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|
package metrics
import (
"net/http"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/promhttp"
)
// HTTPHandlerOpts describes a set of configurable options of http metrics
type HTTPHandlerOpts struct {
DurationBuckets []float64
RequestSizeBuckets []float64
ResponseSizeBuckets []float64
}
const (
InstrumentHandlerResponseSize = iota
InstrumentHandlerRequestSize
InstrumentHandlerDuration
InstrumentHandlerCounter
InstrumentHandlerInFlight
)
type HTTPMetric struct {
prometheus.Collector
handlerType int
}
var (
defaultDurationBuckets = []float64{.005, .01, .025, .05, .1, .25, .5, 1, 2.5, 5, 10, 25, 60}
defaultRequestSizeBuckets = prometheus.ExponentialBuckets(1024, 2, 22) //1K to 4G
defaultResponseSizeBuckets = defaultRequestSizeBuckets
)
// Handler returns the global http.Handler that provides the prometheus
// metrics format on GET requests. This handler is no longer instrumented.
func Handler() http.Handler {
return promhttp.Handler()
}
func InstrumentHandler(metrics []*HTTPMetric, handler http.Handler) http.HandlerFunc {
return InstrumentHandlerFunc(metrics, handler.ServeHTTP)
}
func InstrumentHandlerFunc(metrics []*HTTPMetric, handlerFunc http.HandlerFunc) http.HandlerFunc {
var handler http.Handler
handler = http.HandlerFunc(handlerFunc)
for _, metric := range metrics {
switch metric.handlerType {
case InstrumentHandlerResponseSize:
if collector, ok := metric.Collector.(prometheus.ObserverVec); ok {
handler = promhttp.InstrumentHandlerResponseSize(collector, handler)
}
case InstrumentHandlerRequestSize:
if collector, ok := metric.Collector.(prometheus.ObserverVec); ok {
handler = promhttp.InstrumentHandlerRequestSize(collector, handler)
}
case InstrumentHandlerDuration:
if collector, ok := metric.Collector.(prometheus.ObserverVec); ok {
handler = promhttp.InstrumentHandlerDuration(collector, handler)
}
case InstrumentHandlerCounter:
if collector, ok := metric.Collector.(*prometheus.CounterVec); ok {
handler = promhttp.InstrumentHandlerCounter(collector, handler)
}
case InstrumentHandlerInFlight:
if collector, ok := metric.Collector.(prometheus.Gauge); ok {
handler = promhttp.InstrumentHandlerInFlight(collector, handler)
}
}
}
return handler.ServeHTTP
}
|
