roachtest: Set localhost as the http listener when --local flag

is used. This prevents OSX from prompting to allow incoming
network connections when running a roachtest from an ide or
 shell.

Release justification: test-only change
Release note: None

pkg/cmd/roachtest/main.go

@@ -376,8 +376,15 @@ func runTests(register func(registry.Registry), cfg cliCfg) error {
 
 	filter := registry.NewTestFilter(cfg.args)
 	clusterType := roachprodCluster
+	bindTo := ""
 	if local {
 		clusterType = localCluster
+
+		// This will suppress the annoying "Allow incoming network connections" popup from
+		// OSX when running a roachtest
+		bindTo = "localhost"
+
+		fmt.Printf("--local specified. Binding http listener to localhost only")
 		if cfg.parallelism != 1 {
 			fmt.Printf("--local specified. Overriding --parallelism to 1.\n")
 			cfg.parallelism = 1
@@ -392,7 +399,7 @@ func runTests(register func(registry.Registry), cfg cliCfg) error {
 		keepClustersOnTestFailure: cfg.debugEnabled,
 		clusterID:                 cfg.clusterID,
 	}
-	if err := runner.runHTTPServer(cfg.httpPort, os.Stdout); err != nil {
+	if err := runner.runHTTPServer(cfg.httpPort, os.Stdout, bindTo); err != nil {
 		return err
 	}
 

pkg/cmd/roachtest/test_runner.go

@@ -1187,14 +1187,15 @@ func (r *testRunner) removeWorker(ctx context.Context, name string) {
 // runHTTPServer starts a server running in the background.
 //
 // httpPort: The port on which to serve the web interface. Pass 0 for allocating
+// bindTo: The host/ip on which to bind. Leave empty to bind on all local ips
 //
 //	a port automatically (which will be printed to stdout).
-func (r *testRunner) runHTTPServer(httpPort int, stdout io.Writer) error {
+func (r *testRunner) runHTTPServer(httpPort int, stdout io.Writer, bindTo string) error {
 	http.HandleFunc("/", r.serveHTTP)
 	// Run an http server in the background.
 	// We handle the case where httpPort is 0, which means we automatically
 	// allocate a port.
-	listener, err := net.Listen("tcp", fmt.Sprintf(":%d", httpPort))
+	listener, err := net.Listen("tcp", fmt.Sprintf("%s:%d", bindTo, httpPort))
 	if err != nil {
 		return err
 	}
@@ -1204,7 +1205,11 @@ func (r *testRunner) runHTTPServer(httpPort int, stdout io.Writer) error {
 			panic(err)
 		}
 	}()
-	fmt.Fprintf(stdout, "HTTP server listening on all network interfaces, port %d.\n", httpPort)
+	bindToDesc := "all network interfaces"
+	if bindTo != "" {
+		bindToDesc = bindTo
+	}
+	fmt.Fprintf(stdout, "HTTP server listening on %s, port %d.\n", bindToDesc, httpPort)
 	return nil
 }