Alerting: Update references to alertmanager (#40904)

* update module reference for alertmanager
* remove workaround

pkg/services/ngalert/notifier/alertmanager.go

@@ -8,7 +8,6 @@ import (
 	"errors"
 	"fmt"
 	"net/url"
-	"os"
 	"path/filepath"
 	"regexp"
 	"strconv"
@@ -31,6 +30,8 @@ import (
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/model"
 
+	pb "github.com/prometheus/alertmanager/silence/silencepb"
+
 	"github.com/grafana/grafana/pkg/infra/kvstore"
 	"github.com/grafana/grafana/pkg/infra/log"
 	apimodels "github.com/grafana/grafana/pkg/services/ngalert/api/tooling/definitions"
@@ -40,7 +41,6 @@ import (
 	"github.com/grafana/grafana/pkg/services/ngalert/notifier/channels"
 	"github.com/grafana/grafana/pkg/services/ngalert/store"
 	"github.com/grafana/grafana/pkg/setting"
-	pb "github.com/prometheus/alertmanager/silence/silencepb"
 )
 
 const (
@@ -165,7 +165,12 @@ func newAlertmanager(orgID int64, cfg *setting.Cfg, store store.AlertingStore, k
 	c := am.peer.AddState(fmt.Sprintf("notificationlog:%d", am.orgID), am.notificationLog, m.Registerer)
 	am.notificationLog.SetBroadcast(c.Broadcast)
 
-	am.silences, err = newSilences(silencesFilePath, m.Registerer)
+	// Initialize silences
+	am.silences, err = silence.New(silence.Options{
+		Metrics:      m.Registerer,
+		SnapshotFile: silencesFilePath,
+		Retention:    retentionNotificationsAndSilences,
+	})
 	if err != nil {
 		return nil, fmt.Errorf("unable to initialize the silencing component of alerting: %w", err)
 	}
@@ -190,31 +195,6 @@ func newAlertmanager(orgID int64, cfg *setting.Cfg, store store.AlertingStore, k
 	return am, nil
 }
 
-// newSilences initializes returns *silence.Silences (from the Alertmanager) with silences taken from the file by path silencesFilePath and specific metrics registerer.
-func newSilences(silencesFilePath string, registerer prometheus.Registerer) (*silence.Silences, error) {
-	//TODO yuriy: Replace with silencesFilePath when fix in https://github.com/prometheus/alertmanager/pull/2710 is merged.
-	silenceOpts := silence.Options{
-		Metrics:   registerer,
-		Retention: retentionNotificationsAndSilences,
-	}
-
-	//The path is generated by the filestore. So presumably it should be safe
-	//nolint:gosec
-	silencesFileReader, err := os.Open(silencesFilePath)
-	if err != nil && !os.IsNotExist(err) {
-		return nil, err
-	}
-
-	if silencesFileReader != nil {
-		silenceOpts.SnapshotReader = silencesFileReader
-		defer func(file *os.File) {
-			_ = file.Close()
-		}(silencesFileReader)
-	}
-	// Initialize silences
-	return silence.New(silenceOpts)
-}
-
 func (am *Alertmanager) Ready() bool {
 	// We consider AM as ready only when the config has been
 	// applied at least once successfully. Until then, some objects