*: support Alertmanager API v2

Signed-off-by: Simon Pasquier <spasquie@redhat.com>

CHANGELOG.md

@@ -50,6 +50,7 @@ Compactor now properly handles partial block uploads for all operation like rete
 - [#1904](https://github.com/thanos-io/thanos/pull/1904) Add a skip-chunks option in Store Series API to improve the response time of `/api/v1/series` endpoint.
 - [#1910](https://github.com/thanos-io/thanos/pull/1910) Query: `/api/v1/labels` now understands `POST` - useful for sending bigger requests
 - [#1939](https://github.com/thanos-io/thanos/pull/1939) Ruler: Add TLS and authentication support for query endpoints with the `--query.config` and `--query.config-file` CLI flags. See [documentation](docs/components/rule.md/#configuration) for further information.
+- [#1982](https://github.com/thanos-io/thanos/pull/1982) Ruler: Add support for Alertmanager v2 API endpoints.
 
 ### Changed
 

Makefile

@@ -71,7 +71,7 @@ ME                ?= $(shell whoami)
 PROM_VERSIONS           ?= v2.4.3 v2.5.0 v2.8.1 v2.9.2 v2.13.0
 PROMS ?= $(GOBIN)/prometheus-v2.4.3 $(GOBIN)/prometheus-v2.5.0 $(GOBIN)/prometheus-v2.8.1 $(GOBIN)/prometheus-v2.9.2 $(GOBIN)/prometheus-v2.13.0
 
-ALERTMANAGER_VERSION    ?= v0.15.2
+ALERTMANAGER_VERSION    ?= v0.20.0
 ALERTMANAGER            ?= $(GOBIN)/alertmanager-$(ALERTMANAGER_VERSION)
 
 MINIO_SERVER_VERSION    ?= RELEASE.2018-10-06T00-15-16Z

cmd/thanos/rule.go

@@ -381,7 +381,7 @@ func runRule(
 		// Discover and resolve Alertmanager addresses.
 		addDiscoveryGroups(g, amClient, alertmgrsDNSSDInterval)
 
-		alertmgrs = append(alertmgrs, alert.NewAlertmanager(logger, amClient, time.Duration(cfg.Timeout)))
+		alertmgrs = append(alertmgrs, alert.NewAlertmanager(logger, amClient, time.Duration(cfg.Timeout), cfg.APIVersion))
 	}
 
 	// Run rule evaluation and alert notifications.

