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Merge pull request #214 from prometheus/beorn7/registry 

Create a public registry interface and separate out HTTP exposition
This commit is contained in:
Björn Rabenstein 2016-08-15 13:47:46 +02:00 committed by GitHub
parent 52437c81da a6321dd0b1
commit 66058aac3a
29 changed files with 1970 additions and 1133 deletions
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5
NOTICE
View File

@ -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

54
prometheus/README.md
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@ -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).

52
prometheus/collector.go
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@ -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
}

7
prometheus/counter.go
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@ -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
}
@ -102,7 +105,7 @@ func NewCounterVec(opts CounterOpts, labelNames []string) *CounterVec {
valType: CounterValue,
labelPairs: makeLabelPairs(desc, lvs),
}}
result.Init(result) // Init self-collection.
result.init(result) // Init self-collection.
return result
},
},

13
prometheus/desc.go
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@ -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 (

172
prometheus/doc.go
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@ -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 (
@ -37,75 +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 later with a label attached to turn it into a (one-dimensional) vector.
//
// Two more advanced metric types are the Summary and Histogram. A more
// thorough description of metric types can be found in the prometheus docs:
// Metrics
//
// 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/
//
// 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
// 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

94
prometheus/example_clustermanager_test.go
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@ -13,11 +13,7 @@
package prometheus_test
import (
"sync"
"github.com/prometheus/client_golang/prometheus"
)
import "github.com/prometheus/client_golang/prometheus"
// ClusterManager is an example for a system that might have been built without
// Prometheus in mind. It models a central manager of jobs running in a
@ -30,9 +26,8 @@ import (
// with Prometheus.
type ClusterManager struct {
Zone string
OOMCount *prometheus.CounterVec
RAMUsage *prometheus.GaugeVec
mtx sync.Mutex // Protects OOMCount and RAMUsage.
OOMCountDesc *prometheus.Desc
RAMUsageDesc *prometheus.Desc
// ... many more fields
}
@ -55,76 +50,69 @@ func (c *ClusterManager) ReallyExpensiveAssessmentOfTheSystemState() (
return
}
// Describe faces the interesting challenge that the two metric vectors that are
// used in this example are already Collectors themselves. However, thanks to
// the use of channels, it is really easy to "chain" Collectors. Here we simply
// call the Describe methods of the two metric vectors.
// Describe simply sends the two Descs in the struct to the channel.
func (c *ClusterManager) Describe(ch chan<- *prometheus.Desc) {
c.OOMCount.Describe(ch)
c.RAMUsage.Describe(ch)
ch <- c.OOMCountDesc
ch <- c.RAMUsageDesc
}
// Collect first triggers the ReallyExpensiveAssessmentOfTheSystemState. Then it
// sets the retrieved values in the two metric vectors and then sends all their
// metrics to the channel (again using a chaining technique as in the Describe
// method). Since Collect could be called multiple times concurrently, that part
// is protected by a mutex.
// creates constant metrics for each host on the fly based on the returned data.
//
// Note that Collect could be called concurrently, so we depend on
// ReallyExpensiveAssessmentOfTheSystemState to be concurrency-safe.
func (c *ClusterManager) Collect(ch chan<- prometheus.Metric) {
oomCountByHost, ramUsageByHost := c.ReallyExpensiveAssessmentOfTheSystemState()
c.mtx.Lock()
defer c.mtx.Unlock()
for host, oomCount := range oomCountByHost {
c.OOMCount.WithLabelValues(host).Set(float64(oomCount))
ch <- prometheus.MustNewConstMetric(
c.OOMCountDesc,
prometheus.CounterValue,
float64(oomCount),
host,
)
}
for host, ramUsage := range ramUsageByHost {
c.RAMUsage.WithLabelValues(host).Set(ramUsage)
ch <- prometheus.MustNewConstMetric(
c.RAMUsageDesc,
prometheus.GaugeValue,
ramUsage,
host,
)
}
c.OOMCount.Collect(ch)
c.RAMUsage.Collect(ch)
// All metrics in OOMCount and RAMUsage are sent to the channel now. We
// can safely reset the two metric vectors now, so that we can start
// fresh in the next Collect cycle. (Imagine a host disappears from the
// cluster. If we did not reset here, its Metric would stay in the
// metric vectors forever.)
c.OOMCount.Reset()
c.RAMUsage.Reset()
}
// NewClusterManager creates the two metric vectors OOMCount and RAMUsage. Note
// NewClusterManager creates the two Descs OOMCountDesc and RAMUsageDesc. Note
// that the zone is set as a ConstLabel. (It's different in each instance of the
// ClusterManager, but constant over the lifetime of an instance.) The reported
// values are partitioned by host, which is therefore a variable label.
// ClusterManager, but constant over the lifetime of an instance.) Then there is
// a variable label "host", since we want to partition the collected metrics by
// host. Since all Descs created in this way are consistent across instances,
// with a guaranteed distinction by the "zone" label, we can register different
// ClusterManager instances with the same registry.
func NewClusterManager(zone string) *ClusterManager {
return &ClusterManager{
Zone: zone,
OOMCount: prometheus.NewCounterVec(
prometheus.CounterOpts{
Subsystem: "clustermanager",
Name: "oom_count",
Help: "number of OOM crashes",
ConstLabels: prometheus.Labels{"zone": zone},
},
OOMCountDesc: prometheus.NewDesc(
"clustermanager_oom_crashes_total",
"Number of OOM crashes.",
[]string{"host"},
prometheus.Labels{"zone": zone},
),
RAMUsage: prometheus.NewGaugeVec(
prometheus.GaugeOpts{
Subsystem: "clustermanager",
Name: "ram_usage_bytes",
Help: "RAM usage as reported to the cluster manager",
ConstLabels: prometheus.Labels{"zone": zone},
},
RAMUsageDesc: prometheus.NewDesc(
"clustermanager_ram_usage_bytes",
"RAM usage as reported to the cluster manager.",
[]string{"host"},
prometheus.Labels{"zone": zone},
),
}
}
func ExampleCollector_clustermanager() {
func ExampleCollector() {
workerDB := NewClusterManager("db")
workerCA := NewClusterManager("ca")
prometheus.MustRegister(workerDB)
prometheus.MustRegister(workerCA)
// Since we are dealing with custom Collector implementations, it might
// be a good idea to enable the collect checks in the registry.
prometheus.EnableCollectChecks(true)
// be a good idea to try it out with a pedantic registry.
reg := prometheus.NewPedanticRegistry()
reg.MustRegister(workerDB)
reg.MustRegister(workerCA)
}

