fix(context switching concurrency + dedicated health column)

Author: jr-k

internal/dao/common/utils.go

@@ -33,7 +33,6 @@ func ParseStatus(s string) (status, age, health string) {
 				status = "Paused"
 			} else if detail != "" {
 				health = detail
-				status = fmt.Sprintf("Up (%s)", detail)
 			}
 		}
 

internal/dao/docker.go

@@ -78,6 +78,7 @@ type DockerClient struct {
 	Cli         *client.Client
 	Ctx         context.Context
 	ContextName string
+	cancel      context.CancelFunc
 
 	// Managers
 	Container *container.Manager
@@ -135,12 +136,13 @@ func NewDockerClient(contextName string, apiTimeout time.Duration, defaultContex
 	if err != nil {
 		return nil, err
 	}
-	ctx := context.Background()
+	ctx, cancel := context.WithCancel(context.Background())
 
 	return &DockerClient{
 		Cli:              cli,
 		Ctx:              ctx,
 		ContextName:      ctxName,
+		cancel:           cancel,
 		Container:        container.NewManager(cli, ctx),
 		Image:            image.NewManager(cli, ctx),
 		Volume:           volume.NewManager(cli, ctx),
@@ -157,6 +159,20 @@ func NewDockerClient(contextName string, apiTimeout time.Duration, defaultContex
 	}, nil
 }
 
+// Close cancels in-flight API calls and releases the client's idle connections.
+func (d *DockerClient) Close() error {
+	if d == nil {
+		return nil
+	}
+	if d.cancel != nil {
+		d.cancel()
+	}
+	if d.Cli != nil {
+		return d.Cli.Close()
+	}
+	return nil
+}
+
 func initLogger() (*log.Logger, func()) {
 	f, err := os.OpenFile("/tmp/d4s_debug_dao.log", os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
 	if err != nil {

internal/dao/docker/container/container.go

@@ -75,43 +75,37 @@ type Container struct {
 }
 
 func (c Container) GetID() string { return c.ID }
+
+func (c Container) healthStatus() string {
+	health := strings.TrimSpace(c.Health)
+	health = strings.TrimSpace(strings.TrimPrefix(strings.ToLower(health), "health:"))
+	if health == "" {
+		return ""
+	}
+	return strings.ToUpper(health[:1]) + health[1:]
+}
+
 func (c Container) GetCells() []string {
 	id := c.ID
 	if len(id) > 12 {
 		id = id[:12]
 	}
-	return []string{id, c.Names, c.Image, c.Status, c.CPU, c.Mem, c.Age, c.IP, c.Ports, c.Compose, c.Cmd, c.Created}
+	return []string{id, c.Names, c.Image, c.Status, c.healthStatus(), c.CPU, c.Mem, c.Age, c.IP, c.Ports, c.Compose, c.Cmd, c.Created}
 }
 
 func (c Container) GetStatusColor() (tcell.Color, tcell.Color) {
-	lower := strings.ToLower(c.State)
 	health := strings.ToLower(strings.TrimSpace(c.Health))
 	health = strings.TrimPrefix(health, "health: ")
 
 	switch health {
 	case "healthy":
-		return styles.ColorStatusGreen, styles.ColorBlack
+		return styles.ColorIdle, styles.ColorBlack
 	case "unhealthy":
 		return styles.ColorStatusRed, styles.ColorBlack
 	case "starting":
 		return styles.ColorStatusBlue, styles.ColorBlack
 	}
 
-	switch lower {
-	case "paused":
-		return styles.ColorStatusYellow, styles.ColorBlack
-	case "restarting":
-		return styles.ColorStatusOrange, styles.ColorBlack
-	case "stopping":
-		return styles.ColorStatusRed, styles.ColorBlack
-	case "starting":
-		return styles.ColorStatusBlue, styles.ColorBlack
-	case "exited", "dead":
-		return styles.ColorStatusGray, styles.ColorBlack
-	case "created":
-		return styles.ColorStatusBlue, styles.ColorBlack
-	}
-
 	return styles.ColorIdle, styles.ColorBlack
 }
 
@@ -127,6 +121,8 @@ func (c Container) GetColumnValue(column string) string {
 		return c.IP
 	case "status":
 		return c.Status
+	case "health":
+		return c.healthStatus()
 	case "age":
 		return c.Age
 	case "ports":

internal/ui/app.go

@@ -6,6 +6,7 @@ import (
 	"sort"
 	"strings"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"runtime/debug"
@@ -44,6 +45,7 @@ type App struct {
 	TviewApp     *tview.Application
 	Screen       tcell.Screen
 	Docker       *dao.DockerClient
+	dockerMx     sync.RWMutex
 	Cfg          *config.Config
 	PortForwards *portforward.Manager
 
