Add alert lifecycle observer

Signed-off-by: Emmanuel Lodovice <[email protected]>

alertobserver/alertobserver.go

@@ -0,0 +1,36 @@
+// Copyright 2023 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 alertobserver
+
+import (
+	"github.com/prometheus/alertmanager/types"
+)
+
+const (
+	EventAlertReceived             string = "received"
+	EventAlertRejected             string = "rejected"
+	EventAlertAddedToAggrGroup     string = "addedAggrGroup"
+	EventAlertFailedAddToAggrGroup string = "failedAddAggrGroup"
+	EventAlertPipelineStart        string = "pipelineStart"
+	EventAlertPipelinePassStage    string = "pipelinePassStage"
+	EventAlertMuted                string = "muted"
+	EventAlertSent                 string = "sent"
+	EventAlertSendFailed           string = "sendFailed"
+)
+
+type AlertEventMeta map[string]interface{}
+
+type LifeCycleObserver interface {
+	Observe(event string, alerts []*types.Alert, meta AlertEventMeta)
+}

alertobserver/testing.go

@@ -0,0 +1,46 @@
+// Copyright 2023 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 alertobserver
+
+import (
+	"sync"
+
+	"github.com/prometheus/alertmanager/types"
+)
+
+type FakeLifeCycleObserver struct {
+	AlertsPerEvent      map[string][]*types.Alert
+	PipelineStageAlerts map[string][]*types.Alert
+	MetaPerEvent        map[string][]AlertEventMeta
+	Mtx                 sync.RWMutex
+}
+
+func (o *FakeLifeCycleObserver) Observe(event string, alerts []*types.Alert, meta AlertEventMeta) {
+	o.Mtx.Lock()
+	defer o.Mtx.Unlock()
+	if event == EventAlertPipelinePassStage {
+		o.PipelineStageAlerts[meta["stageName"].(string)] = append(o.PipelineStageAlerts[meta["stageName"].(string)], alerts...)
+	} else {
+		o.AlertsPerEvent[event] = append(o.AlertsPerEvent[event], alerts...)
+	}
+	o.MetaPerEvent[event] = append(o.MetaPerEvent[event], meta)
+}
+
+func NewFakeLifeCycleObserver() *FakeLifeCycleObserver {
+	return &FakeLifeCycleObserver{
+		PipelineStageAlerts: map[string][]*types.Alert{},
+		AlertsPerEvent:      map[string][]*types.Alert{},
+		MetaPerEvent:        map[string][]AlertEventMeta{},
+	}
+}

api/api.go

@@ -27,6 +27,7 @@ import (
 	"github.com/prometheus/common/model"
 	"github.com/prometheus/common/route"
 
+	"github.com/prometheus/alertmanager/alertobserver"
 	apiv2 "github.com/prometheus/alertmanager/api/v2"
 	"github.com/prometheus/alertmanager/cluster"
 	"github.com/prometheus/alertmanager/config"
@@ -81,6 +82,9 @@ type Options struct {
 	GroupInfoFunc func(func(*dispatch.Route) bool) dispatch.AlertGroupInfos
 	// APICallback define the callback function that each api call will perform before returned.
 	APICallback callback.Callback
+	// AlertLCObserver is used to add hooks to the different alert life cycle events.
+	// If nil then no observer methods will be invoked in the life cycle events.
+	AlertLCObserver alertobserver.LifeCycleObserver
 }
 
 func (o Options) validate() error {
@@ -127,6 +131,7 @@ func New(opts Options) (*API, error) {
 		opts.Peer,
 		log.With(l, "version", "v2"),
 		opts.Registry,
+		opts.AlertLCObserver,
 	)
 	if err != nil {
 		return nil, err