87
prometheus/example_memstats_test.go
View File

@ -1,87 +0,0 @@
// 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_test
import (
"runtime"
"github.com/prometheus/client_golang/prometheus"
)
var (
allocDesc = prometheus.NewDesc(
prometheus.BuildFQName("", "memstats", "alloc_bytes"),
"bytes allocated and still in use",
nil, nil,
)
totalAllocDesc = prometheus.NewDesc(
prometheus.BuildFQName("", "memstats", "total_alloc_bytes"),
"bytes allocated (even if freed)",
nil, nil,
)
numGCDesc = prometheus.NewDesc(
prometheus.BuildFQName("", "memstats", "num_gc_total"),
"number of GCs run",
nil, nil,
)
)
// MemStatsCollector is an example for a custom Collector that solves the
// problem of feeding into multiple metrics at the same time. The
// runtime.ReadMemStats should happen only once, and then the results need to be
// fed into a number of separate Metrics. In this example, only a few of the
// values reported by ReadMemStats are used. For each, there is a Desc provided
// as a var, so the MemStatsCollector itself needs nothing else in the
// struct. Only the methods need to be implemented.
type MemStatsCollector struct{}
// Describe just sends the three Desc objects for the Metrics we intend to
// collect.
func (_ MemStatsCollector) Describe(ch chan<- *prometheus.Desc) {
ch <- allocDesc
ch <- totalAllocDesc
ch <- numGCDesc
}
// Collect does the trick by calling ReadMemStats once and then constructing
// three different Metrics on the fly.
func (_ MemStatsCollector) Collect(ch chan<- prometheus.Metric) {
var ms runtime.MemStats
runtime.ReadMemStats(&ms)
ch <- prometheus.MustNewConstMetric(
allocDesc,
prometheus.GaugeValue,
float64(ms.Alloc),
)
ch <- prometheus.MustNewConstMetric(
totalAllocDesc,
prometheus.GaugeValue,
float64(ms.TotalAlloc),
)
ch <- prometheus.MustNewConstMetric(
numGCDesc,
prometheus.CounterValue,
float64(ms.NumGC),
)
// To avoid new allocations on each collection, you could also keep
// metric objects around and return the same objects each time, just
// with new values set.
}
func ExampleCollector_memstats() {
prometheus.MustRegister(&MemStatsCollector{})
// Since we are dealing with custom Collector implementations, it might
// be a good idea to enable the collect checks in the registry.
prometheus.EnableCollectChecks(true)
}

69
prometheus/example_selfcollector_test.go
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@ -1,69 +0,0 @@
// 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_test
import (
"runtime"
"github.com/golang/protobuf/proto"
dto "github.com/prometheus/client_model/go"
"github.com/prometheus/client_golang/prometheus"
)
func NewCallbackMetric(desc *prometheus.Desc, callback func() float64) *CallbackMetric {
result := &CallbackMetric{desc: desc, callback: callback}
result.Init(result) // Initialize the SelfCollector.
return result
}
// TODO: Come up with a better example.
// CallbackMetric is an example for a user-defined Metric that exports the
// result of a function call as a metric of type "untyped" without any
// labels. It uses SelfCollector to turn the Metric into a Collector so that it
// can be registered with Prometheus.
//
// Note that this example is pretty much academic as the prometheus package
// already provides an UntypedFunc type.
type CallbackMetric struct {
prometheus.SelfCollector
desc *prometheus.Desc
callback func() float64
}
func (cm *CallbackMetric) Desc() *prometheus.Desc {
return cm.desc
}
func (cm *CallbackMetric) Write(m *dto.Metric) error {
m.Untyped = &dto.Untyped{Value: proto.Float64(cm.callback())}
return nil
}
func ExampleSelfCollector() {
m := NewCallbackMetric(
prometheus.NewDesc(
"runtime_goroutines_count",
"Total number of goroutines that currently exist.",
nil, nil, // No labels, these must be nil.
),
func() float64 {
return float64(runtime.NumGoroutine())
},
)
prometheus.MustRegister(m)
}

