Implementing Prometheus Metrics Exporter as in #477

Signed-off-by: Flávio Stutz <flaviostutz@gmail.com>

README.md

@@ -785,7 +785,7 @@ It'll read and sort them by timestamp before generating reports.
 vegeta report *.bin
 ```
 
-Another way to gather results in distributed tests is to use the built-in Prometheus Exporter and configure a Prometheus Server to get test results from all Vegeta instances. See `attack` option "prom-enable" for more details and a complete example in the section "Prometheus Exporter Support"
+Another way to gather results in distributed tests is to use the built-in Prometheus Exporter and configure a Prometheus Server to get test results from all Vegeta instances. See `attack` option "prometheus-url" for more details and a complete example in the section "Prometheus Exporter Support"
 
 ## Usage: Real-time Analysis
 
@@ -868,7 +868,6 @@ Just pass a new number as the argument to change it.
 Vegeta has a built-in Prometheus Exporter that may be enabled during "attacks" so that you can point any Prometheus instance to Vegeta instances and get some metrics about http requests performance and about the Vegeta process itself.
 
 To enable the Prometheus Exporter on the command line, use the "prometheus-url" flag.
-To enable Prometheus Exporter on lib usage, add Option "PrometheusEnable" and/or "PrometheusSettings".
 
 A Prometheus HTTP endpoint will be available only during the lifespan of an "attack" and will be closed right after the attack is finished.
 

attack.go

@@ -215,14 +215,15 @@ func attack(opts *attackOpts) (err error) {
 	sig := make(chan os.Signal, 1)
 	signal.Notify(sig, os.Interrupt, syscall.SIGTERM)
 
-	return processAttack(atk, res, enc, sig)
+	return processAttack(atk, res, enc, sig, promMetrics)
 }
 
 func processAttack(
 	atk *vegeta.Attacker,
 	res <-chan *vegeta.Result,
 	enc vegeta.Encoder,
 	sig <-chan os.Signal,
+	promMetrics *prom.PrometheusMetrics,
 ) error {
 	for {
 		select {
@@ -235,10 +236,10 @@ func processAttack(
 			if !ok {
 				return nil
 			}
-			if opts.promURL != "" {
+			if promMetrics != nil {
 				promMetrics.Observe(r)
 			}
-			if err = enc.Encode(r); err != nil {
+			if err := enc.Encode(r); err != nil {
 				return err
 			}
 		}

attack_test.go

@@ -86,7 +86,7 @@ func TestAttackSignalOnce(t *testing.T) {
 	wg.Add(1)
 	go func() {
 		defer wg.Done()
-		processAttack(atk, res, enc, sig)
+		processAttack(atk, res, enc, sig, nil)
 	}()
 
 	// Allow more than one request to have started before stopping.
@@ -139,7 +139,7 @@ func TestAttackSignalTwice(t *testing.T) {
 	wg.Add(1)
 	go func() {
 		defer wg.Done()
-		processAttack(atk, res, enc, sig)
+		processAttack(atk, res, enc, sig, nil)
 	}()
 
 	// Exit as soon as possible.

