(cli): Refactor dash package

tools/asynq/cmd/dash/dash.go

@@ -72,13 +72,19 @@ func Run(opts Options) {
 		fmt.Printf("failed to initialize screen: %v\n", err)
 		os.Exit(1)
 	}
-	// Set default text style
+	s.SetStyle(baseStyle) // set default text style
-	s.SetStyle(baseStyle)
+	opts.PollInterval = 2 * time.Second
 
-	inspector := asynq.NewInspector(asynq.RedisClientOpt{Addr: ":6379"})
-
-	// channels to send/receive data fetched asynchronously
 	var (
+		state = State{} // confined in this goroutine only; DO NOT SHARE
+
+		inspector = asynq.NewInspector(asynq.RedisClientOpt{Addr: ":6379"})
+		ticker    = time.NewTicker(opts.PollInterval)
+
+		eventCh = make(chan tcell.Event)
+		done    = make(chan struct{})
+
+		// channels to send/receive data fetched asynchronously
 		errorCh     = make(chan error)
 		queueCh     = make(chan *asynq.QueueInfo)
 		queuesCh    = make(chan []*asynq.QueueInfo)
@@ -86,17 +92,6 @@ func Run(opts Options) {
 		tasksCh     = make(chan []*asynq.TaskInfo)
 		redisInfoCh = make(chan *redisInfo)
 	)
-	go fetchQueues(inspector, queuesCh, errorCh, opts)
-
-	var state State // contained in this goroutine only; do not share
-
-	// draw initial screen
-	drawDash(s, &state, opts)
-
-	eventCh := make(chan tcell.Event)
-	done := make(chan struct{})
-	opts.PollInterval = 2 * time.Second
-	ticker := time.NewTicker(opts.PollInterval)
 	defer ticker.Stop()
 
 	f := dataFetcher{
@@ -111,16 +106,22 @@ func Run(opts Options) {
 		redisInfoCh,
 	}
 
+	d := dashDrawer{
+		s,
+		opts,
+	}
+
 	h := keyEventHandler{
 		s:       s,
 		fetcher: &f,
+		drawer:  &d,
 		state:   &state,
-		opts:    opts,
 		done:    done,
 	}
 
-	// TODO: Double check that we are not leaking goroutine with this one.
+	go fetchQueues(inspector, queuesCh, errorCh, opts)
-	go s.ChannelEvents(eventCh, done)
+	go s.ChannelEvents(eventCh, done) // TODO: Double check that we are not leaking goroutine with this one.
+	d.draw(&state)                    // draw initial screen
 
 	for {
 		// Update screen
@@ -158,31 +159,31 @@ func Run(opts Options) {
 		case queues := <-queuesCh:
 			state.queues = queues
 			state.err = nil
-			drawDash(s, &state, opts)
+			d.draw(&state)
 
 		case q := <-queueCh:
 			state.selectedQueue = q
 			state.err = nil
-			drawDash(s, &state, opts)
+			d.draw(&state)
 
 		case groups := <-groupsCh:
 			state.groups = groups
 			state.err = nil
-			drawDash(s, &state, opts)
+			d.draw(&state)
 
 		case tasks := <-tasksCh:
 			state.tasks = tasks
 			state.err = nil
-			drawDash(s, &state, opts)
+			d.draw(&state)
 
 		case redisInfo := <-redisInfoCh:
 			state.redisInfo = *redisInfo
 			state.err = nil
-			drawDash(s, &state, opts)
+			d.draw(&state)
 
 		case err := <-errorCh:
 			state.err = err
-			drawDash(s, &state, opts)
+			d.draw(&state)
 		}
 	}
 

tools/asynq/cmd/dash/draw.go

@@ -16,7 +16,18 @@ import (
 	"github.com/mattn/go-runewidth"
 )
 