177
prometheus/examples_test.go
View File

@ -14,15 +14,16 @@
package prometheus_test
import (
"bytes"
"fmt"
"math"
"net/http"
"os"
"runtime"
"sort"
"time"
"strings"
dto "github.com/prometheus/client_model/go"
"github.com/prometheus/common/expfmt"
"github.com/golang/protobuf/proto"
@ -387,26 +388,23 @@ func ExampleSummaryVec() {
temps.WithLabelValues("leiopelma-hochstetteri")
// Just for demonstration, let's check the state of the summary vector
// by (ab)using its Collect method and the Write method of its elements
// (which is usually only used by Prometheus internally - code like the
// following will never appear in your own code).
metricChan := make(chan prometheus.Metric)
go func() {
defer close(metricChan)
temps.Collect(metricChan)
}()
// by registering it with a custom registry and then let it collect the
// metrics.
reg := prometheus.NewRegistry()
reg.MustRegister(temps)
metricStrings := []string{}
for metric := range metricChan {
dtoMetric := &dto.Metric{}
metric.Write(dtoMetric)
metricStrings = append(metricStrings, proto.MarshalTextString(dtoMetric))
metricFamilies, err := reg.Gather()
if err != nil || len(metricFamilies) != 1 {
panic("unexpected behavior of custom test registry")
}
sort.Strings(metricStrings) // For reproducible print order.
fmt.Println(metricStrings)
fmt.Println(proto.MarshalTextString(metricFamilies[0]))
// Output:
// [label: <
// name: "pond_temperature_celsius"
// help: "The temperature of the frog pond."
// type: SUMMARY
// metric: <
// label: <
// name: "species"
// value: "leiopelma-hochstetteri"
// >
@ -426,6 +424,8 @@ func ExampleSummaryVec() {
// value: nan
// >
// >
// >
// metric: <
// label: <
// name: "species"
// value: "lithobates-catesbeianus"
@ -446,6 +446,8 @@ func ExampleSummaryVec() {
// value: 41.9
// >
// >
// >
// metric: <
// label: <
// name: "species"
// value: "litoria-caerulea"
@ -466,10 +468,10 @@ func ExampleSummaryVec() {
// value: 41.9
// >
// >
// ]
// >
}
func ExampleConstSummary() {
func ExampleNewConstSummary() {
desc := prometheus.NewDesc(
"http_request_duration_seconds",
"A summary of the HTTP request durations.",
@ -565,7 +567,7 @@ func ExampleHistogram() {
// >
}
func ExampleConstHistogram() {
func ExampleNewConstHistogram() {
desc := prometheus.NewDesc(
"http_request_duration_seconds",
"A histogram of the HTTP request durations.",
@ -623,18 +625,127 @@ func ExampleConstHistogram() {
// >
}
func ExamplePushCollectors() {
hostname, _ := os.Hostname()
completionTime := prometheus.NewGauge(prometheus.GaugeOpts{
Name: "db_backup_last_completion_time",
Help: "The timestamp of the last succesful completion of a DB backup.",
func ExampleAlreadyRegisteredError() {
reqCounter := prometheus.NewCounter(prometheus.CounterOpts{
Name: "requests_total",
Help: "The total number of requests served.",
})
completionTime.Set(float64(time.Now().Unix()))
if err := prometheus.PushCollectors(
"db_backup", hostname,
"http://pushgateway:9091",
completionTime,
); err != nil {
fmt.Println("Could not push completion time to Pushgateway:", err)
if err := prometheus.Register(reqCounter); err != nil {
if are, ok := err.(prometheus.AlreadyRegisteredError); ok {
// A counter for that metric has been registered before.
// Use the old counter from now on.
reqCounter = are.ExistingCollector.(prometheus.Counter)
} else {
// Something else went wrong!
panic(err)
}
}
}
func ExampleGatherers() {
reg := prometheus.NewRegistry()
temp := prometheus.NewGaugeVec(
prometheus.GaugeOpts{
Name: "temperature_kelvin",
Help: "Temperature in Kelvin.",
},
[]string{"location"},
)
reg.MustRegister(temp)
temp.WithLabelValues("outside").Set(273.14)
temp.WithLabelValues("inside").Set(298.44)
var parser expfmt.TextParser
text := `
# TYPE humidity_percent gauge
# HELP humidity_percent Humidity in %.
humidity_percent{location="outside"} 45.4
humidity_percent{location="inside"} 33.2
# TYPE temperature_kelvin gauge
# HELP temperature_kelvin Temperature in Kelvin.
temperature_kelvin{location="somewhere else"} 4.5
`
parseText := func() ([]*dto.MetricFamily, error) {
parsed, err := parser.TextToMetricFamilies(strings.NewReader(text))
if err != nil {
return nil, err
}
var result []*dto.MetricFamily
for _, mf := range parsed {
result = append(result, mf)
}
return result, nil
}
gatherers := prometheus.Gatherers{
reg,
prometheus.GathererFunc(parseText),
}
gathering, err := gatherers.Gather()
if err != nil {
fmt.Println(err)
}
out := &bytes.Buffer{}
for _, mf := range gathering {
if _, err := expfmt.MetricFamilyToText(out, mf); err != nil {
panic(err)
}
}
fmt.Print(out.String())
fmt.Println("----------")
// Note how the temperature_kelvin metric family has been merged from
// different sources. Now try
text = `
# TYPE humidity_percent gauge
# HELP humidity_percent Humidity in %.
humidity_percent{location="outside"} 45.4
humidity_percent{location="inside"} 33.2
# TYPE temperature_kelvin gauge
# HELP temperature_kelvin Temperature in Kelvin.
# Duplicate metric:
temperature_kelvin{location="outside"} 265.3
# Wrong labels:
temperature_kelvin 4.5
`
gathering, err = gatherers.Gather()
if err != nil {
fmt.Println(err)
}
// Note that still as many metrics as possible are returned:
out.Reset()
for _, mf := range gathering {
if _, err := expfmt.MetricFamilyToText(out, mf); err != nil {
panic(err)
}
}
fmt.Print(out.String())
// Output:
// # HELP humidity_percent Humidity in %.
// # TYPE humidity_percent gauge
// humidity_percent{location="inside"} 33.2
// humidity_percent{location="outside"} 45.4
// # HELP temperature_kelvin Temperature in Kelvin.
// # TYPE temperature_kelvin gauge
// temperature_kelvin{location="inside"} 298.44
// temperature_kelvin{location="outside"} 273.14
// temperature_kelvin{location="somewhere else"} 4.5
// ----------
// 2 error(s) occurred:
// * collected metric temperature_kelvin label:<name:"location" value:"outside" > gauge:<value:265.3 > was collected before with the same name and label values
// * collected metric temperature_kelvin gauge:<value:4.5 > has label dimensions inconsistent with previously collected metrics in the same metric family
// # HELP humidity_percent Humidity in %.
// # TYPE humidity_percent gauge
// humidity_percent{location="inside"} 33.2
// humidity_percent{location="outside"} 45.4
// # HELP temperature_kelvin Temperature in Kelvin.
// # TYPE temperature_kelvin gauge
// temperature_kelvin{location="inside"} 298.44
// temperature_kelvin{location="outside"} 273.14
}

32
prometheus/expvar.go → prometheus/expvar_collector.go
View File

@ -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)

