Merge pull request #14 from cabify/mapno/implement-prometheus-summary

Included the implementation builder for summaries

README.md

@@ -21,8 +21,9 @@ Define your metrics:
 var metrics struct {
 	SomeCounter                     func() prometheus.Counter  `name:"some_counter" help:"some counter"`
 	SomeObserver                    func() prometheus.Observer `name:"some_observer" help:"Some observer with default buckets"`
-	SomeObserverWithSpecificBuckets func() prometheus.Observer `name:"some_observer_with_buckets" help:"Some observer with default buckets" buckets:".01,.05,.1"`
+	SomeObserverWithSpecificBuckets func() prometheus.Observer `name:"some_observer_with_buckets" help:"Some observer with custom buckets" buckets:".01,.05,.1"`
 	SomeGauge                       func() prometheus.Gauge    `name:"some_gauge" help:"Some gauge"`
+	SomeSummaryWithSpecificMaxAge   func() prometheus.Summary  `name:"some_summary_with_specific_max_age" help:"Some summary with custom max age" max_age:"20m"`
 
 	Requests struct {
 		Total func(requestLabels) prometheus.Count `name:"total" help:"Total amount of requests served"`
@@ -57,6 +58,7 @@ By default, only some basic metric types are registered when `gotoprom` is intia
 * `prometheus.Counter`
 * `prometheus.Observer`
 * `prometheus.Gauge`
+* `prometheus.Summary`
 
 You can extend this by adding more types, for instance, if you want to observe time and want
 to avoid repetitive code you can create a `prometheusx.TimeObserver`:

default.go

@@ -14,6 +14,7 @@ func init() {
 	DefaultInitializer.MustAddBuilder(prometheusvanilla.ObserverType, prometheusvanilla.BuildObserver)
 	DefaultInitializer.MustAddBuilder(prometheusvanilla.CounterType, prometheusvanilla.BuildCounter)
 	DefaultInitializer.MustAddBuilder(prometheusvanilla.GaugeType, prometheusvanilla.BuildGauge)
+	DefaultInitializer.MustAddBuilder(prometheusvanilla.SummaryType, prometheusvanilla.BuildSummary)
 }
 
 // MustAddBuilder will AddBuilder and panic if an error occurs

go.mod

@@ -10,7 +10,7 @@ require (
 	github.com/matttproud/golang_protobuf_extensions v1.0.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/prometheus/client_golang v0.9.1
-	github.com/prometheus/client_model v0.0.0-20180712105110-5c3871d89910
+	github.com/prometheus/client_model v0.0.0-20180712105110-5c3871d89910 // indirect
 	github.com/prometheus/common v0.0.0-20181020173914-7e9e6cabbd39 // indirect
 	github.com/prometheus/procfs v0.0.0-20181005140218-185b4288413d // indirect
 	github.com/stretchr/testify v1.2.2

metrics_test.go

@@ -1,10 +1,13 @@
 package gotoprom_test
 
 import (
+	"math"
+	"strings"
 	"testing"
 	"time"
 
 	"github.com/cabify/gotoprom"
+	"github.com/prometheus/client_golang/prometheus/testutil"
 
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/stretchr/testify/assert"
@@ -18,10 +21,11 @@ func Test_InitHappyCase(t *testing.T) {
 	}
 
 	var metrics struct {
-		HTTPRequestTime     func(labels) prometheus.Observer `name:"http_request_count" help:"Time taken to serve a HTTP request" metricsbuckets:"0.001,0.005,0.01,0.05,0.1,0.5,1,5,10"`
-		DuvelsEmptied       func(labels) prometheus.Counter  `name:"duvels_emptied" help:"Delirium floor sweep count"`
-		RubberDuckInTherapy func(labels) prometheus.Gauge    `name:"rubber_ducks_in_therapy" help:"Number of rubber ducks who need help after some intense coding"`
-		NoLabels            func() prometheus.Counter        `name:"no_labels" help:"Metric without labels"`
+		HTTPRequestTime           func(labels) prometheus.Observer `name:"http_request_count" help:"Time taken to serve a HTTP request" metricsbuckets:"0.001,0.005,0.01,0.05,0.1,0.5,1,5,10"`
+		DuvelsEmptied             func(labels) prometheus.Counter  `name:"duvels_emptied" help:"Delirium floor sweep count"`
+		RubberDuckInTherapy       func(labels) prometheus.Gauge    `name:"rubber_ducks_in_therapy" help:"Number of rubber ducks who need help after some intense coding"`
+		BrokenDeploysAccomplished func(labels) prometheus.Summary  `name:"broken_deploys_accomplished" help:"Number of deploys that broke production"`
+		NoLabels                  func() prometheus.Counter        `name:"no_labels" help:"Metric without labels"`
 	}
 
 	gotoprom.MustInit(&metrics, "delirium")
@@ -36,6 +40,7 @@ func Test_InitHappyCase(t *testing.T) {
 	metrics.HTTPRequestTime(theseLabels).Observe(time.Second.Seconds())
 	metrics.DuvelsEmptied(theseLabels).Add(4)
 	metrics.RubberDuckInTherapy(theseLabels).Set(12)
+	metrics.BrokenDeploysAccomplished(theseLabels).Observe(20)
 	metrics.NoLabels().Add(288.88)
 }
 
