Update vendoring for github.com/prometheus/client_golang/prometheus

Pin to 0.8.0 (c5b7fccd204277076155f10851dad72b76a49317)

vendor/github.com/prometheus/client_golang/NOTICE

@@ -7,11 +7,6 @@ SoundCloud Ltd. (http://soundcloud.com/).
 
 The following components are included in this product:
 
-goautoneg
-http://bitbucket.org/ww/goautoneg
-Copyright 2011, Open Knowledge Foundation Ltd.
-See README.txt for license details.
-
 perks - a fork of https://github.com/bmizerany/perks
 https://github.com/beorn7/perks
 Copyright 2013-2015 Blake Mizerany, Björn Rabenstein

vendor/github.com/prometheus/client_golang/prometheus/README.md

@@ -1,53 +1 @@
-# Overview
-This is the [Prometheus](http://www.prometheus.io) telemetric
-instrumentation client [Go](http://golang.org) client library.  It
-enable authors to define process-space metrics for their servers and
-expose them through a web service interface for extraction,
-aggregation, and a whole slew of other post processing techniques.
-
-# Installing
-    $ go get github.com/prometheus/client_golang/prometheus
-
-# Example
-```go
-package main
-
-import (
-	"net/http"
-
-	"github.com/prometheus/client_golang/prometheus"
-)
-
-var (
-	indexed = prometheus.NewCounter(prometheus.CounterOpts{
-		Namespace: "my_company",
-		Subsystem: "indexer",
-		Name:      "documents_indexed",
-		Help:      "The number of documents indexed.",
-	})
-	size = prometheus.NewGauge(prometheus.GaugeOpts{
-		Namespace: "my_company",
-		Subsystem: "storage",
-		Name:      "documents_total_size_bytes",
-		Help:      "The total size of all documents in the storage.",
-	})
-)
-
-func main() {
-	http.Handle("/metrics", prometheus.Handler())
-
-	indexed.Inc()
-	size.Set(5)
-
-	http.ListenAndServe(":8080", nil)
-}
-
-func init() {
-	prometheus.MustRegister(indexed)
-	prometheus.MustRegister(size)
-}
-```
-
-# Documentation
-
-[![GoDoc](https://godoc.org/github.com/prometheus/client_golang?status.png)](https://godoc.org/github.com/prometheus/client_golang)
+See [![go-doc](https://godoc.org/github.com/prometheus/client_golang/prometheus?status.svg)](https://godoc.org/github.com/prometheus/client_golang/prometheus).

vendor/github.com/prometheus/client_golang/prometheus/collector.go

@@ -15,15 +15,15 @@ package prometheus
 
 // Collector is the interface implemented by anything that can be used by
 // Prometheus to collect metrics. A Collector has to be registered for
-// collection. See Register, MustRegister, RegisterOrGet, and MustRegisterOrGet.
+// collection. See Registerer.Register.
 //
-// The stock metrics provided by this package (like Gauge, Counter, Summary) are
-// also Collectors (which only ever collect one metric, namely itself). An
-// implementer of Collector may, however, collect multiple metrics in a
-// coordinated fashion and/or create metrics on the fly. Examples for collectors
-// already implemented in this library are the metric vectors (i.e. collection
-// of multiple instances of the same Metric but with different label values)
-// like GaugeVec or SummaryVec, and the ExpvarCollector.
+// The stock metrics provided by this package (Gauge, Counter, Summary,
+// Histogram, Untyped) are also Collectors (which only ever collect one metric,
+// namely itself). An implementer of Collector may, however, collect multiple
+// metrics in a coordinated fashion and/or create metrics on the fly. Examples
+// for collectors already implemented in this library are the metric vectors
+// (i.e. collection of multiple instances of the same Metric but with different
+// label values) like GaugeVec or SummaryVec, and the ExpvarCollector.
 type Collector interface {
 	// Describe sends the super-set of all possible descriptors of metrics
 	// collected by this Collector to the provided channel and returns once
@@ -37,39 +37,39 @@ type Collector interface {
 	// executing this method, it must send an invalid descriptor (created
 	// with NewInvalidDesc) to signal the error to the registry.
 	Describe(chan<- *Desc)
-	// Collect is called by Prometheus when collecting metrics. The
-	// implementation sends each collected metric via the provided channel
-	// and returns once the last metric has been sent. The descriptor of
-	// each sent metric is one of those returned by Describe. Returned
-	// metrics that share the same descriptor must differ in their variable
-	// label values. This method may be called concurrently and must
-	// therefore be implemented in a concurrency safe way. Blocking occurs
-	// at the expense of total performance of rendering all registered
-	// metrics. Ideally, Collector implementations support concurrent
-	// readers.
+	// Collect is called by the Prometheus registry when collecting
+	// metrics. The implementation sends each collected metric via the
+	// provided channel and returns once the last metric has been sent. The
+	// descriptor of each sent metric is one of those returned by
+	// Describe. Returned metrics that share the same descriptor must differ
+	// in their variable label values. This method may be called
+	// concurrently and must therefore be implemented in a concurrency safe
+	// way. Blocking occurs at the expense of total performance of rendering
+	// all registered metrics. Ideally, Collector implementations support
+	// concurrent readers.
 	Collect(chan<- Metric)
 }
 
-// SelfCollector implements Collector for a single Metric so that that the
-// Metric collects itself. Add it as an anonymous field to a struct that
-// implements Metric, and call Init with the Metric itself as an argument.
-type SelfCollector struct {
+// selfCollector implements Collector for a single Metric so that the Metric
+// collects itself. Add it as an anonymous field to a struct that implements
+// Metric, and call init with the Metric itself as an argument.
+type selfCollector struct {
 	self Metric
 }
 
-// Init provides the SelfCollector with a reference to the metric it is supposed
+// init provides the selfCollector with a reference to the metric it is supposed
 // to collect. It is usually called within the factory function to create a
 // metric. See example.
-func (c *SelfCollector) Init(self Metric) {
+func (c *selfCollector) init(self Metric) {
 	c.self = self
 }
 
 // Describe implements Collector.
-func (c *SelfCollector) Describe(ch chan<- *Desc) {
+func (c *selfCollector) Describe(ch chan<- *Desc) {
 	ch <- c.self.Desc()
 }
 
 // Collect implements Collector.
-func (c *SelfCollector) Collect(ch chan<- Metric) {
+func (c *selfCollector) Collect(ch chan<- Metric) {
 	ch <- c.self
 }

vendor/github.com/prometheus/client_golang/prometheus/counter.go

@@ -35,6 +35,9 @@ type Counter interface {
 	// Prometheus metric. Do not use it for regular handling of a
 	// Prometheus counter (as it can be used to break the contract of
 	// monotonically increasing values).
+	//
+	// Deprecated: Use NewConstMetric to create a counter for an external
+	// value. A Counter should never be set.
 	Set(float64)
 	// Inc increments the counter by 1.
 	Inc()
@@ -55,7 +58,7 @@ func NewCounter(opts CounterOpts) Counter {
 		opts.ConstLabels,
 	)
 	result := &counter{value: value{desc: desc, valType: CounterValue, labelPairs: desc.constLabelPairs}}
-	result.Init(result) // Init self-collection.
+	result.init(result) // Init self-collection.
 	return result
 }
 