-func drawDash(s tcell.Screen, state *State, opts Options) {
+// drawer draws UI with the given state.
+type drawer interface {
+	draw(state *State)
+}
+
+type dashDrawer struct {
+	s    tcell.Screen
+	opts Options
+}
+
+func (dd *dashDrawer) draw(state *State) {
+	s, opts := dd.s, dd.opts
 	s.Clear()
 	// Simulate data update on every render
 	d := NewScreenDrawer(s)

tools/asynq/cmd/dash/fetch.go

@@ -11,6 +11,15 @@ import (
 	"github.com/hibiken/asynq"
 )
 
+type fetcher interface {
+	fetchQueues()
+	fetchQueueInfo(qname string)
+	fetchRedisInfo()
+	fetchTasks(qname string, taskState asynq.TaskState, pageSize, pageNum int)
+	fetchAggregatingTasks(qname, group string, pageSize, pageNum int)
+	fetchGroups(qname string)
+}
+
 type dataFetcher struct {
 	ticker    *time.Ticker
 	inspector *asynq.Inspector

tools/asynq/cmd/dash/key_event.go

@@ -11,13 +11,15 @@ import (
 	"github.com/hibiken/asynq"
 )
 
+// keyEventHandler handles keyboard events and updates the state.
+// It delegates data fetching to fetcher and UI rendering to drawer.
 type keyEventHandler struct {
 	s     tcell.Screen
 	state *State
-	opts  Options
 	done  chan struct{}
 
-	fetcher *dataFetcher
+	fetcher fetcher
+	drawer  drawer
 }
 
 func (h *keyEventHandler) quit() {
@@ -62,16 +64,15 @@ func (h *keyEventHandler) HandleKeyEvent(ev *tcell.EventKey) {
 
 func (h *keyEventHandler) goBack() {
 	var (
-		s     = h.s
 		state = h.state
-		opts  = h.opts
+		d     = h.drawer
 	)
 	if state.view == viewTypeHelp {
 		state.view = state.prevView // exit help
-		drawDash(s, state, opts)
+		d.draw(state)
 	} else if state.view == viewTypeQueueDetails {
 		state.view = viewTypeQueues
-		drawDash(s, state, opts)
+		d.draw(state)
 	} else {
 		h.quit()
 	}
@@ -92,11 +93,11 @@ func (h *keyEventHandler) downKeyQueues() {
 	} else {
 		h.state.queueTableRowIdx = 0 // loop back
 	}
-	drawDash(h.s, h.state, h.opts)
+	h.drawer.draw(h.state)
 }
 
 func (h *keyEventHandler) downKeyQueueDetails() {
-	s, state, opts := h.s, h.state, h.opts
+	s, state := h.s, h.state
 	if shouldShowGroupTable(state) {
 		if state.groupTableRowIdx < groupPageSize(s) {
 			state.groupTableRowIdx++
@@ -110,7 +111,7 @@ func (h *keyEventHandler) downKeyQueueDetails() {
 			state.taskTableRowIdx = 0 // loop back
 		}
 	}
-	drawDash(s, state, opts)
+	h.drawer.draw(state)
 }
 
 func (h *keyEventHandler) handleUpKey() {
@@ -123,17 +124,17 @@ func (h *keyEventHandler) handleUpKey() {
 }
 
 func (h *keyEventHandler) upKeyQueues() {
-	s, state, opts := h.s, h.state, h.opts
+	state := h.state
 	if state.queueTableRowIdx == 0 {
 		state.queueTableRowIdx = len(state.queues)
 	} else {
 		state.queueTableRowIdx--
 	}
-	drawDash(s, state, opts)
+	h.drawer.draw(state)
 }
 
 func (h *keyEventHandler) upKeyQueueDetails() {
-	s, state, opts := h.s, h.state, h.opts
+	s, state := h.s, h.state
 	if shouldShowGroupTable(state) {
 		if state.groupTableRowIdx == 0 {
 			state.groupTableRowIdx = groupPageSize(s)
@@ -147,7 +148,7 @@ func (h *keyEventHandler) upKeyQueueDetails() {
 			state.taskTableRowIdx--
 		}
 	}
-	drawDash(s, state, opts)
+	h.drawer.draw(state)
 }
 
