Add histogram metrics and remove deperecated lib (#56)

- Remove "io/ioutil" which is deprecated since go-1.16.
- Add histogram metrics as a duplicate of existing summaries. Summaries
  are still required/used for in-app results calculation and reporting
  (when using CLI). But if you scrape/push metrics with Prometheus, you
  now have an option to use summaries or histograms.

CHANGELOG.md

@@ -5,6 +5,17 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.5.0] - 2023-10-11
+
+### Added
+
+- New histogram metrics. Every existing summary Prometheus metric now has a corresponding
+  histogram metric, with the `_hist_` in the metrics name.
+
+### Removed
+
+- "io/ioutil" library which is deprecated since go-1.16.
+
 ## [0.4.3] - 2023-02-28
 
 ### Added

README.md

@@ -1,6 +1,6 @@
 # Minigun
 
-[![Minigun Version](https://img.shields.io/badge/Minigun-0.4.3-7f187f.svg)](https://github.com/wayfair-incubator/minigun/blob/main/CHANGELOG.md)
+[![Minigun Version](https://img.shields.io/badge/Minigun-0.5.0-7f187f.svg)](https://github.com/wayfair-incubator/minigun/blob/main/CHANGELOG.md)
 [![Contributor Covenant](https://img.shields.io/badge/Contributor%20Covenant-2.0-4baaaa.svg)](CODE_OF_CONDUCT.md)
 
 ## About The Project

main.go

@@ -13,7 +13,7 @@ import (
 	"encoding/json"
 	"flag"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"math/rand"
 	"net"
 	"net/http"
@@ -35,18 +35,16 @@ import (
 )
 
 // Constants and vars
-const version = "0.4.3"
+const version = "0.5.0"
 const workersCannelSize = 1024
 const errorBadHTTPCode = "Bad HTTP status code"
 
 var applog *logger.Logger
 var workerStatuses []workerStatus
 var registry = prometheus.NewRegistry()
 
-// NOTES: histograms have been replaced with summaries. I'm keeping it just in case I decide
-// to use histograms again.
 // Let's use the same buckets for histograms as NGINX Ingress controller
-// var secondsDurationBuckets = []float64{0.005, 0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1, 2.5, 5, 10}
+var secondsDurationBuckets = []float64{0.005, 0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1, 2.5, 5, 10}
 
 // Objectives for summary distributions
 var summaryObjectives = map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.95: 0.005, 0.99: 0.001}
@@ -297,31 +295,36 @@ func sendDataHTTP(data []byte, config appConfig, client *http.Client) error {
 	trace := &httptrace.ClientTrace{
 		DNSStart: func(dsi httptrace.DNSStartInfo) { dns = time.Now() },
 		DNSDone: func(ddi httptrace.DNSDoneInfo) {
+			config.metrics.histDNSDuration.WithLabelValues(config.metrics.labelValues...).Observe(time.Since(dns).Seconds())
 			config.metrics.summaryDNSDuration.WithLabelValues(config.metrics.labelValues...).Observe(time.Since(dns).Seconds())
 			applog.Infof("DNS Done: %v\n", time.Since(dns))
 			applog.Infof("DNS Result: %v\n", ddi.Addrs)
 		},
 
 		TLSHandshakeStart: func() { tlsHandshake = time.Now() },
 		TLSHandshakeDone: func(cs tls.ConnectionState, err error) {
+			config.metrics.histTLSHandshakeDuration.WithLabelValues(config.metrics.labelValues...).Observe(time.Since(tlsHandshake).Seconds())
 			config.metrics.summaryTLSHandshakeDuration.WithLabelValues(config.metrics.labelValues...).Observe(time.Since(tlsHandshake).Seconds())
 			applog.Infof("TLS Handshake: %v\n", time.Since(tlsHandshake))
 		},
 
 		ConnectStart: func(network, addr string) { connect = time.Now() },
 		ConnectDone: func(network, addr string, err error) {
+			config.metrics.histConnectDuration.WithLabelValues(config.metrics.labelValues...).Observe(time.Since(connect).Seconds())
 			config.metrics.summaryConnectDuration.WithLabelValues(config.metrics.labelValues...).Observe(time.Since(connect).Seconds())
 			applog.Infof("Connect time: %v\n", time.Since(connect))
 		},
 
 		WroteHeaders: func() { headers = time.Now() },
 		WroteRequest: func(wri httptrace.WroteRequestInfo) {
+			config.metrics.histWroteRequestBodyDuration.WithLabelValues(config.metrics.labelValues...).Observe(time.Since(headers).Seconds())
 			config.metrics.summaryWroteRequestBodyDuration.WithLabelValues(config.metrics.labelValues...).Observe(time.Since(headers).Seconds())
 			wroteRequest = time.Now()
 			applog.Infof("Wrote request body time: %v\n", time.Since(headers))
 		},
 