@@ -79,7 +82,7 @@ func (c *counter) Add(v float64) {
 // CounterVec embeds MetricVec. See there for a full list of methods with
 // detailed documentation.
 type CounterVec struct {
-	MetricVec
+	*MetricVec
 }
 
 // NewCounterVec creates a new CounterVec based on the provided CounterOpts and
@@ -93,19 +96,15 @@ func NewCounterVec(opts CounterOpts, labelNames []string) *CounterVec {
 		opts.ConstLabels,
 	)
 	return &CounterVec{
-		MetricVec: MetricVec{
-			children: map[uint64]Metric{},
-			desc:     desc,
-			newMetric: func(lvs ...string) Metric {
+		MetricVec: newMetricVec(desc, func(lvs ...string) Metric {
 			result := &counter{value: value{
 				desc:       desc,
 				valType:    CounterValue,
 				labelPairs: makeLabelPairs(desc, lvs),
 			}}
-				result.Init(result) // Init self-collection.
+			result.init(result) // Init self-collection.
 			return result
-			},
-		},
+		}),
 	}
 }
 

vendor/github.com/prometheus/client_golang/prometheus/desc.go

@@ -1,3 +1,16 @@
+// Copyright 2016 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 (

vendor/github.com/prometheus/client_golang/prometheus/doc.go

@@ -11,18 +11,17 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// Package prometheus provides embeddable metric primitives for servers and
-// standardized exposition of telemetry through a web services interface.
+// Package prometheus provides metrics primitives to instrument code for
+// monitoring. It also offers a registry for metrics. Sub-packages allow to
+// expose the registered metrics via HTTP (package promhttp) or push them to a
+// Pushgateway (package push).
 //
 // All exported functions and methods are safe to be used concurrently unless
 //specified otherwise.
 //
-// To expose metrics registered with the Prometheus registry, an HTTP server
-// needs to know about the Prometheus handler. The usual endpoint is "/metrics".
+// A Basic Example
 //
-//     http.Handle("/metrics", prometheus.Handler())
-//
-// As a starting point a very basic usage example:
+// As a starting point, a very basic usage example:
 //
 //    package main
 //
@@ -30,6 +29,7 @@
 //    	"net/http"
 //
 //    	"github.com/prometheus/client_golang/prometheus"
+//    	"github.com/prometheus/client_golang/prometheus/promhttp"
 //    )
 //
 //    var (
@@ -37,73 +37,145 @@
 //    		Name: "cpu_temperature_celsius",
 //    		Help: "Current temperature of the CPU.",
 //    	})
-//    	hdFailures = prometheus.NewCounter(prometheus.CounterOpts{
+//    	hdFailures = prometheus.NewCounterVec(
+//    		prometheus.CounterOpts{
 //    			Name: "hd_errors_total",
 //    			Help: "Number of hard-disk errors.",
-//    	})
+//    		},
+//    		[]string{"device"},
+//    	)
 //    )
 //
 //    func init() {
+//    	// Metrics have to be registered to be exposed:
 //    	prometheus.MustRegister(cpuTemp)
 //    	prometheus.MustRegister(hdFailures)
 //    }
 //
 //    func main() {
 //    	cpuTemp.Set(65.3)
-//    	hdFailures.Inc()
+//    	hdFailures.With(prometheus.Labels{"device":"/dev/sda"}).Inc()
 //
-//    	http.Handle("/metrics", prometheus.Handler())
+//    	// The Handler function provides a default handler to expose metrics
+//    	// via an HTTP server. "/metrics" is the usual endpoint for that.
+//    	http.Handle("/metrics", promhttp.Handler())
 //    	http.ListenAndServe(":8080", nil)
 //    }
 //
 //
-// This is a complete program that exports two metrics, a Gauge and a Counter.
-// It also exports some stats about the HTTP usage of the /metrics
-// endpoint. (See the Handler function for more detail.)
+// This is a complete program that exports two metrics, a Gauge and a Counter,
+// the latter with a label attached to turn it into a (one-dimensional) vector.
 //
-// Two more advanced metric types are the Summary and Histogram.
+// Metrics
 //
-// In addition to the fundamental metric types Gauge, Counter, Summary, and
-// Histogram, a very important part of the Prometheus data model is the
-// partitioning of samples along dimensions called labels, which results in
+// The number of exported identifiers in this package might appear a bit
+// overwhelming. Hovever, in addition to the basic plumbing shown in the example
+// above, you only need to understand the different metric types and their
+// vector versions for basic usage.
+//
+// Above, you have already touched the Counter and the Gauge. There are two more
+// advanced metric types: the Summary and Histogram. A more thorough description
+// of those four metric types can be found in the Prometheus docs:
+// https://prometheus.io/docs/concepts/metric_types/
+//
+// A fifth "type" of metric is Untyped. It behaves like a Gauge, but signals the
+// Prometheus server not to assume anything about its type.
+//
+// In addition to the fundamental metric types Gauge, Counter, Summary,
+// Histogram, and Untyped, a very important part of the Prometheus data model is
+// the partitioning of samples along dimensions called labels, which results in
 // metric vectors. The fundamental types are GaugeVec, CounterVec, SummaryVec,
-// and HistogramVec.
+// HistogramVec, and UntypedVec.
 //
-// Those are all the parts needed for basic usage. Detailed documentation and
-// examples are provided below.
+// While only the fundamental metric types implement the Metric interface, both
+// the metrics and their vector versions implement the Collector interface. A
+// Collector manages the collection of a number of Metrics, but for convenience,
+// a Metric can also “collect itself”. Note that Gauge, Counter, Summary,
+// Histogram, and Untyped are interfaces themselves while GaugeVec, CounterVec,
+// SummaryVec, HistogramVec, and UntypedVec are not.
 //
-// Everything else this package offers is essentially for "power users" only. A
-// few pointers to "power user features":
+// To create instances of Metrics and their vector versions, you need a suitable
+// …Opts struct, i.e. GaugeOpts, CounterOpts, SummaryOpts,
+// HistogramOpts, or UntypedOpts.
 //
-// All the various ...Opts structs have a ConstLabels field for labels that
-// never change their value (which is only useful under special circumstances,
-// see documentation of the Opts type).
+// Custom Collectors and constant Metrics
 //
-// The Untyped metric behaves like a Gauge, but signals the Prometheus server
-// not to assume anything about its type.
+// While you could create your own implementations of Metric, most likely you
+// will only ever implement the Collector interface on your own. At a first
+// glance, a custom Collector seems handy to bundle Metrics for common
+// registration (with the prime example of the different metric vectors above,
+// which bundle all the metrics of the same name but with different labels).
 //
-// Functions to fine-tune how the metric registry works: EnableCollectChecks,
-// PanicOnCollectError, Register, Unregister, SetMetricFamilyInjectionHook.
+// There is a more involved use case, too: If you already have metrics
+// available, created outside of the Prometheus context, you don't need the
+// interface of the various Metric types. You essentially want to mirror the
+// existing numbers into Prometheus Metrics during collection. An own
+// implementation of the Collector interface is perfect for that. You can create
+// Metric instances “on the fly” using NewConstMetric, NewConstHistogram, and
+// NewConstSummary (and their respective Must… versions). That will happen in
+// the Collect method. The Describe method has to return separate Desc
+// instances, representative of the “throw-away” metrics to be created
+// later. NewDesc comes in handy to create those Desc instances.
 //
-// For custom metric collection, there are two entry points: Custom Metric
-// implementations and custom Collector implementations. A Metric is the
-// fundamental unit in the Prometheus data model: a sample at a point in time
-// together with its meta-data (like its fully-qualified name and any number of
-// pairs of label name and label value) that knows how to marshal itself into a
-// data transfer object (aka DTO, implemented as a protocol buffer). A Collector
-// gets registered with the Prometheus registry and manages the collection of
-// one or more Metrics. Many parts of this package are building blocks for
-// Metrics and Collectors. Desc is the metric descriptor, actually used by all
-// metrics under the hood, and by Collectors to describe the Metrics to be
-// collected, but only to be dealt with by users if they implement their own
-// Metrics or Collectors. To create a Desc, the BuildFQName function will come
-// in handy. Other useful components for Metric and Collector implementation
-// include: LabelPairSorter to sort the DTO version of label pairs,
-// NewConstMetric and MustNewConstMetric to create "throw away" Metrics at
-// collection time, MetricVec to bundle custom Metrics into a metric vector
-// Collector, SelfCollector to make a custom Metric collect itself.
+// The Collector example illustrates the use case. You can also look at the
+// source code of the processCollector (mirroring process metrics), the
+// goCollector (mirroring Go metrics), or the expvarCollector (mirroring expvar
+// metrics) as examples that are used in this package itself.
 //
-// A good example for a custom Collector is the ExpVarCollector included in this
-// package, which exports variables exported via the "expvar" package as
-// Prometheus metrics.
+// If you just need to call a function to get a single float value to collect as
+// a metric, GaugeFunc, CounterFunc, or UntypedFunc might be interesting
+// shortcuts.
+//
+// Advanced Uses of the Registry
+//
+// While MustRegister is the by far most common way of registering a Collector,
+// sometimes you might want to handle the errors the registration might
+// cause. As suggested by the name, MustRegister panics if an error occurs. With
+// the Register function, the error is returned and can be handled.
+//
+// An error is returned if the registered Collector is incompatible or
+// inconsistent with already registered metrics. The registry aims for
+// consistency of the collected metrics according to the Prometheus data
+// model. Inconsistencies are ideally detected at registration time, not at
+// collect time. The former will usually be detected at start-up time of a
+// program, while the latter will only happen at scrape time, possibly not even
+// on the first scrape if the inconsistency only becomes relevant later. That is
+// the main reason why a Collector and a Metric have to describe themselves to
+// the registry.
+//
+// So far, everything we did operated on the so-called default registry, as it
+// can be found in the global DefaultRegistry variable. With NewRegistry, you
+// can create a custom registry, or you can even implement the Registerer or
+// Gatherer interfaces yourself. The methods Register and Unregister work in
+// the same way on a custom registry as the global functions Register and
+// Unregister on the default registry.
+//
+// There are a number of uses for custom registries: You can use registries
+// with special properties, see NewPedanticRegistry. You can avoid global state,
+// as it is imposed by the DefaultRegistry. You can use multiple registries at
+// the same time to expose different metrics in different ways. You can use
+// separate registries for testing purposes.
+//
+// Also note that the DefaultRegistry comes registered with a Collector for Go
+// runtime metrics (via NewGoCollector) and a Collector for process metrics (via
+// NewProcessCollector). With a custom registry, you are in control and decide
+// yourself about the Collectors to register.
+//
+// HTTP Exposition
+//
+// The Registry implements the Gatherer interface. The caller of the Gather
+// method can then expose the gathered metrics in some way. Usually, the metrics
+// are served via HTTP on the /metrics endpoint. That's happening in the example
+// above. The tools to expose metrics via HTTP are in the promhttp
+// sub-package. (The top-level functions in the prometheus package are
+// deprecated.)
+//
+// Pushing to the Pushgateway
+//
+// Function for pushing to the Pushgateway can be found in the push sub-package.
+//
+// Other Means of Exposition
+//
+// More ways of exposing metrics can easily be added. Sending metrics to
+// Graphite would be an example that will soon be implemented.
 package prometheus

