notifier: dispatch to multiple Alertmanagers

This commit extends the notifier to dispatch alert batches
to multiple Alertmanagers concurrently.
It changes the `-alertmanager.url` flag to accept a comma
separated list of URLs and/or to be set multiple times.
pull/1699/head
Fabian Reinartz 9 years ago
parent 0b6e5eb7dd
commit 9baf120cd5

@ -19,6 +19,7 @@ import (
"net"
"net/url"
"os"
"sort"
"strings"
"text/template"
"time"
@ -48,9 +49,12 @@ var cfg = struct {
web web.Options
remote remote.Options
prometheusURL string
influxdbURL string
}{}
alertmanagerURLs stringset
prometheusURL string
influxdbURL string
}{
alertmanagerURLs: stringset{},
}
func init() {
flag.CommandLine.Init(os.Args[0], flag.ContinueOnError)
@ -202,9 +206,9 @@ func init() {
)
// Alertmanager.
cfg.fs.StringVar(
&cfg.notifier.AlertmanagerURL, "alertmanager.url", "",
"The URL of the alert manager to send notifications to.",
cfg.fs.Var(
&cfg.alertmanagerURLs, "alertmanager.url",
"Comma-separated list of Alertmanager URLs to send notifications to.",
)
cfg.fs.IntVar(
&cfg.notifier.QueueCapacity, "alertmanager.notification-queue-capacity", 10000,
@ -245,8 +249,11 @@ func parse(args []string) error {
if err := parseInfluxdbURL(); err != nil {
return err
}
if err := validateAlertmanagerURL(); err != nil {
return err
for u := range cfg.alertmanagerURLs {
if err := validateAlertmanagerURL(u); err != nil {
return err
}
cfg.notifier.AlertmanagerURLs = cfg.alertmanagerURLs.slice()
}
cfg.remote.InfluxdbPassword = os.Getenv("INFLUXDB_PW")
@ -303,19 +310,19 @@ func parseInfluxdbURL() error {
return nil
}
func validateAlertmanagerURL() error {
if cfg.notifier.AlertmanagerURL == "" {
func validateAlertmanagerURL(u string) error {
if u == "" {
return nil
}
if ok := govalidator.IsURL(cfg.notifier.AlertmanagerURL); !ok {
return fmt.Errorf("invalid Alertmanager URL: %s", cfg.notifier.AlertmanagerURL)
if ok := govalidator.IsURL(u); !ok {
return fmt.Errorf("invalid Alertmanager URL: %s", u)
}
url, err := url.Parse(cfg.notifier.AlertmanagerURL)
url, err := url.Parse(u)
if err != nil {
return err
}
if url.Scheme == "" {
return fmt.Errorf("missing scheme in Alertmanager URL: %s", cfg.notifier.AlertmanagerURL)
return fmt.Errorf("missing scheme in Alertmanager URL: %s", u)
}
return nil
}
@ -380,3 +387,28 @@ func usage() {
panic(fmt.Errorf("error executing usage template: %s", err))
}
}
type stringset map[string]struct{}
func (ss stringset) Set(s string) error {
for _, v := range strings.Split(s, ",") {
v = strings.TrimSpace(v)
if v != "" {
ss[v] = struct{}{}
}
}
return nil
}
func (ss stringset) String() string {
return strings.Join(ss.slice(), ",")
}
func (ss stringset) slice() []string {
slice := make([]string, 0, len(ss))
for k := range ss {
slice = append(slice, k)
}
sort.Strings(slice)
return slice
}