docs/components/rule.md

@@ -416,6 +416,7 @@ alertmanagers:
   scheme: http
   path_prefix: ""
   timeout: 10s
+  api_version: v1
 ```
 
 ### Query API

go.mod

@@ -29,6 +29,7 @@ require (
 	github.com/fortytw2/leaktest v1.3.0
 	github.com/fsnotify/fsnotify v1.4.7
 	github.com/go-kit/kit v0.9.0
+	github.com/go-openapi/strfmt v0.19.2
 	github.com/gogo/protobuf v1.3.1
 	github.com/golang/groupcache v0.0.0-20191027212112-611e8accdfc9 // indirect
 	github.com/golang/snappy v0.0.1
@@ -66,6 +67,7 @@ require (
 	github.com/opentracing/basictracer-go v1.0.0
 	github.com/opentracing/opentracing-go v1.1.0
 	github.com/pkg/errors v0.8.1
+	github.com/prometheus/alertmanager v0.20.0
 	github.com/prometheus/client_golang v1.2.1
 	github.com/prometheus/client_model v0.0.0-20190812154241-14fe0d1b01d4
 	github.com/prometheus/common v0.7.0

pkg/alert/alert.go

@@ -16,7 +16,9 @@ import (
 
 	"github.com/go-kit/kit/log"
 	"github.com/go-kit/kit/log/level"
+	"github.com/go-openapi/strfmt"
 	"github.com/pkg/errors"
+	"github.com/prometheus/alertmanager/api/v2/models"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/prometheus/pkg/labels"
 
@@ -26,7 +28,6 @@ import (
 
 const (
 	defaultAlertmanagerPort = 9093
-	alertPushEndpoint       = "/api/v1/alerts"
 	contentTypeJSON         = "application/json"
 )
 
@@ -255,6 +256,7 @@ func (q *Queue) Push(alerts []*Alert) {
 type Sender struct {
 	logger        log.Logger
 	alertmanagers []*Alertmanager
+	versions      []APIVersion
 
 	sent    *prometheus.CounterVec
 	errs    *prometheus.CounterVec
@@ -272,9 +274,20 @@ func NewSender(
 	if logger == nil {
 		logger = log.NewNopLogger()
 	}
+	var (
+		versions       []APIVersion
+		versionPresent map[APIVersion]struct{}
+	)
+	for _, am := range alertmanagers {
+		if _, found := versionPresent[am.version]; found {
+			continue
+		}
+		versions = append(versions, am.version)
+	}
 	s := &Sender{
 		logger:        logger,
 		alertmanagers: alertmanagers,
+		versions:      versions,
 
 		sent: prometheus.NewCounterVec(prometheus.CounterOpts{
 			Name: "thanos_alert_sender_alerts_sent_total",
@@ -302,6 +315,15 @@ func NewSender(
 	return s
 }
 
+func toAPILabels(labels labels.Labels) models.LabelSet {
+	apiLabels := make(models.LabelSet, len(labels))
+	for _, label := range labels {
+		apiLabels[label.Name] = label.Value
+	}
+
+	return apiLabels
+}
+
 // Send an alert batch to all given Alertmanager clients.
 // TODO(bwplotka): https://github.com/thanos-io/thanos/issues/660.
 func (s *Sender) Send(ctx context.Context, alerts []*Alert) {
@@ -310,10 +332,38 @@ func (s *Sender) Send(ctx context.Context, alerts []*Alert) {
 	if len(alerts) == 0 {
 		return
 	}
-	b, err := json.Marshal(alerts)
-	if err != nil {
-		level.Warn(s.logger).Log("msg", "sending alerts failed", "err", err)
-		return
+
+	payload := make(map[APIVersion][]byte)
+	for _, version := range s.versions {
+		var (
+			b   []byte
+			err error
+		)
+		switch version {
+		case APIv1:
+			if b, err = json.Marshal(alerts); err != nil {
+				level.Warn(s.logger).Log("msg", "encoding alerts for v1 API failed", "err", err)
+				return
+			}
+		case APIv2:
+			apiAlerts := make(models.PostableAlerts, 0, len(alerts))
+			for _, a := range alerts {
+				apiAlerts = append(apiAlerts, &models.PostableAlert{
+					Annotations: toAPILabels(a.Annotations),
+					EndsAt:      strfmt.DateTime(a.EndsAt),
