[FSSDK-8707] feat(metrics): Adds support for prometheus

cmd/optimizely/main.go

@@ -144,7 +144,8 @@ func main() {
 
 	setRuntimeEnvironment(conf.Runtime)
 
-	agentMetricsRegistry := metrics.NewRegistry()
+	// Set metrics type to be used
+	agentMetricsRegistry := metrics.NewRegistry(conf.Admin.MetricsType)
 	sdkMetricsRegistry := optimizely.NewRegistry(agentMetricsRegistry)
 
 	ctx, cancel := context.WithCancel(context.Background()) // Create default service context

cmd/optimizely/main_test.go

@@ -121,6 +121,7 @@ func assertLog(t *testing.T, actual config.LogConfig) {
 
 func assertAdmin(t *testing.T, actual config.AdminConfig) {
 	assert.Equal(t, "3002", actual.Port)
+	assert.Equal(t, "prometheus", actual.MetricsType)
 }
 
 func assertAdminAuth(t *testing.T, actual config.ServiceAuthConfig) {
@@ -282,6 +283,7 @@ func TestViperProps(t *testing.T) {
 	v.Set("log.level", "debug")
 
 	v.Set("admin.port", "3002")
+	v.Set("admin.metricsType", "prometheus")
 	v.Set("admin.auth.ttl", "30m")
 	v.Set("admin.auth.hmacSecrets", "efgh,ijkl")
 	v.Set("admin.auth.jwksURL", "admin_jwks_url")
@@ -375,6 +377,7 @@ func TestViperEnv(t *testing.T) {
 	_ = os.Setenv("OPTIMIZELY_LOG_LEVEL", "debug")
 
 	_ = os.Setenv("OPTIMIZELY_ADMIN_PORT", "3002")
+	_ = os.Setenv("OPTIMIZELY_ADMIN_METRICSTYPE", "prometheus")
 
 	_ = os.Setenv("OPTIMIZELY_API_MAXCONNS", "100")
 	_ = os.Setenv("OPTIMIZELY_API_PORT", "3000")

cmd/optimizely/testdata/default.yaml

@@ -70,6 +70,7 @@ client:
 
 admin:
   port: "3002"
+  metricsType: "prometheus"
   auth:
     ttl: 30m
     hmacSecrets:

config.yaml

@@ -95,6 +95,10 @@ api:
 admin:
     ## http listener port
     port: "8088"
+    ## metrics package to use
+    ## supported packages are expvar and prometheus
+    ## default is expvar
+    metricsType: ""
 ##
 ## webhook service receives update notifications to your Optimizely project. Receipt of the webhook will
 ## trigger an immediate download of the datafile from the CDN

config/config.go

@@ -39,7 +39,8 @@ func NewDefaultConfig() *AgentConfig {
 				JwksURL:            "",
 				JwksUpdateInterval: 0,
 			},
-			Port: "8088",
+			Port:        "8088",
+			MetricsType: "expvar",
 		},
 		API: APIConfig{
 			Auth: ServiceAuthConfig{
@@ -255,8 +256,9 @@ type CORSConfig struct {
 
 // AdminConfig holds the configuration for the admin web interface
 type AdminConfig struct {
-	Auth ServiceAuthConfig `json:"-"`
-	Port string            `json:"port"`
+	Auth        ServiceAuthConfig `json:"-"`
+	Port        string            `json:"port"`
+	MetricsType string            `json:"metricsType"`
 }
 
 // WebhookConfig holds configuration for Optimizely Webhooks

config/config_test.go

@@ -50,6 +50,7 @@ func TestDefaultConfig(t *testing.T) {
 	assert.Equal(t, "info", conf.Log.Level)
 
 	assert.Equal(t, "8088", conf.Admin.Port)
+	assert.Equal(t, "expvar", conf.Admin.MetricsType)
 	assert.Equal(t, make([]OAuthClientCredentials, 0), conf.Admin.Auth.Clients)
 	assert.Equal(t, make([]string, 0), conf.Admin.Auth.HMACSecrets)
 	assert.Equal(t, time.Duration(0), conf.Admin.Auth.TTL)

go.mod

@@ -12,8 +12,9 @@ require (
 	github.com/golang-jwt/jwt/v4 v4.5.0
 	github.com/google/uuid v1.3.0
 	github.com/lestrrat-go/jwx v0.9.0
-	github.com/optimizely/go-sdk v1.8.4-0.20230411182937-99d0bcfccf75
+	github.com/optimizely/go-sdk v1.8.4-0.20230515121609-7ffed835c991
 	github.com/orcaman/concurrent-map v1.0.0
+	github.com/prometheus/client_golang v1.11.0
 	github.com/rakyll/statik v0.1.7
 	github.com/rs/zerolog v1.29.0
 	github.com/spf13/viper v1.15.0
@@ -23,6 +24,16 @@ require (
 	gopkg.in/yaml.v2 v2.4.0
 )
 