0
prometheus/expvar_test.go → prometheus/expvar_collector_test.go
View File

2
prometheus/go_collector.go
View File

@ -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",

12
prometheus/histogram.go
View File

@ -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

115
prometheus/http.go
View File

@ -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 {
@ -58,7 +158,7 @@ func nowSeries(t ...time.Time) nower {
// value. http_requests_total is a metric vector partitioned by HTTP method
// (label name "method") and HTTP status code (label name "code").
//
// Note that InstrumentHandler has several issues:
// Deprecated: InstrumentHandler has several issues:
//
// - It uses Summaries rather than Histograms. Summaries are not useful if
// aggregation across multiple instances is required.
@ -73,8 +173,8 @@ func nowSeries(t ...time.Time) nower {
// performing such writes.
//
// Upcoming versions of this package will provide ways of instrumenting HTTP
// handlers that are more flexible and have fewer issues. Consider this function
// DEPRECATED and prefer direct instrumentation in the meantime.
// 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)
}
@ -82,6 +182,9 @@ func InstrumentHandler(handlerName string, handler http.Handler) http.HandlerFun
// InstrumentHandlerFunc wraps the given function for instrumentation. It
// 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{
@ -117,6 +220,9 @@ 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)
}
@ -125,6 +231,9 @@ func InstrumentHandlerWithOpts(opts SummaryOpts, handler http.Handler) http.Hand
// 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{

34
prometheus/metric.go
View File

@ -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

4
prometheus/process_collector.go
View File

@ -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) {},

34
prometheus/process_collector_test.go
View File

@ -1,13 +1,12 @@
package prometheus
import (
"io/ioutil"
"net/http"
"net/http/httptest"
"bytes"
"os"
"regexp"
"testing"
"github.com/prometheus/common/expfmt"
"github.com/prometheus/procfs"
)
@ -16,22 +15,27 @@ func TestProcessCollector(t *testing.T) {
t.Skipf("skipping TestProcessCollector, procfs not available: %s", err)
}
registry := newRegistry()
registry.Register(NewProcessCollector(os.Getpid(), ""))
registry.Register(NewProcessCollectorPIDFn(
func() (int, error) { return os.Getpid(), nil }, "foobar"))
registry := NewRegistry()
if err := registry.Register(NewProcessCollector(os.Getpid(), "")); err != nil {
t.Fatal(err)
}
if err := registry.Register(NewProcessCollectorPIDFn(
func() (int, error) { return os.Getpid(), nil }, "foobar"),
); err != nil {
t.Fatal(err)
}
s := httptest.NewServer(InstrumentHandler("prometheus", registry))
defer s.Close()
r, err := http.Get(s.URL)
mfs, err := registry.Gather()
if err != nil {
t.Fatal(err)
}
defer r.Body.Close()
body, err := ioutil.ReadAll(r.Body)
if err != nil {
var buf bytes.Buffer
for _, mf := range mfs {
if _, err := expfmt.MetricFamilyToText(&buf, mf); err != nil {
t.Fatal(err)
}
}
for _, re := range []*regexp.Regexp{
regexp.MustCompile("process_cpu_seconds_total [0-9]"),
@ -47,8 +51,8 @@ func TestProcessCollector(t *testing.T) {
regexp.MustCompile("foobar_process_resident_memory_bytes [1-9]"),
regexp.MustCompile("foobar_process_start_time_seconds [0-9.]{10,}"),
} {
if !re.Match(body) {
t.Errorf("want body to match %s\n%s", re, body)
if !re.Match(buf.Bytes()) {
t.Errorf("want body to match %s\n%s", re, buf.String())
}
}
}

201
prometheus/promhttp/http.go Normal file
View File

@ -0,0 +1,201 @@
// 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.
// 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 promhttp contains functions to create http.Handler instances to
// expose Prometheus metrics via HTTP. In later versions of this package, it
// will also contain tooling to instrument instances of http.Handler and
// http.RoundTripper.
//
// promhttp.Handler acts on the prometheus.DefaultGatherer. With HandlerFor,
// you can create a handler for a custom registry or anything that implements
// the Gatherer interface. It also allows to create handlers that act
// differently on errors or allow to log errors.
package promhttp
import (
"bytes"
"compress/gzip"
"fmt"
"io"
"net/http"
"strings"
"sync"
"github.com/prometheus/common/expfmt"
"github.com/prometheus/client_golang/prometheus"
)
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 prometheus.DefaultGatherer. The
// Handler uses the default HandlerOpts, i.e. report the first error as an HTTP
// error, no error logging, and compression if requested by the client.
//
// If you want to create a Handler for the DefaultGatherer with different
// HandlerOpts, create it with HandlerFor with prometheus.DefaultGatherer and
// your desired HandlerOpts.
func Handler() http.Handler {
return HandlerFor(prometheus.DefaultGatherer, HandlerOpts{})
}
// HandlerFor returns an http.Handler for the provided Gatherer. The behavior
// ef the Handler is defined by the provided HandlerOpts.
func HandlerFor(reg prometheus.Gatherer, opts HandlerOpts) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
mfs, err := reg.Gather()
if err != nil {
if opts.ErrorLog != nil {
opts.ErrorLog.Println("error gathering metrics:", err)
}
switch opts.ErrorHandling {
case PanicOnError:
panic(err)
case ContinueOnError:
if len(mfs) == 0 {
http.Error(w, "No metrics gathered, last error:\n\n"+err.Error(), http.StatusInternalServerError)
return
}
case HTTPErrorOnError:
http.Error(w, "An error has occurred during metrics gathering:\n\n"+err.Error(), http.StatusInternalServerError)
return
}
}
contentType := expfmt.Negotiate(req.Header)
buf := getBuf()
defer giveBuf(buf)
writer, encoding := decorateWriter(req, buf, opts.DisableCompression)
enc := expfmt.NewEncoder(writer, contentType)
var lastErr error
for _, mf := range mfs {
if err := enc.Encode(mf); err != nil {
lastErr = err
if opts.ErrorLog != nil {
opts.ErrorLog.Println("error encoding metric family:", err)
}
switch opts.ErrorHandling {
case PanicOnError:
panic(err)
case ContinueOnError:
// Handled later.
case HTTPErrorOnError:
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())
// TODO(beorn7): Consider streaming serving of metrics.
})
}
// HandlerErrorHandling defines how a Handler serving metrics will handle
// errors.
type HandlerErrorHandling int
// These constants cause handlers serving metrics to behave as described if
// errors are encountered.
const (
// Serve an HTTP status code 500 upon the first error
// encountered. Report the error message in the body.
HTTPErrorOnError HandlerErrorHandling = iota
// Ignore errors and try to serve as many metrics as possible. However,
// if no metrics can be served, serve an HTTP status code 500 and the
// last error message in the body. Only use this in deliberate "best
// effort" metrics collection scenarios. It is recommended to at least
// log errors (by providing an ErrorLog in HandlerOpts) to not mask
// errors completely.
ContinueOnError
// Panic upon the first error encountered (useful for "crash only" apps).
PanicOnError
)
// Logger is the minimal interface HandlerOpts needs for logging. Note that
// log.Logger from the standard library implements this interface, and it is
// easy to implement by custom loggers, if they don't do so already anyway.
type Logger interface {
Println(v ...interface{})
}
// HandlerOpts specifies options how to serve metrics via an http.Handler. The
// zero value of HandlerOpts is a reasonable default.
type HandlerOpts struct {
// ErrorLog specifies an optional logger for errors collecting and
// serving metrics. If nil, errors are not logged at all.
ErrorLog Logger
// ErrorHandling defines how errors are handled. Note that errors are
// logged regardless of the configured ErrorHandling provided ErrorLog
// is not nil.
ErrorHandling HandlerErrorHandling
// If DisableCompression is true, the handler will never compress the
// response, even if requested by the client.
DisableCompression bool
}
// 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, compressionDisabled bool) (io.Writer, string) {
if compressionDisabled {
return writer, ""
}
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, ""
}