docker-compose.yml

@@ -7,7 +7,7 @@ services:
     image: tsenart/vegeta
     ports:
       - 8880:8880
-    command: sh -c 'echo "GET https://www.yahoo.com" | vegeta attack -duration=30s -rate=5 -prometheus-enable=true'
+    command: sh -c 'echo "GET https://www.yahoo.com" | vegeta attack -duration=30s -rate=5 -prometheus-url=0.0.0.0:8880'
 
   prometheus:
     image: flaviostutz/prometheus

go.mod

@@ -12,6 +12,7 @@ require (
 	github.com/influxdata/tdigest v0.0.1
 	github.com/mailru/easyjson v0.7.7
 	github.com/miekg/dns v1.1.55
+	github.com/prometheus/client_golang v1.16.0
 	github.com/rs/dnscache v0.0.0-20211102005908-e0241e321417
 	github.com/streadway/quantile v0.0.0-20220407130108-4246515d968d
 	github.com/tsenart/go-tsz v0.0.0-20180814235614-0bd30b3df1c3
@@ -26,7 +27,6 @@ require (
 	github.com/iancoleman/orderedmap v0.3.0 // indirect
 	github.com/josharian/intern v1.0.0 // indirect
 	github.com/matttproud/golang_protobuf_extensions v1.0.4 // indirect
-	github.com/prometheus/client_golang v1.16.0 // indirect
 	github.com/prometheus/client_model v0.3.0 // indirect
 	github.com/prometheus/common v0.42.0 // indirect
 	github.com/prometheus/procfs v0.10.1 // indirect

go.sum

@@ -59,7 +59,6 @@ github.com/rs/dnscache v0.0.0-20211102005908-e0241e321417/go.mod h1:qe5TWALJ8/a1
 github.com/streadway/quantile v0.0.0-20220407130108-4246515d968d h1:X4+kt6zM/OVO6gbJdAfJR60MGPsqCzbtXNnjoGqdfAs=
 github.com/streadway/quantile v0.0.0-20220407130108-4246515d968d/go.mod h1:lbP8tGiBjZ5YWIc2fzuRpTaz0b/53vT6PEs3QuAWzuU=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/testify v1.3.1-0.20190311161405-34c6fa2dc709 h1:Ko2LQMrRU+Oy/+EDBwX7eZ2jp3C47eDBB8EIhKTun+I=
 github.com/stretchr/testify v1.3.1-0.20190311161405-34c6fa2dc709/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/tsenart/go-tsz v0.0.0-20180814235614-0bd30b3df1c3 h1:pcQGQzTwCg//7FgVywqge1sW9Yf8VMsMdG58MI5kd8s=
 github.com/tsenart/go-tsz v0.0.0-20180814235614-0bd30b3df1c3/go.mod h1:SWZznP1z5Ki7hDT2ioqiFKEse8K9tU2OUvaRI0NeGQo=

lib/prom/prom.go

@@ -16,8 +16,8 @@ import (
 	vegeta "github.com/tsenart/vegeta/v12/lib"
 )
 
-//PrometheusMetrics vegeta metrics observer with exposition as Prometheus metrics endpoint
-type PrometheusMetrics struct {
+// Metrics vegeta metrics observer with exposition as Prometheus metrics endpoint
+type Metrics struct {
 	requestSecondsHistogram *prometheus.HistogramVec
 	requestBytesInCounter   *prometheus.CounterVec
 	requestBytesOutCounter  *prometheus.CounterVec
@@ -26,18 +26,18 @@ type PrometheusMetrics struct {
 	registry                *prometheus.Registry
 }
 
-//NewPrometheusMetrics same as NewPrometheusMetricsWithParams with default params:
-func NewPrometheusMetrics() (*PrometheusMetrics, error) {
-	return NewPrometheusMetricsWithParams("http://0.0.0.0:8880")
+// NewMetrics same as NewMetricsWithParams with default params:
+func NewMetrics() (*Metrics, error) {
+	return NewMetricsWithParams("http://0.0.0.0:8880")
 }
 
-// NewPrometheusMetricsWithParams creates a new Prometheus Metrics to Observe attack results and expose metrics
-// For example, after using NewPrometheusMetricsWithParams("http://0.0.0.0:8880"),
+// NewMetricsWithParams creates a new Prometheus Metrics to Observe attack results and expose metrics
+// For example, after using NewMetricsWithParams("http://0.0.0.0:8880"),
 // during an "attack" you can call "curl http://127.0.0.0:8880" to see current metrics.
 // This endpoint can be configured in scrapper section of your Prometheus server.