vendor/github.com/prometheus/client_golang/prometheus/expvar_collector.go

@@ -18,21 +18,21 @@ import (
 	"expvar"
 )
 
-// ExpvarCollector collects metrics from the expvar interface. It provides a
-// quick way to expose numeric values that are already exported via expvar as
-// Prometheus metrics. Note that the data models of expvar and Prometheus are
-// fundamentally different, and that the ExpvarCollector is inherently
-// slow. Thus, the ExpvarCollector is probably great for experiments and
-// prototying, but you should seriously consider a more direct implementation of
-// Prometheus metrics for monitoring production systems.
-//
-// Use NewExpvarCollector to create new instances.
-type ExpvarCollector struct {
+type expvarCollector struct {
 	exports map[string]*Desc
 }
 
-// NewExpvarCollector returns a newly allocated ExpvarCollector that still has
-// to be registered with the Prometheus registry.
+// NewExpvarCollector returns a newly allocated expvar Collector that still has
+// to be registered with a Prometheus registry.
+//
+// An expvar Collector collects metrics from the expvar interface. It provides a
+// quick way to expose numeric values that are already exported via expvar as
+// Prometheus metrics. Note that the data models of expvar and Prometheus are
+// fundamentally different, and that the expvar Collector is inherently slower
+// than native Prometheus metrics. Thus, the expvar Collector is probably great
+// for experiments and prototying, but you should seriously consider a more
+// direct implementation of Prometheus metrics for monitoring production
+// systems.
 //
 // The exports map has the following meaning:
 //
@@ -59,21 +59,21 @@ type ExpvarCollector struct {
 // sample values.
 //
 // Anything that does not fit into the scheme above is silently ignored.
-func NewExpvarCollector(exports map[string]*Desc) *ExpvarCollector {
-	return &ExpvarCollector{
+func NewExpvarCollector(exports map[string]*Desc) Collector {
+	return &expvarCollector{
 		exports: exports,
 	}
 }
 
