Allow specifying duration for --ref-rate/-r flag

This commit changes the --ref-rate/-r flag so that it accepts both an
integer in seconds (original behavior) and a custom duration string (new
behavior). This lets the user draw the UI at a higher refresh rate such
as 30fps.

It also makes a minor change in src/tui/proc-table.go, changing from
using `time.After` to `time.Ticker` to make the code slightly more
performant.

src/cmd/attach.go

@@ -15,7 +15,7 @@ var attachCmd = &cobra.Command{
 
 func init() {
 	rootCmd.AddCommand(attachCmd)
-	attachCmd.Flags().IntVarP(pcFlags.RefreshRate, "ref-rate", "r", *pcFlags.RefreshRate, "TUI refresh rate in seconds")
+	attachCmd.Flags().VarP(refreshRateFlag{pcFlags.RefreshRate}, "ref-rate", "r", "TUI refresh rate in seconds or as a Go duration string (e.g. 1s)")
 	attachCmd.Flags().StringVarP(pcFlags.Address, "address", "a", *pcFlags.Address, "address of the target process compose server")
 	attachCmd.Flags().IntVarP(pcFlags.LogLength, "log-length", "l", *pcFlags.LogLength, "log length to display in TUI")
 	attachCmd.Flags().AddFlag(commonFlags.Lookup(flagReverse))

src/cmd/project_runner.go

@@ -10,7 +10,6 @@ import (
 	"os"
 	"os/signal"
 	"syscall"
-	"time"
 )
 
 func getProjectRunner(process []string, noDeps bool, mainProcess string, mainProcessArgs []string) *app.ProjectRunner {
@@ -82,7 +81,7 @@ func runTui(project *app.ProjectRunner) int {
 
 func startTui(runner app.IProject) {
 	tuiOptions := []tui.Option{
-		tui.WithRefreshRate(time.Duration(*pcFlags.RefreshRate) * time.Second),
+		tui.WithRefreshRate(*pcFlags.RefreshRate),
 	}
 	if !*pcFlags.IsReadOnlyMode {
 		config.CreateProcCompHome()

src/cmd/root.go

@@ -15,6 +15,7 @@ import (
 	"os"
 	"path"
 	"runtime"
+	"strconv"
 	"time"
 )
 
@@ -72,7 +73,7 @@ func init() {
 	rootCmd.PersistentFlags().BoolVar(pcFlags.NoServer, "no-server", *pcFlags.NoServer, "disable HTTP server (env: "+config.EnvVarNameNoServer+")")
 	rootCmd.PersistentFlags().BoolVar(pcFlags.IsOrderedShutDown, "ordered-shutdown", *pcFlags.IsOrderedShutDown, "shut down processes in reverse dependency order")
 	rootCmd.Flags().BoolVarP(pcFlags.HideDisabled, "hide-disabled", "d", *pcFlags.HideDisabled, "hide disabled processes")
-	rootCmd.Flags().IntVarP(pcFlags.RefreshRate, "ref-rate", "r", *pcFlags.RefreshRate, "TUI refresh rate in seconds")
+	rootCmd.Flags().VarP(refreshRateFlag{pcFlags.RefreshRate}, "ref-rate", "r", "TUI refresh rate in seconds or as a Go duration string (e.g. 1s)")
 	rootCmd.PersistentFlags().IntVarP(pcFlags.PortNum, "port", "p", *pcFlags.PortNum, "port number (env: "+config.EnvVarNamePort+")")
 	rootCmd.Flags().StringArrayVarP(&opts.FileNames, "config", "f", config.GetConfigDefault(), "path to config files to load (env: "+config.EnvVarNameConfig+")")
 	rootCmd.Flags().StringArrayVarP(&nsAdmitter.EnabledNamespaces, "namespace", "n", nil, "run only specified namespaces (default all)")
@@ -159,3 +160,37 @@ func isUnixSocketMode(cmd *cobra.Command) bool {
 		os.Getenv(config.EnvVarUnixSocketPath) != "" ||
 		cmd.Flags().Changed("unix-socket")
 }
+
+// refreshRateFlag is a custom flag type for the TUI's refresh rate.
+// It accepts both an integer in seconds and a duration string.
+type refreshRateFlag struct {
+	dst *time.Duration
+}
+
+func (f refreshRateFlag) String() string {
+	d := *f.dst
+	if d%time.Second == 0 {
+		return strconv.Itoa(int(d / time.Second))
+	}
+	return d.String()
+}
+
+func (f refreshRateFlag) Set(str string) error {
+	i, err := strconv.Atoi(str)
+	if err == nil {
+		*f.dst = time.Duration(i) * time.Second
+		return nil
+	}
+	d, err := time.ParseDuration(str)
+	if err == nil {
+		*f.dst = d
+		return nil
+	}
+	return fmt.Errorf(
+		"invalid refresh rate %q, must be a duration or an integer in seconds",
+		str)
+}
+
+func (f refreshRateFlag) Type() string {
+	return "duration"
+}

src/config/Flags.go

@@ -2,11 +2,12 @@ package config
 
 import (
 	"math"
+	"time"
 )
 
 const (
 	// DefaultRefreshRate represents the refresh interval.
-	DefaultRefreshRate = 1 // secs
+	DefaultRefreshRate = 1 * time.Second
 
 	// DefaultLogLevel represents the default log level.
 	DefaultLogLevel = "info"
@@ -38,7 +39,7 @@ const (
 
 // Flags represents PC configuration flags.
 type Flags struct {
-	RefreshRate       *int
+	RefreshRate       *time.Duration
 	PortNum           *int
 	Address           *string
 	LogLevel          *string

src/tui/proc-table.go

@@ -195,12 +195,14 @@ func (pv *pcView) updateTable(ctx context.Context) {
 	pv.appView.QueueUpdateDraw(func() {
 		pv.fillTableData()
 	})
+	ticker := time.NewTicker(pv.refreshRate)
+	defer ticker.Stop()
 	for {
 		select {
 		case <-ctx.Done():
 			log.Debug().Msg("Table monitoring canceled")
 			return
-		case <-time.After(pv.refreshRate):
+		case <-ticker.C:
 			pv.appView.QueueUpdateDraw(func() {
 				pv.fillTableData()
 			})