 		GotFirstResponseByte: func() {
+			config.metrics.histGotFirstByteDuration.WithLabelValues(config.metrics.labelValues...).Observe(time.Since(start).Seconds())
 			config.metrics.summaryGotFirstByteDuration.WithLabelValues(config.metrics.labelValues...).Observe(time.Since(start).Seconds())
 			applog.Infof("Time from start to first byte: %v\n", time.Since(start))
 		},
@@ -335,13 +338,15 @@ func sendDataHTTP(data []byte, config appConfig, client *http.Client) error {
 		responseTime := time.Since(wroteRequest)
 		if err == nil && resp != nil {
 			localLabelValues := append(config.metrics.labelValues, fmt.Sprintf("%v", resp.StatusCode))
+			config.metrics.histResponseDuration.WithLabelValues(localLabelValues...).Observe(responseTime.Seconds())
 			config.metrics.summaryResponseDuration.WithLabelValues(localLabelValues...).Observe(responseTime.Seconds())
 		}
 	}
 
 	totalTime := time.Since(start)
 
 	config.metrics.requestsSendBytesSum.WithLabelValues(config.metrics.labelValues...).Add(float64(len(config.sendPayload)))
+	config.metrics.histRequestsDuration.WithLabelValues(config.metrics.labelValues...).Observe(totalTime.Seconds())
 	config.metrics.summaryRequestsDuration.WithLabelValues(config.metrics.labelValues...).Observe(totalTime.Seconds())
 
 	applog.Infof("Total time: %v\n", totalTime)
@@ -357,7 +362,7 @@ func sendDataHTTP(data []byte, config appConfig, client *http.Client) error {
 
 	if resp.StatusCode >= 200 && resp.StatusCode <= 299 {
 
-		bodyBytes, err := ioutil.ReadAll(resp.Body)
+		bodyBytes, err := io.ReadAll(resp.Body)
 		if err != nil {
 			applog.Errorf("Failed to read response body from %q, error: %s", config.sendEndpoint, err.Error())
 			return err
@@ -676,7 +681,7 @@ func main() {
 	workerStatuses = make([]workerStatus, config.workers)
 
 	// Logger
-	applog = logger.Init("minigun", config.verbose, false, ioutil.Discard)
+	applog = logger.Init("minigun", config.verbose, false, io.Discard)
 
 	// Some checks
 	if config.sendEndpoint == "" {
@@ -697,7 +702,7 @@ func main() {
 	// Load file if requested
 	if config.sendFile != "" {
 		applog.Infof("Reading file %q", config.sendFile)
-		if data, err := ioutil.ReadFile(config.sendFile); err == nil {
+		if data, err := os.ReadFile(config.sendFile); err == nil {
 			config.sendPayload = data
 		} else {
 			applog.Fatalf("Error reading file %q: %s", config.sendFile, err.Error())

metrics.go

@@ -33,6 +33,15 @@ type appMetrics struct {
 	channelLength       *prometheus.GaugeVec
 	channelConfigLength *prometheus.GaugeVec
 
+	// Histograms
+	histRequestsDuration         *prometheus.HistogramVec
+	histDNSDuration              *prometheus.HistogramVec
+	histConnectDuration          *prometheus.HistogramVec
+	histGotFirstByteDuration     *prometheus.HistogramVec
+	histTLSHandshakeDuration     *prometheus.HistogramVec
+	histWroteRequestBodyDuration *prometheus.HistogramVec
+	histResponseDuration         *prometheus.HistogramVec
+
 	// Summaries
 	summaryRequestsDuration         *prometheus.SummaryVec
 	summaryDNSDuration              *prometheus.SummaryVec
@@ -95,6 +104,17 @@ func initMetrics(config appConfig, labelNames, labelValues []string) appMetrics
 		am.labelNames,
 	)
 
+	am.histRequestsDuration = promauto.With(registry).NewHistogramVec(
+		prometheus.HistogramOpts{
+			Namespace: "minigun",
+			Subsystem: "requests",
+			Name:      "hist_duration_seconds",
+			Help:      "Histogram distribution of request durations, in seconds",
+			Buckets:   secondsDurationBuckets,
+		},
+		am.labelNames,
+	)
+
 	am.summaryRequestsDuration = promauto.With(registry).NewSummaryVec(
 		prometheus.SummaryOpts{
 			Namespace:  "minigun",
@@ -107,6 +127,17 @@ func initMetrics(config appConfig, labelNames, labelValues []string) appMetrics
 	)
 
