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|
package health
import (
"net/http"
"sync"
"time"
"github.com/coredns/coredns/plugin"
"github.com/prometheus/client_golang/prometheus"
)
// overloaded queries the health end point and updates a metrics showing how long it took.
func (h *health) overloaded() {
timeout := time.Duration(5 * time.Second)
client := http.Client{
Timeout: timeout,
}
url := "http://" + h.Addr
tick := time.NewTicker(1 * time.Second)
for {
select {
case <-tick.C:
start := time.Now()
resp, err := client.Get(url)
if err != nil {
HealthDuration.Observe(timeout.Seconds())
continue
}
resp.Body.Close()
HealthDuration.Observe(time.Since(start).Seconds())
case <-h.stop:
tick.Stop()
return
}
}
}
var (
// HealthDuration is the metric used for exporting how fast we can retrieve the /health endpoint.
HealthDuration = prometheus.NewHistogram(prometheus.HistogramOpts{
Namespace: plugin.Namespace,
Subsystem: "health",
Name: "request_duration_seconds",
Buckets: plugin.TimeBuckets,
Help: "Histogram of the time (in seconds) each request took.",
})
)
var once sync.Once
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