More dbus tests

README.md

@@ -6,3 +6,25 @@ Go bindings to systemd socket activation, journal and D-BUS APIs.
 
 See an example in `examples/activation/httpserver.go`. For easy debugging use
 `/usr/lib/systemd/systemd-activate`
+
+## D-Bus
+
+The D-Bus API lets you start, stop and introspect systemd units. The API docs are here:
+
+http://godoc.org/github.com/coreos/go-systemd/dbus
+
+### Debugging
+
+Create `/etc/dbus-1/system-local.conf` that looks like this:
+
+```
+<!DOCTYPE busconfig PUBLIC
+"-//freedesktop//DTD D-Bus Bus Configuration 1.0//EN"
+"http://www.freedesktop.org/standards/dbus/1.0/busconfig.dtd">
+<busconfig>
+    <policy user="root">
+        <allow eavesdrop="true"/>
+        <allow eavesdrop="true" send_destination="*"/>
+    </policy>
+</busconfig>
+```

dbus/dbus.go

@@ -20,6 +20,7 @@ func ObjectPath(path string) dbus.ObjectPath {
 	return dbus.ObjectPath(path)
 }
 
+// Conn is a connection to systemds dbus endpoint.
 type Conn struct {
 	sysconn     *dbus.Conn
 	sysobj      *dbus.Object
@@ -37,6 +38,7 @@ type Conn struct {
 	dispatch map[string]func(dbus.Signal)
 }
 
+// New() establishes a connection to the system bus and authenticates.
 func New() (*Conn, error) {
 	c := new(Conn)
 
@@ -69,7 +71,11 @@ func (c *Conn) initConnection() error {
 
 	c.sysobj = c.sysconn.Object("org.freedesktop.systemd1", dbus.ObjectPath("/org/freedesktop/systemd1"))
 
+	// Setup the listeners on jobs so that we can get completions
+	c.sysconn.BusObject().Call("org.freedesktop.DBus.AddMatch", 0,
+		"type='signal', interface='org.freedesktop.systemd1.Manager', member='JobRemoved'")
+	c.initSubscription()
+	c.initDispatch()
+
 	return nil
 }
-
-

dbus/dbus_test.go

@@ -4,6 +4,7 @@ import (
 	"testing"
 )
 
+// TestObjectPath ensures path encoding of the systemd rules works.
 func TestObjectPath(t *testing.T) {
 	input := "/silly-path/to@a/unit..service"
 	output := ObjectPath(input)
@@ -13,3 +14,12 @@ func TestObjectPath(t *testing.T) {
 		t.Fatalf("Output '%s' did not match expected '%s'", output, expected)
 	}
 }
+
+// TestNew ensures that New() works without errors.
+func TestNew(t *testing.T) {
+	_, err := New()
+
+	if err != nil {
+		t.Fatal(err)
+	}
+}

dbus/methods.go

@@ -137,7 +137,7 @@ func (c *Conn) GetUnitProperties(unit string) (map[string]interface{}, error) {
 	}
 
 	out := make(map[string]interface{}, len(props))
-	for k, v := range(props) {
+	for k, v := range props {
 		out[k] = v.Value()
 	}
 

dbus/methods_test.go

@@ -1,17 +1,109 @@
 package dbus
 
 import (
+	"os"
+	"path/filepath"
 	"testing"
 )
 
-// TestActivation forks out a copy of activation.go example and reads back two
-// strings from the pipes that are passed in.
-func TestGetUnitProperties(t *testing.T) {
+func setupConn(t *testing.T) *Conn {
 	conn, err := New()
 	if err != nil {
 		t.Fatal(err)
 	}
-	//defer conn.Close()
+
+	return conn
+}
+
+func setupUnit(target string, conn *Conn, t *testing.T) {
+	// Blindly stop the unit in case it is running
+	conn.StopUnit(target, "replace")
+
+	// Blindly remove the symlink in case it exists
+	targetRun := filepath.Join("/run/systemd/system/", target)
+	err := os.Remove(targetRun)
+
+	// 1. Enable the unit
+	abs, err := filepath.Abs("../fixtures/" + target)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	fixture := []string{abs}
+
+	install, changes, err := conn.EnableUnitFiles(fixture, true, true)
+
+	if install != false {
+		t.Fatal("Install was true")
+	}
+
+	if len(changes) < 1 {
+		t.Fatal("Expected one change, got %v", changes)
+	}
+
+	if changes[0].Filename != targetRun {
+		t.Fatal("Unexpected target filename")
+	}
+}
+
+// Ensure that basic unit starting and stopping works.
+func TestStartStopUnit(t *testing.T) {
+	target := "start-stop.service"
+	conn := setupConn(t)
+
+	setupUnit(target, conn, t)
+
+	// 2. Start the unit
+	job, err := conn.StartUnit(target, "replace")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if job != "done" {
+		t.Fatal("Job is not done, %v", job)
+	}
+
+	units, err := conn.ListUnits()
+
+	var unit *UnitStatus
+	for _, u := range units {
+		if u.Name == target {
+			unit = &u
+		}
+	}
+
+	if unit == nil {
+		t.Fatalf("Test unit not found in list")
+	}
+
+	if unit.ActiveState != "active" {
+		t.Fatalf("Test unit not active")
+	}
+
+	// 3. Stop the unit
+	job, err = conn.StopUnit(target, "replace")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	units, err = conn.ListUnits()
+
+	unit = nil
+	for _, u := range units {
+		if u.Name == target {
+			unit = &u
+		}
+	}
+
+	if unit != nil {
+		t.Fatalf("Test unit found in list, should be stopped")
+	}
+}
+
+// TestGetUnitProperties reads the `-.mount` which should exist on all systemd
+// systems and ensures that one of its properties is valid.
+func TestGetUnitProperties(t *testing.T) {
+	conn := setupConn(t)
 
