update promethues api.

examples/prometheus_test.go

@@ -28,7 +28,7 @@ func HandlerAddCounter(ctx espresso.Context) error {
 }
 
 func LaunchWithPrometheus() (addr string, cancel func()) {
-	server, _ := espresso.New(prometheus.New("/metrics"))
+	server, _ := espresso.New(prometheus.New())
 
 	server.HandleFunc(HandlerAddCounter)
 
@@ -81,16 +81,8 @@ func ExampleMonitoringWithPrometheus() {
 	// 200 text/plain; version=0.0.4; charset=utf-8 # HELP mycounter
 	// # TYPE mycounter counter
 	// mycounter 0
-	// # HELP promhttp_metric_handler_errors_total Total number of internal errors encountered by the promhttp metric handler.
-	// # TYPE promhttp_metric_handler_errors_total counter
-	// promhttp_metric_handler_errors_total{cause="encoding"} 0
-	// promhttp_metric_handler_errors_total{cause="gathering"} 0
 
 	// 200 text/plain; version=0.0.4; charset=utf-8 # HELP mycounter
 	// # TYPE mycounter counter
 	// mycounter 100
-	// # HELP promhttp_metric_handler_errors_total Total number of internal errors encountered by the promhttp metric handler.
-	// # TYPE promhttp_metric_handler_errors_total counter
-	// promhttp_metric_handler_errors_total{cause="encoding"} 0
-	// promhttp_metric_handler_errors_total{cause="gathering"} 0
 }

monitoring/prometheus/metric.go

@@ -8,92 +8,132 @@ import (
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 )
 
-var DefaultRegistry = prometheus.NewRegistry()
-
 type GaugeOpts = prometheus.GaugeOpts
 
 func NewGauge(opt GaugeOpts) prometheus.Gauge {
 	ret := prometheus.NewGauge(opt)
-	DefaultRegistry.MustRegister(ret)
+	prometheus.MustRegister(ret)
 	return ret
 }
 
 func NewGaugeFunc(opt GaugeOpts, fn func() float64) prometheus.GaugeFunc {
 	ret := prometheus.NewGaugeFunc(opt, fn)
-	DefaultRegistry.MustRegister(ret)
+	prometheus.MustRegister(ret)
 	return ret
 }
 
 func NewGaugeVec(opt GaugeOpts, labels []string) *prometheus.GaugeVec {
 	ret := prometheus.NewGaugeVec(opt, labels)
-	DefaultRegistry.MustRegister(ret)
+	prometheus.MustRegister(ret)
 	return ret
 }
 
 type CounterOpts = prometheus.CounterOpts
 
 func NewCounter(opt CounterOpts) prometheus.Counter {
 	ret := prometheus.NewCounter(opt)
-	DefaultRegistry.MustRegister(ret)
+	prometheus.MustRegister(ret)
 	return ret
 }
 
 func NewCounterFunc(opt CounterOpts, fn func() float64) prometheus.CounterFunc {
 	ret := prometheus.NewCounterFunc(opt, fn)
-	DefaultRegistry.MustRegister(ret)
+	prometheus.MustRegister(ret)
 	return ret
 }
 
 func NewCounterVec(opt CounterOpts, labels []string) *prometheus.CounterVec {
 	ret := prometheus.NewCounterVec(opt, labels)
-	DefaultRegistry.MustRegister(ret)
+	prometheus.MustRegister(ret)
 	return ret
 }
 
 type SummaryOpts = prometheus.SummaryOpts
 
 func NewSummary(opt SummaryOpts) prometheus.Summary {
 	ret := prometheus.NewSummary(opt)
-	DefaultRegistry.MustRegister(ret)
+	prometheus.MustRegister(ret)
 	return ret
 }
 
 func NewSummaryVec(opt SummaryOpts, labels []string) *prometheus.SummaryVec {
 	ret := prometheus.NewSummaryVec(opt, labels)
-	DefaultRegistry.MustRegister(ret)
+	prometheus.MustRegister(ret)
 	return ret
 }
 
 type HistogramOpts = prometheus.HistogramOpts
 
 func NewHistogram(opt HistogramOpts) prometheus.Histogram {
 	ret := prometheus.NewHistogram(opt)
-	DefaultRegistry.MustRegister(ret)
+	prometheus.MustRegister(ret)
 	return ret
 }
 
 func NewHistogramVec(opt HistogramOpts, labels []string) *prometheus.HistogramVec {
 	ret := prometheus.NewHistogramVec(opt, labels)
-	DefaultRegistry.MustRegister(ret)
+	prometheus.MustRegister(ret)
 	return ret
 }
 
 type UntypedOpts = prometheus.UntypedOpts
 
 func NewUntypedFunc(opt UntypedOpts, fn func() float64) prometheus.UntypedFunc {
 	ret := prometheus.NewUntypedFunc(opt, fn)
-	DefaultRegistry.MustRegister(ret)
+	prometheus.MustRegister(ret)
 	return ret
 }
 
-func New(path string) espresso.ServerOption {
-	handler := promhttp.HandlerFor(DefaultRegistry, promhttp.HandlerOpts{
-		Registry: DefaultRegistry,
-	})
+type Prometheus struct {
+	path      string
+	registry  prometheus.Registerer
+	gatherers prometheus.Gatherers
+}
+
+type Option func(*Prometheus)
+
+func WithPath(path string) Option {
+	return func(p *Prometheus) {
+		if path == "" {
+			return
+		}
+
+		p.path = path
+	}
+}
+
+func WithRegistry(registry *prometheus.Registry) Option {
+	return func(p *Prometheus) {
+		if registry == nil {
+			return
+		}
+
+		p.registry = registry
+	}
+}
+
+func WithGatherers(gatherer ...prometheus.Gatherer) Option {
+	return func(p *Prometheus) {
+		p.gatherers = gatherer
+	}
+}
+
+func New(opts ...Option) espresso.ServerOption {
+	p := Prometheus{
+		path:      "/metrics",
+		registry:  prometheus.DefaultRegisterer,
+		gatherers: []prometheus.Gatherer{prometheus.DefaultGatherer},
+	}
+
+	for _, opt := range opts {
+		opt(&p)
+	}
+
+	handler := promhttp.InstrumentMetricHandler(p.registry, promhttp.HandlerFor(p.gatherers, promhttp.HandlerOpts{}))
 
 	return func(s *espresso.Server) error {
 		s.HandleFunc(func(ctx espresso.Context) error {
-			if err := ctx.Endpoint(http.MethodGet, path).End(); err != nil {
+			if err := ctx.Endpoint(http.MethodGet, p.path).End(); err != nil {
 				return err
 			}