improve subprocess approach

pkg/app/app.go

@@ -56,8 +56,7 @@ func NewApp(config *config.AppConfig) (*App, error) {
 }
 
 func (app *App) Run() error {
-	err := app.Gui.RunWithSubprocesses()
-	return err
+	return app.Gui.Run()
 }
 
 func (app *App) Close() error {

pkg/gui/containers_panel.go

@@ -492,8 +492,7 @@ func (gui *Gui) handleContainerAttach(g *gocui.Gui, v *gocui.View) error {
 		return gui.createErrorPanel(gui.g, err.Error())
 	}
 
-	gui.SubProcess = c
-	return gui.Errors.ErrSubProcess
+	return gui.runSubprocess(c)
 }
 
 func (gui *Gui) handlePruneContainers() error {
@@ -537,8 +536,7 @@ func (gui *Gui) containerExecShell(container *commands.Container) error {
 	resolvedCommand := utils.ApplyTemplate("docker exec -it {{ .Container.ID }} /bin/sh -c 'eval $(grep ^$(id -un): /etc/passwd | cut -d : -f 7-)'", commandObject)
 	// attach and return the subprocess error
 	cmd := gui.OSCommand.ExecutableFromString(resolvedCommand)
-	gui.SubProcess = cmd
-	return gui.Errors.ErrSubProcess
+	return gui.runSubprocess(cmd)
 }
 
 func (gui *Gui) handleContainersCustomCommand(g *gocui.Gui, v *gocui.View) error {

pkg/gui/custom_commands.go

@@ -53,8 +53,7 @@ func (gui *Gui) createCommandMenu(customCommands []config.CustomCommand, command
 		// if we have a command for attaching, we attach and return the subprocess error
 		if option.customCommand.Attach {
 			cmd := gui.OSCommand.ExecutableFromString(option.command)
-			gui.SubProcess = cmd
-			return gui.Errors.ErrSubProcess
+			return gui.runSubprocess(cmd)
 		}
 
 		return gui.WithWaitingStatus(waitingStatus, func() error {

pkg/gui/gui.go

@@ -2,20 +2,14 @@ package gui
 
 import (
 	"context"
-	"os/exec"
 	"strings"
 	"sync"
 	"time"
 
 	"github.com/docker/docker/api/types"
 
-	// "io"
-	// "io/ioutil"
-
 	"github.com/go-errors/errors"
 
-	// "strings"
-
 	throttle "github.com/boz/go-throttle"
 	"github.com/jesseduffield/gocui"
 	"github.com/jesseduffield/lazydocker/pkg/commands"
@@ -31,7 +25,6 @@ var OverlappingEdges = false
 // SentinelErrors are the errors that have special meaning and need to be checked
 // by calling functions. The less of these, the better
 type SentinelErrors struct {
-	ErrSubProcess   error
 	ErrNoContainers error
 	ErrNoImages     error
 	ErrNoVolumes    error
@@ -49,7 +42,6 @@ type SentinelErrors struct {
 // localising things in the code.
 func (gui *Gui) GenerateSentinelErrors() {
 	gui.Errors = SentinelErrors{
-		ErrSubProcess:   errors.New(gui.Tr.RunningSubprocess),
 		ErrNoContainers: errors.New(gui.Tr.NoContainers),
 		ErrNoImages:     errors.New(gui.Tr.NoImages),
 		ErrNoVolumes:    errors.New(gui.Tr.NoVolumes),
@@ -62,7 +54,6 @@ type Gui struct {
 	Log           *logrus.Entry
 	DockerCommand *commands.DockerCommand
 	OSCommand     *commands.OSCommand
-	SubProcess    *exec.Cmd
 	State         guiState
 	Config        *config.AppConfig
 	Tr            *i18n.TranslationSet
@@ -73,8 +64,20 @@ type Gui struct {
 	ErrorChan     chan error
 	CyclableViews []string
 	Views         Views
-
+	// returns true if our views have been created and assigned to gui.Views.
+	// Views are setup only once, upon application start.
 	ViewsSetup bool
+
+	// if we've suspended the gui (e.g. because we've switched to a subprocess)
+	// we typically want to pause some things that are running like background
+	// file refreshes
+	PauseBackgroundThreads bool
+
+	Mutexes
+}
+
+type Mutexes struct {
+	SubprocessMutex sync.Mutex
 }
 
 type servicePanelState struct {
@@ -130,11 +133,6 @@ type guiState struct {
 	SubProcessOutput string
 	Stats            map[string]commands.ContainerStats
 