 // Describe implements Collector.
-func (e *ExpvarCollector) Describe(ch chan<- *Desc) {
+func (e *expvarCollector) Describe(ch chan<- *Desc) {
 	for _, desc := range e.exports {
 		ch <- desc
 	}
 }
 
 // Collect implements Collector.
-func (e *ExpvarCollector) Collect(ch chan<- Metric) {
+func (e *expvarCollector) Collect(ch chan<- Metric) {
 	for name, desc := range e.exports {
 		var m Metric
 		expVar := expvar.Get(name)

vendor/github.com/prometheus/client_golang/prometheus/gauge.go

@@ -58,7 +58,7 @@ func NewGauge(opts GaugeOpts) Gauge {
 // (e.g. number of operations queued, partitioned by user and operation
 // type). Create instances with NewGaugeVec.
 type GaugeVec struct {
-	MetricVec
+	*MetricVec
 }
 
 // NewGaugeVec creates a new GaugeVec based on the provided GaugeOpts and
@@ -72,13 +72,9 @@ func NewGaugeVec(opts GaugeOpts, labelNames []string) *GaugeVec {
 		opts.ConstLabels,
 	)
 	return &GaugeVec{
-		MetricVec: MetricVec{
-			children: map[uint64]Metric{},
-			desc:     desc,
-			newMetric: func(lvs ...string) Metric {
+		MetricVec: newMetricVec(desc, func(lvs ...string) Metric {
 			return newValue(desc, GaugeValue, 0, lvs...)
-			},
-		},
+		}),
 	}
 }
 

vendor/github.com/prometheus/client_golang/prometheus/go_collector.go

@@ -17,7 +17,7 @@ type goCollector struct {
 
 // NewGoCollector returns a collector which exports metrics about the current
 // go process.
-func NewGoCollector() *goCollector {
+func NewGoCollector() Collector {
 	return &goCollector{
 		goroutines: NewGauge(GaugeOpts{
 			Namespace: "go",
@@ -211,7 +211,7 @@ func NewGoCollector() *goCollector {
 					"Number of seconds since 1970 of last garbage collection.",
 					nil, nil,
 				),
-				eval:    func(ms *runtime.MemStats) float64 { return float64(ms.LastGC*10 ^ 9) },
+				eval:    func(ms *runtime.MemStats) float64 { return float64(ms.LastGC) / 1e9 },
 				valType: GaugeValue,
 			},
 		},

vendor/github.com/prometheus/client_golang/prometheus/histogram.go

@@ -51,11 +51,11 @@ type Histogram interface {
 // bucket of a histogram ("le" -> "less or equal").
 const bucketLabel = "le"
 
-var (
 // DefBuckets are the default Histogram buckets. The default buckets are
-	// tailored to broadly measure the response time (in seconds) of a
-	// network service. Most likely, however, you will be required to define
-	// buckets customized to your use case.
+// tailored to broadly measure the response time (in seconds) of a network
+// service. Most likely, however, you will be required to define buckets
+// customized to your use case.
+var (
 	DefBuckets = []float64{.005, .01, .025, .05, .1, .25, .5, 1, 2.5, 5, 10}
 
 	errBucketLabelNotAllowed = fmt.Errorf(
@@ -210,7 +210,7 @@ func newHistogram(desc *Desc, opts HistogramOpts, labelValues ...string) Histogr
 	// Finally we know the final length of h.upperBounds and can make counts.
 	h.counts = make([]uint64, len(h.upperBounds))
 
-	h.Init(h) // Init self-collection.
+	h.init(h) // Init self-collection.
 	return h
 }
 
@@ -222,7 +222,7 @@ type histogram struct {
 	sumBits uint64
 	count   uint64
 
-	SelfCollector
+	selfCollector
 	// Note that there is no mutex required.
 
 	desc *Desc
@@ -287,7 +287,7 @@ func (h *histogram) Write(out *dto.Metric) error {
 // (e.g. HTTP request latencies, partitioned by status code and method). Create
 // instances with NewHistogramVec.
 type HistogramVec struct {
-	MetricVec
+	*MetricVec
 }
 
 // NewHistogramVec creates a new HistogramVec based on the provided HistogramOpts and
@@ -301,13 +301,9 @@ func NewHistogramVec(opts HistogramOpts, labelNames []string) *HistogramVec {
 		opts.ConstLabels,
 	)
 	return &HistogramVec{
-		MetricVec: MetricVec{
-			children: map[uint64]Metric{},
-			desc:     desc,
-			newMetric: func(lvs ...string) Metric {
+		MetricVec: newMetricVec(desc, func(lvs ...string) Metric {
 			return newHistogram(desc, opts, lvs...)
-			},
-		},
+		}),
 	}
 }
 

vendor/github.com/prometheus/client_golang/prometheus/http.go

@@ -15,14 +15,114 @@ package prometheus
 
 import (
 	"bufio"
+	"bytes"
+	"compress/gzip"
+	"fmt"
 	"io"
 	"net"
 	"net/http"
 	"strconv"
 	"strings"
+	"sync"
 	"time"
+
+	"github.com/prometheus/common/expfmt"
 )
 
+// TODO(beorn7): Remove this whole file. It is a partial mirror of
+// promhttp/http.go (to avoid circular import chains) where everything HTTP
+// related should live. The functions here are just for avoiding
+// breakage. Everything is deprecated.
+
+const (
+	contentTypeHeader     = "Content-Type"
+	contentLengthHeader   = "Content-Length"
+	contentEncodingHeader = "Content-Encoding"
+	acceptEncodingHeader  = "Accept-Encoding"
+)
+
+var bufPool sync.Pool
+
+func getBuf() *bytes.Buffer {
+	buf := bufPool.Get()
+	if buf == nil {
+		return &bytes.Buffer{}
+	}
+	return buf.(*bytes.Buffer)
+}
+
+func giveBuf(buf *bytes.Buffer) {
+	buf.Reset()
+	bufPool.Put(buf)
+}
+
+// Handler returns an HTTP handler for the DefaultGatherer. It is
+// already instrumented with InstrumentHandler (using "prometheus" as handler
+// name).
+//
+// Deprecated: Please note the issues described in the doc comment of
+// InstrumentHandler. You might want to consider using promhttp.Handler instead
+// (which is non instrumented).
+func Handler() http.Handler {
+	return InstrumentHandler("prometheus", UninstrumentedHandler())
+}
+
+// UninstrumentedHandler returns an HTTP handler for the DefaultGatherer.
+//
+// Deprecated: Use promhttp.Handler instead. See there for further documentation.
+func UninstrumentedHandler() http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
+		mfs, err := DefaultGatherer.Gather()
+		if err != nil {
+			http.Error(w, "An error has occurred during metrics collection:\n\n"+err.Error(), http.StatusInternalServerError)
+			return
+		}
+
+		contentType := expfmt.Negotiate(req.Header)
+		buf := getBuf()
+		defer giveBuf(buf)
+		writer, encoding := decorateWriter(req, buf)
+		enc := expfmt.NewEncoder(writer, contentType)
+		var lastErr error
+		for _, mf := range mfs {
+			if err := enc.Encode(mf); err != nil {
+				lastErr = err
+				http.Error(w, "An error has occurred during metrics encoding:\n\n"+err.Error(), http.StatusInternalServerError)
+				return
+			}
+		}
+		if closer, ok := writer.(io.Closer); ok {
+			closer.Close()
+		}
+		if lastErr != nil && buf.Len() == 0 {
+			http.Error(w, "No metrics encoded, last error:\n\n"+err.Error(), http.StatusInternalServerError)
+			return
+		}
+		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())
+	})
+}
+
+// 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, ""
+}
+
 var instLabels = []string{"method", "code"}
 
