From e3415e953fe7fc4eb52775aa5f1adf347010ee5a Mon Sep 17 00:00:00 2001
From: Julius Volz <julius.volz@gmail.com>
Date: Wed, 31 Jul 2013 00:46:01 +0200
Subject: [PATCH] Add notifications telemetry.

---
 notification/instrumentation.go   | 54 +++++++++++++++++++++++++++++++
 notification/notification.go      | 25 ++++++++++++--
 storage/metric/instrumentation.go |  3 +-
 3 files changed, 79 insertions(+), 3 deletions(-)
 create mode 100644 notification/instrumentation.go

diff --git a/notification/instrumentation.go b/notification/instrumentation.go
new file mode 100644
index 000000000..1556263ff
--- /dev/null
+++ b/notification/instrumentation.go
@@ -0,0 +1,54 @@
+// Copyright 2013 Prometheus Team
+// 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 notification
+
+import (
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+const (
+	result  = "result"
+	success = "success"
+	failure = "failure"
+	dropped = "dropped"
+
+	facet     = "facet"
+	occupancy = "occupancy"
+	capacity  = "capacity"
+)
+
+var (
+	notificationsCount     = prometheus.NewCounter()
+	notificationLatency    = prometheus.NewDefaultHistogram()
+	notificationsQueueSize = prometheus.NewGauge()
+)
+
+func recordOutcome(duration time.Duration, err error) {
+	labels := map[string]string{result: success}
+	if err != nil {
+		labels[result] = failure
+	}
+
+	notificationsCount.Increment(labels)
+	ms := float64(duration / time.Millisecond)
+	notificationLatency.Add(labels, ms)
+}
+
+func init() {
+	prometheus.Register("prometheus_notifications_total", "Total number of processed alert notifications.", prometheus.NilLabels, notificationsCount)
+	prometheus.Register("prometheus_notifications_latency_ms", "Latency quantiles for sending alert notifications in milliseconds.", prometheus.NilLabels, notificationLatency)
+	prometheus.Register("prometheus_notifications_queue_size_total", "The size and capacity of the alert notification queue.", prometheus.NilLabels, notificationsQueueSize)
+}
diff --git a/notification/notification.go b/notification/notification.go
index 6df5c6de3..3f8873fe6 100644
--- a/notification/notification.go
+++ b/notification/notification.go
@@ -95,13 +95,34 @@ func (n *NotificationHandler) sendNotifications(reqs rules.NotificationReqs) err
 	return nil
 }
 
-// Continusouly dispatch notifications.
+// Report notification queue occupancy and capacity.
+func (n *NotificationHandler) reportQueues() {
+	notificationsQueueSize.Set(map[string]string{facet: occupancy}, float64(len(n.pendingNotifications)))
+	notificationsQueueSize.Set(map[string]string{facet: capacity}, float64(cap(n.pendingNotifications)))
+}
+
+// Continuously dispatch notifications.
 func (n *NotificationHandler) Run() {
+	queueReportTicker := time.NewTicker(time.Second)
+	go func() {
+		for _ = range queueReportTicker.C {
+			n.reportQueues()
+		}
+	}()
+	defer queueReportTicker.Stop()
+
 	for reqs := range n.pendingNotifications {
 		if n.alertmanagerUrl == "" {
 			log.Println("No alert manager configured, not dispatching notification")
+			notificationsCount.Increment(map[string]string{result: dropped})
+			continue
 		}
-		if err := n.sendNotifications(reqs); err != nil {
+
+		begin := time.Now()
+		err := n.sendNotifications(reqs)
+		recordOutcome(time.Since(begin), err)
+
+		if err != nil {
 			log.Println("Error sending notification:", err)
 		}
 	}
diff --git a/storage/metric/instrumentation.go b/storage/metric/instrumentation.go
index 71e95238d..dbef506ba 100644
--- a/storage/metric/instrumentation.go
+++ b/storage/metric/instrumentation.go
@@ -14,8 +14,9 @@
 package metric
 
 import (
-	"github.com/prometheus/client_golang/prometheus"
 	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
 )
 
 const (