mirror of https://github.com/prometheus/prometheus
225 lines
6.5 KiB
Go
225 lines
6.5 KiB
Go
// Copyright 2013 Prometheus Team
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package notification
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import (
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"bytes"
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"encoding/json"
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"flag"
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"io"
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"io/ioutil"
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"net/http"
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"time"
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"github.com/golang/glog"
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"github.com/prometheus/client_golang/prometheus"
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clientmodel "github.com/prometheus/client_golang/model"
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"github.com/prometheus/prometheus/utility"
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)
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const (
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alertmanagerAPIEventsPath = "/api/alerts"
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contentTypeJSON = "application/json"
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)
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// String constants for instrumentation.
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const (
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namespace = "prometheus"
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subsystem = "notifications"
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result = "result"
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success = "success"
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failure = "failure"
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dropped = "dropped"
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)
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var (
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deadline = flag.Duration("alertmanager.http-deadline", 10*time.Second, "Alert manager HTTP API timeout.")
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)
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// NotificationReq is a request for sending a notification to the alert manager
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// for a single alert vector element.
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type NotificationReq struct {
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// Short-form alert summary. May contain text/template-style interpolations.
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Summary string
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// Longer alert description. May contain text/template-style interpolations.
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Description string
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// Labels associated with this alert notification, including alert name.
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Labels clientmodel.LabelSet
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// Current value of alert
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Value clientmodel.SampleValue
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// Since when this alert has been active (pending or firing).
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ActiveSince time.Time
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// A textual representation of the rule that triggered the alert.
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RuleString string
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// Prometheus console link to alert expression.
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GeneratorURL string
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}
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// NotificationReqs is just a short-hand for []*NotificationReq. No methods
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// attached. Arguably, it's more confusing than helpful. Perhaps we should
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// remove it...
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type NotificationReqs []*NotificationReq
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type httpPoster interface {
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Post(url string, bodyType string, body io.Reader) (*http.Response, error)
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}
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// NotificationHandler is responsible for dispatching alert notifications to an
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// alert manager service.
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type NotificationHandler struct {
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// The URL of the alert manager to send notifications to.
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alertmanagerURL string
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// Buffer of notifications that have not yet been sent.
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pendingNotifications chan NotificationReqs
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// HTTP client with custom timeout settings.
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httpClient httpPoster
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notificationLatency *prometheus.SummaryVec
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notificationsQueueLength prometheus.Gauge
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notificationsQueueCapacity prometheus.Metric
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stopped chan struct{}
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}
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// NewNotificationHandler constructs a new NotificationHandler.
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func NewNotificationHandler(alertmanagerURL string, notificationQueueCapacity int) *NotificationHandler {
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return &NotificationHandler{
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alertmanagerURL: alertmanagerURL,
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pendingNotifications: make(chan NotificationReqs, notificationQueueCapacity),
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httpClient: utility.NewDeadlineClient(*deadline),
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notificationLatency: prometheus.NewSummaryVec(
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prometheus.SummaryOpts{
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Namespace: namespace,
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Subsystem: subsystem,
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Name: "latency_milliseconds",
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Help: "Latency quantiles for sending alert notifications.",
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},
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[]string{result},
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),
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notificationsQueueLength: prometheus.NewGauge(prometheus.GaugeOpts{
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Namespace: namespace,
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Subsystem: subsystem,
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Name: "queue_length",
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Help: "The number of alert notifications in the queue.",
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}),
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notificationsQueueCapacity: prometheus.MustNewConstMetric(
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prometheus.NewDesc(
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prometheus.BuildFQName(namespace, subsystem, "queue_capacity"),
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"The capacity of the alert notifications queue.",
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nil, nil,
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),
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prometheus.GaugeValue,
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float64(notificationQueueCapacity),
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),
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stopped: make(chan struct{}),
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}
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}
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// Send a list of notifications to the configured alert manager.
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func (n *NotificationHandler) sendNotifications(reqs NotificationReqs) error {
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alerts := make([]map[string]interface{}, 0, len(reqs))
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for _, req := range reqs {
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alerts = append(alerts, map[string]interface{}{
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"Summary": req.Summary,
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"Description": req.Description,
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"Labels": req.Labels,
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"Payload": map[string]interface{}{
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"Value": req.Value,
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"ActiveSince": req.ActiveSince,
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"GeneratorURL": req.GeneratorURL,
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"AlertingRule": req.RuleString,
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},
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})
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}
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buf, err := json.Marshal(alerts)
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if err != nil {
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return err
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}
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glog.V(1).Infoln("Sending notifications to alertmanager:", string(buf))
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resp, err := n.httpClient.Post(
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n.alertmanagerURL+alertmanagerAPIEventsPath,
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contentTypeJSON,
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bytes.NewBuffer(buf),
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)
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if err != nil {
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return err
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}
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defer resp.Body.Close()
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_, err = ioutil.ReadAll(resp.Body)
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if err != nil {
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return err
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}
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// BUG: Do we need to check the response code?
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return nil
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}
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// Run dispatches notifications continuously.
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func (n *NotificationHandler) Run() {
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for reqs := range n.pendingNotifications {
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if n.alertmanagerURL == "" {
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glog.Warning("No alert manager configured, not dispatching notification")
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n.notificationLatency.WithLabelValues(dropped).Observe(0)
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continue
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}
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begin := time.Now()
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err := n.sendNotifications(reqs)
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labelValue := success
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if err != nil {
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glog.Error("Error sending notification: ", err)
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labelValue = failure
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}
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n.notificationLatency.WithLabelValues(labelValue).Observe(
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float64(time.Since(begin) / time.Millisecond),
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)
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}
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close(n.stopped)
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}
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// SubmitReqs queues the given notification requests for processing.
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func (n *NotificationHandler) SubmitReqs(reqs NotificationReqs) {
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n.pendingNotifications <- reqs
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}
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// Stop shuts down the notification handler.
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func (n *NotificationHandler) Stop() {
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glog.Info("Stopping notification handler...")
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close(n.pendingNotifications)
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<-n.stopped
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glog.Info("Notification handler stopped.")
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}
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// Describe implements prometheus.Collector.
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func (n *NotificationHandler) Describe(ch chan<- *prometheus.Desc) {
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n.notificationLatency.Describe(ch)
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ch <- n.notificationsQueueLength.Desc()
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ch <- n.notificationsQueueCapacity.Desc()
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}
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// Collect implements prometheus.Collector.
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func (n *NotificationHandler) Collect(ch chan<- prometheus.Metric) {
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n.notificationLatency.Collect(ch)
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n.notificationsQueueLength.Set(float64(len(n.pendingNotifications)))
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ch <- n.notificationsQueueLength
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ch <- n.notificationsQueueCapacity
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}
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