Cleans up after code review, adds a -short option to "consul rtt" command.

command/rtt.go

@@ -38,6 +38,7 @@ Usage: consul rtt [options] node1 node2
 Options:
 
   -wan                       Use WAN coordinates instead of LAN coordinates.
+  -short                     Print just the round trip time (eg. "1.234 ms").
   -http-addr=127.0.0.1:8500  HTTP address of the Consul agent.
 `
 	return strings.TrimSpace(helpText)
@@ -45,11 +46,13 @@ Options:
 
 func (c *RttCommand) Run(args []string) int {
 	var wan bool
+	var short bool
 
 	cmdFlags := flag.NewFlagSet("rtt", flag.ContinueOnError)
 	cmdFlags.Usage = func() { c.Ui.Output(c.Help()) }
 
 	cmdFlags.BoolVar(&wan, "wan", false, "wan")
+	cmdFlags.BoolVar(&short, "short", false, "short")
 	httpAddr := HTTPAddrFlag(cmdFlags)
 	if err := cmdFlags.Parse(args); err != nil {
 		return 1
@@ -77,6 +80,8 @@ func (c *RttCommand) Run(args []string) int {
 	var source string
 	var coord1, coord2 *coordinate.Coordinate
 	if wan {
+		source = "WAN"
+
 		// Parse the input nodes.
 		parts1 := strings.Split(nodes[0], ".")
 		parts2 := strings.Split(nodes[1], ".")
@@ -103,10 +108,15 @@ func (c *RttCommand) Run(args []string) int {
 				if dc.Datacenter == dc2 && entry.Node == node2 {
 					coord2 = entry.Coord
 				}
+
+				if coord1 != nil && coord2 != nil {
+					goto SHOW_RTT
+				}
 			}
 		}
-		source = "WAN"
 	} else {
+		source = "LAN"
+
 		// Pull all the LAN coordinates.
 		entries, _, err := coordClient.Nodes(nil)
 		if err != nil {
@@ -122,8 +132,11 @@ func (c *RttCommand) Run(args []string) int {
 			if entry.Node == nodes[1] {
 				coord2 = entry.Coord
 			}
+
+			if coord1 != nil && coord2 != nil {
+				goto SHOW_RTT
+			}
 		}
-		source = "LAN"
 	}
 
 	// Make sure we found both coordinates.
@@ -136,12 +149,18 @@ func (c *RttCommand) Run(args []string) int {
 		return 1
 	}
 
+SHOW_RTT:
+
 	// Report the round trip time.
-	dist := coord1.DistanceTo(coord2).Seconds()
-	c.Ui.Output(fmt.Sprintf("Estimated %s <-> %s rtt=%.3f ms (using %s coordinates)", nodes[0], nodes[1], dist*1000.0, source))
+	dist := fmt.Sprintf("%.3f ms", coord1.DistanceTo(coord2).Seconds()*1000.0)
+	if short {
+		c.Ui.Output(dist)
+	} else {
+		c.Ui.Output(fmt.Sprintf("Estimated %s <-> %s rtt=%s (using %s coordinates)", nodes[0], nodes[1], dist, source))
+	}
 	return 0
 }
 
 func (c *RttCommand) Synopsis() string {
-	return "Estimates round trip times between nodes"
+	return "Estimates network round trip time between nodes"
 }

command/rtt_test.go

@@ -57,6 +57,7 @@ func TestRttCommand_Run_LAN(t *testing.T) {
 	c1 := coordinate.NewCoordinate(coordinate.DefaultConfig())
 	c2 := c1.Clone()
 	c2.Vec[0] = 0.123
+	dist_str := fmt.Sprintf("%.3f ms", c1.DistanceTo(c2).Seconds()*1000.0)
 
 	req1 := structs.CoordinateUpdateRequest{
 		Datacenter: a.config.Datacenter,
@@ -80,11 +81,10 @@ func TestRttCommand_Run_LAN(t *testing.T) {
 	// Wait for the updates to get flushed to the data store.
 	time.Sleep(2 * updatePeriod)
 
+	// Try two known nodes.
+	{
 		ui := new(cli.MockUi)
 		c := &RttCommand{Ui: ui}
-
-	// Try two known nodes.
-	func() {
 		args := []string{
 			"-http-addr=" + a.httpAddr,
 			a.config.NodeName,
@@ -96,14 +96,38 @@ func TestRttCommand_Run_LAN(t *testing.T) {
 		}
 
 		// Make sure the proper RTT was reported in the output.
-		dist_str := fmt.Sprintf("%.3f ms", c1.DistanceTo(c2).Seconds()*1000.0)
-		if !strings.Contains(ui.OutputWriter.String(), dist_str) {
+		expected := fmt.Sprintf("rtt=%s", dist_str)
+		if !strings.Contains(ui.OutputWriter.String(), expected) {
 			t.Fatalf("bad: %#v", ui.OutputWriter.String())
 		}
-	}()
+	}
+
+	// Try the short mode.
+	{
+		ui := new(cli.MockUi)
+		c := &RttCommand{Ui: ui}
+		args := []string{
+			"-short",
+			"-http-addr=" + a.httpAddr,
+			a.config.NodeName,
+			"dogs",
+		}
+		code := c.Run(args)
+		if code != 0 {
+			t.Fatalf("bad: %d: %#v", code, ui.ErrorWriter.String())
+		}
+
+		// Make sure the proper RTT was reported in the output.
+		expected := fmt.Sprintf("%s\n", dist_str)
+		if ui.OutputWriter.String() != expected {
+			t.Fatalf("bad: %#v", ui.OutputWriter.String())
+		}
+	}
 
