(expfmt.NewEncoder(buf, expfmt.FmtProtoDelim)); err != nil { + if r.panicOnCollectError { + panic(err) + } + return err + } + req, err := http.NewRequest(method, pushURL, buf) + if err != nil { + return err + } + req.Header.Set(contentTypeHeader, DelimitedTelemetryContentType) + resp, err := http.DefaultClient.Do(req) + if err != nil { + return err + } + defer resp.Body.Close() + if resp.StatusCode != 202 { + return fmt.Errorf("unexpected status code %d while pushing to %s", resp.StatusCode, pushURL) + } + return nil +} + +func (r *registry) ServeHTTP(w http.ResponseWriter, req *http.Request) { + contentType := expfmt.Negotiate(req.Header) + buf := r.getBuf() + defer r.giveBuf(buf) + writer, encoding := decorateWriter(req, buf) + if err := r.writePB(expfmt.NewEncoder(writer, contentType)); err != nil { + if r.panicOnCollectError { + panic(err) + } + http.Error(w, "An error has occurred:\n\n"+err.Error(), http.StatusInternalServerError) + return + } + if closer, ok := writer.(io.Closer); ok { + closer.Close() + } + header := w.Header() + header.Set(contentTypeHeader, string(contentType)) + header.Set(contentLengthHeader, fmt.Sprint(buf.Len())) + if encoding != "" { + header.Set(contentEncodingHeader, encoding) + } + w.Write(buf.Bytes()) +} + +func (r *registry) writePB(encoder expfmt.Encoder) error { + var metricHashes map[uint64]struct{} + if r.collectChecksEnabled { + metricHashes = make(map[uint64]struct{}) + } + metricChan := make(chan Metric, capMetricChan) + wg := sync.WaitGroup{} + + 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) + } + 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() + metricFamily, ok := metricFamiliesByName[desc.fqName] + if !ok { + metricFamily = r.getMetricFamily() + defer r.giveMetricFamily(metricFamily) + metricFamily.Name = proto.String(desc.fqName) + metricFamily.Help = proto.String(desc.help) + metricFamiliesByName[desc.fqName] = metricFamily + } + dtoMetric := r.getMetric() + defer r.giveMetric(dtoMetric) + if err := metric.Write(dtoMetric); err != nil { + // TODO: Consider different means of error reporting so + // that a single erroneous metric could be skipped + // instead of blowing up the whole collection. + return fmt.Errorf("error collecting metric %v: %s", desc, err) + } + switch { + case metricFamily.Type != nil: + // Type already set. We are good. + 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: + return fmt.Errorf("empty metric collected: %s", dtoMetric) + } + if r.collectChecksEnabled { + if err := r.checkConsistency(metricFamily, dtoMetric, desc, metricHashes); err != nil { + return err + } + } + metricFamily.Metric = append(metricFamily.Metric, dtoMetric) + } + + if r.metricFamilyInjectionHook != nil { + for _, mf := range r.metricFamilyInjectionHook() { + existingMF, exists := metricFamiliesByName[mf.GetName()] + if !exists { + metricFamiliesByName[mf.GetName()] = mf + if r.collectChecksEnabled { + for _, m := range mf.Metric { + if err := r.checkConsistency(mf, m, nil, metricHashes); err != nil { + return err + } + } + } + continue + } + for _, m := range mf.Metric { + if r.collectChecksEnabled { + if err := r.checkConsistency(existingMF, m, nil, metricHashes); err != nil { + return err + } + } + existingMF.Metric = append(existingMF.Metric, m) + } + } + } + + // Now that MetricFamilies are all set, sort their Metrics + // lexicographically by their label values. + for _, mf := range metricFamiliesByName { + sort.Sort(metricSorter(mf.Metric)) + } + + // Write out MetricFamilies sorted by their name. + names := make([]string, 0, len(metricFamiliesByName)) + for name := range metricFamiliesByName { + names = append(names, name) + } + sort.Strings(names) + + for _, name := range names { + if err := encoder.Encode(metricFamiliesByName[name]); err != nil { + return err + } + } + return nil +} + +func (r *registry) checkConsistency(metricFamily *dto.MetricFamily, dtoMetric *dto.Metric, desc *Desc, metricHashes map[uint64]struct{}) 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 := fnv.New64a() + var buf bytes.Buffer + buf.WriteString(metricFamily.GetName()) + buf.WriteByte(separatorByte) + h.Write(buf.Bytes()) + // Make sure label pairs are sorted. We depend on it for the consistency + // check. Label pairs must be sorted by contract. But the point of this + // method is to check for contract violations. So we better do the sort + // now. + sort.Sort(LabelPairSorter(dtoMetric.Label)) + for _, lp := range dtoMetric.Label { + buf.Reset() + buf.WriteString(lp.GetValue()) + buf.WriteByte(separatorByte) + h.Write(buf.Bytes()) + } + metricHash := h.Sum64() + if _, exists := metricHashes[metricHash]; exists { + return fmt.Errorf( + "collected metric %s %s was collected before with the same name and label values", + metricFamily.GetName(), dtoMetric, + ) + } + metricHashes[metricHash] = struct{}{} + + if desc == nil { + return nil // Nothing left to check if we have no desc. + } + + // Desc consistency with metric family. + if metricFamily.GetName() != desc.fqName { + return fmt.Errorf( + "collected metric %s %s has name %q but should have %q", + metricFamily.GetName(), dtoMetric, metricFamily.GetName(), desc.fqName, + ) + } + 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, + ) + } + } + + r.mtx.RLock() // Remaining checks need the read lock. + defer r.mtx.RUnlock() + + // Is the desc registered? + if _, exist := r.descIDs[desc.id]; !exist { + return fmt.Errorf( + "collected metric %s %s with unregistered descriptor %s", + metricFamily.GetName(), dtoMetric, desc, + ) + } + + return nil +} + +func (r *registry) getBuf() *bytes.Buffer { + select { + case buf := <-r.bufPool: + return buf + default: + return &bytes.Buffer{} + } +} + +func (r *registry) giveBuf(buf *bytes.Buffer) { + buf.Reset() + select { + case r.bufPool <- buf: + default: + } +} + +func (r *registry) getMetricFamily() *dto.MetricFamily { + select { + case mf := <-r.metricFamilyPool: + return mf + default: + return &dto.MetricFamily{} + } +} + +func (r *registry) giveMetricFamily(mf *dto.MetricFamily) { + mf.Reset() + select { + case r.metricFamilyPool <- mf: + default: + } +} + +func (r *registry) getMetric() *dto.Metric { + select { + case m := <-r.metricPool: + return m + default: + return &dto.Metric{} + } +} + +func (r *registry) giveMetric(m *dto.Metric) { + m.Reset() + select { + case r.metricPool <- m: + default: + } +} + +func newRegistry() *registry { + return ®istry{ + collectorsByID: map[uint64]Collector{}, + descIDs: map[uint64]struct{}{}, + dimHashesByName: map[string]uint64{}, + bufPool: make(chan *bytes.Buffer, numBufs), + metricFamilyPool: make(chan *dto.MetricFamily, numMetricFamilies), + metricPool: make(chan *dto.Metric, numMetrics), + } +} + +func newDefaultRegistry() *registry { + r := newRegistry() + r.Register(NewProcessCollector(os.Getpid(), "")) + r.Register(NewGoCollector()) + return r +} + +// decorateWriter wraps a writer to handle gzip compression if requested. It +// returns the decorated writer and the appropriate "Content-Encoding" header +// (which is empty if no compression is enabled). +func decorateWriter(request *http.Request, writer io.Writer) (io.Writer, string) { + header := request.Header.Get(acceptEncodingHeader) + parts := strings.Split(header, ",") + for _, part := range parts { + part := strings.TrimSpace(part) + if part == "gzip" || strings.HasPrefix(part, "gzip;") { + return gzip.NewWriter(writer), "gzip" + } + } + return writer, "" +} + +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 + } + } + return true +} |