cmd/pubsub: fix peers command topic filtering

License: MIT
Signed-off-by: Jeromy <why@ipfs.io>

core/commands/pubsub.go

@@ -274,16 +274,21 @@ To use, the daemon must be run with '--enable-pubsub-experiment'.
 
 var PubsubPeersCmd = &cmds.Command{
 	Helptext: cmds.HelpText{
-		Tagline: "List all peers we are currently pubsubbing with.",
+		Tagline: "List peers we are currently pubsubbing with.",
 		ShortDescription: `
-ipfs pubsub peers lists out the pubsub peers you are currently connected to.
+ipfs pubsub peers with no arguments lists out the pubsub peers you are
+currently connected to. If given a topic, it will list connected
+peers who are subscribed to the named topic.
 
 This is an experimental feature. It is not intended in its current state
 to be used in a production environment.
 
 To use, the daemon must be run with '--enable-pubsub-experiment'.
 `,
 	},
+	Arguments: []cmds.Argument{
+		cmds.StringArg("topic", false, false, "topic to list connected peers of"),
+	},
 	Run: func(req cmds.Request, res cmds.Response) {
 		n, err := req.InvocContext().GetNode()
 		if err != nil {
@@ -302,8 +307,13 @@ To use, the daemon must be run with '--enable-pubsub-experiment'.
 			return
 		}
 
+		var topic string
+		if len(req.Arguments()) == 1 {
+			topic = req.Arguments()[0]
+		}
+
 		var out []string
-		for _, p := range n.Floodsub.ListPeers("") {
+		for _, p := range n.Floodsub.ListPeers(topic) {
 			out = append(out, p.Pretty())
 		}
 		res.SetOutput(&stringList{out})

test/sharness/t0180-pubsub.sh

@@ -32,16 +32,27 @@ test_expect_success 'pubsub' '
 				echo > wait
 			fi
 	) &
+'
 
-	# wait until ipfs pubsub sub is ready to do work
-	sleep 1 &&
+test_expect_success "wait until ipfs pubsub sub is ready to do work" '
+	sleep 1
+'
 
-	# publish something
-	ipfsi 1 pubsub pub testTopic "testOK" &> pubErr &&
+test_expect_success "can see peer subscribed to testTopic" '
+	ipfsi 1 pubsub peers testTopic > peers_out
+'
 
-	# wait until `echo > wait` executed
-	cat wait &&
+test_expect_success "output looks good" '
+	echo $PEERID_0 > peers_exp &&
+	test_cmp peers_exp peers_out
+'
+
+test_expect_success "publish something" '
+	ipfsi 1 pubsub pub testTopic "testOK" &> pubErr
+'
 
+test_expect_success "wait until echo > wait executed" '
+	cat wait &&
 	test_cmp pubErr empty &&
 	test_cmp expected actual 
 '