 	// Try an unknown node.
-	func() {
+	{
+		ui := new(cli.MockUi)
+		c := &RttCommand{Ui: ui}
 		args := []string{
 			"-http-addr=" + a.httpAddr,
 			a.config.NodeName,
@@ -113,7 +137,7 @@ func TestRttCommand_Run_LAN(t *testing.T) {
 		if code != 1 {
 			t.Fatalf("bad: %d: %#v", code, ui.ErrorWriter.String())
 		}
-	}()
+	}
 }
 
 func TestRttCommand_Run_WAN(t *testing.T) {
@@ -121,17 +145,16 @@ func TestRttCommand_Run_WAN(t *testing.T) {
 	defer a.Shutdown()
 	waitForLeader(t, a.httpAddr)
 
-	ui := new(cli.MockUi)
-	c := &RttCommand{Ui: ui}
-
 	node := fmt.Sprintf("%s.%s", a.config.Datacenter, a.config.NodeName)
 
 	// We can't easily inject WAN coordinates, so we will just query the
 	// node with itself.
-	func() {
+	{
+		ui := new(cli.MockUi)
+		c := &RttCommand{Ui: ui}
 		args := []string{
-			"-http-addr=" + a.httpAddr,
 			"-wan",
+			"-http-addr=" + a.httpAddr,
 			node,
 			node,
 		}
@@ -144,13 +167,37 @@ func TestRttCommand_Run_WAN(t *testing.T) {
 		if !strings.Contains(ui.OutputWriter.String(), "rtt=") {
 			t.Fatalf("bad: %#v", ui.OutputWriter.String())
 		}
-	}()
+	}
+
+	// Try the short mode.
+	{
+		ui := new(cli.MockUi)
+		c := &RttCommand{Ui: ui}
+		args := []string{
+			"-wan",
+			"-short",
+			"-http-addr=" + a.httpAddr,
+			node,
+			node,
+		}
+		code := c.Run(args)
+		if code != 0 {
+			t.Fatalf("bad: %d: %#v", code, ui.ErrorWriter.String())
+		}
+
+		// Make sure there was some kind of RTT reported in the output.
+		if !strings.Contains(ui.OutputWriter.String(), " ms\n") {
+			t.Fatalf("bad: %#v", ui.OutputWriter.String())
+		}
+	}
 
 	// Try an unknown node.
-	func() {
+	{
+		ui := new(cli.MockUi)
+		c := &RttCommand{Ui: ui}
 		args := []string{
-			"-http-addr=" + a.httpAddr,
 			"-wan",
+			"-http-addr=" + a.httpAddr,
 			node,
 			"dc1.nope",
 		}
@@ -158,5 +205,5 @@ func TestRttCommand_Run_WAN(t *testing.T) {
 		if code != 1 {
 			t.Fatalf("bad: %d: %#v", code, ui.ErrorWriter.String())
 		}
-	}()
+	}
 }

website/source/docs/commands/index.html.markdown

@@ -39,7 +39,7 @@ Available commands are:
     members        Lists the members of a Consul cluster
     monitor        Stream logs from a Consul agent
     reload         Triggers the agent to reload configuration files
-    rtt            Estimates round trip times between nodes
+    rtt            Estimates network round trip time between nodes
     version        Prints the Consul version
     watch          Watch for changes in Consul
 ```

website/source/docs/commands/rtt.html.markdown

@@ -3,7 +3,7 @@ layout: "docs"
 page_title: "Commands: RTT"
 sidebar_current: "docs-commands-rtt"
 description: >
-  The `rtt` command estimates the netowrk round trip time between two nodes using Consul's network coordinate model of the cluster.
+  The rtt command estimates the network round trip time between two nodes.
 ---
 
 # Consul RTT
@@ -36,6 +36,8 @@ The list of available flags are:
   by the datacenter and a period (eg. "dc1.sever"). By default, the two nodes are
   assumed to be nodes in the local datacenter the LAN coordinates are used.
 
+* `-short` - Abbreviates the output to just the round trip time (eg. "1.234 ms").
+
 * `-http-addr` - Address to the HTTP server of the agent you want to contact
   to send this command. If this isn't specified, the command will contact
   "127.0.0.1:8500" which is the default HTTP address of a Consul agent.
@@ -43,12 +45,15 @@ The list of available flags are:
 ## Output
 
 If coordinates are available, the command will print the estimated round trip
-time beteeen the given nodes:
+time between the given nodes:
 
 ```
 $ consul rtt n1 n2
 Estimated n1 <-> n2 rtt=0.610 ms (using LAN coordinates)
 
+$ consul rtt -short n1 n2
+0.610 ms
+
 $ consul rtt -wan dc1.n1 dc2.n2
 Estimated dc1.n1 <-> dc2.n2 rtt=1.275 ms (using WAN coordinates)
 ```