metrics: Fix panic when headers aren't written (#3737)

Signed-off-by: Dave Henderson <dhenderson@gmail.com>
This commit is contained in:
Dave Henderson
2020-09-21 15:42:47 -04:00
committed by GitHub
parent d16ede358a
commit b1d456d8ab
2 changed files with 27 additions and 1 deletions

View File

@ -108,7 +108,7 @@ func newMetricsInstrumentedHandler(handler string, mh MiddlewareHandler) *metric
func (h *metricsInstrumentedHandler) ServeHTTP(w http.ResponseWriter, r *http.Request, next Handler) error {
server := serverNameFromContext(r.Context())
labels := prometheus.Labels{"server": server, "handler": h.handler}
statusLabels := prometheus.Labels{"server": server, "handler": h.handler, "method": r.Method}
statusLabels := prometheus.Labels{"server": server, "handler": h.handler, "method": r.Method, "code": ""}
inFlight := httpMetrics.requestInFlight.With(labels)
inFlight.Inc()
@ -134,6 +134,14 @@ func (h *metricsInstrumentedHandler) ServeHTTP(w http.ResponseWriter, r *http.Re
return err
}
// If the code hasn't been set yet, and we didn't encounter an error, we're
// probably falling through with an empty handler.
if statusLabels["code"] == "" {
// we still sanitize it, even though it's likely to be 0. A 200 is
// returned on fallthrough so we want to reflect that.
statusLabels["code"] = sanitizeCode(wrec.Status())
}
httpMetrics.requestDuration.With(statusLabels).Observe(dur)
httpMetrics.requestSize.With(statusLabels).Observe(float64(computeApproximateRequestSize(r)))
httpMetrics.responseSize.With(statusLabels).Observe(float64(wrec.Size()))