Implement a early AddButton() via a golang plugin

pass a name to gocui.AddButton()
    cleaner plugin usage
    add the start to golang plugin
    plugin stuff in a single file
    added a button correctly
    andlabs/ui added a button via plugin to gocli
  	  hot diggity!
    trying to invoke a gocli plugin function from the andlabs ui
    load the plugin
    hide more debugging output
    turn off all output

Signed-off-by: Jeff Carr <jcarr@wit.com>

cmds/buttonAsPlugin/Makefile

@@ -1,5 +1,5 @@
 run: build
-	./buttonAsPlugin
+	./buttonAsPlugin >/tmp/buttonAsPlugin.log 2>&1
 
 build-release:
 	go get -v -u -x .

cmds/buttonAsPlugin/log.go

@@ -0,0 +1,64 @@
+// This creates a simple hello world window
+package main
+
+import 	(
+	"log"
+	"fmt"
+	"os"
+	"io"
+	"time"
+	"bufio"
+	arg "github.com/alexflint/go-arg"
+)
+
+
+var args struct {
+	Foo string
+	Bar bool
+	User string `arg:"env:USER"`
+	Demo bool `help:"run a demo"`
+}
+
+var f1 *os.File
+var f2 *os.File
+var err error
+
+func init() {
+	arg.MustParse(&args)
+	fmt.Println(args.Foo, args.Bar, args.User)
+
+	f1, err = os.OpenFile("/tmp/guilogfile", os.O_RDWR | os.O_CREATE | os.O_APPEND, 0666)
+	if err != nil {
+		log.Fatalf("error opening file: %v", err)
+	}
+	// hmm. is there a trick here or must this be in main()
+	// defer f.Close()
+
+	log.SetOutput(f1)
+	log.Println("This is a test log entry")
+}
+
+func captureSTDOUT() {
+	f2, _ = os.OpenFile("/tmp/my.log", os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0664)
+	multiWriter := io.MultiWriter(os.Stderr, f2)
+	rd, wr, err := os.Pipe()
+	if err != nil {
+	    os.Exit(1)
+	}
+
+	// overwrite os.Stdout
+	os.Stderr = wr
+
+	go func() {
+	    scanner := bufio.NewScanner(rd)
+	    for scanner.Scan() {
+	        stdoutLine := scanner.Text()
+	        multiWriter.Write([]byte(stdoutLine + "\n"))
+	    }
+	}()
+
+	fmt.Println("foobar")
+
+	// hacky sleep to ensure the go routine can write before program exits
+	time.Sleep(time.Second)
+}

cmds/buttonAsPlugin/main.go

@@ -7,6 +7,12 @@ import 	(
 )
 
 func main() {
+	// go loadPlugin(plugHello, "../../toolkit/hello.so")
+
+	// this doesn't seem to work
+	captureSTDOUT()
+
+	// go loadPlugin("../../toolkit/gocli.so")
 	gui.Main(buttonWindow)
 }
 
@@ -17,9 +23,6 @@ func buttonWindow() {
 	gui.Config.Width = 640
 	gui.Config.Height = 480
 
-//	gui.Config.Exit = gui.StandardClose
-//	gui.SetDebug(true)
-
 	w = gui.NewWindow()
 	g = w.NewGroup("buttonGroup")
 
@@ -27,7 +30,25 @@ func buttonWindow() {
 		log.Println("world")
 	})
 
-	g.NewButton("foo", func () {
+	/*
-		log.Println("bar")
+	g.NewButton("LoadPlugin()", func () {
+		log.Println("world")
+		gui.LoadPlugin("../../toolkit/gocli.so")
+	})
+	*/
+
+	g.NewButton("RunGreet()", func () {
+		log.Println("world")
+		go gui.RunGreet()
+	})
+
+	g.NewButton("gui.LookupJcarrButton()", func () {
+		log.Println("gui.LookupJcarrButton()")
+		gui.LookupJcarrButton()
+	})
+
+	g.NewButton("gui.GocuiAddButton()", func () {
+		log.Println("gui.GocuiAddButton()")
+		gui.GocuiAddButton("new foobar")
 	})
 }

