/
metrics.go
113 lines (99 loc) · 2.94 KB
/
metrics.go
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// Copyright 2020 The Swarm Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package api
import (
"fmt"
"net/http"
"time"
m "github.com/ethsana/sana/pkg/metrics"
"github.com/prometheus/client_golang/prometheus"
)
type metrics struct {
// all metrics fields must be exported
// to be able to return them by Metrics()
// using reflection
RequestCount prometheus.Counter
ResponseDuration prometheus.Histogram
PingRequestCount prometheus.Counter
ResponseCodeCounts *prometheus.CounterVec
}
func newMetrics() metrics {
subsystem := "api"
return metrics{
RequestCount: prometheus.NewCounter(prometheus.CounterOpts{
Namespace: m.Namespace,
Subsystem: subsystem,
Name: "request_count",
Help: "Number of API requests.",
}),
ResponseDuration: prometheus.NewHistogram(prometheus.HistogramOpts{
Namespace: m.Namespace,
Subsystem: subsystem,
Name: "response_duration_seconds",
Help: "Histogram of API response durations.",
Buckets: []float64{0.01, 0.1, 0.25, 0.5, 1, 2.5, 5, 10},
}),
ResponseCodeCounts: prometheus.NewCounterVec(
prometheus.CounterOpts{
Namespace: m.Namespace,
Subsystem: subsystem,
Name: "response_code_count",
Help: "Response count grouped by status code",
},
[]string{"code", "method"},
),
}
}
func (s *server) Metrics() []prometheus.Collector {
return m.PrometheusCollectorsFromFields(s.metrics)
}
func (s *server) pageviewMetricsHandler(h http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
start := time.Now()
s.metrics.RequestCount.Inc()
h.ServeHTTP(w, r)
s.metrics.ResponseDuration.Observe(time.Since(start).Seconds())
})
}
func (s *server) responseCodeMetricsHandler(h http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
wrapper := newResponseWriter(w)
h.ServeHTTP(wrapper, r)
s.metrics.ResponseCodeCounts.WithLabelValues(
fmt.Sprintf("%d", wrapper.statusCode),
r.Method,
).Inc()
})
}
// UpgradedResponseWriter adds more functionality on top of ResponseWriter
type UpgradedResponseWriter interface {
http.ResponseWriter
http.Pusher
http.Hijacker
http.Flusher
// staticcheck SA1019 CloseNotifier interface is required by gorilla compress handler
// nolint:staticcheck
http.CloseNotifier // skipcq: SCC-SA1019
}
type responseWriter struct {
UpgradedResponseWriter
statusCode int
wroteHeader bool
}
func newResponseWriter(w http.ResponseWriter) *responseWriter {
// StatusOK is called by default if nothing else is called
uw := w.(UpgradedResponseWriter)
return &responseWriter{uw, http.StatusOK, false}
}
func (rw *responseWriter) Status() int {
return rw.statusCode
}
func (rw *responseWriter) WriteHeader(code int) {
if rw.wroteHeader {
return
}
rw.statusCode = code
rw.UpgradedResponseWriter.WriteHeader(code)
rw.wroteHeader = true
}