-func NewPrometheusMetricsWithParams(bindURL string) (*PrometheusMetrics, error) {
+func NewMetricsWithParams(bindURL string) (*Metrics, error) {
 
-	//parse bind url elements
+	// parse bind url elements
 	p, err := url.Parse(bindURL)
 	if err != nil {
 		return nil, fmt.Errorf("Invalid bindURL %s. Must be in format 'http://0.0.0.0:8880'. err=%s", bindURL, err)
@@ -47,7 +47,7 @@ func NewPrometheusMetricsWithParams(bindURL string) (*PrometheusMetrics, error)
 		return nil, fmt.Errorf("Invalid bindURL %s. Must be in format 'http://0.0.0.0:8880'. err=%s", bindURL, err)
 	}
 
-	pm := &PrometheusMetrics{
+	pm := &Metrics{
 		registry: prometheus.NewRegistry(),
 	}
 
@@ -92,7 +92,7 @@ func NewPrometheusMetricsWithParams(bindURL string) (*PrometheusMetrics, error)
 	})
 	pm.registry.MustRegister(pm.requestFailCounter)
 
-	//setup prometheus metrics http server
+	// setup prometheus metrics http server
 	pm.srv = http.Server{
 		Addr:    fmt.Sprintf("%s:%s", bindHost, bindPort),
 		Handler: promhttp.HandlerFor(pm.registry, promhttp.HandlerOpts{}),
@@ -105,18 +105,18 @@ func NewPrometheusMetricsWithParams(bindURL string) (*PrometheusMetrics, error)
 	return pm, nil
 }
 
-//Close shutdown http server exposing Prometheus metrics and unregister
-//all prometheus collectors
-func (pm *PrometheusMetrics) Close() error {
+// Close shutdown http server exposing Prometheus metrics and unregister
+// all prometheus collectors
+func (pm *Metrics) Close() error {
 	prometheus.Unregister(pm.requestSecondsHistogram)
 	prometheus.Unregister(pm.requestBytesInCounter)
 	prometheus.Unregister(pm.requestBytesOutCounter)
 	prometheus.Unregister(pm.requestFailCounter)
 	return pm.srv.Shutdown(context.Background())
 }
 
-//Observe register metrics about hit results
-func (pm *PrometheusMetrics) Observe(res *vegeta.Result) {
+// Observe register metrics about hit results
+func (pm *Metrics) Observe(res *vegeta.Result) {
 	code := strconv.FormatUint(uint64(res.Code), 10)
 	pm.requestBytesInCounter.WithLabelValues(res.Method, res.URL, code).Add(float64(res.BytesIn))
 	pm.requestBytesOutCounter.WithLabelValues(res.Method, res.URL, code).Add(float64(res.BytesOut))

lib/prom/prom_test.go

@@ -7,12 +7,11 @@ import (
 	"testing"
 	"time"
 
-	"github.com/stretchr/testify/assert"
 	vegeta "github.com/tsenart/vegeta/v12/lib"
 )
 
 func TestPromServerBasic1(t *testing.T) {
-	pm, err := NewPrometheusMetrics()
+	pm, err := NewMetrics()
 	if err != nil {
 		t.Errorf("Error launching Prometheus http server. err=%s", err)
 	}
@@ -24,7 +23,7 @@ func TestPromServerBasic1(t *testing.T) {
 }
 
 func TestPromServerBasic2(t *testing.T) {
-	pm, err := NewPrometheusMetrics()
+	pm, err := NewMetrics()
 	if err != nil {
 		t.Errorf("Error launching Prometheus metrics. err=%s", err)
 	}
@@ -33,7 +32,7 @@ func TestPromServerBasic2(t *testing.T) {
 		t.Errorf("Error stopping Prometheus http server. err=%s", err)
 	}
 
-	pm, err = NewPrometheusMetrics()
+	pm, err = NewMetrics()
 	if err != nil {
 		t.Errorf("Error launching Prometheus metrics. err=%s", err)
 	}
@@ -42,7 +41,7 @@ func TestPromServerBasic2(t *testing.T) {
 		t.Errorf("Error stopping Prometheus http server. err=%s", err)
 	}
 
-	pm, err = NewPrometheusMetrics()
+	pm, err = NewMetrics()
 	if err != nil {
 		t.Errorf("Error launching Prometheus metrics. err=%s", err)
 	}
@@ -53,8 +52,12 @@ func TestPromServerBasic2(t *testing.T) {
 }
 
 func TestPromServerObserve(t *testing.T) {
-	pm, err := NewPrometheusMetrics()
-	assert.Nil(t, err, "Error launching Prometheus http server. err=%s", err)
+	pm, err := NewMetrics()
+	if err != nil {
+		if err != nil {
+			t.Errorf("Error launching Prometheus http server. err=%s", err)
+		}
+	}
 
 	r := &vegeta.Result{
 		URL:      "http://test.com/test1",