Alerting: Implement CreateSilence in the forked Alertmanager (remote primary mode) (#85716)

pkg/services/ngalert/remote/forked_alertmanager_test.go

@@ -435,19 +435,31 @@ func TestForkedAlertmanager_ModeRemotePrimary(t *testing.T) {
 	})
 
 	t.Run("CreateSilence", func(tt *testing.T) {
-		// We should create the silence in the remote Alertmanager.
-		_, remote, forked := genTestAlertmanagers(tt, modeRemotePrimary)
-
+		// We should create the silence in both Alertmanagers using the same uid.
+		testSilence := &apimodels.PostableSilence{}
 		expID := "test-id"
-		remote.EXPECT().CreateSilence(mock.Anything, mock.Anything).Return(expID, nil).Once()
-		id, err := forked.CreateSilence(ctx, nil)
+
+		internal, remote, forked := genTestAlertmanagers(tt, modeRemotePrimary)
+		remote.EXPECT().CreateSilence(mock.Anything, testSilence).Return(expID, nil).Once()
+		internal.EXPECT().CreateSilence(mock.Anything, testSilence).Return(testSilence.ID, nil).Once()
+		id, err := forked.CreateSilence(ctx, testSilence)
 		require.NoError(tt, err)
+		require.Equal(tt, expID, testSilence.ID)
 		require.Equal(tt, expID, id)
 
 		// If there's an error in the remote Alertmanager, the error should be returned.
-		remote.EXPECT().CreateSilence(mock.Anything, mock.Anything).Return("", expErr).Maybe()
-		_, err = forked.CreateSilence(ctx, nil)
+		_, remote, forked = genTestAlertmanagers(tt, modeRemotePrimary)
+		remote.EXPECT().CreateSilence(mock.Anything, mock.Anything).Return("", expErr).Once()
+		_, err = forked.CreateSilence(ctx, testSilence)
 		require.ErrorIs(tt, expErr, err)
+
+		// An error in the internal Alertmanager should not be returned.
+		internal, remote, forked = genTestAlertmanagers(tt, modeRemotePrimary)
+		remote.EXPECT().CreateSilence(mock.Anything, mock.Anything).Return(expID, nil).Once()
+		internal.EXPECT().CreateSilence(mock.Anything, mock.Anything).Return("", expErr).Once()
+		id, err = forked.CreateSilence(ctx, testSilence)
+		require.NoError(tt, err)
+		require.Equal(tt, expID, id)
 	})
 
 	t.Run("DeleteSilence", func(tt *testing.T) {

pkg/services/ngalert/remote/remote_primary_forked_alertmanager.go

@@ -72,7 +72,16 @@ func (fam *RemotePrimaryForkedAlertmanager) GetStatus() apimodels.GettableStatus
 }
 
 func (fam *RemotePrimaryForkedAlertmanager) CreateSilence(ctx context.Context, silence *apimodels.PostableSilence) (string, error) {
-	return fam.remote.CreateSilence(ctx, silence)
+	uid, err := fam.remote.CreateSilence(ctx, silence)
+	if err != nil {
+		return "", err
+	}
+
+	silence.ID = uid
+	if _, err := fam.internal.CreateSilence(ctx, silence); err != nil {
+		fam.log.Error("Error creating silence in the internal Alertmanager", "err", err, "silence", silence)
+	}
+	return uid, nil
 }
 
 func (fam *RemotePrimaryForkedAlertmanager) DeleteSilence(ctx context.Context, id string) error {