dbus: add StartTransientUnitAux and StartTransientUnitAuxContext for starting transient units with auxiliary units

the existing StartTransientUnit methods pass an empty slice to the list of auxiliary units, this adds new methods for specifying those auxiliary units.

Fixes #488

Author: gwenya

dbus/methods.go

@@ -194,7 +194,13 @@ func (c *Conn) StartTransientUnit(name string, mode string, properties []Propert
 // unique. mode is the same as in StartUnitContext, properties contains properties
 // of the unit.
 func (c *Conn) StartTransientUnitContext(ctx context.Context, name string, mode string, properties []Property, ch chan<- string) (int, error) {
-	return c.startJob(ctx, ch, "org.freedesktop.systemd1.Manager.StartTransientUnit", name, mode, properties, make([]PropertyCollection, 0))
+	return c.startJob(ctx, ch, "org.freedesktop.systemd1.Manager.StartTransientUnit", name, mode, properties, make([]AuxiliaryUnit, 0))
+}
+
+// StartTransientUnitAux is the same as StartTransientUnitContext but allows passing
+// auxiliary units in the aux parameter.
+func (c *Conn) StartTransientUnitAux(ctx context.Context, name string, mode string, properties []Property, aux []AuxiliaryUnit, ch chan<- string) (int, error) {
+	return c.startJob(ctx, ch, "org.freedesktop.systemd1.Manager.StartTransientUnit", name, mode, properties, aux)
 }
 
 // Deprecated: use [KillUnitWithTarget] instead.

dbus/methods_test.go

@@ -128,6 +128,28 @@ func runStartTrUnit(t *testing.T, conn *Conn, trTarget TrUnitProp) error {
 	return nil
 }
 
+func runStartTrUnitWithAux(t *testing.T, conn *Conn, trTarget TrUnitProp, trAux TrUnitProp) error {
+	reschan := make(chan string)
+	_, err := conn.StartTransientUnitAux(
+		context.TODO(), // Switch to t.Context once go < 1.24 is not supported.
+		trTarget.name,
+		"replace",
+		trTarget.props,
+		[]AuxiliaryUnit{{Name: trAux.name, Properties: trAux.props}},
+		reschan,
+	)
+	if err != nil {
+		return err
+	}
+
+	job := <-reschan
+	if job != "done" {
+		return fmt.Errorf("Job is not done: %s", job)
+	}
+
+	return nil
+}
+
 func runStopUnit(t *testing.T, conn *Conn, trTarget TrUnitProp) error {
 	reschan := make(chan string)
 	_, err := conn.StopUnit(trTarget.name, "replace", reschan)
@@ -850,6 +872,11 @@ func TestSetUnitProperties(t *testing.T) {
 	}
 }
 
+type TrUnitSocketListenProp struct {
+	Type    string
+	Address string
+}
+
 // Ensure that oneshot transient unit starting and stopping works.
 func TestStartStopTransientUnitAll(t *testing.T) {
 	testCases := []struct {
@@ -991,6 +1018,29 @@ func TestStartStopTransientUnitAll(t *testing.T) {
 			},
 			checkFunc: checkTransientUnitConflicts,
 		},
+		{
+			trTarget: TrUnitProp{
+				name: "testing-aux-unit.socket",
+				props: []Property{
+					{
+						Name: "Listen",
+						Value: dbus.MakeVariant([]TrUnitSocketListenProp{
+							{
+								Type:    "Stream",
+								Address: path.Join(t.TempDir(), "go-systemd-test.sock"),
+							},
+						}),
+					},
+				},
+			},
+			trDep: TrUnitProp{
+				name: "testing-aux-unit.service",
+				props: []Property{
+					PropExecStart([]string{"/bin/sleep", "400"}, false),
+				},
+			},
+			checkFunc: checkTransientUnitAux,
+		},
 	}
 
 	for i, tt := range testCases {
@@ -1332,6 +1382,47 @@ func checkTransientUnitConflicts(t *testing.T, trTarget TrUnitProp, trDep TrUnit
 	return nil
 }
 
+func checkTransientUnitAux(t *testing.T, trTarget TrUnitProp, trDep TrUnitProp) error {
+	conn := setupConn(t)
+
+	// Start the target unit with dep as auxiliary unit
+	err := runStartTrUnitWithAux(t, conn, trTarget, trDep)
+	if err != nil {
+		return err
+	}
+
+	target := getUnitStatusSingle(conn, trTarget.name)
+	if target == nil || target.ActiveState != "active" {
+		return fmt.Errorf("Test unit %s not active, should be active", trTarget.name)
+	}
+
+	aux := getUnitStatusSingle(conn, trDep.name)
+	if aux == nil {
+		return fmt.Errorf("Test unit %s not found", trDep.name)
+	}
+
+	if aux.ActiveState == "active" {
+		return fmt.Errorf("Test unit %s active, should be inactive", trDep.name)
+	}
+
+	err = runStopUnit(t, conn, trTarget)
+	if err != nil {
+		return err
+	}
+
+	target = getUnitStatusSingle(conn, trTarget.name)
+	if target != nil {
+		return fmt.Errorf("Test unit %s found in list, should be stopped", trTarget.name)
+	}
+
+	aux = getUnitStatusSingle(conn, trDep.name)
+	if aux != nil {
+		return fmt.Errorf("Test unit %s found in list, should be stopped", trTarget.name)
+	}
+
+	return nil
+}
+
 func runSleep(t *testing.T) uint32 {
 	cmd := exec.Command("/bin/sleep", "400")
 	err := cmd.Start()

dbus/properties.go

@@ -39,11 +39,14 @@ type Property struct {
 	Value dbus.Variant
 }
 
-type PropertyCollection struct {
+type AuxiliaryUnit struct {
 	Name       string
 	Properties []Property
 }
 
+// PropertyCollection is deprecated: use AuxiliaryUnit instead.
+type PropertyCollection = AuxiliaryUnit
+
 type execStart struct {
 	Path             string   // the binary path to execute
 	Args             []string // an array with all arguments to pass to the executed command, starting with argument 0