+					StartsAt:    strfmt.DateTime(a.StartsAt),
+					Alert: models.Alert{
+						GeneratorURL: strfmt.URI(a.GeneratorURL),
+						Labels:       toAPILabels(a.Labels),
+					},
+				})
+			}
+			if b, err = json.Marshal(apiAlerts); err != nil {
+				level.Warn(s.logger).Log("msg", "encoding alerts for v2 API failed", "err", err)
+				return
+			}
+		}
+		payload[version] = b
 	}
 
 	var (
@@ -323,18 +373,19 @@ func (s *Sender) Send(ctx context.Context, alerts []*Alert) {
 	for _, am := range s.alertmanagers {
 		for _, u := range am.dispatcher.Endpoints() {
 			wg.Add(1)
-			go func(am *Alertmanager, u *url.URL) {
+			go func(am *Alertmanager, u url.URL) {
 				defer wg.Done()
 
 				level.Debug(s.logger).Log("msg", "sending alerts", "alertmanager", u.Host, "numAlerts", len(alerts))
 				start := time.Now()
+				u.Path = path.Join(u.Path, fmt.Sprintf("/api/%s/alerts", string(am.version)))
 				span, ctx := tracing.StartSpan(ctx, "post_alerts HTTP[client]")
 				defer span.Finish()
-				if err := am.postAlerts(ctx, *u, bytes.NewReader(b)); err != nil {
+				if err := am.postAlerts(ctx, u, bytes.NewReader(payload[am.version])); err != nil {
 					level.Warn(s.logger).Log(
 						"msg", "sending alerts failed",
 						"alertmanager", u.Host,
-						"numAlerts", len(alerts),
+						"alerts", string(payload[am.version]),
 						"err", err,
 					)
 					s.errs.WithLabelValues(u.Host).Inc()
@@ -344,7 +395,7 @@ func (s *Sender) Send(ctx context.Context, alerts []*Alert) {
 				s.sent.WithLabelValues(u.Host).Add(float64(len(alerts)))
 
 				atomic.AddUint64(&numSuccess, 1)
-			}(am, u)
+			}(am, *u)
 		}
 	}
 	wg.Wait()
@@ -354,7 +405,7 @@ func (s *Sender) Send(ctx context.Context, alerts []*Alert) {
 	}
 
 	s.dropped.Add(float64(len(alerts)))
-	level.Warn(s.logger).Log("msg", "failed to send alerts to all alertmanagers", "alerts", string(b))
+	level.Warn(s.logger).Log("msg", "failed to send alerts to all alertmanagers")
 }
 
 type Dispatcher interface {
@@ -369,10 +420,11 @@ type Alertmanager struct {
 	logger     log.Logger
 	dispatcher Dispatcher
 	timeout    time.Duration
+	version    APIVersion
 }
 
 // NewAlertmanager returns a new Alertmanager client.
-func NewAlertmanager(logger log.Logger, dispatcher Dispatcher, timeout time.Duration) *Alertmanager {
+func NewAlertmanager(logger log.Logger, dispatcher Dispatcher, timeout time.Duration, version APIVersion) *Alertmanager {
 	if logger == nil {
 		logger = log.NewNopLogger()
 	}
@@ -381,11 +433,11 @@ func NewAlertmanager(logger log.Logger, dispatcher Dispatcher, timeout time.Dura
 		logger:     logger,
 		dispatcher: dispatcher,
 		timeout:    timeout,
+		version:    version,
 	}
 }
 
 func (a *Alertmanager) postAlerts(ctx context.Context, u url.URL, r io.Reader) error {
-	u.Path = path.Join(u.Path, alertPushEndpoint)
 	req, err := http.NewRequest("POST", u.String(), r)
 	if err != nil {
 		return err

pkg/alert/alert_test.go

@@ -77,7 +77,7 @@ func TestSenderSendsOk(t *testing.T) {
 	poster := &fakeClient{
 		urls: []*url.URL{{Host: "am1:9090"}, {Host: "am2:9090"}},
 	}
-	s := NewSender(nil, nil, []*Alertmanager{NewAlertmanager(nil, poster, time.Minute)})
+	s := NewSender(nil, nil, []*Alertmanager{NewAlertmanager(nil, poster, time.Minute, APIv1)})
 
 	s.Send(context.Background(), []*Alert{{}, {}})
 
@@ -104,7 +104,7 @@ func TestSenderSendsOneFails(t *testing.T) {
 			return rec.Result(), nil