137
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@ -0,0 +1,137 @@
// 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.
// 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 promhttp
import (
"bytes"
"errors"
"log"
"net/http"
"net/http/httptest"
"testing"
"github.com/prometheus/client_golang/prometheus"
)
type errorCollector struct{}
func (e errorCollector) Describe(ch chan<- *prometheus.Desc) {
ch <- prometheus.NewDesc("invalid_metric", "not helpful", nil, nil)
}
func (e errorCollector) Collect(ch chan<- prometheus.Metric) {
ch <- prometheus.NewInvalidMetric(
prometheus.NewDesc("invalid_metric", "not helpful", nil, nil),
errors.New("collect error"),
)
}
func TestHandlerErrorHandling(t *testing.T) {
// Create a registry that collects a MetricFamily with two elements,
// another with one, and reports an error.
reg := prometheus.NewRegistry()
cnt := prometheus.NewCounter(prometheus.CounterOpts{
Name: "the_count",
Help: "Ah-ah-ah! Thunder and lightning!",
})
reg.MustRegister(cnt)
cntVec := prometheus.NewCounterVec(
prometheus.CounterOpts{
Name: "name",
Help: "docstring",
ConstLabels: prometheus.Labels{"constname": "constvalue"},
},
[]string{"labelname"},
)
cntVec.WithLabelValues("val1").Inc()
cntVec.WithLabelValues("val2").Inc()
reg.MustRegister(cntVec)
reg.MustRegister(errorCollector{})
logBuf := &bytes.Buffer{}
logger := log.New(logBuf, "", 0)
writer := httptest.NewRecorder()
request, _ := http.NewRequest("GET", "/", nil)
request.Header.Add("Accept", "test/plain")
errorHandler := HandlerFor(reg, HandlerOpts{
ErrorLog: logger,
ErrorHandling: HTTPErrorOnError,
})
continueHandler := HandlerFor(reg, HandlerOpts{
ErrorLog: logger,
ErrorHandling: ContinueOnError,
})
panicHandler := HandlerFor(reg, HandlerOpts{
ErrorLog: logger,
ErrorHandling: PanicOnError,
})
wantMsg := `error gathering metrics: error collecting metric Desc{fqName: "invalid_metric", help: "not helpful", constLabels: {}, variableLabels: []}: collect error
`
wantErrorBody := `An error has occurred during metrics gathering:
error collecting metric Desc{fqName: "invalid_metric", help: "not helpful", constLabels: {}, variableLabels: []}: collect error
`
wantOKBody := `# HELP name docstring
# TYPE name counter
name{constname="constvalue",labelname="val1"} 1
name{constname="constvalue",labelname="val2"} 1
# HELP the_count Ah-ah-ah! Thunder and lightning!
# TYPE the_count counter
the_count 0
`
errorHandler.ServeHTTP(writer, request)
if got, want := writer.Code, http.StatusInternalServerError; got != want {
t.Errorf("got HTTP status code %d, want %d", got, want)
}
if got := logBuf.String(); got != wantMsg {
t.Errorf("got log message:\n%s\nwant log mesage:\n%s\n", got, wantMsg)
}
if got := writer.Body.String(); got != wantErrorBody {
t.Errorf("got body:\n%s\nwant body:\n%s\n", got, wantErrorBody)
}
logBuf.Reset()
writer.Body.Reset()
writer.Code = http.StatusOK
continueHandler.ServeHTTP(writer, request)
if got, want := writer.Code, http.StatusOK; got != want {
t.Errorf("got HTTP status code %d, want %d", got, want)
}
if got := logBuf.String(); got != wantMsg {
t.Errorf("got log message %q, want %q", got, wantMsg)
}
if got := writer.Body.String(); got != wantOKBody {
t.Errorf("got body %q, want %q", got, wantOKBody)
}
defer func() {
if err := recover(); err == nil {
t.Error("expected panic from panicHandler")
}
}()
panicHandler.ServeHTTP(writer, request)
}

65
prometheus/push.go
View File

@ -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)
}

56
prometheus/push/examples_test.go Normal file
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@ -0,0 +1,56 @@
// 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 push_test
import (
"fmt"
"time"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/push"
)
func ExampleCollectors() {
completionTime := prometheus.NewGauge(prometheus.GaugeOpts{
Name: "db_backup_last_completion_timestamp_seconds",
Help: "The timestamp of the last succesful completion of a DB backup.",
})
completionTime.Set(float64(time.Now().Unix()))
if err := push.Collectors(
"db_backup", push.HostnameGroupingKey(),
"http://pushgateway:9091",
completionTime,
); err != nil {
fmt.Println("Could not push completion time to Pushgateway:", err)
}
}
func ExampleRegistry() {
registry := prometheus.NewRegistry()
completionTime := prometheus.NewGauge(prometheus.GaugeOpts{
Name: "db_backup_last_completion_timestamp_seconds",
Help: "The timestamp of the last succesful completion of a DB backup.",
})
registry.MustRegister(completionTime)
completionTime.Set(float64(time.Now().Unix()))
if err := push.FromGatherer(
"db_backup", push.HostnameGroupingKey(),
"http://pushgateway:9091",
registry,
); err != nil {
fmt.Println("Could not push completion time to Pushgateway:", err)
}
}

