This update provides:
1) workaround around the build failures. In
summary, it forces the download of some packages during the build
process.
2) update the set of packages that should go inside the vendor
directory
3) Update the dockerfile to use go 1.10
Change-Id: I2bfd090ce0f25b0c10aa214755ae2da7e5384d60
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..b5e70b9
--- /dev/null
+++ b/vendor/github.com/prometheus/client_golang/prometheus/registry.go
@@ -0,0 +1,937 @@
+// 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"
+ "fmt"
+ "io/ioutil"
+ "os"
+ "path/filepath"
+ "runtime"
+ "sort"
+ "strings"
+ "sync"
+ "unicode/utf8"
+
+ "github.com/golang/protobuf/proto"
+ "github.com/prometheus/common/expfmt"
+
+ dto "github.com/prometheus/client_model/go"
+
+ "github.com/prometheus/client_golang/prometheus/internal"
+)
+
+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 (currently on Linux only, see NewProcessCollector)
+// and a Go collector (see NewGoCollector, in particular the note about
+// stop-the-world implication with Go versions older than 1.9) 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 functions and act on custom instances instead.
+var (
+ defaultRegistry = NewRegistry()
+ DefaultRegisterer Registerer = defaultRegistry
+ DefaultGatherer Gatherer = defaultRegistry
+)
+
+func init() {
+ MustRegister(NewProcessCollector(ProcessCollectorOpts{}))
+ 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. Unchecked Collectors (those whose
+// Describe methed does not yield any descriptors) are excluded from the check.
+//
+// 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 than 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.
+ //
+ // A Collector whose Describe method does not yield any Desc is treated
+ // as unchecked. Registration will always succeed. No check for
+ // re-registering (see previous paragraph) is performed. Thus, the
+ // caller is responsible for not double-registering the same unchecked
+ // Collector, and for providing a Collector that will not cause
+ // inconsistent metrics on collection. (This would lead to scrape
+ // errors.)
+ 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 an unchecked
+ // Collector cannot be unregistered (as its Describe method does not
+ // yield any descriptor).
+ //
+ // 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 uniquely named MetricFamily protobufs. Gather ensures that the
+ // returned slice is valid and self-consistent so that it can be used
+ // for valid exposition. As an exception to the strict consistency
+ // requirements described for metric.Desc, Gather will tolerate
+ // different sets of label names for metrics of the same metric family.
+ //
+ // 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. Note that this is mostly useful for
+ // debugging purposes. If the gathered protobufs are to be used for
+ // exposition in actual monitoring, it is almost always better to not
+ // expose an incomplete result and instead disregard the returned
+ // MetricFamily protobufs in case 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()
+}
+
+// Append appends the provided error if it is not nil.
+func (errs *MultiError) Append(err error) {
+ if err != nil {
+ *errs = append(*errs, err)
+ }
+}
+
+// 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
+ uncheckedCollectors []Collector
+ 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 func() {
+ // Drain channel in case of premature return to not leak a goroutine.
+ for range descChan {
+ }
+ r.mtx.Unlock()
+ }()
+ // Conduct 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
+ }
+ }
+ }
+ // A Collector yielding no Desc at all is considered unchecked.
+ if len(newDescIDs) == 0 {
+ r.uncheckedCollectors = append(r.uncheckedCollectors, c)
+ return nil
+ }
+ 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 (
+ checkedMetricChan = make(chan Metric, capMetricChan)
+ uncheckedMetricChan = make(chan Metric, capMetricChan)
+ metricHashes = map[uint64]struct{}{}
+ 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()
+ goroutineBudget := len(r.collectorsByID) + len(r.uncheckedCollectors)
+ metricFamiliesByName := make(map[string]*dto.MetricFamily, len(r.dimHashesByName))
+ checkedCollectors := make(chan Collector, len(r.collectorsByID))
+ uncheckedCollectors := make(chan Collector, len(r.uncheckedCollectors))
+ for _, collector := range r.collectorsByID {
+ checkedCollectors <- collector
+ }
+ for _, collector := range r.uncheckedCollectors {
+ uncheckedCollectors <- 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()
+
+ wg.Add(goroutineBudget)
+
+ collectWorker := func() {
+ for {
+ select {
+ case collector := <-checkedCollectors:
+ collector.Collect(checkedMetricChan)
+ case collector := <-uncheckedCollectors:
+ collector.Collect(uncheckedMetricChan)
+ default:
+ return
+ }
+ wg.Done()
+ }
+ }
+
+ // Start the first worker now to make sure at least one is running.