+require (
+	github.com/beorn7/perks v1.0.1 // indirect
+	github.com/golang/protobuf v1.5.2 // indirect
+	github.com/matttproud/golang_protobuf_extensions v1.0.1 // indirect
+	github.com/prometheus/client_model v0.2.0 // indirect
+	github.com/prometheus/common v0.30.0 // indirect
+	github.com/prometheus/procfs v0.7.3 // indirect
+	google.golang.org/protobuf v1.28.1 // indirect
+)
+
 require (
 	github.com/VividCortex/gohistogram v1.0.0 // indirect
 	github.com/ajg/form v1.5.1 // indirect

pkg/handlers/admin_entities.go

@@ -1,5 +1,5 @@
 /****************************************************************************
- * Copyright 2019-2020, Optimizely, Inc. and contributors                   *
+ * Copyright 2019-2020,2023 Optimizely, Inc. and contributors               *
  *                                                                          *
  * Licensed under the Apache License, Version 2.0 (the "License");          *
  * you may not use this file except in compliance with the License.         *
@@ -18,14 +18,13 @@
 package handlers
 
 import (
-	"expvar"
 	"net/http"
 	"os"
 	"time"
 
 	"github.com/go-chi/render"
-
 	"github.com/optimizely/agent/config"
+	"github.com/optimizely/agent/pkg/metrics"
 )
 
 var startTime = time.Now()
@@ -87,5 +86,5 @@ func (a Admin) AppInfoHeader(next http.Handler) http.Handler {
 
 // Metrics returns expvar info
 func (a Admin) Metrics(w http.ResponseWriter, r *http.Request) {
-	expvar.Handler().ServeHTTP(w, r)
+	metrics.GetHandler(a.Config.Admin.MetricsType).ServeHTTP(w, r)
 }

pkg/metrics/metrics.go

@@ -18,11 +18,17 @@
 package metrics
 
 import (
+	"expvar"
+	"net/http"
+	"regexp"
+	"strings"
 	"sync"
 
 	go_kit_metrics "github.com/go-kit/kit/metrics"
-
 	go_kit_expvar "github.com/go-kit/kit/metrics/expvar"
+	go_kit_prometheus "github.com/go-kit/kit/metrics/prometheus"
+	stdprometheus "github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"github.com/rs/zerolog/log"
 )
 
@@ -33,37 +39,49 @@ const (
 	TimerPrefix   = "timer"
 )
 
+const (
+	prometheusPackage = "prometheus"
+)
+
+// GetHandler returns request handler for provided metrics package type
+func GetHandler(packageType string) http.Handler {
+	switch packageType {
+	case prometheusPackage:
+		return promhttp.Handler()
+	default:
+		// expvar
+		return expvar.Handler()
+	}
+}
+
+// Timer is the collection of some timers
+type Timer struct {
+	hits      go_kit_metrics.Counter
+	totalTime go_kit_metrics.Counter
+	histogram go_kit_metrics.Histogram
+}
+
+// Update timer components
+func (t *Timer) Update(delta float64) {
+	t.hits.Add(1)
+	t.totalTime.Add(delta)
+	t.histogram.Observe(delta)
+}
+
 // Registry initializes expvar metrics registry
 type Registry struct {
 	metricsCounterVars   map[string]go_kit_metrics.Counter
 	metricsGaugeVars     map[string]go_kit_metrics.Gauge
 	metricsHistogramVars map[string]go_kit_metrics.Histogram
 	metricsTimerVars     map[string]*Timer
+	metricsType          string
 
 	gaugeLock     sync.RWMutex
 	counterLock   sync.RWMutex
 	histogramLock sync.RWMutex
 	timerLock     sync.RWMutex
 }
 
-// NewRegistry initializes metrics registry
-func NewRegistry() *Registry {
-
-	return &Registry{
-		metricsCounterVars:   map[string]go_kit_metrics.Counter{},
-		metricsGaugeVars:     map[string]go_kit_metrics.Gauge{},
-		metricsHistogramVars: map[string]go_kit_metrics.Histogram{},
-		metricsTimerVars:     map[string]*Timer{},
-	}
-}
-
-// Timer is the collection of some timers
-type Timer struct {
-	hits      go_kit_metrics.Counter
-	totalTime go_kit_metrics.Counter
-	histogram go_kit_metrics.Histogram
-}
-
 // NewTimer constructs Timer
 func (m *Registry) NewTimer(key string) *Timer {
 	if key == "" {
@@ -81,16 +99,22 @@ func (m *Registry) NewTimer(key string) *Timer {
 	return m.createTimer(combinedKey)
 }
 
-// Update timer components
-func (t *Timer) Update(delta float64) {
-	t.hits.Add(1)
-	t.totalTime.Add(delta)
-	t.histogram.Observe(delta)
+// GetCounter gets go-kit expvar Counter
+// NewRegistry initializes metrics registry
+func NewRegistry(metricsType string) *Registry {
+
+	registry := &Registry{
+		metricsCounterVars:   map[string]go_kit_metrics.Counter{},
+		metricsGaugeVars:     map[string]go_kit_metrics.Gauge{},
+		metricsHistogramVars: map[string]go_kit_metrics.Histogram{},
+		metricsTimerVars:     map[string]*Timer{},
+		metricsType:          metricsType,
+	}
+	return registry
 }
 