-	// SessionIndex tells us how many times we've come back from a subprocess.
-	// We increment it each time we switch to a new subprocess
-	// Every time we go to a subprocess we need to close a few goroutines so this index is used for that purpose
-	SessionIndex int
-
 	ScreenMode WindowMaximisation
 }
 
@@ -165,8 +163,7 @@ func NewGui(log *logrus.Entry, dockerCommand *commands.DockerCommand, oSCommand
 			},
 			Project: &projectState{ContextIndex: 0},
 		},
-		SessionIndex: 0,
-		ViewStack:    []string{},
+		ViewStack: []string{},
 	}
 
 	cyclableViews := []string{"project", "containers", "images", "volumes"}
@@ -193,13 +190,6 @@ func NewGui(log *logrus.Entry, dockerCommand *commands.DockerCommand, oSCommand
 	return gui, nil
 }
 
-func max(a, b int) int {
-	if a > b {
-		return a
-	}
-	return b
-}
-
 func (gui *Gui) renderGlobalOptions() error {
 	return gui.renderOptionsMap(map[string]string{
 		"PgUp/PgDn": gui.Tr.Scroll,
@@ -211,15 +201,15 @@ func (gui *Gui) renderGlobalOptions() error {
 }
 
 func (gui *Gui) goEvery(interval time.Duration, function func() error) {
-	currentSessionIndex := gui.State.SessionIndex
 	_ = function() // time.Tick doesn't run immediately so we'll do that here // TODO: maybe change
 	go func() {
 		ticker := time.NewTicker(interval)
 		defer ticker.Stop()
 		for range ticker.C {
-			if gui.State.SessionIndex > currentSessionIndex {
+			if gui.PauseBackgroundThreads {
 				return
 			}
+
 			_ = function()
 		}
 	}()
@@ -289,6 +279,9 @@ func (gui *Gui) Run() error {
 	}
 
 	err = g.MainLoop()
+	if err == gocui.ErrQuit {
+		return nil
+	}
 	return err
 }
 
@@ -411,8 +404,12 @@ func (gui *Gui) handleDonate(g *gocui.Gui, v *gocui.View) error {
 }
 
 func (gui *Gui) editFile(filename string) error {
-	_, err := gui.runSyncOrAsyncCommand(gui.OSCommand.EditFile(filename))
-	return err
+	cmd, err := gui.OSCommand.EditFile(filename)
+	if err != nil {
+		return gui.createErrorPanel(gui.g, err.Error())
+	}
+
+	return gui.runSubprocess(cmd)
 }
 
 func (gui *Gui) openFile(filename string) error {
@@ -422,28 +419,10 @@ func (gui *Gui) openFile(filename string) error {
 	return nil
 }
 
-// runSyncOrAsyncCommand takes the output of a command that may have returned
-// either no error, an error, or a subprocess to execute, and if a subprocess
-// needs to be set on the gui object, it does so, and then returns the error
-// the bool returned tells us whether the calling code should continue
-func (gui *Gui) runSyncOrAsyncCommand(sub *exec.Cmd, err error) (bool, error) {
-	if err != nil {
-		if err != gui.Errors.ErrSubProcess {
-			return false, gui.createErrorPanel(gui.g, err.Error())
-		}
-	}
-	if sub != nil {
-		gui.SubProcess = sub
-		return false, gui.Errors.ErrSubProcess
-	}
-	return true, nil
-}
-
 func (gui *Gui) handleCustomCommand(g *gocui.Gui, v *gocui.View) error {
 	return gui.createPromptPanel(g, v, gui.Tr.CustomCommandTitle, func(g *gocui.Gui, v *gocui.View) error {
 		command := gui.trimmedContent(v)
-		gui.SubProcess = gui.OSCommand.RunCustomCommand(command)
-		return gui.Errors.ErrSubProcess
+		return gui.runSubprocess(gui.OSCommand.RunCustomCommand(command))
 	})
 }
 

pkg/gui/project_panel.go

@@ -224,6 +224,5 @@ func (gui *Gui) handleViewAllLogs(g *gocui.Gui, v *gocui.View) error {
 		return gui.createErrorPanel(gui.g, err.Error())
 	}
 
