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Merge pull request prometheus#1699 from prometheus/fabxc-multiam
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notifier: dispatch to multiple Alertmanagers
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@fabxc
fabxc committed Jun 6, 2016
2 parents 35ccca0 + 9baf120 commit dd57e7e
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Showing 3 changed files with 166 additions and 94 deletions.
60 changes: 46 additions & 14 deletions cmd/prometheus/config.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,7 @@ import (
"net"
"net/url"
"os"
"sort"
"strings"
"text/template"
"time"
Expand Down Expand Up @@ -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)
Expand Down Expand Up @@ -206,9 +210,9 @@ 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,
Expand Down Expand Up @@ -249,8 +253,11 @@ 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")
Expand Down Expand Up @@ -307,19 +314,19 @@ 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
}
Expand Down Expand Up @@ -384,3 +391,28 @@ 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
}
140 changes: 87 additions & 53 deletions notifier/notifier.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,7 @@ import (
"net/http"
"strings"
"sync"
"sync/atomic"
"time"

"github.com/prometheus/client_golang/prometheus"
Expand All @@ -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
Expand All @@ -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.
Expand All @@ -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,
Expand Down Expand Up @@ -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 {
Expand All @@ -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()
Expand Down Expand Up @@ -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 {
Expand All @@ -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()
Expand All @@ -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
Expand Down
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