@@ -68,9 +70,11 @@ type App struct {
 	LatestVersion   string
 
 	// Concurrency
-	pauseMx    sync.RWMutex
-	paused     bool
-	stopTicker chan struct{}
+	pauseMx          sync.RWMutex
+	paused           bool
+	stopTicker       chan struct{}
+	contextSwitchGen atomic.Uint64
+	contextSaveMx    sync.Mutex
 
 	flashMx     sync.Mutex
 	flashExpiry time.Time
@@ -666,9 +670,19 @@ func (a *App) GetScreen() tcell.Screen {
 }
 
 func (a *App) GetDocker() *dao.DockerClient {
+	a.dockerMx.RLock()
+	defer a.dockerMx.RUnlock()
 	return a.Docker
 }
 
+func (a *App) swapDocker(newDocker *dao.DockerClient) *dao.DockerClient {
+	a.dockerMx.Lock()
+	defer a.dockerMx.Unlock()
+	oldDocker := a.Docker
+	a.Docker = newDocker
+	return oldDocker
+}
+
 func (a *App) GetPortForwardManager() *portforward.Manager {
 	return a.PortForwards
 }

internal/ui/app_context.go

@@ -8,16 +8,18 @@ import (
 	"github.com/jr-k/d4s/internal/config"
 	"github.com/jr-k/d4s/internal/dao"
 	"github.com/jr-k/d4s/internal/ui/dialogs"
+	"github.com/jr-k/d4s/internal/ui/styles"
 )
 
 func (a *App) ShowContextPicker() {
-	contexts, err := a.Docker.ListContexts()
+	docker := a.GetDocker()
+	contexts, err := docker.ListContexts()
 	if err != nil {
 		a.AppendFlashError(fmt.Sprintf("failed to load docker contexts: %v", err))
 		return
 	}
 
-	active := strings.TrimSpace(a.Docker.ContextName)
+	active := strings.TrimSpace(docker.ContextName)
 	saved := strings.TrimSpace(a.Cfg.D4S.DefaultContext)
 
 	items := make([]dialogs.PickerItem, 0, len(contexts))
@@ -66,14 +68,11 @@ func (a *App) SetDefaultContext(contextName string) {
 		return
 	}
 
-	if a.Docker != nil && a.Docker.ContextName == contextName {
-		a.Cfg.D4S.DefaultContext = contextName
-		if err := config.Save(a.Cfg); err != nil {
-			a.AppendFlashError(fmt.Sprintf("failed to save default context: %v", err))
-			return
-		}
-
-		a.AppendFlashSuccess(contextSavedMessage(contextName))
+	if docker := a.GetDocker(); docker != nil && docker.ContextName == contextName {
+		// Re-selecting the active context cancels any older switch that may
+		// still be preparing another client in the background.
+		switchGen := a.contextSwitchGen.Add(1)
+		a.saveDefaultContext(contextName, switchGen)
 		a.updateHeader()
 		return
 	}
@@ -90,60 +89,94 @@ func (a *App) ReloadContext(contextName string) {
 		return
 	}
 
+	switchGen := a.contextSwitchGen.Add(1)
 	a.SetFlashPending(fmt.Sprintf("switching context to %s...", contextName))
-	a.SetPaused(true)
-	a.StopAutoRefresh()
-
-	if a.ActiveInspector != nil {
-		a.ActiveInspector.OnUnmount()
-		a.ActiveInspector = nil
-	}
-	if a.Pages.HasPage("inspect") {
-		a.Pages.RemovePage("inspect")
-	}
-
-	a.SafeSetScope(nil)
-	a.ActiveFilter = ""
-	for _, v := range a.Views {
-		v.SetLoading(true)
-		// Free the fetch guard held by any fetch still running against the
-		// old endpoint (possibly hung), and mark its results as stale.
-		v.InvalidateFetch()
-	}
-	a.RestoreFocus()
-	a.UpdateShortcuts()
 
 	a.RunInBackground(func() {
 		newDocker, err := dao.NewDockerClient(contextName, a.Cfg.D4S.GetAPIServerTimeout(), contextName)
 		if err != nil {
 			a.TviewApp.QueueUpdateDraw(func() {
-				a.SetPaused(false)
-				a.StartAutoRefresh()
+				if a.contextSwitchGen.Load() != switchGen {
+					return
+				}
 				a.AppendFlashError(fmt.Sprintf("failed to switch context: %v", err))
-				a.RefreshCurrentView()
 				a.updateHeader()
 			})
 			return
 		}
 
