getting custom metrics on prometheus

Makefile

@@ -109,7 +109,7 @@ benchmark-test-grpc: ensure-e2e-deps-grpc ensure-testing-bin
 
 unit-test-coverage: kill-testing-deps
 	@echo "===============RUNNING UNIT TESTS==============="
-	@go test $(TESTABLE_PACKAGES) -coverprofile coverprofile.out
+	@go test $(TESTABLE_PACKAGES) -coverprofile coverprofile.out -v
 
 test: kill-testing-deps test-coverage
 	@make rm-test-temp-files

app.go

@@ -142,21 +142,19 @@ func Configure(
 
 func configureMetrics(serverType string) {
 	app.metricsReporters = make([]metrics.Reporter, 0)
-
 	constTags := app.config.GetStringMapString("pitaya.metrics.constTags")
+
 	if app.config.GetBool("pitaya.metrics.prometheus.enabled") {
 		port := app.config.GetInt("pitaya.metrics.prometheus.port")
-		game := app.config.GetString("pitaya.game")
-		logger.Log.Infof(
-			"prometheus is enabled, configuring the metrics reporter on port %d", port,
-		)
-
-		additionalTags := app.config.GetStringMapString("pitaya.metrics.additionalTags")
-		prometheus := metrics.GetPrometheusReporter(serverType, game, port,
-			constTags, additionalTags)
-		AddMetricsReporter(prometheus)
+		logger.Log.Infof("prometheus is enabled, configuring reporter on port %d", port)
+		prometheus, err := metrics.GetPrometheusReporter(serverType, app.config, constTags)
+		if err != nil {
+			logger.Log.Errorf("failed to start prometheus metrics reporter, skipping %v", err)
+		} else {
+			AddMetricsReporter(prometheus)
+		}
 	} else {
-		logger.Log.Info("prometheus is disabled, the metrics reporter will not be enabled")
+		logger.Log.Info("prometheus is disabled, reporter will not be enabled")
 	}
 
 	if app.config.GetBool("pitaya.metrics.statsd.enabled") {

config/config.go

@@ -98,6 +98,7 @@ func (c *Config) fillDefaultValues() {
 		"pitaya.metrics.constTags":                              map[string]string{},
 		"pitaya.metrics.additionalTags":                         map[string]string{},
 		"pitaya.metrics.periodicMetrics.period":                 "15s",
+		"pitaya.metrics.custom":                                 map[string]interface{}{},
 		"pitaya.defaultpipelines.structvalidation.enabled":      false,
 		"pitaya.worker.redis.url":                               "localhost:6379",
 		"pitaya.worker.redis.pool":                              "10",

metrics/models.go

@@ -0,0 +1,55 @@
+package metrics
+
+import (
+	"encoding/json"
+
+	"github.com/topfreegames/pitaya/config"
+)
+
+// Summary ...
+type Summary struct {
+	Subsystem  string
+	Name       string
+	Help       string
+	Objectives map[float64]float64
+	Labels     []string
+}
+
+// Gauge ...
+type Gauge struct {
+	Subsystem string
+	Name      string
+	Help      string
+	Labels    []string
+}
+
+// Counter ...
+type Counter struct {
+	Subsystem string
+	Name      string
+	Help      string
+	Labels    []string
+}
+
+// CustomMetricsSpec ...
+type CustomMetricsSpec struct {
+	Summaries []*Summary
+	Gauges    []*Gauge
+	Counters  []*Counter
+}
+
+// NewCustomMetricsSpec ...
+func NewCustomMetricsSpec(config *config.Config) (*CustomMetricsSpec, error) {
+	bts, err := json.Marshal(config.Get("pitaya.metrics.custom"))
+	if err != nil {
+		return nil, err
+	}
+
+	var spec CustomMetricsSpec
+	err = json.Unmarshal(bts, &spec)
+	if err != nil {
+		return nil, err
+	}
+
+	return &spec, nil
+}

metrics/prometheus_reporter.go

@@ -27,6 +27,7 @@ import (
 	"sync"
 
