feat: Random HTTP port support (port=0) and disable HTTP support (por…

…t=-1)
grafana · Aug 15, 2023 · 5e49cf7 · 5e49cf7
1 parent 6d7aef6
commit 5e49cf7
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Showing 7 changed files with 41 additions and 17 deletions.
diff --git a/README.md b/README.md
@@ -123,7 +123,7 @@ The following parameters are recognized:
 parameter | description
 ----------|------------
 host      | Hostname or IP address for HTTP endpoint (default: "", empty, listen on all interfaces)
-port      | TCP port for HTTP endpoint (default: `5665`), example: `8080`
+port      | TCP port for HTTP endpoint (default: `5665`; `0` = random, `-1` = no HTTP), example: `8080`
 period    | Event emitting frequency (default: `10s`), example: `1m`
 open      | Set to `true` (or empty) for opening browser window automatically
 config    | UI configuration file location (default: `.dashboard.js`) (see [Customization](#customization))

diff --git a/dashboard/command.go b/dashboard/command.go
@@ -78,7 +78,7 @@ func buildRootCmd(opts *options, uiFS fs.FS) *cobra.Command {
 	opts = new(options)
 
 	flags.StringVar(&opts.Host, flagHost, defaultHost, "Hostname or IP address for HTTP endpoint (default: '', empty, listen on all interfaces)")
-	flags.IntVar(&opts.Port, flagPort, defaultPort, "TCP port for HTTP endpoint (default: 5665), example: 8080")
+	flags.IntVar(&opts.Port, flagPort, defaultPort, "TCP port for HTTP endpoint (default: 5665; 0=random, -1=no HTTP), example: 8080")
 	flags.DurationVar(&opts.Period, flagPeriod, defaultPeriod, "Event emitting frequency (default: `10s`), example: `1m`")
 	flags.BoolVar(&opts.Open, flagOpen, defaultOpen, "Open browser window automatically")
 	flags.StringVar(&opts.Config, flagConfig, defaultHost, "UI configuration file location (default: '.dashboard.js')")

diff --git a/dashboard/extension.go b/dashboard/extension.go
@@ -30,7 +30,7 @@ type Extension struct {
 
 	cumulative *meter
 
-	description string
+	name string
 
 	briefFS fs.FS
 }
@@ -49,7 +49,7 @@ func New(params output.Params, uiFS fs.FS, briefFS fs.FS) (*Extension, error) {
 		briefFS:     briefFS,
 		logger:      params.Logger,
 		options:     opts,
-		description: fmt.Sprintf("%s (%s) %s", params.OutputType, opts.addr(), opts.url()),
+		name:        params.OutputType,
 		buffer:      nil,
 		server:      nil,
 		flusher:     nil,
@@ -61,7 +61,11 @@ func New(params output.Params, uiFS fs.FS, briefFS fs.FS) (*Extension, error) {
 }
 
 func (ext *Extension) Description() string {
-	return ext.description
+	if ext.options.Port < 0 {
+		return ext.name
+	}
+
+	return fmt.Sprintf("%s (%s) %s", ext.name, ext.options.addr(), ext.options.url())
 }
 
 func (ext *Extension) Start() error {
@@ -85,11 +89,14 @@ func (ext *Extension) Start() error {
 		return err
 	}
 
-	go func() {
-		if err := ext.server.listenAndServe(ext.options.addr()); err != nil {
-			ext.logger.Error(err)
-		}
-	}()
+	addr, err := ext.server.listenAndServe(ext.options.addr())
+	if err != nil {
+		return err
+	}
+
+	if ext.options.Port == 0 {
+		ext.options.Port = addr.Port
+	}
 
 	ext.buffer = new(output.SampleBuffer)
 

diff --git a/dashboard/options.go b/dashboard/options.go
@@ -97,6 +97,10 @@ func (opts *options) config() ([]byte, error) {
 }
 
 func (opts *options) addr() string {
+	if opts.Port < 0 {
+		return ""
+	}
+
 	return net.JoinHostPort(opts.Host, strconv.Itoa(opts.Port))
 }
 

diff --git a/dashboard/replay.go b/dashboard/replay.go
@@ -55,10 +55,15 @@ func replay(opts *options, uiFS fs.FS, filename string) error {
 	rep.eventSource = new(eventSource)
 	rep.addEventListener(rep.server)
 
-	if err := rep.server.listenAndServe(rep.options.addr()); err != nil {
+	addr, err := rep.server.listenAndServe(rep.options.addr())
+	if err != nil {
 		return err
 	}
 
+	if rep.options.Port == 0 {
+		rep.options.Port = addr.Port
+	}
+
 	if rep.options.Open {
 		browser.OpenURL(rep.options.url()) // nolint:errcheck
 	}

diff --git a/dashboard/web.go b/dashboard/web.go
@@ -41,10 +41,10 @@ func newWebServer(uiFS fs.FS, uiConfig []byte, logger logrus.FieldLogger) *webSe
 	return srv
 }
 
-func (srv *webServer) listenAndServe(addr string) error {
+func (srv *webServer) listenAndServe(addr string) (*net.TCPAddr, error) {
 	listener, err := net.Listen("tcp", addr)
 	if err != nil {
-		return err
+		return nil, err
 	}
 
 	go func() {
@@ -55,7 +55,9 @@ func (srv *webServer) listenAndServe(addr string) error {
 		}
 	}()
 
-	return nil
+	a, _ := listener.Addr().(*net.TCPAddr)
+
+	return a, nil
 }
 
 func rootHandler(uiPath string) http.HandlerFunc {

diff --git a/dashboard/web_test.go b/dashboard/web_test.go
@@ -29,7 +29,9 @@ func Test_newWebServer(t *testing.T) {
 
 	addr := getRandomAddr(t)
 
-	assert.NoError(t, srv.listenAndServe(addr))
+	_, err := srv.listenAndServe(addr)
+
+	assert.NoError(t, err)
 
 	base := "http://" + addr
 
@@ -57,8 +59,12 @@ func Test_webServer_used_addr(t *testing.T) {
 
 	addr := getRandomAddr(t)
 
-	assert.NoError(t, srv.listenAndServe(addr))
-	assert.Error(t, srv.listenAndServe(addr))
+	_, err := srv.listenAndServe(addr)
+	assert.NoError(t, err)
+
+	_, err = srv.listenAndServe(addr)
+
+	assert.Error(t, err)
 }
 
 func Test_uiHandler_no_config(t *testing.T) {