Alerting: Add SaveAndApply methods to the forked Alertmanager (remote secondary) (#78827)

* Alerting: Add configuration methods to the forked Alertmanager for remote secondary modes

* update comments

pkg/services/ngalert/remote/forked_alertmanager_test.go

@@ -21,6 +21,32 @@ func TestForkedAlertmanager_ModeRemoteSecondary(t *testing.T) {
 	ctx := context.Background()
 	expErr := errors.New("test error")
 
+	t.Run("SaveAndApplyConfig", func(tt *testing.T) {
+		// SaveAndApplyConfig should only be called on the remote Alertmanager.
+		// State and configuration are updated on an interval.
+		internal, _, forked := genTestAlertmanagers(tt, modeRemoteSecondary)
+		internal.EXPECT().SaveAndApplyConfig(ctx, mock.Anything).Return(nil).Once()
+		require.NoError(tt, forked.SaveAndApplyConfig(ctx, &apimodels.PostableUserConfig{}))
+
+		// If there's an error, it should be returned.
+		internal, _, forked = genTestAlertmanagers(tt, modeRemoteSecondary)
+		internal.EXPECT().SaveAndApplyConfig(ctx, mock.Anything).Return(expErr).Once()
+		require.ErrorIs(tt, forked.SaveAndApplyConfig(ctx, &apimodels.PostableUserConfig{}), expErr)
+	})
+
+	t.Run("SaveAndApplyDefaultConfig", func(tt *testing.T) {
+		// SaveAndApplyDefaultConfig should only be called on the remote Alertmanager.
+		// State and configuration are updated on an interval.
+		internal, _, forked := genTestAlertmanagers(tt, modeRemoteSecondary)
+		internal.EXPECT().SaveAndApplyDefaultConfig(ctx).Return(nil).Once()
+		require.NoError(tt, forked.SaveAndApplyDefaultConfig(ctx))
+
+		// If there's an error, it should be returned.
+		internal, _, forked = genTestAlertmanagers(tt, modeRemoteSecondary)
+		internal.EXPECT().SaveAndApplyDefaultConfig(ctx).Return(expErr).Once()
+		require.ErrorIs(tt, forked.SaveAndApplyDefaultConfig(ctx), expErr)
+	})
+
 	t.Run("GetStatus", func(tt *testing.T) {
 		// We care about the status of the internal Alertmanager.
 		internal, _, forked := genTestAlertmanagers(tt, modeRemoteSecondary)
@@ -225,7 +251,7 @@ func TestForkedAlertmanager_ModeRemoteSecondary(t *testing.T) {
 	})
 
 	t.Run("StopAndWait", func(tt *testing.T) {
-		// StopAndWait should be called in both Alertmanagers.
+		// StopAndWait should be called on both Alertmanagers.
 		internal, remote, forked := genTestAlertmanagers(tt, modeRemotePrimary)
 		internal.EXPECT().StopAndWait().Once()
 		remote.EXPECT().StopAndWait().Once()
@@ -457,7 +483,7 @@ func TestForkedAlertmanager_ModeRemotePrimary(t *testing.T) {
 	})
 
 	t.Run("StopAndWait", func(tt *testing.T) {
-		// StopAndWait should be called in both Alertmanagers.
+		// StopAndWait should be called on both Alertmanagers.
 		internal, remote, forked := genTestAlertmanagers(tt, modeRemotePrimary)
 		internal.EXPECT().StopAndWait().Once()
 		remote.EXPECT().StopAndWait().Once()

pkg/services/ngalert/remote/remote_secondary_forked_alertmanager.go

@@ -24,12 +24,14 @@ func (fam *RemoteSecondaryForkedAlertmanager) ApplyConfig(ctx context.Context, c
 	return nil
 }
 
+// SaveAndApplyConfig is only called on the internal Alertmanager when running in remote secondary mode.
 func (fam *RemoteSecondaryForkedAlertmanager) SaveAndApplyConfig(ctx context.Context, config *apimodels.PostableUserConfig) error {
-	return nil
+	return fam.internal.SaveAndApplyConfig(ctx, config)
 }
 
+// SaveAndApplyDefaultConfig is only called on the internal Alertmanager when running in remote secondary mode.
 func (fam *RemoteSecondaryForkedAlertmanager) SaveAndApplyDefaultConfig(ctx context.Context) error {
-	return nil
+	return fam.internal.SaveAndApplyDefaultConfig(ctx)
 }
 
 func (fam *RemoteSecondaryForkedAlertmanager) GetStatus() apimodels.GettableStatus {