prometheus/notification/notification.go

135 lines
3.9 KiB
Go

// 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 (
"bytes"
"encoding/json"
"flag"
"io/ioutil"
"log"
"net/http"
"time"
clientmodel "github.com/prometheus/client_golang/model"
"github.com/prometheus/prometheus/rules"
"github.com/prometheus/prometheus/utility"
)
const (
alertmanagerApiEventsPath = "/api/events"
contentTypeJson = "application/json"
)
var (
deadline = flag.Duration("alertmanager.httpDeadline", 10*time.Second, "Alert manager HTTP API timeout.")
)
// NotificationHandler is responsible for dispatching alert notifications to an
// alert manager service.
type NotificationHandler struct {
// The URL of the alert manager to send notifications to.
alertmanagerUrl string
// The URL of this Prometheus instance to include in notifications.
prometheusUrl string
// Buffer of notifications that have not yet been sent.
pendingNotifications <-chan rules.NotificationReqs
// HTTP client with custom timeout settings.
httpClient http.Client
}
// Construct a new NotificationHandler.
func NewNotificationHandler(alertmanagerUrl string, prometheusUrl string, notificationReqs <-chan rules.NotificationReqs) *NotificationHandler {
return &NotificationHandler{
alertmanagerUrl: alertmanagerUrl,
pendingNotifications: notificationReqs,
httpClient: utility.NewDeadlineClient(*deadline),
prometheusUrl: prometheusUrl,
}
}
// Send a list of notifications to the configured alert manager.
func (n *NotificationHandler) sendNotifications(reqs rules.NotificationReqs) error {
alerts := make([]map[string]interface{}, 0, len(reqs))
for _, req := range reqs {
alerts = append(alerts, map[string]interface{}{
"Summary": req.Rule.Summary,
"Description": req.Rule.Description,
"Labels": req.ActiveAlert.Labels.Merge(clientmodel.LabelSet{
rules.AlertNameLabel: clientmodel.LabelValue(req.Rule.Name()),
}),
"Payload": map[string]interface{}{
"Value": req.ActiveAlert.Value,
"ActiveSince": req.ActiveAlert.ActiveSince,
"GeneratorUrl": n.prometheusUrl,
"AlertingRule": req.Rule.String(),
},
})
}
buf, err := json.Marshal(alerts)
if err != nil {
return err
}
resp, err := n.httpClient.Post(
n.alertmanagerUrl+alertmanagerApiEventsPath,
contentTypeJson,
bytes.NewBuffer(buf),
)
if err != nil {
return err
}
defer resp.Body.Close()
_, err = ioutil.ReadAll(resp.Body)
if err != nil {
return err
}
// BUG: Do we need to check the response code?
return nil
}
// 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
}
begin := time.Now()
err := n.sendNotifications(reqs)
recordOutcome(time.Since(begin), err)
if err != nil {
log.Println("Error sending notification:", err)
}
}
}