 func (h *keyEventHandler) handleEnterKey() {
@@ -163,8 +164,8 @@ func (h *keyEventHandler) enterKeyQueues() {
 	var (
 		s     = h.s
 		state = h.state
-		opts  = h.opts
 		f     = h.fetcher
+		d     = h.drawer
 	)
 	if state.queueTableRowIdx != 0 {
 		state.selectedQueue = state.queues[state.queueTableRowIdx-1]
@@ -173,7 +174,7 @@ func (h *keyEventHandler) enterKeyQueues() {
 		state.tasks = nil
 		state.pageNum = 1
 		f.fetchTasks(state.selectedQueue.Queue, state.taskState, taskPageSize(s), state.pageNum)
-		drawDash(s, state, opts)
+		d.draw(state)
 	}
 }
 
@@ -181,15 +182,15 @@ func (h *keyEventHandler) enterKeyQueueDetails() {
 	var (
 		s     = h.s
 		state = h.state
-		opts  = h.opts
 		f     = h.fetcher
+		d     = h.drawer
 	)
 	if shouldShowGroupTable(state) && state.groupTableRowIdx != 0 {
 		state.selectedGroup = state.groups[state.groupTableRowIdx-1]
 		state.tasks = nil
 		state.pageNum = 1
 		f.fetchAggregatingTasks(state.selectedQueue.Queue, state.selectedGroup.Group, taskPageSize(s), state.pageNum)
-		drawDash(s, state, opts)
+		d.draw(state)
 	}
 }
 
@@ -197,8 +198,8 @@ func (h *keyEventHandler) handleLeftKey() {
 	var (
 		s     = h.s
 		state = h.state
-		opts  = h.opts
 		f     = h.fetcher
+		d     = h.drawer
 	)
 	if state.view == viewTypeQueueDetails {
 		state.taskState = prevTaskState(state.taskState)
@@ -211,7 +212,7 @@ func (h *keyEventHandler) handleLeftKey() {
 		} else {
 			f.fetchTasks(state.selectedQueue.Queue, state.taskState, taskPageSize(s), state.pageNum)
 		}
-		drawDash(s, state, opts)
+		d.draw(state)
 	}
 }
 
@@ -219,8 +220,8 @@ func (h *keyEventHandler) handleRightKey() {
 	var (
 		s     = h.s
 		state = h.state
-		opts  = h.opts
 		f     = h.fetcher
+		d     = h.drawer
 	)
 	if state.view == viewTypeQueueDetails {
 		state.taskState = nextTaskState(state.taskState)
@@ -233,7 +234,7 @@ func (h *keyEventHandler) handleRightKey() {
 		} else {
 			f.fetchTasks(state.selectedQueue.Queue, state.taskState, taskPageSize(s), state.pageNum)
 		}
-		drawDash(s, state, opts)
+		d.draw(state)
 	}
 }
 
@@ -241,8 +242,8 @@ func (h *keyEventHandler) nextPage() {
 	var (
 		s     = h.s
 		state = h.state
-		opts  = h.opts
 		f     = h.fetcher
+		d     = h.drawer
 	)
 	if state.view == viewTypeQueueDetails {
 		if shouldShowGroupTable(state) {
@@ -252,7 +253,7 @@ func (h *keyEventHandler) nextPage() {
 			end := start + pageSize
 			if end <= total {
 				state.pageNum++
-				drawDash(s, state, opts)
+				d.draw(state)
 			}
 		} else {
 			pageSize := taskPageSize(s)
@@ -269,8 +270,8 @@ func (h *keyEventHandler) prevPage() {
 	var (
 		s     = h.s
 		state = h.state
-		opts  = h.opts
 		f     = h.fetcher
+		d     = h.drawer
 	)
 	if state.view == viewTypeQueueDetails {
 		if shouldShowGroupTable(state) {
@@ -278,7 +279,7 @@ func (h *keyEventHandler) prevPage() {
 			start := (state.pageNum - 1) * pageSize
 			if start > 0 {
 				state.pageNum--
-				drawDash(s, state, opts)
+				d.draw(state)
 			}
 		} else {
 			if state.pageNum > 1 {
@@ -291,67 +292,62 @@ func (h *keyEventHandler) prevPage() {
 