-// GetCounter gets go-kit expvar Counter
+// GetCounter gets go-kit Counter
 func (m *Registry) GetCounter(key string) go_kit_metrics.Counter {
-
 	if key == "" {
 		log.Warn().Msg("metrics counter key is empty")
 		return nil
@@ -103,13 +127,11 @@ func (m *Registry) GetCounter(key string) go_kit_metrics.Counter {
 	if val, ok := m.metricsCounterVars[combinedKey]; ok {
 		return val
 	}
-
 	return m.createCounter(combinedKey)
 }
 
-// GetGauge gets go-kit expvar Gauge
+// GetGauge gets go-kit Gauge
 func (m *Registry) GetGauge(key string) go_kit_metrics.Gauge {
-
 	if key == "" {
 		log.Warn().Msg("metrics gauge key is empty")
 		return nil
@@ -127,9 +149,8 @@ func (m *Registry) GetGauge(key string) go_kit_metrics.Gauge {
 
 // GetHistogram gets go-kit Histogram
 func (m *Registry) GetHistogram(key string) go_kit_metrics.Histogram {
-
 	if key == "" {
-		log.Warn().Msg("metrics gauge key is empty")
+		log.Warn().Msg("metrics histogram key is empty")
 		return nil
 	}
 
@@ -141,25 +162,52 @@ func (m *Registry) GetHistogram(key string) go_kit_metrics.Histogram {
 	return m.createHistogram(key)
 }
 
-func (m *Registry) createGauge(key string) *go_kit_expvar.Gauge {
-	gaugeVar := go_kit_expvar.NewGauge(key)
+func (m *Registry) createGauge(key string) (gaugeVar go_kit_metrics.Gauge) {
+	// This is required since naming convention for every package differs
+	name := m.getPackageSupportedName(key)
+	switch m.metricsType {
+	case prometheusPackage:
+		gaugeVar = go_kit_prometheus.NewGaugeFrom(stdprometheus.GaugeOpts{
+			Name: name,
+		}, []string{})
+	default:
+		// Default expvar
+		gaugeVar = go_kit_expvar.NewGauge(name)
+	}
 	m.metricsGaugeVars[key] = gaugeVar
-	return gaugeVar
-
+	return
 }
 
-func (m *Registry) createCounter(key string) *go_kit_expvar.Counter {
-	counterVar := go_kit_expvar.NewCounter(key)
+func (m *Registry) createCounter(key string) (counterVar go_kit_metrics.Counter) {
+	// This is required since naming convention for every package differs
+	name := m.getPackageSupportedName(key)
+	switch m.metricsType {
+	case prometheusPackage:
+		counterVar = go_kit_prometheus.NewCounterFrom(stdprometheus.CounterOpts{
+			Name: name,
+		}, []string{})
+	default:
+		// Default expvar
+		counterVar = go_kit_expvar.NewCounter(name)
+	}
 	m.metricsCounterVars[key] = counterVar
-	return counterVar
-
+	return
 }
 
-func (m *Registry) createHistogram(key string) *go_kit_expvar.Histogram {
-	histogramVar := go_kit_expvar.NewHistogram(key, 50)
+func (m *Registry) createHistogram(key string) (histogramVar go_kit_metrics.Histogram) {
+	// This is required since naming convention for every package differs
+	name := m.getPackageSupportedName(key)
+	switch m.metricsType {
+	case prometheusPackage:
+		histogramVar = go_kit_prometheus.NewHistogramFrom(stdprometheus.HistogramOpts{
+			Name: name,
+		}, []string{})
+	default:
+		// Default expvar
+		histogramVar = go_kit_expvar.NewHistogram(name, 50)
+	}
 	m.metricsHistogramVars[key] = histogramVar
-	return histogramVar
-
+	return
 }
 
 func (m *Registry) createTimer(key string) *Timer {
@@ -168,8 +216,33 @@ func (m *Registry) createTimer(key string) *Timer {
 		totalTime: m.createCounter(key + ".responseTime"),
 		histogram: m.createHistogram(key + ".responseTimeHist"),
 	}
-
 	m.metricsTimerVars[key] = timerVar
 	return timerVar
+}
 
+// getPackageSupportedName converts name to package supported type
+func (m *Registry) getPackageSupportedName(name string) string {
+	switch m.metricsType {
+	case prometheusPackage:
+		// https://prometheus.io/docs/practices/naming/
+		return toSnakeCase(name)
+	default:
+		// Default expvar
+		return name
+	}
+}
+
+func toSnakeCase(name string) string {
+	v := strings.Replace(name, "-", "_", -1)
+	strArray := strings.Split(v, ".")
+	var matchFirstCap = regexp.MustCompile("(.)([A-Z][a-z]+)")
+	var matchAllCap = regexp.MustCompile("([a-z0-9])([A-Z])")
+	convertedArray := []string{}
+
+	for _, v := range strArray {
+		snake := matchFirstCap.ReplaceAllString(v, "${1}_${2}")
+		snake = matchAllCap.ReplaceAllString(snake, "${1}_${2}")
+		convertedArray = append(convertedArray, strings.ToLower(snake))
+	}
+	return strings.Join(convertedArray, "_")
 }