group.go

@@ -9,7 +9,10 @@ import toolkit "git.wit.org/wit/gui/toolkit/andlabs"
 func (n *Node) NewGroup(name string) *Node {
 	var newT *toolkit.Toolkit
 	var gNode *Node
-	log.Println("toolkit.NewGroup() START", name)
+
+	if (GetDebug()) {
+		log.Println("toolkit.NewGroup() START", name)
+	}
 
 	if (n.toolkit == nil) {
 		log.Println("toolkit.NewGroup() toolkit == nil")

main.go

@@ -29,10 +29,15 @@ func init() {
 	if (Config.Options.Debug) {
 		Config.master.Dump()
 	}
+
+	// load the gocli plugin
+	PlugGocli = LoadPlugin("../../toolkit/gocli.so")
 }
 
 func Main(f func()) {
-	log.Println("Starting gui.Main() (using gtk via andlabs/ui)")
+	if (Config.Options.Debug) {
+		log.Println("Starting gui.Main() (using gtk via andlabs/ui)")
+	}
 	toolkit.Main(f)
 }
 

plugin.go

@@ -0,0 +1,90 @@
+package gui
+
+import (
+	"log"
+	"os"
+
+	"plugin"
+	"github.com/davecgh/go-spew/spew"
+)
+
+type Greeter interface {
+	Greet()
+	JcarrButton()
+	AddButton(string)
+}
+
+var PlugGocli *plugin.Plugin
+var PlugHello *plugin.Plugin
+
+// var gBut plugin.Symbol
+var jcarrBut plugin.Symbol
+var symGreeter plugin.Symbol
+var greeter Greeter
+var ok bool
+
+func LoadPlugin(name string) *plugin.Plugin {
+	scs := spew.ConfigState{MaxDepth: 1}
+
+	// load module
+	// 1. open the so file to load the symbols
+	plug, err := plugin.Open(name)
+	log.Println("plug =")
+	log.Println(scs.Sdump(plug))
+	if err != nil {
+		log.Println(err)
+		os.Exit(1)
+	}
+	PlugGocli = plug
+
+	// 2. look up a symbol (an exported function or variable)
+	// in this case, variable Greeter
+	symGreeter, err = plug.Lookup("Greeter")
+	log.Println("symGreater", symGreeter)
+	log.Println(scs.Sdump(symGreeter))
+	if err != nil {
+		log.Println(err)
+		os.Exit(1)
+	}
+
+	// 3. Assert that loaded symbol is of a desired type
+	// in this case interface type Greeter (defined above)
+	// var greeter Greeter
+	greeter, ok = symGreeter.(Greeter)
+	log.Println("greeter", symGreeter)
+	log.Println(scs.Sdump(greeter))
+	if !ok {
+		log.Println("unexpected type from module symbol")
+		os.Exit(1)
+	}
+	return plug
+}
+
+func RunGreet() {
+	log.Println("gui.RunGreet() START")
+	if (greeter == nil) {
+		log.Println("wit/gui gocui plugin didn't load")
+		return
+	}
+	greeter.Greet()
+}
+
+func LookupJcarrButton() {
+	log.Println("lookupJcarrButton() START")
+
+	if (greeter == nil) {
+		log.Println("wit/gui gocui plugin didn't load")
+		return
+	}
+	greeter.JcarrButton()
+}
+
+func GocuiAddButton(name string) {
+	log.Println("GocuiAddButton() START", name)
+
+	if (greeter == nil) {
+		log.Println("wit/gui gocui plugin didn't load")
+		return
+	}
+	greeter.AddButton(name)
+}

structs.go

@@ -46,13 +46,13 @@ func ShowDebugValues() {
 	log.Println("\t wit/gui DebugDump =", Config.Options.DebugDump)
 	log.Println("\t wit/gui DebugNode =", Config.Options.DebugNode)
 	log.Println("\t wit/gui DebugTabs =", Config.Options.DebugTabs)
-//	log.Println("\t wit/gui DebugTable =", Config.Options.DebugTable)
+	log.Println("\t wit/gui DebugPlugin =", Config.Options.DebugPlugin)
-//	log.Println("\t wit/gui DebugWindow =", Config.Options.DebugWindow)
 	log.Println("\t wit/gui DebugChange =", Config.Options.DebugChange)
 