+ go collectWorker()
+ goroutineBudget--
+
+ // Close checkedMetricChan and uncheckedMetricChan once all collectors
+ // are collected.
+ go func() {
+ wg.Wait()
+ close(checkedMetricChan)
+ close(uncheckedMetricChan)
+ }()
+
+ // Drain checkedMetricChan and uncheckedMetricChan in case of premature return.
+ defer func() {
+ if checkedMetricChan != nil {
+ for range checkedMetricChan {
+ }
+ }
+ if uncheckedMetricChan != nil {
+ for range uncheckedMetricChan {
+ }
+ }
+ }()
+
+ // Copy the channel references so we can nil them out later to remove
+ // them from the select statements below.
+ cmc := checkedMetricChan
+ umc := uncheckedMetricChan
+
+ for {
+ select {
+ case metric, ok := <-cmc:
+ if !ok {
+ cmc = nil
+ break
+ }
+ errs.Append(processMetric(
+ metric, metricFamiliesByName,
+ metricHashes,
+ registeredDescIDs,
+ ))
+ case metric, ok := <-umc:
+ if !ok {
+ umc = nil
+ break
+ }
+ errs.Append(processMetric(
+ metric, metricFamiliesByName,
+ metricHashes,
+ nil,
+ ))
+ default:
+ if goroutineBudget <= 0 || len(checkedCollectors)+len(uncheckedCollectors) == 0 {
+ // All collectors are already being worked on or
+ // we have already as many goroutines started as
+ // there are collectors. Do the same as above,
+ // just without the default.
+ select {
+ case metric, ok := <-cmc:
+ if !ok {
+ cmc = nil
+ break
+ }
+ errs.Append(processMetric(
+ metric, metricFamiliesByName,
+ metricHashes,
+ registeredDescIDs,
+ ))
+ case metric, ok := <-umc:
+ if !ok {
+ umc = nil
+ break
+ }
+ errs.Append(processMetric(
+ metric, metricFamiliesByName,
+ metricHashes,
+ nil,
+ ))
+ }
+ break
+ }
+ // Start more workers.
+ go collectWorker()
+ goroutineBudget--
+ runtime.Gosched()
+ }
+ // Once both checkedMetricChan and uncheckdMetricChan are closed
+ // and drained, the contraption above will nil out cmc and umc,
+ // and then we can leave the collect loop here.
+ if cmc == nil && umc == nil {
+ break
+ }
+ }
+ return internal.NormalizeMetricFamilies(metricFamiliesByName), errs.MaybeUnwrap()
+}
+
+// WriteToTextfile calls Gather on the provided Gatherer, encodes the result in the
+// Prometheus text format, and writes it to a temporary file. Upon success, the
+// temporary file is renamed to the provided filename.
+//
+// This is intended for use with the textfile collector of the node exporter.
+// Note that the node exporter expects the filename to be suffixed with ".prom".
+func WriteToTextfile(filename string, g Gatherer) error {
+ tmp, err := ioutil.TempFile(filepath.Dir(filename), filepath.Base(filename))
+ if err != nil {
+ return err
+ }
+ defer os.Remove(tmp.Name())
+
+ mfs, err := g.Gather()
+ if err != nil {
+ return err
+ }
+ for _, mf := range mfs {
+ if _, err := expfmt.MetricFamilyToText(tmp, mf); err != nil {
+ return err
+ }
+ }
+ if err := tmp.Close(); err != nil {
+ return err
+ }
+
+ if err := os.Chmod(tmp.Name(), 0644); err != nil {
+ return err
+ }
+ return os.Rename(tmp.Name(), filename)
+}
+
+// processMetric is an internal helper method only used by the Gather method.
+func processMetric(
+ metric Metric,
+ metricFamiliesByName map[string]*dto.MetricFamily,
+ metricHashes map[uint64]struct{},
+ registeredDescIDs map[uint64]struct{},
+) error {
+ desc := metric.Desc()
+ // Wrapped metrics collected by an unchecked Collector can have an
+ // invalid Desc.
+ if desc.err != nil {
+ return desc.err
+ }
+ dtoMetric := &dto.Metric{}
+ if err := metric.Write(dtoMetric); err != nil {
+ return fmt.Errorf("error collecting metric %v: %s", desc, err)
+ }
+ metricFamily, ok := metricFamiliesByName[desc.fqName]
+ if ok { // Existing name.
