Merge pull request #214 from prometheus/beorn7/registry

Create a public registry interface and separate out HTTP exposition

Author: beorn7

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

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).

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
 }

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
 }
 
@@ -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
 			},
 		},

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 (