 type nower interface {
@@ -57,12 +157,34 @@ func nowSeries(t ...time.Time) nower {
 // has a constant label named "handler" with the provided handlerName as
 // value. http_requests_total is a metric vector partitioned by HTTP method
 // (label name "method") and HTTP status code (label name "code").
+//
+// Deprecated: InstrumentHandler has several issues:
+//
+// - It uses Summaries rather than Histograms. Summaries are not useful if
+// aggregation across multiple instances is required.
+//
+// - It uses microseconds as unit, which is deprecated and should be replaced by
+// seconds.
+//
+// - The size of the request is calculated in a separate goroutine. Since this
+// calculator requires access to the request header, it creates a race with
+// any writes to the header performed during request handling.
+// httputil.ReverseProxy is a prominent example for a handler
+// performing such writes.
+//
+// Upcoming versions of this package will provide ways of instrumenting HTTP
+// handlers that are more flexible and have fewer issues. Please prefer direct
+// instrumentation in the meantime.
 func InstrumentHandler(handlerName string, handler http.Handler) http.HandlerFunc {
 	return InstrumentHandlerFunc(handlerName, handler.ServeHTTP)
 }
 
 // InstrumentHandlerFunc wraps the given function for instrumentation. It
-// otherwise works in the same way as InstrumentHandler.
+// otherwise works in the same way as InstrumentHandler (and shares the same
+// issues).
+//
+// Deprecated: InstrumentHandlerFunc is deprecated for the same reasons as
+// InstrumentHandler is.
 func InstrumentHandlerFunc(handlerName string, handlerFunc func(http.ResponseWriter, *http.Request)) http.HandlerFunc {
 	return InstrumentHandlerFuncWithOpts(
 		SummaryOpts{
@@ -73,13 +195,13 @@ func InstrumentHandlerFunc(handlerName string, handlerFunc func(http.ResponseWri
 	)
 }
 
-// InstrumentHandlerWithOpts works like InstrumentHandler but provides more
-// flexibility (at the cost of a more complex call syntax). As
-// InstrumentHandler, this function registers four metric collectors, but it
-// uses the provided SummaryOpts to create them. However, the fields "Name" and
-// "Help" in the SummaryOpts are ignored. "Name" is replaced by
-// "requests_total", "request_duration_microseconds", "request_size_bytes", and
-// "response_size_bytes", respectively. "Help" is replaced by an appropriate
+// InstrumentHandlerWithOpts works like InstrumentHandler (and shares the same
+// issues) but provides more flexibility (at the cost of a more complex call
+// syntax). As InstrumentHandler, this function registers four metric
+// collectors, but it uses the provided SummaryOpts to create them. However, the
+// fields "Name" and "Help" in the SummaryOpts are ignored. "Name" is replaced
+// by "requests_total", "request_duration_microseconds", "request_size_bytes",
+// and "response_size_bytes", respectively. "Help" is replaced by an appropriate
 // help string. The names of the variable labels of the http_requests_total
 // CounterVec are "method" (get, post, etc.), and "code" (HTTP status code).
 //
@@ -98,13 +220,20 @@ func InstrumentHandlerFunc(handlerName string, handlerFunc func(http.ResponseWri
 // cannot use SummaryOpts. Instead, a CounterOpts struct is created internally,
 // and all its fields are set to the equally named fields in the provided
 // SummaryOpts.
+//
+// Deprecated: InstrumentHandlerWithOpts is deprecated for the same reasons as
+// InstrumentHandler is.
 func InstrumentHandlerWithOpts(opts SummaryOpts, handler http.Handler) http.HandlerFunc {
 	return InstrumentHandlerFuncWithOpts(opts, handler.ServeHTTP)
 }
 
-// InstrumentHandlerFuncWithOpts works like InstrumentHandlerFunc but provides
-// more flexibility (at the cost of a more complex call syntax). See
-// InstrumentHandlerWithOpts for details how the provided SummaryOpts are used.
+// InstrumentHandlerFuncWithOpts works like InstrumentHandlerFunc (and shares
+// the same issues) but provides more flexibility (at the cost of a more complex
+// call syntax). See InstrumentHandlerWithOpts for details how the provided
+// SummaryOpts are used.
+//
+// Deprecated: InstrumentHandlerFuncWithOpts is deprecated for the same reasons
+// as InstrumentHandler is.
 func InstrumentHandlerFuncWithOpts(opts SummaryOpts, handlerFunc func(http.ResponseWriter, *http.Request)) http.HandlerFunc {
 	reqCnt := NewCounterVec(
 		CounterOpts{