 	log.Println("\t wit/gui DebugToolkit =", toolkit.DebugToolkit)
 }
 
+// This struct can be used with go-arg
 type GuiOptions struct {
 	// These are global debugging settings
 	// TODO: move to a standard logging system
@@ -60,8 +60,7 @@ type GuiOptions struct {
 	DebugDump    bool
 	DebugNode    bool
 	DebugTabs    bool
-//	DebugTable   bool
+	DebugPlugin  bool
-//	DebugWindow  bool
 	DebugChange  bool `help:"debug mouse clicks and keyboard input"`
 }
 

toolkit/andlabs/box.go

@@ -12,10 +12,14 @@ func (t *Toolkit) GetBox() *ui.Box {
 
 // create a new box
 func (t *Toolkit) NewBox() *Toolkit {
-	log.Println("gui.Toolbox.NewBox() START create default")
+	if (DebugToolkit) {
+		log.Println("gui.Toolbox.NewBox() START create default")
+	}
 	t.Dump()
 	if (t.uiGroup != nil) {
-		log.Println("\tgui.Toolbox.NewBox() is a Group")
+		if (DebugToolkit) {
+			log.Println("\tgui.Toolbox.NewBox() is a Group")
+		}
 		var newTK Toolkit
 
 		vbox := ui.NewVerticalBox()
@@ -26,7 +30,9 @@ func (t *Toolkit) NewBox() *Toolkit {
 		return &newTK
 	}
 	if (t.uiBox != nil) {
-		log.Println("\tgui.Toolbox.NewBox() is a Box")
+		if (DebugToolkit) {
+			log.Println("\tgui.Toolbox.NewBox() is a Box")
+		}
 		var newTK Toolkit
 
 		vbox := ui.NewVerticalBox()
@@ -38,7 +44,9 @@ func (t *Toolkit) NewBox() *Toolkit {
 		return &newTK
 	}
 	if (t.uiWindow != nil) {
-		log.Println("\tgui.Toolbox.NewBox() is a Window")
+		if (DebugToolkit) {
+			log.Println("\tgui.Toolbox.NewBox() is a Window")
+		}
 		var newT Toolkit
 
 		vbox := ui.NewVerticalBox()
@@ -50,7 +58,9 @@ func (t *Toolkit) NewBox() *Toolkit {
 		// panic("WTF")
 		return &newT
 	}
-	log.Println("\tgui.Toolbox.NewBox() FAILED. Couldn't figure out where to make a box")
+	if (DebugToolkit) {
+		log.Println("\tgui.Toolbox.NewBox() FAILED. Couldn't figure out where to make a box")
+	}
 	t.Dump()
 	return nil
 }

toolkit/andlabs/common.go

@@ -3,7 +3,9 @@ package toolkit
 import "log"
 
 func init() {
-	log.Println("gui/toolkit init() Setting defaultBehavior = true")
+	if (DebugToolkit) {
+		log.Println("gui/toolkit init() Setting defaultBehavior = true")
+	}
 	setDefaultBehavior(true)
 }
 
@@ -37,7 +39,9 @@ func (t Toolkit) commonChange(widget string) {
 func (t *Toolkit) broken() bool {
 	if (t.uiBox == nil) {
 		if (t.uiWindow != nil) {
-			log.Println("gui.Toolkit.UiBox == nil. This is an empty window. Try to add a box")
+			if (DebugToolkit) {
+				log.Println("gui.Toolkit.UiBox == nil. This is an empty window. Try to add a box")
+			}
 			t.NewBox()
 			return false
 		}

toolkit/andlabs/main.go

@@ -9,7 +9,9 @@ import (
 )
 
 func Main(f func()) {
-	log.Println("Starting gui.Main() (using gtk via andlabs/ui)")
+	if (DebugToolkit) {
+		log.Println("Starting gui.Main() (using gtk via andlabs/ui)")
+	}
 	ui.Main(f)
 }
 