172
prometheus/push/push.go Normal file
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@ -0,0 +1,172 @@
// 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 push provides functions to push metrics to a Pushgateway. The metrics
// to push are either collected from a provided registry, or from explicitly
// listed collectors.
//
// See the documentation of the Pushgateway to understand the meaning of the
// grouping parameters and the differences between push.Registry and
// push.Collectors on the one hand and push.AddRegistry and push.AddCollectors
// on the other hand: https://github.com/prometheus/pushgateway
package push
import (
"bytes"
"fmt"
"io/ioutil"
"net/http"
"net/url"
"os"
"strings"
"github.com/prometheus/common/expfmt"
"github.com/prometheus/common/model"
"github.com/prometheus/client_golang/prometheus"
)
const contentTypeHeader = "Content-Type"
// FromGatherer triggers a metric collection by the provided Gatherer (which is
// usually implemented by a prometheus.Registry) and pushes all gathered metrics
// to the Pushgateway specified by url, using the provided job name and the
// (optional) further grouping labels (the grouping map may be nil). See the
// Pushgateway documentation for detailed implications of the job and other
// grouping labels. Neither the job name nor any grouping label value may
// contain a "/". The metrics pushed must not contain a job label of their own
// nor any of the grouping labels.
//
// 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 other grouping
// labels will be replaced with the metrics pushed by this call. (It uses HTTP
// method 'PUT' to push to the Pushgateway.)
func FromGatherer(job string, grouping map[string]string, url string, g prometheus.Gatherer) error {
return push(job, grouping, url, g, "PUT")
}
// AddFromGatherer works like FromGatherer, but only previously pushed metrics
// with the same name (and the same job and other grouping labels) will be
// replaced. (It uses HTTP method 'POST' to push to the Pushgateway.)
func AddFromGatherer(job string, grouping map[string]string, url string, g prometheus.Gatherer) error {
return push(job, grouping, url, g, "POST")
}
func push(job string, grouping map[string]string, pushURL string, g prometheus.Gatherer, method string) error {
if !strings.Contains(pushURL, "://") {
pushURL = "http://" + pushURL
}
if strings.HasSuffix(pushURL, "/") {
pushURL = pushURL[:len(pushURL)-1]
}
if strings.Contains(job, "/") {
return fmt.Errorf("job contains '/': %s", job)
}
urlComponents := []string{url.QueryEscape(job)}
for ln, lv := range grouping {
if !model.LabelNameRE.MatchString(ln) {
return fmt.Errorf("grouping label has invalid name: %s", ln)
}
if strings.Contains(lv, "/") {
return fmt.Errorf("value of grouping label %s contains '/': %s", ln, lv)
}
urlComponents = append(urlComponents, ln, lv)
}
pushURL = fmt.Sprintf("%s/metrics/job/%s", pushURL, strings.Join(urlComponents, "/"))
mfs, err := g.Gather()
if err != nil {
return err
}
buf := &bytes.Buffer{}
enc := expfmt.NewEncoder(buf, expfmt.FmtProtoDelim)
// Check for pre-existing grouping labels:
for _, mf := range mfs {
for _, m := range mf.GetMetric() {
for _, l := range m.GetLabel() {
if l.GetName() == "job" {
return fmt.Errorf("pushed metric %s (%s) already contains a job label", mf.GetName(), m)
}
if _, ok := grouping[l.GetName()]; ok {
return fmt.Errorf(
"pushed metric %s (%s) already contains grouping label %s",
mf.GetName(), m, l.GetName(),
)
}
}
}
enc.Encode(mf)
}
req, err := http.NewRequest(method, pushURL, buf)
if err != nil {
return err
}
req.Header.Set(contentTypeHeader, string(expfmt.FmtProtoDelim))
resp, err := http.DefaultClient.Do(req)
if err != nil {
return err
}
defer resp.Body.Close()
if resp.StatusCode != 202 {
body, _ := ioutil.ReadAll(resp.Body) // Ignore any further error as this is for an error message only.
return fmt.Errorf("unexpected status code %d while pushing to %s: %s", resp.StatusCode, pushURL, body)
}
return nil
}
// Collectors works like FromGatherer, but it does not use a Gatherer. Instead,
// it collects from the provided collectors directly. It is a convenient way to
// push only a few metrics.
func Collectors(job string, grouping map[string]string, url string, collectors ...prometheus.Collector) error {
return pushCollectors(job, grouping, url, "PUT", collectors...)
}
// AddCollectors works like AddFromGatherer, but it does not use a Gatherer.
// Instead, it collects from the provided collectors directly. It is a
// convenient way to push only a few metrics.
func AddCollectors(job string, grouping map[string]string, url string, collectors ...prometheus.Collector) error {
return pushCollectors(job, grouping, url, "POST", collectors...)
}
func pushCollectors(job string, grouping map[string]string, url, method string, collectors ...prometheus.Collector) error {
r := prometheus.NewRegistry()
for _, collector := range collectors {
if err := r.Register(collector); err != nil {
return err
}
}
return push(job, grouping, url, r, method)
}
// HostnameGroupingKey returns a label map with the only entry
// {instance="<hostname>"}. This can be conveniently used as the grouping
// parameter if metrics should be pushed with the hostname as label. The
// returned map is created upon each call so that the caller is free to add more
// labels to the map.
func HostnameGroupingKey() map[string]string {
hostname, err := os.Hostname()
if err != nil {
return map[string]string{"instance": "unknown"}
}
return map[string]string{"instance": hostname}
}

