20602: Add queue metrics.

Arvados-DCO-1.1-Signed-off-by: Tom Clegg <tom@curii.com>

diff --git a/sdk/go/httpserver/request_limiter.go b/sdk/go/httpserver/request_limiter.go
index cd928e6ea85f6199575563bd552d73eca066a074..f9f94ff987e2b23feafdee0c38d0abbe705ad0a4 100644 (file)
--- a/sdk/go/httpserver/request_limiter.go
+++ b/sdk/go/httpserver/request_limiter.go
@@ -147,6 +147,13 @@ func (rl *RequestLimiter) setup() {
                        },
                        func() float64 { return float64(rl.MaxQueue) },
                ))
+               rl.mQueueDelay = prometheus.NewSummary(prometheus.SummaryOpts{
+                       Namespace:  "arvados",
+                       Name:       "queue_delay_seconds",
+                       Help:       "Number of seconds spent in the incoming request queue",
+                       Objectives: map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.95: 0.005, 0.99: 0.001},
+               })
+               reg.MustRegister(rl.mQueueDelay)
        }
 }