 		},
 	}
-	s := NewSender(nil, nil, []*Alertmanager{NewAlertmanager(nil, poster, time.Minute)})
+	s := NewSender(nil, nil, []*Alertmanager{NewAlertmanager(nil, poster, time.Minute, APIv1)})
 
 	s.Send(context.Background(), []*Alert{{}, {}})
 
@@ -125,7 +125,7 @@ func TestSenderSendsAllFail(t *testing.T) {
 			return nil, errors.New("no such host")
 		},
 	}
-	s := NewSender(nil, nil, []*Alertmanager{NewAlertmanager(nil, poster, time.Minute)})
+	s := NewSender(nil, nil, []*Alertmanager{NewAlertmanager(nil, poster, time.Minute, APIv1)})
 
 	s.Send(context.Background(), []*Alert{{}, {}})
 

pkg/alert/config.go

@@ -7,6 +7,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/pkg/errors"
 	"github.com/prometheus/common/model"
 	"gopkg.in/yaml.v2"
 
@@ -19,11 +20,39 @@ type AlertingConfig struct {
 }
 
 // AlertmanagerConfig represents a client to a cluster of Alertmanager endpoints.
-// TODO(simonpasquier): add support for API version (v1 or v2).
 type AlertmanagerConfig struct {
 	HTTPClientConfig http_util.ClientConfig    `yaml:"http_config"`
 	EndpointsConfig  http_util.EndpointsConfig `yaml:",inline"`
 	Timeout          model.Duration            `yaml:"timeout"`
+	APIVersion       APIVersion                `yaml:"api_version"`
+}
+
+// APIVersion represents the API version of the Alertmanager endpoint.
+type APIVersion string
+
+const (
+	APIv1 APIVersion = "v1"
+	APIv2 APIVersion = "v2"
+)
+
+var supportedAPIVersions = []APIVersion{
+	APIv1, APIv2,
+}
+
+// UnmarshalYAML implements the yaml.Unmarshaler interface.
+func (v *APIVersion) UnmarshalYAML(unmarshal func(interface{}) error) error {
+	var s string
+	if err := unmarshal(&s); err != nil {
+		return errors.Wrap(err, "invalid Alertmanager API version")
+	}
+
+	for _, ver := range supportedAPIVersions {
+		if APIVersion(s) == ver {
+			*v = ver
+			return nil
+		}
+	}
+	return errors.Errorf("expected Alertmanager API version to be one of %v but got %q", supportedAPIVersions, s)
 }
 
 func DefaultAlertmanagerConfig() AlertmanagerConfig {
@@ -33,7 +62,8 @@ func DefaultAlertmanagerConfig() AlertmanagerConfig {
 			StaticAddresses: []string{},
 			FileSDConfigs:   []http_util.FileSDConfig{},
 		},
-		Timeout: model.Duration(time.Second * 10),
+		Timeout:    model.Duration(time.Second * 10),
+		APIVersion: APIv1,
 	}
 }
 

pkg/alert/config_test.go

@@ -4,10 +4,43 @@ import (
 	"testing"
 	"time"
 
+	"gopkg.in/yaml.v2"
+
 	"github.com/thanos-io/thanos/pkg/http"
 	"github.com/thanos-io/thanos/pkg/testutil"
 )
 
+func TestUnmarshalAPIVersion(t *testing.T) {
+	for _, tc := range []struct {
+		v string
+
+		err      bool
+		expected APIVersion
+	}{
+		{
+			v:        "v1",
+			expected: APIv1,
+		},
+		{
+			v:   "v3",
+			err: true,
+		},
+		{
+			v:   "{}",
+			err: true,
+		},
+	} {
+		var got APIVersion
+		err := yaml.Unmarshal([]byte(tc.v), &got)
+		if tc.err {
+			testutil.NotOk(t, err)
+			continue
+		}
+		testutil.Ok(t, err)
+		testutil.Equals(t, tc.expected, got)
+	}
+}
+
 func TestBuildAlertmanagerConfiguration(t *testing.T) {
 	for _, tc := range []struct {
 		address string

pkg/testutil/prometheus.go

@@ -28,7 +28,7 @@ import (
 
 const (
 	defaultPrometheusVersion   = "v2.13.0"
-	defaultAlertmanagerVersion = "v0.15.2"
+	defaultAlertmanagerVersion = "v0.20.0"
 	defaultMinioVersion        = "RELEASE.2018-10-06T00-15-16Z"
 
 	// Space delimited list of versions.