vendor/github.com/prometheus/client_golang/prometheus/metric.go

@@ -22,10 +22,8 @@ import (
 const separatorByte byte = 255
 
 // A Metric models a single sample value with its meta data being exported to
-// Prometheus. Implementers of Metric in this package inclued Gauge, Counter,
-// Untyped, and Summary. Users can implement their own Metric types, but that
-// should be rarely needed. See the example for SelfCollector, which is also an
-// example for a user-implemented Metric.
+// Prometheus. Implementations of Metric in this package are Gauge, Counter,
+// Histogram, Summary, and Untyped.
 type Metric interface {
 	// Desc returns the descriptor for the Metric. This method idempotently
 	// returns the same descriptor throughout the lifetime of the
@@ -36,21 +34,23 @@ type Metric interface {
 	// Write encodes the Metric into a "Metric" Protocol Buffer data
 	// transmission object.
 	//
-	// Implementers of custom Metric types must observe concurrency safety
-	// as reads of this metric may occur at any time, and any blocking
-	// occurs at the expense of total performance of rendering all
-	// registered metrics. Ideally Metric implementations should support
-	// concurrent readers.
+	// Metric implementations must observe concurrency safety as reads of
+	// this metric may occur at any time, and any blocking occurs at the
+	// expense of total performance of rendering all registered
+	// metrics. Ideally, Metric implementations should support concurrent
+	// readers.
 	//
-	// The Prometheus client library attempts to minimize memory allocations
-	// and will provide a pre-existing reset dto.Metric pointer. Prometheus
-	// may recycle the dto.Metric proto message, so Metric implementations
-	// should just populate the provided dto.Metric and then should not keep
-	// any reference to it.
-	//
-	// While populating dto.Metric, labels must be sorted lexicographically.
-	// (Implementers may find LabelPairSorter useful for that.)
+	// While populating dto.Metric, it is the responsibility of the
+	// implementation to ensure validity of the Metric protobuf (like valid
+	// UTF-8 strings or syntactically valid metric and label names). It is
+	// recommended to sort labels lexicographically. (Implementers may find
+	// LabelPairSorter useful for that.) Callers of Write should still make
+	// sure of sorting if they depend on it.
 	Write(*dto.Metric) error
+	// TODO(beorn7): The original rationale of passing in a pre-allocated
+	// dto.Metric protobuf to save allocations has disappeared. The
+	// signature of this method should be changed to "Write() (*dto.Metric,
+	// error)".
 }
 
 // Opts bundles the options for creating most Metric types. Each metric

vendor/github.com/prometheus/client_golang/prometheus/process_collector.go

@@ -28,7 +28,7 @@ type processCollector struct {
 // NewProcessCollector returns a collector which exports the current state of
 // process metrics including cpu, memory and file descriptor usage as well as
 // the process start time for the given process id under the given namespace.
-func NewProcessCollector(pid int, namespace string) *processCollector {
+func NewProcessCollector(pid int, namespace string) Collector {
 	return NewProcessCollectorPIDFn(
 		func() (int, error) { return pid, nil },
 		namespace,
@@ -43,7 +43,7 @@ func NewProcessCollector(pid int, namespace string) *processCollector {
 func NewProcessCollectorPIDFn(
 	pidFn func() (int, error),
 	namespace string,
-) *processCollector {
+) Collector {
 	c := processCollector{
 		pidFn:     pidFn,
 		collectFn: func(chan<- Metric) {},

vendor/github.com/prometheus/client_golang/prometheus/push.go

@@ -1,65 +0,0 @@
-// Copyright 2015 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
-
-// Push triggers a metric collection by the default registry and pushes all
-// collected metrics to the Pushgateway specified by url. See the Pushgateway
-// documentation for detailed implications of the job and instance
-// parameter. instance can be left empty. You can use just host:port or ip:port
-// as url, in which case 'http://' is added automatically. You can also include
-// the schema in the URL. However, do not include the '/metrics/jobs/...' part.
-//
-// Note that all previously pushed metrics with the same job and instance will
-// be replaced with the metrics pushed by this call. (It uses HTTP method 'PUT'
-// to push to the Pushgateway.)
-func Push(job, instance, url string) error {
-	return defRegistry.Push(job, instance, url, "PUT")
-}
-
-// PushAdd works like Push, but only previously pushed metrics with the same
-// name (and the same job and instance) will be replaced. (It uses HTTP method
-// 'POST' to push to the Pushgateway.)
-func PushAdd(job, instance, url string) error {
-	return defRegistry.Push(job, instance, url, "POST")
-}
-
-// PushCollectors works like Push, but it does not collect from the default
-// registry. Instead, it collects from the provided collectors. It is a
-// convenient way to push only a few metrics.
-func PushCollectors(job, instance, url string, collectors ...Collector) error {
-	return pushCollectors(job, instance, url, "PUT", collectors...)
-}
-
-// PushAddCollectors works like PushAdd, but it does not collect from the
-// default registry. Instead, it collects from the provided collectors. It is a
-// convenient way to push only a few metrics.
-func PushAddCollectors(job, instance, url string, collectors ...Collector) error {
-	return pushCollectors(job, instance, url, "POST", collectors...)
-}
-
-func pushCollectors(job, instance, url, method string, collectors ...Collector) error {
-	r := newRegistry()
-	for _, collector := range collectors {
-		if _, err := r.Register(collector); err != nil {
-			return err
-		}
-	}
-	return r.Push(job, instance, url, method)
-}

vendor/github.com/prometheus/client_golang/prometheus/summary.go

@@ -53,8 +53,8 @@ type Summary interface {
 	Observe(float64)
 }
 
-var (
 // DefObjectives are the default Summary quantile values.
+var (
 	DefObjectives = map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001}
 
 	errQuantileLabelNotAllowed = fmt.Errorf(
@@ -139,11 +139,11 @@ type SummaryOpts struct {
 	BufCap uint32
 }
 
-// TODO: Great fuck-up with the sliding-window decay algorithm... The Merge
-// method of perk/quantile is actually not working as advertised - and it might
-// be unfixable, as the underlying algorithm is apparently not capable of
-// merging summaries in the first place. To avoid using Merge, we are currently
-// adding observations to _each_ age bucket, i.e. the effort to add a sample is
+// Great fuck-up with the sliding-window decay algorithm... The Merge method of
+// perk/quantile is actually not working as advertised - and it might be
+// unfixable, as the underlying algorithm is apparently not capable of merging
+// summaries in the first place. To avoid using Merge, we are currently adding
+// observations to _each_ age bucket, i.e. the effort to add a sample is
 // essentially multiplied by the number of age buckets. When rotating age
 // buckets, we empty the previous head stream. On scrape time, we simply take
 // the quantiles from the head stream (no merging required). Result: More effort
@@ -227,12 +227,12 @@ func newSummary(desc *Desc, opts SummaryOpts, labelValues ...string) Summary {
 	}
 	sort.Float64s(s.sortedObjectives)
 
-	s.Init(s) // Init self-collection.
+	s.init(s) // Init self-collection.
 	return s
 }
 
 type summary struct {
-	SelfCollector
+	selfCollector
 
 	bufMtx sync.Mutex // Protects hotBuf and hotBufExpTime.
 	mtx    sync.Mutex // Protects every other moving part.
@@ -390,7 +390,7 @@ func (s quantSort) Less(i, j int) bool {
 // (e.g. HTTP request latencies, partitioned by status code and method). Create
 // instances with NewSummaryVec.
 type SummaryVec struct {
-	MetricVec
+	*MetricVec
 }
 
 // NewSummaryVec creates a new SummaryVec based on the provided SummaryOpts and
@@ -404,13 +404,9 @@ func NewSummaryVec(opts SummaryOpts, labelNames []string) *SummaryVec {
 		opts.ConstLabels,
 	)
 	return &SummaryVec{
-		MetricVec: MetricVec{
-			children: map[uint64]Metric{},
-			desc:     desc,
-			newMetric: func(lvs ...string) Metric {
+		MetricVec: newMetricVec(desc, func(lvs ...string) Metric {
 			return newSummary(desc, opts, lvs...)
-			},
-		},
+		}),
 	}
 }
 

vendor/github.com/prometheus/client_golang/prometheus/untyped.go

@@ -56,7 +56,7 @@ func NewUntyped(opts UntypedOpts) Untyped {
 // labels. This is used if you want to count the same thing partitioned by
 // various dimensions. Create instances with NewUntypedVec.
 type UntypedVec struct {
-	MetricVec
+	*MetricVec
 }
 