+ if metricFamily.GetHelp() != desc.help {
+ return fmt.Errorf(
+ "collected metric %s %s has help %q but should have %q",
+ desc.fqName, dtoMetric, desc.help, metricFamily.GetHelp(),
+ )
+ }
+ // TODO(beorn7): Simplify switch once Desc has type.
+ switch metricFamily.GetType() {
+ case dto.MetricType_COUNTER:
+ if dtoMetric.Counter == nil {
+ return fmt.Errorf(
+ "collected metric %s %s should be a Counter",
+ desc.fqName, dtoMetric,
+ )
+ }
+ case dto.MetricType_GAUGE:
+ if dtoMetric.Gauge == nil {
+ return fmt.Errorf(
+ "collected metric %s %s should be a Gauge",
+ desc.fqName, dtoMetric,
+ )
+ }
+ case dto.MetricType_SUMMARY:
+ if dtoMetric.Summary == nil {
+ return fmt.Errorf(
+ "collected metric %s %s should be a Summary",
+ desc.fqName, dtoMetric,
+ )
+ }
+ case dto.MetricType_UNTYPED:
+ if dtoMetric.Untyped == nil {
+ return fmt.Errorf(
+ "collected metric %s %s should be Untyped",
+ desc.fqName, dtoMetric,
+ )
+ }
+ case dto.MetricType_HISTOGRAM:
+ if dtoMetric.Histogram == nil {
+ return fmt.Errorf(
+ "collected metric %s %s should be a Histogram",
+ desc.fqName, dtoMetric,
+ )
+ }
+ default:
+ panic("encountered MetricFamily with invalid type")
+ }
+ } else { // New name.
+ 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:
+ return fmt.Errorf("empty metric collected: %s", dtoMetric)
+ }
+ if err := checkSuffixCollisions(metricFamily, metricFamiliesByName); err != nil {
+ return err
+ }
+ metricFamiliesByName[desc.fqName] = metricFamily
+ }
+ if err := checkMetricConsistency(metricFamily, dtoMetric, metricHashes); err != nil {
+ return err
+ }
+ if registeredDescIDs != nil {
+ // Is the desc registered at all?
+ if _, exist := registeredDescIDs[desc.id]; !exist {
+ return fmt.Errorf(
+ "collected metric %s %s with unregistered descriptor %s",
+ metricFamily.GetName(), dtoMetric, desc,
+ )
+ }
+ if err := checkDescConsistency(metricFamily, dtoMetric, desc); err != nil {
+ return err
+ }
+ }
+ metricFamily.Metric = append(metricFamily.Metric, dtoMetric)
+ return nil
+}
+
+// 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{}{}
+ 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
+ if err := checkSuffixCollisions(existingMF, metricFamiliesByName); err != nil {
+ errs = append(errs, err)
+ continue
+ }
+ metricFamiliesByName[mf.GetName()] = existingMF
+ }
+ for _, m := range mf.Metric {
+ if err := checkMetricConsistency(existingMF, m, metricHashes); err != nil {
+ errs = append(errs, err)
+ continue
+ }
+ existingMF.Metric = append(existingMF.Metric, m)
+ }
+ }
+ }
+ return internal.NormalizeMetricFamilies(metricFamiliesByName), errs.MaybeUnwrap()
+}
+
+// checkSuffixCollisions checks for collisions with the “magic” suffixes the
+// Prometheus text format and the internal metric representation of the
+// Prometheus server add while flattening Summaries and Histograms.