176
prometheus/push/push_test.go Normal file
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@ -0,0 +1,176 @@
// 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.
// 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 push
import (
"bytes"
"io/ioutil"
"net/http"
"net/http/httptest"
"os"
"testing"
"github.com/prometheus/common/expfmt"
"github.com/prometheus/client_golang/prometheus"
)
func TestPush(t *testing.T) {
var (
lastMethod string
lastBody []byte
lastPath string
)
host, err := os.Hostname()
if err != nil {
t.Error(err)
}
// Fake a Pushgateway that always responds with 202.
pgwOK := httptest.NewServer(
http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
lastMethod = r.Method
var err error
lastBody, err = ioutil.ReadAll(r.Body)
if err != nil {
t.Fatal(err)
}
lastPath = r.URL.EscapedPath()
w.Header().Set("Content-Type", `text/plain; charset=utf-8`)
w.WriteHeader(http.StatusAccepted)
}),
)
defer pgwOK.Close()
// Fake a Pushgateway that always responds with 500.
pgwErr := httptest.NewServer(
http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
http.Error(w, "fake error", http.StatusInternalServerError)
}),
)
defer pgwErr.Close()
metric1 := prometheus.NewCounter(prometheus.CounterOpts{
Name: "testname1",
Help: "testhelp1",
})
metric2 := prometheus.NewGauge(prometheus.GaugeOpts{
Name: "testname2",
Help: "testhelp2",
ConstLabels: prometheus.Labels{"foo": "bar", "dings": "bums"},
})
reg := prometheus.NewRegistry()
reg.MustRegister(metric1)
reg.MustRegister(metric2)
mfs, err := reg.Gather()
if err != nil {
t.Fatal(err)
}
buf := &bytes.Buffer{}
enc := expfmt.NewEncoder(buf, expfmt.FmtProtoDelim)
for _, mf := range mfs {
if err := enc.Encode(mf); err != nil {
t.Fatal(err)
}
}
wantBody := buf.Bytes()
// PushCollectors, all good.
if err := Collectors("testjob", HostnameGroupingKey(), pgwOK.URL, metric1, metric2); err != nil {
t.Fatal(err)
}
if lastMethod != "PUT" {
t.Error("want method PUT for PushCollectors, got", lastMethod)
}
if bytes.Compare(lastBody, wantBody) != 0 {
t.Errorf("got body %v, want %v", lastBody, wantBody)
}
if lastPath != "/metrics/job/testjob/instance/"+host {
t.Error("unexpected path:", lastPath)
}
// PushAddCollectors, with nil grouping, all good.
if err := AddCollectors("testjob", nil, pgwOK.URL, metric1, metric2); err != nil {
t.Fatal(err)
}
if lastMethod != "POST" {
t.Error("want method POST for PushAddCollectors, got", lastMethod)
}
if bytes.Compare(lastBody, wantBody) != 0 {
t.Errorf("got body %v, want %v", lastBody, wantBody)
}
if lastPath != "/metrics/job/testjob" {
t.Error("unexpected path:", lastPath)
}
// PushCollectors with a broken PGW.
if err := Collectors("testjob", nil, pgwErr.URL, metric1, metric2); err == nil {
t.Error("push to broken Pushgateway succeeded")
} else {
if got, want := err.Error(), "unexpected status code 500 while pushing to "+pgwErr.URL+"/metrics/job/testjob: fake error\n"; got != want {
t.Errorf("got error %q, want %q", got, want)
}
}
// PushCollectors with invalid grouping or job.
if err := Collectors("testjob", map[string]string{"foo": "bums"}, pgwErr.URL, metric1, metric2); err == nil {
t.Error("push with grouping contained in metrics succeeded")
}
if err := Collectors("test/job", nil, pgwErr.URL, metric1, metric2); err == nil {
t.Error("push with invalid job value succeeded")
}
if err := Collectors("testjob", map[string]string{"foo/bar": "bums"}, pgwErr.URL, metric1, metric2); err == nil {
t.Error("push with invalid grouping succeeded")
}
if err := Collectors("testjob", map[string]string{"foo-bar": "bums"}, pgwErr.URL, metric1, metric2); err == nil {
t.Error("push with invalid grouping succeeded")
}
// Push registry, all good.
if err := FromGatherer("testjob", HostnameGroupingKey(), pgwOK.URL, reg); err != nil {
t.Fatal(err)
}
if lastMethod != "PUT" {
t.Error("want method PUT for Push, got", lastMethod)
}
if bytes.Compare(lastBody, wantBody) != 0 {
t.Errorf("got body %v, want %v", lastBody, wantBody)
}
// PushAdd registry, all good.
if err := AddFromGatherer("testjob", map[string]string{"a": "x", "b": "y"}, pgwOK.URL, reg); err != nil {
t.Fatal(err)
}
if lastMethod != "POST" {
t.Error("want method POSTT for PushAdd, got", lastMethod)
}
if bytes.Compare(lastBody, wantBody) != 0 {
t.Errorf("got body %v, want %v", lastBody, wantBody)
}
if lastPath != "/metrics/job/testjob/a/x/b/y" && lastPath != "/metrics/job/testjob/b/y/a/x" {
t.Error("unexpected path:", lastPath)
}
}

1015
prometheus/registry.go
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140
prometheus/registry_test.go
View File