 	"github.com/prometheus/client_golang/prometheus"
+	"github.com/topfreegames/pitaya/config"
 	"github.com/topfreegames/pitaya/constants"
 )
 
@@ -45,9 +46,57 @@ type PrometheusReporter struct {
 	additionalLabels    map[string]string
 }
 
+func (p *PrometheusReporter) registerCustomMetrics(
+	constLabels map[string]string,
+	spec *CustomMetricsSpec,
+) {
+	for _, summary := range spec.Summaries {
+		p.summaryReportersMap[summary.Name] = prometheus.NewSummaryVec(
+			prometheus.SummaryOpts{
+				Namespace:   "pitaya",
+				Subsystem:   summary.Subsystem,
+				Name:        summary.Name,
+				Help:        summary.Help,
+				Objectives:  summary.Objectives,
+				ConstLabels: constLabels,
+			},
+			summary.Labels,
+		)
+	}
+
+	for _, gauge := range spec.Gauges {
+		p.gaugeReportersMap[gauge.Name] = prometheus.NewGaugeVec(
+			prometheus.GaugeOpts{
+				Namespace:   "pitaya",
+				Subsystem:   gauge.Subsystem,
+				Name:        gauge.Name,
+				Help:        gauge.Help,
+				ConstLabels: constLabels,
+			},
+			gauge.Labels,
+		)
+	}
+
+	for _, counter := range spec.Counters {
+		p.countReportersMap[counter.Name] = prometheus.NewCounterVec(
+			prometheus.CounterOpts{
+				Namespace:   "pitaya",
+				Subsystem:   counter.Subsystem,
+				Name:        counter.Name,
+				Help:        counter.Help,
+				ConstLabels: constLabels,
+			},
+			counter.Labels,
+		)
+	}
+}
+
 func (p *PrometheusReporter) registerMetrics(
 	constLabels, additionalLabels map[string]string,
+	spec *CustomMetricsSpec,
 ) {
+	p.registerCustomMetrics(constLabels, spec)
+
 	constLabels["game"] = p.game
 	constLabels["serverType"] = p.serverType
 
@@ -212,10 +261,21 @@ func (p *PrometheusReporter) registerMetrics(
 
 // GetPrometheusReporter gets the prometheus reporter singleton
 func GetPrometheusReporter(
-	serverType, game string,
-	port int,
-	constLabels, additionalLabels map[string]string,
-) *PrometheusReporter {
+	serverType string,
+	config *config.Config,
+	constLabels map[string]string,
+) (*PrometheusReporter, error) {
+	var (
+		port             = config.GetInt("pitaya.metrics.prometheus.port")
+		game             = config.GetString("pitaya.game")
+		additionalLabels = config.GetStringMapString("pitaya.metrics.additionalTags")
+	)
+
+	spec, err := NewCustomMetricsSpec(config)
+	if err != nil {
+		return nil, err
+	}
+
 	once.Do(func() {
 		prometheusReporter = &PrometheusReporter{
 			serverType:          serverType,
@@ -224,13 +284,14 @@ func GetPrometheusReporter(
 			summaryReportersMap: make(map[string]*prometheus.SummaryVec),
 			gaugeReportersMap:   make(map[string]*prometheus.GaugeVec),
 		}
-		prometheusReporter.registerMetrics(constLabels, additionalLabels)
+		prometheusReporter.registerMetrics(constLabels, additionalLabels, spec)
 		http.Handle("/metrics", prometheus.Handler())
 		go (func() {
 			log.Fatal(http.ListenAndServe(fmt.Sprintf(":%d", port), nil))
 		})()
 	})
-	return prometheusReporter
+
+	return prometheusReporter, nil
 }
 
 // ReportSummary reports a summary metric