 // NewUntypedVec creates a new UntypedVec based on the provided UntypedOpts and
@@ -70,13 +70,9 @@ func NewUntypedVec(opts UntypedOpts, labelNames []string) *UntypedVec {
 		opts.ConstLabels,
 	)
 	return &UntypedVec{
-		MetricVec: MetricVec{
-			children: map[uint64]Metric{},
-			desc:     desc,
-			newMetric: func(lvs ...string) Metric {
+		MetricVec: newMetricVec(desc, func(lvs ...string) Metric {
 			return newValue(desc, UntypedValue, 0, lvs...)
-			},
-		},
+		}),
 	}
 }
 

vendor/github.com/prometheus/client_golang/prometheus/value.go

@@ -48,7 +48,7 @@ type value struct {
 	// operations.  http://golang.org/pkg/sync/atomic/#pkg-note-BUG
 	valBits uint64
 
-	SelfCollector
+	selfCollector
 
 	desc       *Desc
 	valType    ValueType
@@ -68,7 +68,7 @@ func newValue(desc *Desc, valueType ValueType, val float64, labelValues ...strin
 		valBits:    math.Float64bits(val),
 		labelPairs: makeLabelPairs(desc, labelValues),
 	}
-	result.Init(result)
+	result.init(result)
 	return result
 }
 
@@ -113,7 +113,7 @@ func (v *value) Write(out *dto.Metric) error {
 // library to back the implementations of CounterFunc, GaugeFunc, and
 // UntypedFunc.
 type valueFunc struct {
-	SelfCollector
+	selfCollector
 
 	desc       *Desc
 	valType    ValueType
@@ -134,7 +134,7 @@ func newValueFunc(desc *Desc, valueType ValueType, function func() float64) *val
 		function:   function,
 		labelPairs: makeLabelPairs(desc, nil),
 	}
-	result.Init(result)
+	result.init(result)
 	return result
 }
 

vendor/github.com/prometheus/client_golang/prometheus/vec.go

@@ -16,6 +16,8 @@ package prometheus
 import (
 	"fmt"
 	"sync"
+
+	"github.com/prometheus/common/model"
 )
 
 // MetricVec is a Collector to bundle metrics of the same name that
@@ -25,10 +27,31 @@ import (
 // provided in this package.
 type MetricVec struct {
 	mtx      sync.RWMutex // Protects the children.
-	children map[uint64]Metric
+	children map[uint64][]metricWithLabelValues
 	desc     *Desc
 
 	newMetric   func(labelValues ...string) Metric
+	hashAdd     func(h uint64, s string) uint64 // replace hash function for testing collision handling
+	hashAddByte func(h uint64, b byte) uint64
+}
+
+// newMetricVec returns an initialized MetricVec. The concrete value is
+// returned for embedding into another struct.
+func newMetricVec(desc *Desc, newMetric func(lvs ...string) Metric) *MetricVec {
+	return &MetricVec{
+		children:    map[uint64][]metricWithLabelValues{},
+		desc:        desc,
+		newMetric:   newMetric,
+		hashAdd:     hashAdd,
+		hashAddByte: hashAddByte,
+	}
+}
+
+// metricWithLabelValues provides the metric and its label values for
+// disambiguation on hash collision.
+type metricWithLabelValues struct {
+	values []string
+	metric Metric
 }
 
 // Describe implements Collector. The length of the returned slice
@@ -42,8 +65,10 @@ func (m *MetricVec) Collect(ch chan<- Metric) {
 	m.mtx.RLock()
 	defer m.mtx.RUnlock()
 
-	for _, metric := range m.children {
-		ch <- metric
+	for _, metrics := range m.children {
+		for _, metric := range metrics {
+			ch <- metric.metric
+		}
 	}
 }
 
@@ -77,16 +102,7 @@ func (m *MetricVec) GetMetricWithLabelValues(lvs ...string) (Metric, error) {
 		return nil, err
 	}
 
-	m.mtx.RLock()
-	metric, ok := m.children[h]
-	m.mtx.RUnlock()
-	if ok {
-		return metric, nil
-	}
-
-	m.mtx.Lock()
-	defer m.mtx.Unlock()
-	return m.getOrCreateMetric(h, lvs...), nil
+	return m.getOrCreateMetricWithLabelValues(h, lvs), nil
 }
 
 // GetMetricWith returns the Metric for the given Labels map (the label names
@@ -107,20 +123,7 @@ func (m *MetricVec) GetMetricWith(labels Labels) (Metric, error) {
 		return nil, err
 	}
 
-	m.mtx.RLock()
-	metric, ok := m.children[h]
-	m.mtx.RUnlock()
-	if ok {
-		return metric, nil
-	}
-
-	lvs := make([]string, len(labels))
-	for i, label := range m.desc.variableLabels {
-		lvs[i] = labels[label]
-	}
-	m.mtx.Lock()
-	defer m.mtx.Unlock()
-	return m.getOrCreateMetric(h, lvs...), nil
+	return m.getOrCreateMetricWithLabels(h, labels), nil
 }
 
 // WithLabelValues works as GetMetricWithLabelValues, but panics if an error
@@ -168,11 +171,7 @@ func (m *MetricVec) DeleteLabelValues(lvs ...string) bool {
 	if err != nil {
 		return false
 	}
-	if _, ok := m.children[h]; !ok {
-		return false
-	}
-	delete(m.children, h)
-	return true
+	return m.deleteByHashWithLabelValues(h, lvs)
 }
 
 // Delete deletes the metric where the variable labels are the same as those
@@ -193,10 +192,50 @@ func (m *MetricVec) Delete(labels Labels) bool {
 	if err != nil {
 		return false
 	}
-	if _, ok := m.children[h]; !ok {
+
+	return m.deleteByHashWithLabels(h, labels)
+}
+
+// deleteByHashWithLabelValues removes the metric from the hash bucket h. If
+// there are multiple matches in the bucket, use lvs to select a metric and
+// remove only that metric.
+func (m *MetricVec) deleteByHashWithLabelValues(h uint64, lvs []string) bool {
+	metrics, ok := m.children[h]
+	if !ok {
 		return false
 	}
+
+	i := m.findMetricWithLabelValues(metrics, lvs)
+	if i >= len(metrics) {
+		return false
+	}
+
+	if len(metrics) > 1 {
+		m.children[h] = append(metrics[:i], metrics[i+1:]...)
+	} else {
 		delete(m.children, h)
+	}
+	return true
+}
+
+// deleteByHashWithLabels removes the metric from the hash bucket h. If there
+// are multiple matches in the bucket, use lvs to select a metric and remove
+// only that metric.
+func (m *MetricVec) deleteByHashWithLabels(h uint64, labels Labels) bool {
+	metrics, ok := m.children[h]
+	if !ok {
+		return false
+	}
+	i := m.findMetricWithLabels(metrics, labels)
+	if i >= len(metrics) {
+		return false
+	}
+
+	if len(metrics) > 1 {
+		m.children[h] = append(metrics[:i], metrics[i+1:]...)
+	} else {
+		delete(m.children, h)
+	}
 	return true
 }
 