 	// DNS metrics
+	am.histDNSDuration = promauto.With(registry).NewHistogramVec(
+		prometheus.HistogramOpts{
+			Namespace: "minigun",
+			Subsystem: "httptrace",
+			Name:      "hist_dns_duration_seconds",
+			Help:      "Histogram distribution of DNS durations, in seconds",
+			Buckets:   secondsDurationBuckets,
+		},
+		am.labelNames,
+	)
+
 	am.summaryDNSDuration = promauto.With(registry).NewSummaryVec(
 		prometheus.SummaryOpts{
 			Namespace:  "minigun",
@@ -119,6 +150,17 @@ func initMetrics(config appConfig, labelNames, labelValues []string) appMetrics
 	)
 
 	// Connection metrics
+	am.histConnectDuration = promauto.With(registry).NewHistogramVec(
+		prometheus.HistogramOpts{
+			Namespace: "minigun",
+			Subsystem: "httptrace",
+			Name:      "hist_connect_duration_seconds",
+			Help:      "Histogram distribution of connection durations, in seconds",
+			Buckets:   secondsDurationBuckets,
+		},
+		am.labelNames,
+	)
+
 	am.summaryConnectDuration = promauto.With(registry).NewSummaryVec(
 		prometheus.SummaryOpts{
 			Namespace:  "minigun",
@@ -131,6 +173,17 @@ func initMetrics(config appConfig, labelNames, labelValues []string) appMetrics
 	)
 
 	// Response first byte metrics
+	am.histGotFirstByteDuration = promauto.With(registry).NewHistogramVec(
+		prometheus.HistogramOpts{
+			Namespace: "minigun",
+			Subsystem: "httptrace",
+			Name:      "hist_time_to_first_byte_seconds",
+			Help:      "Histogram distribution of time to first byte durations, in seconds",
+			Buckets:   secondsDurationBuckets,
+		},
+		am.labelNames,
+	)
+
 	am.summaryGotFirstByteDuration = promauto.With(registry).NewSummaryVec(
 		prometheus.SummaryOpts{
 			Namespace:  "minigun",
@@ -143,6 +196,17 @@ func initMetrics(config appConfig, labelNames, labelValues []string) appMetrics
 	)
 
 	// TLS handshake metrics
+	am.histTLSHandshakeDuration = promauto.With(registry).NewHistogramVec(
+		prometheus.HistogramOpts{
+			Namespace: "minigun",
+			Subsystem: "httptrace",
+			Name:      "hist_tls_handshake_duration_seconds",
+			Help:      "Histogram distribution of TLS Handshake durations, in seconds",
+			Buckets:   secondsDurationBuckets,
+		},
+		am.labelNames,
+	)
+
 	am.summaryTLSHandshakeDuration = promauto.With(registry).NewSummaryVec(
 		prometheus.SummaryOpts{
 			Namespace:  "minigun",
@@ -155,6 +219,17 @@ func initMetrics(config appConfig, labelNames, labelValues []string) appMetrics
 	)
 
 	// Request body sent metrics
+	am.histWroteRequestBodyDuration = promauto.With(registry).NewHistogramVec(
+		prometheus.HistogramOpts{
+			Namespace: "minigun",
+			Subsystem: "httptrace",
+			Name:      "hist_write_request_body_duration_seconds",
+			Help:      "Histogram distribution of WroteRequestBody durations, in seconds",
+			Buckets:   secondsDurationBuckets,
+		},
+		am.labelNames,
+	)
+
 	am.summaryWroteRequestBodyDuration = promauto.With(registry).NewSummaryVec(
 		prometheus.SummaryOpts{
 			Namespace:  "minigun",
@@ -187,6 +262,17 @@ func initMetrics(config appConfig, labelNames, labelValues []string) appMetrics
 		am.labelNames,
 	)
 
+	am.histResponseDuration = promauto.With(registry).NewHistogramVec(
+		prometheus.HistogramOpts{
+			Namespace: "minigun",
+			Subsystem: "response",
+			Name:      "hist_duration_seconds",
+			Help:      "Histogram distribution of response durations, in seconds",
+			Buckets:   secondsDurationBuckets,
+		},
+		append(am.labelNames, "status"),
+	)
+
 	am.summaryResponseDuration = promauto.With(registry).NewSummaryVec(
 		prometheus.SummaryOpts{
 			Namespace:  "minigun",