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package metrics
import (
"net/http"
"strconv"
"time"
"github.com/ethereum-optimism/optimism/op-service/httputil"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/promauto"
)
var httpLabels = []string{
"method",
"response_code",
}
type HTTPParams struct {
Method string
StatusCode int
}
type HTTPRecorder interface {
RecordHTTPRequestDuration(params *HTTPParams, dur time.Duration)
RecordHTTPResponseSize(params *HTTPParams, size int)
RecordInflightRequest(params *HTTPParams, quantity int)
RecordHTTPRequest(params *HTTPParams)
RecordHTTPResponse(params *HTTPParams)
}
type noopHTTPRecorder struct{}
var NoopHTTPRecorder = new(noopHTTPRecorder)
func (n *noopHTTPRecorder) RecordHTTPRequestDuration(*HTTPParams, time.Duration) {}
func (n *noopHTTPRecorder) RecordHTTPResponseSize(*HTTPParams, int) {}
func (n *noopHTTPRecorder) RecordInflightRequest(*HTTPParams, int) {}
func (n *noopHTTPRecorder) RecordHTTPRequest(*HTTPParams) {}
func (n *noopHTTPRecorder) RecordHTTPResponse(*HTTPParams) {}
type PromHTTPRecorder struct {
HTTPRequestDuration *prometheus.HistogramVec
HTTPResponseSize *prometheus.HistogramVec
HTTPInflightRequests *prometheus.GaugeVec
HTTPRequests *prometheus.CounterVec
HTTPResponses *prometheus.CounterVec
}
func NewPromHTTPRecorder(r *prometheus.Registry, ns string) HTTPRecorder {
return &PromHTTPRecorder{
HTTPRequestDuration: promauto.With(r).NewHistogramVec(prometheus.HistogramOpts{
Namespace: ns,
Name: "http_request_duration_ms",
Help: "Tracks HTTP request durations, in ms",
Buckets: prometheus.DefBuckets,
}, httpLabels),
HTTPResponseSize: promauto.With(r).NewHistogramVec(prometheus.HistogramOpts{
Namespace: ns,
Name: "http_response_size",
Help: "Tracks HTTP response sizes",
Buckets: prometheus.DefBuckets,
}, httpLabels),
HTTPInflightRequests: promauto.With(r).NewGaugeVec(prometheus.GaugeOpts{
Namespace: ns,
Name: "http_inflight_requests_count",
Help: "Tracks currently in-flight requests",
}, []string{"method"}),
HTTPRequests: promauto.With(r).NewCounterVec(prometheus.CounterOpts{
Namespace: ns,
Name: "http_requests_count_total",
Help: "Tracks total HTTP requests",
}, []string{"method"}),
HTTPResponses: promauto.With(r).NewCounterVec(prometheus.CounterOpts{
Namespace: ns,
Name: "http_responses_count_total",
Help: "Tracks total HTTP responses",
}, httpLabels),
}
}
func (p *PromHTTPRecorder) RecordHTTPRequestDuration(params *HTTPParams, dur time.Duration) {
p.HTTPRequestDuration.WithLabelValues(params.Method, strconv.Itoa(params.StatusCode)).
Observe(float64(dur.Milliseconds()))
}
func (p *PromHTTPRecorder) RecordHTTPResponseSize(params *HTTPParams, size int) {
p.HTTPResponseSize.WithLabelValues(params.Method, strconv.Itoa(params.StatusCode)).Observe(float64(size))
}
func (p *PromHTTPRecorder) RecordInflightRequest(params *HTTPParams, quantity int) {
p.HTTPInflightRequests.WithLabelValues(params.Method).Add(float64(quantity))
}
func (p *PromHTTPRecorder) RecordHTTPRequest(params *HTTPParams) {
p.HTTPRequests.WithLabelValues(params.Method).Inc()
}
func (p *PromHTTPRecorder) RecordHTTPResponse(params *HTTPParams) {
p.HTTPResponses.WithLabelValues(params.Method, strconv.Itoa(params.StatusCode)).Inc()
}
func NewHTTPRecordingMiddleware(rec HTTPRecorder, next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
ww := httputil.NewWrappedResponseWriter(w)
params := &HTTPParams{
Method: r.Method,
}
rec.RecordInflightRequest(params, 1)
rec.RecordHTTPRequest(params)
start := time.Now()
next.ServeHTTP(ww, r)
params.StatusCode = ww.StatusCode
dur := time.Since(start)
rec.RecordHTTPResponse(params)
rec.RecordHTTPResponseSize(params, ww.ResponseLen)
rec.RecordHTTPRequestDuration(params, dur)
rec.RecordInflightRequest(params, -1)
})
}