@@ -275,6 +280,48 @@ func Test_WrongLabels(t *testing.T) {
 	})
 }
 
+func Test_SummaryWithSpecifiedMaxAge(t *testing.T) {
+	summaryHelp := "Uses default value for max age"
+
+	var metrics struct {
+		Summary func() prometheus.Summary `name:"without_max_age" help:"Uses default value for max age" max_age:"1s"`
+	}
+
+	err := gotoprom.Init(&metrics, "test")
+	assert.NoError(t, err)
+
+	metrics.Summary().Observe(1.0)
+	metrics.Summary().Observe(2.0)
+	metrics.Summary().Observe(3.0)
+
+	nl := "\n"
+
+	expectedUnexpired := "" +
+		`# HELP test_without_max_age ` + summaryHelp + nl +
+		`# TYPE test_without_max_age summary` + nl +
+		`test_without_max_age{quantile="0.5"} 2` + nl +
+		`test_without_max_age{quantile="0.9"} 3` + nl +
+		`test_without_max_age{quantile="0.99"} 3` + nl +
+		`test_without_max_age_sum{} 6` + nl +
+		`test_without_max_age_count{} 3` + nl
+
+	err = testutil.GatherAndCompare(prometheus.DefaultGatherer, strings.NewReader(expectedUnexpired), "test_without_max_age")
+	assert.NoError(t, err)
+
+	time.Sleep(time.Second * 2)
+
+	mfs, err := prometheus.DefaultGatherer.Gather()
+	assert.NoError(t, err)
+
+	for _, m := range mfs {
+		if *m.Name == "test_without_max_age" {
+			for _, mm := range m.Metric {
+				assert.True(t, math.IsNaN(*mm.GetSummary().Quantile[1].Value))
+			}
+		}
+	}
+}
+
 func retrieveReportedLabels(t *testing.T, metric string) map[string]string {
 	mfs, err := prometheus.DefaultGatherer.Gather()
 	assert.Nil(t, err)

prometheusvanilla/builders.go

@@ -5,6 +5,7 @@ import (
 	"reflect"
 	"strconv"
 	"strings"
+	"time"
 
 	"github.com/prometheus/client_golang/prometheus"
 )
@@ -16,6 +17,8 @@ var (
 	CounterType = reflect.TypeOf((*prometheus.Counter)(nil)).Elem()
 	// GaugeType is the type of prometheus.Gauge interface
 	GaugeType = reflect.TypeOf((*prometheus.Gauge)(nil)).Elem()
+	// SummaryType is the type of prometheus.Summary interface
+	SummaryType = reflect.TypeOf((*prometheus.Summary)(nil)).Elem()
 )
 
 // BuildCounter builds a prometheus.Counter in the given prometheus.Registerer
@@ -75,6 +78,29 @@ func BuildObserver(name, help, namespace string, labelNames []string, tag reflec
 	}, hist, nil
 }
 
+// BuildSummary builds a prometheus.Summary
+// The function it returns returns a prometheus.Summary type as an interface{}
+func BuildSummary(name, help, namespace string, labelNames []string, tag reflect.StructTag) (func(prometheus.Labels) interface{}, prometheus.Collector, error) {
+	maxAge, err := maxAgeFromTag(tag)
+	if err != nil {
+		return nil, nil, fmt.Errorf("build summary %q: %s", name, err)
+	}
+
+	sum := prometheus.NewSummaryVec(
+		prometheus.SummaryOpts{
+			Name:      name,
+			Help:      help,
+			Namespace: namespace,
+			MaxAge:    maxAge,
+		},
+		labelNames,
+	)
+
+	return func(labels prometheus.Labels) interface{} {
+		return sum.With(labels)
+	}, sum, nil
+}
+
 func bucketsFromTag(tag reflect.StructTag) ([]float64, error) {
 	bucketsString, ok := tag.Lookup("buckets")
 	if !ok {
@@ -97,3 +123,15 @@ func bucketsFromTag(tag reflect.StructTag) ([]float64, error) {
 func DefaultBuckets() []float64 {
 	return []float64{.005, .01, .025, .05, .1, .25, .5, 1, 2.5, 5, 10, 25}
 }
+
+func maxAgeFromTag(tag reflect.StructTag) (time.Duration, error) {
+	maxAgeString, ok := tag.Lookup("max_age")
+	if !ok {
+		return 0, nil
+	}
+	maxAgeDuration, err := time.ParseDuration(maxAgeString)
+	if err != nil {
+		return 0, fmt.Errorf("invalid max_age tag specified: %s", err)
+	}
+	return maxAgeDuration, nil
+}