feat: add client-id subcommand to yggctl

This patch adds a 'client-id' subcommand
to yggctl which retrieves and prints to stdout
the active client ID of a yggd instance.

This attempts to resolve issue RedHatInsights#243

Signed-off-by: Jason Jerome <jajerome@redhat.com>

cmd/yggctl/actions.go

@@ -173,6 +173,32 @@ func messageJournalAction(ctx *cli.Context) error {
 	return nil
 }
 
+// clientIDAction connects to the Yggdrasil1 dbus interface
+// and attempts to retrieve the active yggd client id
+// and display the client id to stdout.
+func clientIDAction(ctx *cli.Context) error {
+	conn, err := connectBus()
+	if err != nil {
+		return cli.Exit(fmt.Errorf("cannot connect to bus: %w", err), 1)
+	}
+
+	obj := conn.Object("com.redhat.Yggdrasil1", "/com/redhat/Yggdrasil1")
+	var clientID string
+	if err := obj.Call("com.redhat.Yggdrasil1.GetClientID", dbus.Flags(0)).Store(&clientID); err != nil {
+		return cli.Exit(
+			fmt.Errorf(
+				"cannot retrieve active client id from the Yggdrasil1 dbus interface: %v",
+				err,
+			),
+			1,
+		)
+	}
+
+	fmt.Println(clientID)
+
+	return nil
+}
+
 func workersAction(c *cli.Context) error {
 	conn, err := connectBus()
 	if err != nil {

cmd/yggctl/main.go

@@ -30,6 +30,16 @@ func main() {
 	}
 
 	app.Commands = []*cli.Command{
+		{
+
+			Name:        "client-id",
+			Usage:       "Retrieve the current client id",
+			UsageText:   "yggctl client-id",
+			Description: `The client-id command retrieves the current client id of the yggdrasil instance`,
+			Aliases:     []string{},
+			Flags:       []cli.Flag{},
+			Action:      clientIDAction,
+		},
 		{
 			Name:   "generate",
 			Usage:  `Generate messages for publishing to client "in" topics`,

cmd/yggd/client.go

@@ -201,6 +201,10 @@ func (c *Client) ListWorkers() (map[string]map[string]string, *dbus.Error) {
 	return c.dispatcher.FlattenDispatchers(), nil
 }
 
+func (c *Client) GetClientID() (string, *dbus.Error) {
+	return config.DefaultConfig.ClientID, nil
+}
+
 // MessageJournal implements the com.redhat.Yggdrasil1.MessageJournal method.
 func (c *Client) MessageJournal(
 	messageID string,

dbus/com.redhat.Yggdrasil1.xml

@@ -8,6 +8,16 @@
         programmatic interaction with the yggdrasil system service.
     -->
     <interface name="com.redhat.Yggdrasil1">
+        <!--
+            GetClientID:
+            @id: The current client id on the interface.
+
+            Returns the current client id on the interface.
+        -->
+        <method name="GetClientID">
+            <arg type="s" name="id" direction="out" />
+        </method>
+
         <!-- 
             Dispatch:
             @directive: worker identifier for which the data is destined.