+func checkSuffixCollisions(mf *dto.MetricFamily, mfs map[string]*dto.MetricFamily) error {
+ var (
+ newName = mf.GetName()
+ newType = mf.GetType()
+ newNameWithoutSuffix = ""
+ )
+ switch {
+ case strings.HasSuffix(newName, "_count"):
+ newNameWithoutSuffix = newName[:len(newName)-6]
+ case strings.HasSuffix(newName, "_sum"):
+ newNameWithoutSuffix = newName[:len(newName)-4]
+ case strings.HasSuffix(newName, "_bucket"):
+ newNameWithoutSuffix = newName[:len(newName)-7]
+ }
+ if newNameWithoutSuffix != "" {
+ if existingMF, ok := mfs[newNameWithoutSuffix]; ok {
+ switch existingMF.GetType() {
+ case dto.MetricType_SUMMARY:
+ if !strings.HasSuffix(newName, "_bucket") {
+ return fmt.Errorf(
+ "collected metric named %q collides with previously collected summary named %q",
+ newName, newNameWithoutSuffix,
+ )
+ }
+ case dto.MetricType_HISTOGRAM:
+ return fmt.Errorf(
+ "collected metric named %q collides with previously collected histogram named %q",
+ newName, newNameWithoutSuffix,
+ )
+ }
+ }
+ }
+ if newType == dto.MetricType_SUMMARY || newType == dto.MetricType_HISTOGRAM {
+ if _, ok := mfs[newName+"_count"]; ok {
+ return fmt.Errorf(
+ "collected histogram or summary named %q collides with previously collected metric named %q",
+ newName, newName+"_count",
+ )
+ }
+ if _, ok := mfs[newName+"_sum"]; ok {
+ return fmt.Errorf(
+ "collected histogram or summary named %q collides with previously collected metric named %q",
+ newName, newName+"_sum",
+ )
+ }
+ }
+ if newType == dto.MetricType_HISTOGRAM {
+ if _, ok := mfs[newName+"_bucket"]; ok {
+ return fmt.Errorf(
+ "collected histogram named %q collides with previously collected metric named %q",
+ newName, newName+"_bucket",
+ )
+ }
+ }
+ return nil
+}
+
+// checkMetricConsistency checks if the provided Metric is consistent with the
+// provided MetricFamily. It also hashes the Metric labels and the MetricFamily
+// name. If the resulting hash is already in the provided metricHashes, an error
+// is returned. If not, it is added to metricHashes.
+func checkMetricConsistency(
+ metricFamily *dto.MetricFamily,
+ dtoMetric *dto.Metric,
+ metricHashes map[uint64]struct{},
+) error {
+ name := metricFamily.GetName()
+
+ // 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 %q { %s} is not a %s",
+ name, dtoMetric, metricFamily.GetType(),
+ )
+ }
+
+ previousLabelName := ""
+ for _, labelPair := range dtoMetric.GetLabel() {
+ labelName := labelPair.GetName()
+ if labelName == previousLabelName {
+ return fmt.Errorf(
+ "collected metric %q { %s} has two or more labels with the same name: %s",
+ name, dtoMetric, labelName,
+ )
+ }
+ if !checkLabelName(labelName) {
+ return fmt.Errorf(
+ "collected metric %q { %s} has a label with an invalid name: %s",
+ name, dtoMetric, labelName,
+ )
+ }
+ if dtoMetric.Summary != nil && labelName == quantileLabel {
+ return fmt.Errorf(
+ "collected metric %q { %s} must not have an explicit %q label",
+ name, dtoMetric, quantileLabel,
+ )
+ }
+ if !utf8.ValidString(labelPair.GetValue()) {
+ return fmt.Errorf(
+ "collected metric %q { %s} has a label named %q whose value is not utf8: %#v",
+ name, dtoMetric, labelName, labelPair.GetValue())
+ }
+ previousLabelName = labelName
+ }
+
+ // Is the metric unique (i.e. no other metric with the same name and the same labels)?
+ h := hashNew()
+ h = hashAdd(h, name)
+ h = hashAddByte(h, separatorByte)
+ // Make sure label pairs are sorted. We depend on it for the consistency
+ // check.
+ if !sort.IsSorted(labelPairSorter(dtoMetric.Label)) {
+ // We cannot sort dtoMetric.Label in place as it is immutable by contract.
+ copiedLabels := make([]*dto.LabelPair, len(dtoMetric.Label))
+ copy(copiedLabels, dtoMetric.Label)
+ sort.Sort(labelPairSorter(copiedLabels))
+ dtoMetric.Label = copiedLabels
+ }
+ for _, lp := range dtoMetric.Label {
+ h = hashAdd(h, lp.GetName())
+ h = hashAddByte(h, separatorByte)
+ h = hashAdd(h, lp.GetValue())
+ h = hashAddByte(h, separatorByte)
+ }
+ if _, exists := metricHashes[h]; exists {
+ return fmt.Errorf(
+ "collected metric %q { %s} was collected before with the same name and label values",
+ name, dtoMetric,
+ )
+ }
+ 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, len(desc.constLabelPairs), len(dtoMetric.Label))
+ copy(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
+}