etcdserver: add propose summary

etcdserver/metrics.go

@@ -0,0 +1,41 @@
+// Copyright 2015 CoreOS, Inc.
+//
+// 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 etcdserver
+
+import "github.com/coreos/etcd/Godeps/_workspace/src/github.com/prometheus/client_golang/prometheus"
+
+var (
+	// TODO: with label in v3?
+	proposeDurations = prometheus.NewSummary(prometheus.SummaryOpts{
+		Name: "etcdserver_proposal_durations_milliseconds",
+		Help: "The latency distributions of committing proposal.",
+	})
+	proposePending = prometheus.NewGauge(prometheus.GaugeOpts{
+		Name: "etcdserver_pending_proposal_total",
+		Help: "The total number of pending proposals.",
+	})
+	// This is number of proposal failed in client's view.
+	// The proposal might be later got committed in raft.
+	proposeFailed = prometheus.NewCounter(prometheus.CounterOpts{
+		Name: "etcdserver_proposal_failed_total",
+		Help: "The total number of failed proposals.",
+	})
+)
+
+func init() {
+	prometheus.MustRegister(proposeDurations)
+	prometheus.MustRegister(proposePending)
+	prometheus.MustRegister(proposeFailed)
+}

etcdserver/server.go

@@ -487,12 +487,22 @@ func (s *EtcdServer) Do(ctx context.Context, r pb.Request) (Response, error) {
 			return Response{}, err
 		}
 		ch := s.w.Register(r.ID)
+
+		// TODO: benchmark the cost of time.Now()
+		// might be sampling?
+		start := time.Now()
 		s.r.Propose(ctx, data)
+
+		proposePending.Inc()
+		defer proposePending.Dec()
+
 		select {
 		case x := <-ch:
+			proposeDurations.Observe(float64(time.Since(start).Nanoseconds() / int64(time.Millisecond)))
 			resp := x.(Response)
 			return resp, resp.err
 		case <-ctx.Done():
+			proposeFailed.Inc()
 			s.w.Trigger(r.ID, nil) // GC wait
 			return Response{}, parseCtxErr(ctx.Err())
 		case <-s.done: