kvm/internal/timesync/http.go

133 lines
3.2 KiB
Go

package timesync
import (
"context"
"errors"
"math/rand"
"net/http"
"strconv"
"time"
)
var defaultHTTPUrls = []string{
"http://www.gstatic.com/generate_204",
"http://cp.cloudflare.com/",
"http://edge-http.microsoft.com/captiveportal/generate_204",
// Firefox, Apple, and Microsoft have inconsistent results, so we don't use it
// "http://detectportal.firefox.com/",
// "http://www.apple.com/library/test/success.html",
// "http://www.msftconnecttest.com/connecttest.txt",
}
func (t *TimeSync) queryAllHttpTime() (now *time.Time) {
chunkSize := 4
httpUrls := t.httpUrls
// shuffle the http urls to avoid always querying the same servers
rand.Shuffle(len(httpUrls), func(i, j int) { httpUrls[i], httpUrls[j] = httpUrls[j], httpUrls[i] })
for i := 0; i < len(httpUrls); i += chunkSize {
chunk := httpUrls[i:min(i+chunkSize, len(httpUrls))]
results := t.queryMultipleHttp(chunk, timeSyncTimeout)
if results != nil {
return results
}
}
return nil
}
func (t *TimeSync) queryMultipleHttp(urls []string, timeout time.Duration) (now *time.Time) {
results := make(chan *time.Time, len(urls))
ctx, cancel := context.WithTimeout(context.Background(), timeout)
defer cancel()
for _, url := range urls {
go func(url string) {
scopedLogger := t.l.With().
Str("http_url", url).
Logger()
metricHttpRequestCount.WithLabelValues(url).Inc()
metricHttpTotalRequestCount.Inc()
startTime := time.Now()
now, response, err := queryHttpTime(
ctx,
url,
timeout,
)
duration := time.Since(startTime)
metricHttpServerLastRTT.WithLabelValues(url).Set(float64(duration.Milliseconds()))
metricHttpServerRttHistogram.WithLabelValues(url).Observe(float64(duration.Milliseconds()))
status := 0
if response != nil {
status = response.StatusCode
}
metricHttpServerInfo.WithLabelValues(
url,
strconv.Itoa(status),
).Set(1)
if err == nil {
metricHttpTotalSuccessCount.Inc()
metricHttpSuccessCount.WithLabelValues(url).Inc()
requestId := response.Header.Get("X-Request-Id")
if requestId != "" {
requestId = response.Header.Get("X-Msedge-Ref")
}
if requestId == "" {
requestId = response.Header.Get("Cf-Ray")
}
scopedLogger.Info().
Str("time", now.Format(time.RFC3339)).
Int("status", status).
Str("request_id", requestId).
Str("time_taken", duration.String()).
Msg("HTTP server returned time")
cancel()
results <- now
} else if errors.Is(err, context.Canceled) {
metricHttpCancelCount.WithLabelValues(url).Inc()
metricHttpTotalCancelCount.Inc()
} else {
scopedLogger.Warn().
Str("error", err.Error()).
Int("status", status).
Msg("failed to query HTTP server")
}
}(url)
}
return <-results
}
func queryHttpTime(
ctx context.Context,
url string,
timeout time.Duration,
) (now *time.Time, response *http.Response, err error) {
client := http.Client{
Timeout: timeout,
}
req, err := http.NewRequestWithContext(ctx, "GET", url, nil)
if err != nil {
return nil, nil, err
}
resp, err := client.Do(req)
if err != nil {
return nil, nil, err
}
dateStr := resp.Header.Get("Date")
parsedTime, err := time.Parse(time.RFC1123, dateStr)
if err != nil {
return nil, nil, err
}
return &parsedTime, resp, nil
}