-		a.Cfg.D4S.DefaultContext = contextName
-		saveErr := config.Save(a.Cfg)
-
 		a.TviewApp.QueueUpdateDraw(func() {
-			a.Docker = newDocker
-			a.SetPaused(false)
-			a.StartAutoRefresh()
+			if a.contextSwitchGen.Load() != switchGen {
+				a.RunInBackground(func() {
+					_ = newDocker.Close()
+				})
+				return
+			}
+
+			if a.ActiveInspector != nil {
+				a.ActiveInspector.OnUnmount()
+				a.ActiveInspector = nil
+			}
+			if a.Pages.HasPage("inspect") {
+				a.Pages.RemovePage("inspect")
+			}
+
+			a.SafeSetScope(nil)
+			a.ActiveFilter = ""
+			currentPage, _ := a.Pages.GetFrontPage()
+			for title, v := range a.Views {
+				// Context metadata remains usable while resources from the
+				// newly selected Docker endpoint are loading.
+				if title == currentPage && title != styles.TitleContexts {
+					v.SetLoading(true)
+				} else if title != styles.TitleContexts {
+					v.InvalidateData()
+				}
+				// Cancel requests against the previous endpoint and reject
+				// any results that arrive after the client swap.
+				v.InvalidateFetch()
+			}
+
+			oldDocker := a.swapDocker(newDocker)
+			if oldDocker != nil {
+				a.RunInBackground(func() {
+					_ = oldDocker.Close()
+				})
+			}
+
+			a.saveDefaultContext(contextName, switchGen)
+
 			a.RestoreFocus()
 			a.UpdateShortcuts()
 			a.updateHeader()
 			a.RefreshCurrentView()
-			a.preloadViews()
+		})
+	})
+}
+
+func (a *App) saveDefaultContext(contextName string, switchGen uint64) {
+	a.Cfg.D4S.DefaultContext = contextName
+	cfg := *a.Cfg
+
+	a.RunInBackground(func() {
+		// Serialize writes so an older context switch can never overwrite a
+		// newer selection after a slow filesystem operation.
+		a.contextSaveMx.Lock()
+		defer a.contextSaveMx.Unlock()
+
+		if a.contextSwitchGen.Load() != switchGen {
+			return
+		}
+		err := config.Save(&cfg)
 
-			if saveErr != nil {
-				a.AppendFlashError(fmt.Sprintf("switched to %s, but failed to save default: %v", contextName, saveErr))
+		a.TviewApp.QueueUpdateDraw(func() {
+			if a.contextSwitchGen.Load() != switchGen {
+				return
+			}
+			if err != nil {
+				a.AppendFlashError(fmt.Sprintf("failed to save default context: %v", err))
 				return
 			}
-
 			a.AppendFlashSuccess(contextSavedMessage(contextName))
 		})
 	})

internal/ui/app_shortcuts.go

@@ -8,7 +8,7 @@ import (
 func (a *App) getCurrentShortcuts() []string {
 	page, _ := a.Pages.GetFrontPage()
 	var shortcuts []string
-	
+
 	// Handle special pages (modals, logs) manually for now, or could attach view logic too.
 	if page == "inspect" {
 		if a.ActiveInspector != nil {
@@ -20,14 +20,14 @@ func (a *App) getCurrentShortcuts() []string {
 	if view, ok := a.Views[page]; ok && view.ShortcutsFunc != nil {
 		shortcuts = view.ShortcutsFunc()
 	}
-	
+
 	shortcuts = append(shortcuts, common.FormatSCHeaderGlobal("tab", "Context"))
 	shortcuts = append(shortcuts, common.FormatSCHeaderGlobal("shift ←/→", "Sort"))
 	shortcuts = append(shortcuts, common.FormatSCHeaderGlobal("shift-c", "Copy Table"))
 	shortcuts = append(shortcuts, common.FormatSCHeaderGlobal("c", "Copy Cell"))
 	shortcuts = append(shortcuts, common.FormatSCHeaderGlobal("u", "Unselect All"))
 	shortcuts = append(shortcuts, common.FormatSCHeaderGlobal("?", "Help"))
-	
+
 	return shortcuts
 }
 
@@ -49,15 +49,18 @@ func (a *App) UpdateShortcuts() {
 }
 
 func (a *App) updateHeader() {
-	docker := a.Docker
+	docker := a.GetDocker()
+	if docker == nil {
+		return
+	}
 	go func() {
 		stats, err := docker.GetHostStats()
 		if err != nil {
 			return
 		}
 
 		a.TviewApp.QueueUpdateDraw(func() {
-			if a.Docker != docker {
+			if a.GetDocker() != docker {
 				return
 			}
 			shortcuts := a.getCurrentShortcuts()
@@ -68,7 +71,7 @@ func (a *App) updateHeader() {
 		statsWithUsage, err := docker.GetHostStatsWithUsage()
 		if err == nil {
 			a.TviewApp.QueueUpdateDraw(func() {
-				if a.Docker != docker {
+				if a.GetDocker() != docker {
 					return
 				}
 				shortcuts := a.getCurrentShortcuts()