@ -20,6 +20,7 @@ import (
"net/http"
"strings"
"sync"
"sync/atomic"
"time"
"github.com/prometheus/client_golang/prometheus"
@ -38,8 +39,9 @@ const (
// String constants for instrumentation.
const (
namespace = "prometheus"
subsystem = "notifications"
namespace = "prometheus"
subsystem = "notifications"
alertmanagerLabel = "alertmanager"
)
// Notifier is responsible for dispatching alert notifications to an
@ -53,20 +55,20 @@ type Notifier struct {
ctx context.Context
cancel func()
latency prometheus.Summary
errors prometheus.Counter
latency *prometheus.SummaryVec
errors *prometheus.CounterVec
sent *prometheus.CounterVec
dropped prometheus.Counter
sent prometheus.Counter
queueLength prometheus.Gauge
queueCapacity prometheus.Metric
}
// Options are the configurable parameters of a Handler.
type Options struct {
AlertmanagerURL string
QueueCapacity int
Timeout time.Duration
ExternalLabels model.LabelSet
AlertmanagerURLs []string
QueueCapacity int
Timeout time.Duration
ExternalLabels model.LabelSet
}
// New constructs a neww Notifier.
@ -80,24 +82,30 @@ func New(o *Options) *Notifier {
more: make(chan struct{}, 1),
opts: o,
latency: prometheus.NewSummary(prometheus.SummaryOpts{
latency: prometheus.NewSummaryVec(prometheus.SummaryOpts{
Namespace: namespace,
Subsystem: subsystem,
Name: "latency_seconds",
Help: "Latency quantiles for sending alert notifications (not including dropped notifications).",
}),
errors: prometheus.NewCounter(prometheus.CounterOpts{
},
[]string{alertmanagerLabel},
),
errors: prometheus.NewCounterVec(prometheus.CounterOpts{
Namespace: namespace,
Subsystem: subsystem,
Name: "errors_total",
Help: "Total number of errors sending alert notifications.",
}),
sent: prometheus.NewCounter(prometheus.CounterOpts{
},
[]string{alertmanagerLabel},
),
sent: prometheus.NewCounterVec(prometheus.CounterOpts{
Namespace: namespace,
Subsystem: subsystem,
Name: "sent_total",
Help: "Total number of alerts successfully sent.",
}),
},
[]string{alertmanagerLabel},
),
dropped: prometheus.NewCounter(prometheus.CounterOpts{
Namespace: namespace,
Subsystem: subsystem,
@ -160,9 +168,11 @@ func (n *Notifier) nextBatch() []*model.Alert {
// Run dispatches notifications continuously.
func (n *Notifier) Run() {
numAMs := len(n.opts.AlertmanagerURLs)
// Just warn once in the beginning to prevent noisy logs.
if n.opts.AlertmanagerURL == "" {
log.Warnf("No AlertManager configured, not dispatching any alerts")
if numAMs == 0 {
log.Warnf("No AlertManagers configured, not dispatching any alerts")
return
}
for {
@ -171,28 +181,21 @@ func (n *Notifier) Run() {
return
case <-n.more:
}
alerts := n.nextBatch()
if len(alerts) == 0 {
continue
}
if n.opts.AlertmanagerURL == "" {
n.dropped.Add(float64(len(alerts)))
continue
}
begin := time.Now()
if numAMs > 0 {
if err := n.send(alerts...); err != nil {
log.Errorf("Error sending %d alerts: %s", len(alerts), err)
n.errors.Inc()
if len(alerts) > 0 {
numErrors := n.sendAll(alerts...)
// Increment the dropped counter if we could not send
// successfully to a single AlertManager.
if numErrors == numAMs {
n.dropped.Add(float64(len(alerts)))
}
}
} else {
n.dropped.Add(float64(len(alerts)))
}
n.latency.Observe(float64(time.Since(begin)) / float64(time.Second))
n.sent.Add(float64(len(alerts)))
// If the queue still has items left, kick off the next iteration.
if n.queueLen() > 0 {
n.setMore()
@ -239,11 +242,15 @@ func (n *Notifier) setMore() {
}
}
func (n *Notifier) postURL() string {
return strings.TrimRight(n.opts.AlertmanagerURL, "/") + alertPushEndpoint
func postURL(u string) string {
return strings.TrimRight(u, "/") + alertPushEndpoint
}
func (n *Notifier) send(alerts ...*model.Alert) error {
// sendAll sends the alerts to all configured Alertmanagers at concurrently.
// It returns the number of sends that have failed.
func (n *Notifier) sendAll(alerts ...*model.Alert) int {
begin := time.Now()
// Attach external labels before sending alerts.
for _, a := range alerts {
for ln, lv := range n.opts.ExternalLabels {
@ -253,36 +260,62 @@ func (n *Notifier) send(alerts ...*model.Alert) error {
}
}
var buf bytes.Buffer
if err := json.NewEncoder(&buf).Encode(alerts); err != nil {
return err
b, err := json.Marshal(alerts)
if err != nil {
log.Errorf("Encoding alerts failed: %s", err)
return len(n.opts.AlertmanagerURLs)
}
ctx, _ := context.WithTimeout(context.Background(), n.opts.Timeout)
resp, err := ctxhttp.Post(ctx, http.DefaultClient, n.postURL(), contentTypeJSON, &buf)
if err != nil {
send := func(u string) error {
resp, err := ctxhttp.Post(ctx, http.DefaultClient, postURL(u), contentTypeJSON, bytes.NewReader(b))
if err != nil {
return err
}
defer resp.Body.Close()
if resp.StatusCode/100 != 2 {
return fmt.Errorf("bad response status %v", resp.Status)
}
return err
}
defer resp.Body.Close()
if resp.StatusCode/100 != 2 {
return fmt.Errorf("bad response status %v", resp.Status)
var (
wg sync.WaitGroup
numErrors uint64
)
for _, u := range n.opts.AlertmanagerURLs {
wg.Add(1)
go func(u string) {
if err := send(u); err != nil {
log.With("alertmanager", u).With("count", fmt.Sprintf("%d", len(alerts))).Errorf("Error sending alerts: %s", err)
n.errors.WithLabelValues(u).Inc()
atomic.AddUint64(&numErrors, 1)
}
n.latency.WithLabelValues(u).Observe(float64(time.Since(begin)) / float64(time.Second))
n.sent.WithLabelValues(u).Add(float64(len(alerts)))
wg.Done()
}(u)
}
return nil
wg.Wait()
return int(numErrors)
}
// Stop shuts down the notification handler.
func (n *Notifier) Stop() {
log.Info("Stopping notification handler...")
n.cancel()
}
// Describe implements prometheus.Collector.
func (n *Notifier) Describe(ch chan<- *prometheus.Desc) {
ch <- n.latency.Desc()
ch <- n.errors.Desc()
ch <- n.sent.Desc()
n.latency.Describe(ch)
n.errors.Describe(ch)
n.sent.Describe(ch)
ch <- n.dropped.Desc()
ch <- n.queueLength.Desc()
ch <- n.queueCapacity.Desc()
@ -292,9 +325,10 @@ func (n *Notifier) Describe(ch chan<- *prometheus.Desc) {
func (n *Notifier) Collect(ch chan<- prometheus.Metric) {
n.queueLength.Set(float64(n.queueLen()))
ch <- n.latency
ch <- n.errors
ch <- n.sent
n.latency.Collect(ch)
n.errors.Collect(ch)
n.sent.Collect(ch)
ch <- n.dropped
ch <- n.queueLength
ch <- n.queueCapacity