@@ -216,7 +255,8 @@ func (m *MetricVec) hashLabelValues(vals []string) (uint64, error) {
 	}
 	h := hashNew()
 	for _, val := range vals {
-		h = hashAdd(h, val)
+		h = m.hashAdd(h, val)
+		h = m.hashAddByte(h, model.SeparatorByte)
 	}
 	return h, nil
 }
@@ -231,19 +271,134 @@ func (m *MetricVec) hashLabels(labels Labels) (uint64, error) {
 		if !ok {
 			return 0, fmt.Errorf("label name %q missing in label map", label)
 		}
-		h = hashAdd(h, val)
+		h = m.hashAdd(h, val)
+		h = m.hashAddByte(h, model.SeparatorByte)
 	}
 	return h, nil
 }
 
-func (m *MetricVec) getOrCreateMetric(hash uint64, labelValues ...string) Metric {
-	metric, ok := m.children[hash]
+// getOrCreateMetricWithLabelValues retrieves the metric by hash and label value
+// or creates it and returns the new one.
+//
+// This function holds the mutex.
+func (m *MetricVec) getOrCreateMetricWithLabelValues(hash uint64, lvs []string) Metric {
+	m.mtx.RLock()
+	metric, ok := m.getMetricWithLabelValues(hash, lvs)
+	m.mtx.RUnlock()
+	if ok {
+		return metric
+	}
+
+	m.mtx.Lock()
+	defer m.mtx.Unlock()
+	metric, ok = m.getMetricWithLabelValues(hash, lvs)
 	if !ok {
-		// Copy labelValues. Otherwise, they would be allocated even if we don't go
-		// down this code path.
-		copiedLabelValues := append(make([]string, 0, len(labelValues)), labelValues...)
-		metric = m.newMetric(copiedLabelValues...)
-		m.children[hash] = metric
+		// Copy to avoid allocation in case wo don't go down this code path.
+		copiedLVs := make([]string, len(lvs))
+		copy(copiedLVs, lvs)
+		metric = m.newMetric(copiedLVs...)
+		m.children[hash] = append(m.children[hash], metricWithLabelValues{values: copiedLVs, metric: metric})
 	}
 	return metric
 }
+
+// getOrCreateMetricWithLabelValues retrieves the metric by hash and label value
+// or creates it and returns the new one.
+//
+// This function holds the mutex.
+func (m *MetricVec) getOrCreateMetricWithLabels(hash uint64, labels Labels) Metric {
+	m.mtx.RLock()
+	metric, ok := m.getMetricWithLabels(hash, labels)
+	m.mtx.RUnlock()
+	if ok {
+		return metric
+	}
+
+	m.mtx.Lock()
+	defer m.mtx.Unlock()
+	metric, ok = m.getMetricWithLabels(hash, labels)
+	if !ok {
+		lvs := m.extractLabelValues(labels)
+		metric = m.newMetric(lvs...)
+		m.children[hash] = append(m.children[hash], metricWithLabelValues{values: lvs, metric: metric})
+	}
+	return metric
+}
+
+// getMetricWithLabelValues gets a metric while handling possible collisions in
+// the hash space. Must be called while holding read mutex.
+func (m *MetricVec) getMetricWithLabelValues(h uint64, lvs []string) (Metric, bool) {
+	metrics, ok := m.children[h]
+	if ok {
+		if i := m.findMetricWithLabelValues(metrics, lvs); i < len(metrics) {
+			return metrics[i].metric, true
+		}
+	}
+	return nil, false
+}
+
+// getMetricWithLabels gets a metric while handling possible collisions in
+// the hash space. Must be called while holding read mutex.
+func (m *MetricVec) getMetricWithLabels(h uint64, labels Labels) (Metric, bool) {
+	metrics, ok := m.children[h]
+	if ok {
+		if i := m.findMetricWithLabels(metrics, labels); i < len(metrics) {
+			return metrics[i].metric, true
+		}
+	}
+	return nil, false
+}
+
+// findMetricWithLabelValues returns the index of the matching metric or
+// len(metrics) if not found.
+func (m *MetricVec) findMetricWithLabelValues(metrics []metricWithLabelValues, lvs []string) int {
+	for i, metric := range metrics {
+		if m.matchLabelValues(metric.values, lvs) {
+			return i
+		}
+	}
+	return len(metrics)
+}
+
+// findMetricWithLabels returns the index of the matching metric or len(metrics)
+// if not found.
+func (m *MetricVec) findMetricWithLabels(metrics []metricWithLabelValues, labels Labels) int {
+	for i, metric := range metrics {
+		if m.matchLabels(metric.values, labels) {
+			return i
+		}
+	}
+	return len(metrics)
+}
+
+func (m *MetricVec) matchLabelValues(values []string, lvs []string) bool {
+	if len(values) != len(lvs) {
+		return false
+	}
+	for i, v := range values {
+		if v != lvs[i] {
+			return false
+		}
+	}
+	return true
+}
+
+func (m *MetricVec) matchLabels(values []string, labels Labels) bool {
+	if len(labels) != len(values) {
+		return false
+	}
+	for i, k := range m.desc.variableLabels {
+		if values[i] != labels[k] {
+			return false
+		}
+	}
+	return true
+}
+
+func (m *MetricVec) extractLabelValues(labels Labels) []string {
+	labelValues := make([]string, len(labels))
+	for i, k := range m.desc.variableLabels {
+		labelValues[i] = labels[k]
+	}
+	return labelValues
+}

vendor/vendor.json

@@ -50,9 +50,10 @@
 			"revisionTime": "2016-04-24T11:30:07Z"
 		},
 		{
+			"checksumSHA1": "KkB+77Ziom7N6RzSbyUwYGrmDeU=",
 			"path": "github.com/prometheus/client_golang/prometheus",
-			"revision": "67994f177195311c3ea3d4407ed0175e34a4256f",
-			"revisionTime": "2015-11-27T19:24:33+01:00"
+			"revision": "c5b7fccd204277076155f10851dad72b76a49317",
+			"revisionTime": "2016-08-17T15:48:24Z"
 		},
 		{
 			"path": "github.com/prometheus/client_model/go",