@ -17,41 +17,30 @@
// Use of this source code is governed by a BSD-style license that can be found
// in the LICENSE file.
package prometheus
package prometheus_test
import (
"bytes"
"encoding/binary"
"net/http"
"net/http/httptest"
"testing"
"github.com/golang/protobuf/proto"
dto "github.com/prometheus/client_model/go"
"github.com/golang/protobuf/proto"
"github.com/prometheus/common/expfmt"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/promhttp"
)
type fakeResponseWriter struct {
header http.Header
body bytes.Buffer
}
func (r *fakeResponseWriter) Header() http.Header {
return r.header
}
func (r *fakeResponseWriter) Write(d []byte) (l int, err error) {
return r.body.Write(d)
}
func (r *fakeResponseWriter) WriteHeader(c int) {
}
func testHandler(t testing.TB) {
metricVec := NewCounterVec(
CounterOpts{
metricVec := prometheus.NewCounterVec(
prometheus.CounterOpts{
Name: "name",
Help: "docstring",
ConstLabels: Labels{"constname": "constvalue"},
ConstLabels: prometheus.Labels{"constname": "constvalue"},
},
[]string{"labelname"},
)
@ -59,8 +48,6 @@ func testHandler(t testing.TB) {
metricVec.WithLabelValues("val1").Inc()
metricVec.WithLabelValues("val2").Inc()
varintBuf := make([]byte, binary.MaxVarintLen32)
externalMetricFamily := &dto.MetricFamily{
Name: proto.String("externalname"),
Help: proto.String("externaldocstring"),
@ -83,18 +70,9 @@ func testHandler(t testing.TB) {
},
},
}
marshaledExternalMetricFamily, err := proto.Marshal(externalMetricFamily)
if err != nil {
t.Fatal(err)
}
var externalBuf bytes.Buffer
l := binary.PutUvarint(varintBuf, uint64(len(marshaledExternalMetricFamily)))
_, err = externalBuf.Write(varintBuf[:l])
if err != nil {
t.Fatal(err)
}
_, err = externalBuf.Write(marshaledExternalMetricFamily)
if err != nil {
externalBuf := &bytes.Buffer{}
enc := expfmt.NewEncoder(externalBuf, expfmt.FmtProtoDelim)
if err := enc.Encode(externalMetricFamily); err != nil {
t.Fatal(err)
}
externalMetricFamilyAsBytes := externalBuf.Bytes()
@ -160,18 +138,9 @@ metric: <
},
},
}
marshaledExpectedMetricFamily, err := proto.Marshal(expectedMetricFamily)
if err != nil {
t.Fatal(err)
}
var buf bytes.Buffer
l = binary.PutUvarint(varintBuf, uint64(len(marshaledExpectedMetricFamily)))
_, err = buf.Write(varintBuf[:l])
if err != nil {
t.Fatal(err)
}
_, err = buf.Write(marshaledExpectedMetricFamily)
if err != nil {
buf := &bytes.Buffer{}
enc = expfmt.NewEncoder(buf, expfmt.FmtProtoDelim)
if err := enc.Encode(expectedMetricFamily); err != nil {
t.Fatal(err)
}
expectedMetricFamilyAsBytes := buf.Bytes()
@ -216,7 +185,7 @@ metric: <
externalMetricFamilyWithSameName := &dto.MetricFamily{
Name: proto.String("name"),
Help: proto.String("inconsistent help string does not matter here"),
Help: proto.String("docstring"),
Type: dto.MetricType_COUNTER.Enum(),
Metric: []*dto.Metric{
{
@ -248,7 +217,7 @@ metric: <
var scenarios = []struct {
headers map[string]string
out output
collector Collector
collector prometheus.Collector
externalMF []*dto.MetricFamily
}{
{ // 0
@ -485,21 +454,22 @@ metric: <
},
}
for i, scenario := range scenarios {
registry := newRegistry()
registry.collectChecksEnabled = true
registry := prometheus.NewPedanticRegistry()
gatherer := prometheus.Gatherer(registry)
if scenario.externalMF != nil {
gatherer = prometheus.Gatherers{
registry,
prometheus.GathererFunc(func() ([]*dto.MetricFamily, error) {
return scenario.externalMF, nil
}),
}
}
if scenario.collector != nil {
registry.Register(scenario.collector)
}
if scenario.externalMF != nil {
registry.metricFamilyInjectionHook = func() []*dto.MetricFamily {
return scenario.externalMF
}
}
writer := &fakeResponseWriter{
header: http.Header{},
}
handler := InstrumentHandler("prometheus", registry)
writer := httptest.NewRecorder()
handler := prometheus.InstrumentHandler("prometheus", promhttp.HandlerFor(gatherer, promhttp.HandlerOpts{}))
request, _ := http.NewRequest("GET", "/", nil)
for key, value := range scenario.headers {
request.Header.Add(key, value)
@ -507,7 +477,7 @@ metric: <
handler(writer, request)
for key, value := range scenario.out.headers {
if writer.Header().Get(key) != value {
if writer.HeaderMap.Get(key) != value {
t.Errorf(
"%d. expected %q for header %q, got %q",
i, value, key, writer.Header().Get(key),
@ -515,10 +485,10 @@ metric: <
}
}
if !bytes.Equal(scenario.out.body, writer.body.Bytes()) {
if !bytes.Equal(scenario.out.body, writer.Body.Bytes()) {
t.Errorf(
"%d. expected %q for body, got %q",
i, scenario.out.body, writer.body.Bytes(),
"%d. expected body:\n%s\ngot body:\n%s\n",
i, scenario.out.body, writer.Body.Bytes(),
)
}
}
@ -533,3 +503,43 @@ func BenchmarkHandler(b *testing.B) {
testHandler(b)
}
}
func TestRegisterWithOrGet(t *testing.T) {
// Replace the default registerer just to be sure. This is bad, but this
// whole test will go away once RegisterOrGet is removed.
oldRegisterer := prometheus.DefaultRegisterer
defer func() {
prometheus.DefaultRegisterer = oldRegisterer
}()
prometheus.DefaultRegisterer = prometheus.NewRegistry()
original := prometheus.NewCounterVec(
prometheus.CounterOpts{
Name: "test",
Help: "help",
},
[]string{"foo", "bar"},
)
equalButNotSame := prometheus.NewCounterVec(
prometheus.CounterOpts{
Name: "test",
Help: "help",
},
[]string{"foo", "bar"},
)
if err := prometheus.Register(original); err != nil {
t.Fatal(err)
}
if err := prometheus.Register(equalButNotSame); err == nil {
t.Fatal("expected error when registringe equal collector")
}
existing, err := prometheus.RegisterOrGet(equalButNotSame)
if err != nil {
t.Fatal(err)
}
if existing != original {
t.Error("expected original collector but got something else")
}
if existing == equalButNotSame {
t.Error("expected original callector but got new one")
}
}

16
prometheus/summary.go
View File

@ -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.

4
prometheus/summary_test.go
View File

@ -329,8 +329,8 @@ func TestSummaryDecay(t *testing.T) {
}
func getBounds(vars []float64, q, ε float64) (min, max float64) {
// TODO: This currently tolerates an error of up to 2*ε. The error must
// be at most ε, but for some reason, it's sometimes slightly
// TODO(beorn7): This currently tolerates an error of up to 2*ε. The
// error must be at most ε, but for some reason, it's sometimes slightly
// higher. That's a bug.
n := float64(len(vars))
lower := int((q - 2*ε) * n)

8
prometheus/value.go
View File

@ -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
}