@@ -22,6 +24,8 @@ func Main(f func()) {
 // For example: Queue(NewWindow())
 //
 func Queue(f func()) {
-	log.Println("Sending function to gui.Main() (using gtk via andlabs/ui)")
+	if (DebugToolkit) {
+		log.Println("Sending function to gui.Main() (using gtk via andlabs/ui)")
+	}
 	ui.QueueMain(f)
 }

toolkit/andlabs/structs.go

@@ -21,8 +21,10 @@ var DebugToolkit bool
 func setDefaultBehavior(s bool) {
 	defaultBehavior = s
 	if (defaultBehavior) {
-		log.Println("Setting this toolkit to use the default behavior.")
+		if (DebugToolkit) {
-		log.Println("This is the 'guessing' part as defined by the wit/gui 'Principles'. Refer to the docs.")
+			log.Println("Setting this toolkit to use the default behavior.")
+			log.Println("This is the 'guessing' part as defined by the wit/gui 'Principles'. Refer to the docs.")
+		}
 		stretchy = false
 		padded = true
 		menubar = true

toolkit/andlabs/window.go

@@ -17,7 +17,9 @@ func (t *Toolkit) ErrorWindow(msg1 string, msg2 string) {
 
 func NewWindow(title string, x int, y int) *Toolkit {
 	var t Toolkit
-	log.Println("toolkit NewWindow", title, x, y)
+	if (DebugToolkit) {
+		log.Println("toolkit NewWindow", title, x, y)
+	}
 	w := ui.NewWindow(title, x, y, menubar)
 	w.SetBorderless(canvas)
 	w.SetMargined(margin)
@@ -50,11 +52,15 @@ func NewWindow(title string, x int, y int) *Toolkit {
 }
 
 func (t *Toolkit) SetWindowTitle(title string) {
-	log.Println("toolkit NewWindow", t.Name, "title", title)
+	if (DebugToolkit) {
+		log.Println("toolkit NewWindow", t.Name, "title", title)
+	}
 	win := t.uiWindow
 	if (win != nil) {
 		win.SetTitle(title)
 	} else {
-		log.Println("Setting the window title", title)
+		if (DebugToolkit) {
+			log.Println("Setting the window title", title)
+		}
 	}
 }

toolkit/gocui/greeter.go

@@ -11,6 +11,8 @@ import (
 
 type greeting string
 
+// this is exported
+var Greeter greeting
 
 // func main() {
 func (g greeting) Greet() {
@@ -19,16 +21,25 @@ func (g greeting) Greet() {
 	// ToolkitMain()
 }
 
-// this is exported
+func (g greeting) JcarrButton() {
-var Greeter greeting
+	fmt.Println("Hello GreetButton meet Universe")
+	addButton("Greet foo")
+	addButton("Greet foo 2")
+}
 
-func AddGroup(name string) {
+func addGroup(name string) {
 	log.Println("addGroup()", name)
 	currentY = 2
 	currentX += groupSize + 6
 }
 
-func AddButton(name string) error {
+func (g greeting) AddButton(name string) {
+// func (g greeting) AddButton() {
+	log.Println("gui.gocui.AddButton()", name)
+	addButton(name)
+}
+
+func addButton(name string) error {
 	t := len(name)
 	v, err := baseGui.SetView(name, currentX, currentY, currentX+t+3, currentY+2, 0)
 	if err == nil {

toolkit/gocui/main.go

@@ -50,18 +50,18 @@ func Init() {
 		log.Panicln(err)
 	}
 
-	AddButton("hello")
+	addButton("hello")
-	AddButton("world")
+	addButton("world")
-	AddButton("foo")
+	addButton("foo")
 
-	AddGroup("blank")
+	addGroup("blank")
-	AddButton("bar")
+	addButton("bar")
-	AddButton("bar none")
+	addButton("bar none")
-	AddButton("bar going")
+	addButton("bar going")
 
-	AddGroup("te")
+	addGroup("te")
-	AddButton("world 2")
+	addButton("world 2")
-	AddButton("foo 2")
+	addButton("foo 2")
 
 	if err := baseGui.MainLoop(); err != nil && !errors.Is(err, gocui.ErrQuit) {
 		log.Panicln(err)

toolkit/gocui/newJ.go

@@ -20,7 +20,7 @@ var bottomY int = 7
 
 func newJ(g *gocui.Gui) error {
 	// maxX, maxY := g.Size()
-	name := fmt.Sprintf("jcarr %v test ", idxView)
+	name := fmt.Sprintf("jcarr %v foo ", idxView)
 	v, err := g.SetView(name, topX, topY, bottomX, bottomY, 0)
 	if err == nil {
 		return err