 	unit := "-.mount"
 

dbus/subscription.go

@@ -12,11 +12,11 @@ const (
 	ignoreInterval      = int64(30 * time.Millisecond)
 )
 
-// Subscribe sets up this connection to subscribe to all dbus events. This is
-// required before calling SubscribeUnits.
+// Subscribe sets up this connection to subscribe to all systemd dbus events.
+// This is required before calling SubscribeUnits. When the connection closes
+// systemd will automatically stop sending signals so there is no need to
+// explicitly call Unsubscribe().
 func (c *Conn) Subscribe() error {
-	c.sysconn.BusObject().Call("org.freedesktop.DBus.AddMatch", 0,
-		"type='signal',interface='org.freedesktop.systemd1.Manager',member='JobRemoved'")
 	c.sysconn.BusObject().Call("org.freedesktop.DBus.AddMatch", 0,
 		"type='signal',interface='org.freedesktop.systemd1.Manager',member='UnitNew'")
 	c.sysconn.BusObject().Call("org.freedesktop.DBus.AddMatch", 0,
@@ -28,8 +28,16 @@ func (c *Conn) Subscribe() error {
 		return err
 	}
 
-	c.initSubscription()
-	c.initDispatch()
+	return nil
+}
+
+// Unsubscribe this connection from systemd dbus events.
+func (c *Conn) Unsubscribe() error {
+	err := c.sysobj.Call("org.freedesktop.systemd1.Manager.Unsubscribe", 0).Store()
+	if err != nil {
+		c.sysconn.Close()
+		return err
+	}
 
 	return nil
 }
@@ -126,7 +134,7 @@ type SubStateUpdate struct {
 }
 
 // SetSubStateSubscriber writes to updateCh when any unit's substate changes.
-// Althrough this writes to updateCh on every state change, the reported state
+// Although this writes to updateCh on every state change, the reported state
 // may be more recent than the change that generated it (due to an unavoidable
 // race in the systemd dbus interface).  That is, this method provides a good
 // way to keep a current view of all units' states, but is not guaranteed to

dbus/subscription_test.go

@@ -0,0 +1,90 @@
+package dbus
+
+import (
+	"testing"
+	"time"
+)
+
+// TestSubscribe exercises the basics of subscription
+func TestSubscribe(t *testing.T) {
+	conn, err := New()
+
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = conn.Subscribe()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = conn.Unsubscribe()
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+// TestSubscribeUnit exercises the basics of subscription of a particular unit.
+func TestSubscribeUnit(t *testing.T) {
+	target := "subscribe-events.service"
+
+	conn, err := New()
+
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = conn.Subscribe()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = conn.Unsubscribe()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	evChan, errChan := conn.SubscribeUnits(time.Second)
+
+	setupUnit(target, conn, t)
+
+	job, err := conn.StartUnit(target, "replace")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if job != "done" {
+		t.Fatal("Couldn't start", target)
+	}
+
+	timeout := make(chan bool, 1)
+	go func() {
+		time.Sleep(3 * time.Second)
+		close(timeout)
+	}()
+
+	for {
+		select {
+		case changes := <-evChan:
+			tCh, ok := changes[target]
+
+			// Just continue until we see our event.
+			if !ok {
+				continue
+			}
+
+			if tCh.ActiveState == "active" && tCh.Name == target {
+				goto success
+			}
+		case err = <-errChan:
+			t.Fatal(err)
+		case <-timeout:
+			t.Fatal("Reached timeout")
+		}
+	}
+
+success:
+	return
+}
+
+

fixtures/start-stop.service

@@ -0,0 +1,5 @@
+[Unit]
+Description=start stop test
+
+[Service]
+ExecStart=/bin/sleep 400

fixtures/subscribe-events.service

@@ -0,0 +1,5 @@
+[Unit]
+Description=start stop test
+
+[Service]
+ExecStart=/bin/sleep 400