-	gui.SubProcess = c
-	return gui.Errors.ErrSubProcess
+	return gui.runSubprocess(c)
 }

pkg/gui/services_panel.go

@@ -293,8 +293,7 @@ func (gui *Gui) handleServiceAttach(g *gocui.Gui, v *gocui.View) error {
 		return gui.createErrorPanel(gui.g, err.Error())
 	}
 
-	gui.SubProcess = c
-	return gui.Errors.ErrSubProcess
+	return gui.runSubprocess(c)
 }
 
 func (gui *Gui) handleServiceRenderLogsToMain(g *gocui.Gui, v *gocui.View) error {
@@ -308,8 +307,7 @@ func (gui *Gui) handleServiceRenderLogsToMain(g *gocui.Gui, v *gocui.View) error
 		return gui.createErrorPanel(gui.g, err.Error())
 	}
 
-	gui.SubProcess = c
-	return gui.Errors.ErrSubProcess
+	return gui.runSubprocess(c)
 }
 
 func (gui *Gui) handleServiceRestartMenu(g *gocui.Gui, v *gocui.View) error {
@@ -366,8 +364,7 @@ func (gui *Gui) handleServiceRestartMenu(g *gocui.Gui, v *gocui.View) error {
 				gui.DockerCommand.NewCommandObject(commands.CommandObject{Service: service}),
 			),
 			f: func() error {
-				gui.SubProcess = gui.OSCommand.RunCustomCommand(rebuildCommand)
-				return gui.Errors.ErrSubProcess
+				return gui.runSubprocess(gui.OSCommand.RunCustomCommand(rebuildCommand))
 			},
 		},
 		{

pkg/gui/subprocess.go

@@ -4,48 +4,43 @@ import (
 	"fmt"
 	"io/ioutil"
 	"os"
+	"os/exec"
 	"os/signal"
 	"strings"
 
 	"github.com/fatih/color"
-	"github.com/jesseduffield/gocui"
 	"github.com/jesseduffield/lazydocker/pkg/utils"
 )
 
-// RunWithSubprocesses loops, instantiating a new gocui.Gui with each iteration
-// if the error returned from a run is a ErrSubProcess, it runs the subprocess
-// otherwise it handles the error, possibly by quitting the application
-func (gui *Gui) RunWithSubprocesses() error {
-	for {
-		if err := gui.Run(); err != nil {
-			if err == gocui.ErrQuit {
-				break
-			} else if err == gui.Errors.ErrSubProcess {
-				// preparing the state for when we return
-				gui.pushView(gui.currentViewName())
-				// giving goEvery goroutines time to finish
-				gui.State.SessionIndex++
-
-				if err := gui.runCommand(); err != nil {
-					return err
-				}
-
-				// pop here so we don't stack up view names
-				gui.popView()
-				// ensuring we render e.g. the logs of the currently selected item upon return
-				gui.State.Panels.Main.ObjectKey = ""
-			} else {
-				return err
-			}
-		}
+func (gui *Gui) runSubprocess(cmd *exec.Cmd) error {
+	gui.Mutexes.SubprocessMutex.Lock()
+	defer gui.Mutexes.SubprocessMutex.Unlock()
+
+	if err := gui.g.Suspend(); err != nil {
+		return gui.createErrorPanel(gui.g, err.Error())
+	}
+
+	gui.PauseBackgroundThreads = true
+
+	cmdErr := gui.runSubprocess(cmd)
+
+	if err := gui.g.Resume(); err != nil {
+		return gui.createErrorPanel(gui.g, err.Error())
 	}
+
+	gui.PauseBackgroundThreads = false
+
+	if cmdErr != nil {
+		return gui.createErrorPanel(gui.g, cmdErr.Error())
+	}
+
 	return nil
 }
 
-func (gui *Gui) runCommand() error {
-	gui.SubProcess.Stdout = os.Stdout
-	gui.SubProcess.Stderr = os.Stdout
-	gui.SubProcess.Stdin = os.Stdin
+func (gui *Gui) runCommand(cmd *exec.Cmd) error {
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stdout
+	cmd.Stdin = os.Stdin
 
 	stop := make(chan os.Signal, 1)
 	defer signal.Stop(stop)
@@ -54,23 +49,22 @@ func (gui *Gui) runCommand() error {
 		signal.Notify(stop, os.Interrupt)
 		<-stop
 
