forked from knative/serving
/
request_metric.go
65 lines (54 loc) · 1.8 KB
/
request_metric.go
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/*
Copyright 2019 The Knative Authors
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package queue
import (
"errors"
"net/http"
"time"
pkghttp "github.com/knative/serving/pkg/http"
"github.com/knative/serving/pkg/queue/stats"
)
type requestMetricHandler struct {
handler http.Handler
statsReporter stats.StatsReporter
}
// NewRequestMetricHandler creates an http.Handler that emits request metrics.
func NewRequestMetricHandler(h http.Handler, r stats.StatsReporter) (http.Handler, error) {
if r == nil {
return nil, errors.New("StatsReporter must not be nil")
}
return &requestMetricHandler{
handler: h,
statsReporter: r,
}, nil
}
func (h *requestMetricHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
rr := pkghttp.NewResponseRecorder(w, http.StatusOK)
startTime := time.Now()
defer func() {
// If ServeHTTP panics, recover, record the failure and panic again.
err := recover()
latency := time.Since(startTime)
if err != nil {
h.sendRequestMetrics(http.StatusInternalServerError, latency)
panic(err)
} else {
h.sendRequestMetrics(rr.ResponseCode, latency)
}
}()
h.handler.ServeHTTP(rr, r)
}
func (h *requestMetricHandler) sendRequestMetrics(respCode int, latency time.Duration) {
h.statsReporter.ReportRequestCount(respCode, 1)
h.statsReporter.ReportResponseTime(respCode, latency)
}