CmdRunner now updates view while running

modules/cmdrunner/settings.go

@@ -7,17 +7,21 @@ import (
 )
 
 const (
-	defaultFocusable = false
+	defaultFocusable = true
 	defaultTitle     = "CmdRunner"
 )
 
+// Settings for the cmdrunner widget
 type Settings struct {
 	common *cfg.Common
 
 	args     []string `help:"The arguments to the command, with each item as an element in an array. Example: for curl -I cisco.com, the arguments array would be ['-I', 'cisco.com']."`
 	cmd      string   `help:"The terminal command to be run, withouth the arguments. Ie: ping, whoami, curl."`
+	tail     bool     `help:"Automatically scroll to the end of the command output."`
+	maxLines int      `help:"Maximum number of lines kept in the buffer."`
 }
 
+// NewSettingsFromYAML loads the cmdrunner portion of the WTF config
 func NewSettingsFromYAML(name string, moduleConfig *config.Config, globalConfig *config.Config) *Settings {
 
 	settings := Settings{
@@ -25,6 +29,8 @@ func NewSettingsFromYAML(name string, moduleConfig *config.Config, globalConfig
 
 		args:     utils.ToStrs(moduleConfig.UList("args")),
 		cmd:      moduleConfig.UString("cmd"),
+		tail:     moduleConfig.UBool("tail"),
+		maxLines: moduleConfig.UInt("maxLines", -1),
 	}
 
 	return &settings

modules/cmdrunner/widget.go

@@ -1,21 +1,25 @@
 package cmdrunner
 
 import (
+	"bytes"
 	"fmt"
 	"os/exec"
 	"strings"
+	"sync"
 
 	"github.com/rivo/tview"
-	"github.com/wtfutil/wtf/utils"
 	"github.com/wtfutil/wtf/view"
 )
 
+// Widget contains the data for this widget
 type Widget struct {
 	view.TextWidget
 
-	args     []string
-	cmd      string
 	settings *Settings
+
+	m       sync.Mutex
+	buffer  *bytes.Buffer
+	running bool
 }
 
 // NewWidget creates a new instance of the widget
@@ -23,18 +27,18 @@ func NewWidget(app *tview.Application, settings *Settings) *Widget {
 	widget := Widget{
 		TextWidget: view.NewTextWidget(app, settings.common),
 
-		args:     settings.args,
-		cmd:      settings.cmd,
 		settings: settings,
+		buffer:   &bytes.Buffer{},
 	}
 
 	widget.View.SetWrap(true)
+	widget.View.SetScrollable(true)
 
 	return &widget
 }
 
 func (widget *Widget) content() (string, string, bool) {
-	result := widget.execute()
+	result := widget.buffer.String()
 
 	ansiTitle := tview.TranslateANSI(widget.CommonSettings().Title)
 	if ansiTitle == defaultTitle {
@@ -47,23 +51,86 @@ func (widget *Widget) content() (string, string, bool) {
 
 // Refresh executes the command and updates the view with the results
 func (widget *Widget) Refresh() {
+	widget.m.Lock()
+	defer widget.m.Unlock()
+
+	widget.execute()
 	widget.Redraw(widget.content)
+	if widget.settings.tail {
+		widget.View.ScrollToEnd()
+	}
 }
 
 // String returns the string representation of the widget
 func (widget *Widget) String() string {
-	args := strings.Join(widget.args, " ")
+	args := strings.Join(widget.settings.args, " ")
 
 	if args != "" {
-		return fmt.Sprintf(" %s %s ", widget.cmd, args)
+		return fmt.Sprintf(" %s %s ", widget.settings.cmd, args)
 	}
 
-	return fmt.Sprintf(" %s ", widget.cmd)
+	return fmt.Sprintf(" %s ", widget.settings.cmd)
+}
+
+func (widget *Widget) Write(p []byte) (n int, err error) {
+	widget.m.Lock()
+	defer widget.m.Unlock()
+
+	// Write the new data into the buffer
+	n, err = widget.buffer.Write(p)
+
+	// Remove lines that exceed maxLines
+	lines := widget.countLines()
+	if lines > widget.settings.maxLines {
+		widget.drainLines(lines - widget.settings.maxLines)
+	}
+
+	// Redraw the widget
+	widget.Redraw(widget.content)
+
+	return
 }
 
 /* -------------------- Unexported Functions -------------------- */
 
-func (widget *Widget) execute() string {
+func (widget *Widget) execute() {
-	cmd := exec.Command(widget.cmd, widget.args...)
+	// Make sure the command is not already running
-	return utils.ExecuteCommand(cmd)
+	if widget.running {
+		return
+	}
+
+	// Reset the buffer
+	widget.buffer.Reset()
+
+	// Indicate that the command is running
+	widget.running = true
+
+	// Setup the command to run
+	cmd := exec.Command(widget.settings.cmd, widget.settings.args...)
+	cmd.Stdout = widget
+
+	// Run the command and wait for it to exit in another Go-routine
+	go func() {
+		err := cmd.Run()
+
+		// The command has exited, print any error messages
+		widget.m.Lock()
+		if err != nil {
+			widget.buffer.WriteString(err.Error())
+		}
+		widget.running = false
+		widget.m.Unlock()
+	}()
+}
+
+// countLines counts the lines of data in the buffer
+func (widget *Widget) countLines() int {
+	return bytes.Count(widget.buffer.Bytes(), []byte{'\n'})
+}
+
+// drainLines removed the first n lines from the buffer
+func (widget *Widget) drainLines(n int) {
+	for i := 0; i < n; i++ {
+		widget.buffer.ReadBytes('\n')
+	}
 }