-		if err := gui.OSCommand.Kill(gui.SubProcess); err != nil {
+		if err := gui.OSCommand.Kill(cmd); err != nil {
 			gui.Log.Error(err)
 		}
 	}()
 
-	fmt.Fprintf(os.Stdout, "\n%s\n\n", utils.ColoredString("+ "+strings.Join(gui.SubProcess.Args, " "), color.FgBlue))
+	fmt.Fprintf(os.Stdout, "\n%s\n\n", utils.ColoredString("+ "+strings.Join(cmd.Args, " "), color.FgBlue))
 
-	if err := gui.SubProcess.Run(); err != nil {
+	if err := cmd.Run(); err != nil {
 		// not handling the error explicitly because usually we're going to see it
 		// in the output anyway
 		gui.Log.Error(err)
 	}
 
-	gui.SubProcess.Stdin = nil
-	gui.SubProcess.Stdout = ioutil.Discard
-	gui.SubProcess.Stderr = ioutil.Discard
-	gui.SubProcess = nil
+	cmd.Stdin = nil
+	cmd.Stdout = ioutil.Discard
+	cmd.Stderr = ioutil.Discard
 
 	gui.promptToReturn()
 

pkg/i18n/dutch.go

@@ -8,7 +8,6 @@ func dutchSet() TranslationSet {
 		StoppingStatus:             "stoppen",
 		RunningCustomCommandStatus: "Aangepast commando draaien",
 
-		RunningSubprocess:                          "subprocess draaien",
 		NoViewMachingNewLineFocusedSwitchStatement: "No view matching newLineFocused switch statement",
 
 		ErrorOccurred:                     "Er is iets fout gegaan! Zou je hier een issue aan willen maken: https://github.com/jesseduffield/lazydocker/issues",

pkg/i18n/english.go

@@ -13,7 +13,6 @@ type TranslationSet struct {
 	Scroll                                     string
 	Close                                      string
 	ErrorTitle                                 string
-	RunningSubprocess                          string
 	NoViewMachingNewLineFocusedSwitchStatement string
 	OpenConfig                                 string
 	EditConfig                                 string
@@ -121,7 +120,6 @@ func englishSet() TranslationSet {
 		RunningCustomCommandStatus: "running custom command",
 		RunningBulkCommandStatus:   "running bulk command",
 
-		RunningSubprocess:                          "running subprocess",
 		NoViewMachingNewLineFocusedSwitchStatement: "No view matching newLineFocused switch statement",
 
 		ErrorOccurred:                     "An error occurred! Please create an issue at https://github.com/jesseduffield/lazydocker/issues",

pkg/i18n/german.go

@@ -8,7 +8,6 @@ func germanSet() TranslationSet {
 		StoppingStatus:             "anhalten",
 		RunningCustomCommandStatus: "führt benutzerdefinierten Befehl aus",
 
-		RunningSubprocess:                          "Unterprozess ausführen",
 		NoViewMachingNewLineFocusedSwitchStatement: "No view matching newLineFocused switch statement",
 
 		ErrorOccurred:                     "Es ist ein Fehler aufgetreten! Bitte erstelle ein Issue hier: https://github.com/jesseduffield/lazydocker/issues",

pkg/i18n/polish.go

@@ -8,7 +8,6 @@ func polishSet() TranslationSet {
 		StoppingStatus:             "zatrzymywanie",
 		RunningCustomCommandStatus: "uruchamianie własnej komendty",
 
-		RunningSubprocess:                          "uruchamianie podprocesu",
 		NoViewMachingNewLineFocusedSwitchStatement: "Żaden widok nie odpowiada instrukcji przełączenia newLineFocused",
 
 		ErrorOccurred:                     "Wystąpił błąd! Proszę go zgłosić na https://github.com/jesseduffield/lazydocker/issues",

pkg/i18n/turkish.go

@@ -8,7 +8,6 @@ func turkishSet() TranslationSet {
 		StoppingStatus:             "durduruluyor",
 		RunningCustomCommandStatus: "özel komut çalıştır",
 
-		RunningSubprocess:                          "İkincil işlem yürütülüyor",
 		NoViewMachingNewLineFocusedSwitchStatement: "NewLineFocused anahtar deyimi ile eşleşen görünüm yok",
 
 		ErrorOccurred:                     "Bir hata oluştu! Lütfen https://github.com/jesseduffield/lazydocker/issues adresinden bir hataya ilişkin konu oluşturun",