feat: sjekk for eksternt oppsett

For at Alertmanager og Alerterator skal komme opp, så er man avhengig
av at alertmanager.yaml finnes i et felles ConfigMap. Da Alerterator
har ansvaret for å holde den confingen oppdatert ble det naturlig at
den også hadde ansvaret for å sikre at den eksistere.

Author: Kyrremann

controllers/alertmanager/alertmanager.go

@@ -3,6 +3,7 @@ package alertmanager
 import (
 	"context"
 	"fmt"
+	"github.com/go-logr/logr"
 
 	naisiov1 "github.com/nais/liberator/pkg/apis/nais.io/v1"
 	alertmanager "github.com/prometheus/alertmanager/config"
@@ -119,3 +120,24 @@ func Delete(ctx context.Context, client client.Client, alert *naisiov1.Alert) er
 
 	return configmap.MarshalAndUpdateData(ctx, client, alertmanagerConfigMapName, alertmanagerConfigName, newConfig)
 }
+
+func EnsureConfigExists(ctx context.Context, client client.Client, logger logr.Logger) error {
+	configMap, err := configmap.Get(ctx, client, alertmanagerConfigMapName)
+	if err != nil {
+		return err
+	}
+	exists := configMap.Data[alertmanagerConfigName]
+	if exists == "" {
+		logger.Info(fmt.Sprintf("Configmap %v was missing %v, creating it based on %v",
+			alertmanagerConfigMapName.Name, alertmanagerConfigName, alertmanagerTemplateConfigMapName.Name))
+		var newConfig *overrides.Config
+		err = configmap.GetAndUnmarshal(ctx, client, alertmanagerTemplateConfigMapName, alertmanagerConfigName, &newConfig)
+		if err != nil {
+			return err
+		}
+
+		return configmap.MarshalAndUpdateData(ctx, client, alertmanagerConfigMapName, alertmanagerConfigName, newConfig)
+	}
+
+	return nil
+}

main.go

@@ -1,8 +1,11 @@
 package main
 
 import (
+	"context"
 	"flag"
+	"github.com/nais/alerterator/controllers/alertmanager"
 	"os"
+	"sigs.k8s.io/controller-runtime/pkg/client"
 
 	"github.com/go-logr/zapr"
 	alertv1 "github.com/nais/liberator/pkg/apis/nais.io/v1"
@@ -52,6 +55,20 @@ func main() {
 
 	ctrl.SetLogger(zapr.NewLogger(zapLogger))
 
+	kconfig, err := ctrl.GetConfig()
+	simpleClient, err := client.New(kconfig, client.Options{
+		Scheme: scheme,
+	})
+	if err != nil {
+		setupLog.Error(err, "Unable to create go client")
+		os.Exit(1)
+	}
+	err = alertmanager.EnsureConfigExists(context.Background(), simpleClient, setupLog)
+	if err != nil {
+		setupLog.Error(err, "Unable to set up config")
+		os.Exit(1)
+	}
+
 	mgr, err := ctrl.NewManager(ctrl.GetConfigOrDie(), ctrl.Options{
 		Scheme:             scheme,
 		MetricsBindAddress: metricsAddr,