@ -25,7 +25,7 @@ import (
"github.com/prometheus/common/model"
)
func TestHandlerPostURL(t *testing.T) {
func TestPostURL(t *testing.T) {
var cases = []struct {
in, out string
}{
@ -50,13 +50,8 @@ func TestHandlerPostURL(t *testing.T) {
out: "http://localhost:9093/prefix/api/v1/alerts",
},
}
h := &Notifier{
opts: &Options{},
}
for _, c := range cases {
h.opts.AlertmanagerURL = c.in
if res := h.postURL(); res != c.out {
if res := postURL(c.in); res != c.out {
t.Errorf("Expected post URL %q for %q but got %q", c.out, c.in, res)
}
}
@ -119,13 +114,13 @@ func alertsEqual(a, b model.Alerts) bool {
return true
}
func TestHandlerSend(t *testing.T) {
func TestHandlerSendAll(t *testing.T) {
var (
expected model.Alerts
status int
expected model.Alerts
status1, status2 int
)
server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
f := func(w http.ResponseWriter, r *http.Request) {
if r.URL.Path != alertPushEndpoint {
t.Fatalf("Bad endpoint %q used, expected %q", r.URL.Path, alertPushEndpoint)
}
@ -140,16 +135,23 @@ func TestHandlerSend(t *testing.T) {
t.Errorf("%#v %#v", *alerts[0], *expected[0])
t.Fatalf("Unexpected alerts received %v exp %v", alerts, expected)
}
w.WriteHeader(status)
}
server1 := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
f(w, r)
w.WriteHeader(status1)
}))
server2 := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
f(w, r)
w.WriteHeader(status2)
}))
defer server.Close()
defer server1.Close()
defer server2.Close()
h := New(&Options{
AlertmanagerURL: server.URL,
Timeout: time.Minute,
ExternalLabels: model.LabelSet{"a": "b"},
AlertmanagerURLs: []string{server1.URL, server2.URL},
Timeout: time.Minute,
ExternalLabels: model.LabelSet{"a": "b"},
})
for i := range make([]struct{}, maxBatchSize) {
@ -166,16 +168,20 @@ func TestHandlerSend(t *testing.T) {
})
}
status = http.StatusOK
if err := h.send(h.queue...); err != nil {
t.Fatalf("Unexpected error: %s", err)
status1 = http.StatusOK
status2 = http.StatusOK
if ne := h.sendAll(h.queue...); ne != 0 {
t.Fatalf("Unexpected number of failed sends: %d", ne)
}
status = 500
status1 = http.StatusNotFound
if ne := h.sendAll(h.queue...); ne != 1 {
t.Fatalf("Unexpected number of failed sends: %d", ne)
}
if err := h.send(h.queue...); err == nil {
t.Fatalf("Expected error but got none")
status2 = http.StatusInternalServerError
if ne := h.sendAll(h.queue...); ne != 2 {
t.Fatalf("Unexpected number of failed sends: %d", ne)
}
}
@ -203,9 +209,9 @@ func TestHandlerFull(t *testing.T) {
}))
h := New(&Options{
AlertmanagerURL: server.URL,
Timeout: time.Second,
QueueCapacity: 3 * maxBatchSize,
AlertmanagerURLs: []string{server.URL},
Timeout: time.Second,
QueueCapacity: 3 * maxBatchSize,
})
var alerts model.Alerts

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