 func (h *keyEventHandler) showQueues() {
 	var (
-		s     = h.s
 		state = h.state
-		opts  = h.opts
 		f     = h.fetcher
+		d     = h.drawer
 	)
 	if state.view != viewTypeQueues {
 		f.fetchQueues()
 		state.view = viewTypeQueues
-		drawDash(s, state, opts)
+		d.draw(state)
 	}
 }
 
 func (h *keyEventHandler) showServers() {
 	var (
-		s     = h.s
 		state = h.state
-		opts  = h.opts
+		d     = h.drawer
 	)
 	if state.view != viewTypeServers {
 		//TODO Start data fetch and reset ticker
 		state.view = viewTypeServers
-		drawDash(s, state, opts)
+		d.draw(state)
 	}
 }
 
 func (h *keyEventHandler) showSchedulers() {
 	var (
-		s     = h.s
 		state = h.state
-		opts  = h.opts
+		d     = h.drawer
 	)
 	if state.view != viewTypeSchedulers {
 		//TODO Start data fetch and reset ticker
 		state.view = viewTypeSchedulers
-		drawDash(s, state, opts)
+		d.draw(state)
 	}
 }
 
 func (h *keyEventHandler) showRedisInfo() {
 	var (
-		s     = h.s
 		state = h.state
-		opts  = h.opts
 		f     = h.fetcher
+		d     = h.drawer
 	)
 	if state.view != viewTypeRedis {
 		f.fetchRedisInfo()
 		state.view = viewTypeRedis
-		drawDash(s, state, opts)
+		d.draw(state)
 	}
 }
 
 func (h *keyEventHandler) showHelp() {
 	var (
-		s     = h.s
 		state = h.state
-		opts  = h.opts
+		d     = h.drawer
 	)
 	if state.view != viewTypeHelp {
 		state.prevView = state.view
 		state.view = viewTypeHelp
-		drawDash(s, state, opts)
+		d.draw(state)
 	}
 }

tools/asynq/cmd/dash/key_event_test.go

@@ -0,0 +1,70 @@
+// Copyright 2022 Kentaro Hibino. All rights reserved.
+// Use of this source code is governed by a MIT license
+// that can be found in the LICENSE file.
+
+package dash
+
+import (
+	"testing"
+
+	"github.com/gdamore/tcell/v2"
+	"github.com/google/go-cmp/cmp"
+	"github.com/hibiken/asynq"
+)
+
+func makeKeyEventHandler(state *State) *keyEventHandler {
+	return &keyEventHandler{
+		s:       tcell.NewSimulationScreen("UTF-8"),
+		state:   state,
+		done:    make(chan struct{}),
+		fetcher: &fakeFetcher{},
+		drawer:  &fakeDrawer{},
+	}
+}
+
+type keyEventHandlerTest struct {
+	desc      string            // test description
+	state     *State            // initial state, to be mutated by the handler
+	events    []*tcell.EventKey // keyboard events
+	wantState State             // expected state after the events
+}
+
+func TestKeyEventHandler(t *testing.T) {
+	tests := []*keyEventHandlerTest{
+		{
+			desc:      "navigates to help page",
+			state:     &State{view: viewTypeQueues},
+			events:    []*tcell.EventKey{tcell.NewEventKey(tcell.KeyRune, '?', tcell.ModNone)},
+			wantState: State{view: viewTypeHelp},
+		},
+		// TODO: Add more tests
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.desc, func(t *testing.T) {
+			h := makeKeyEventHandler(tc.state)
+			for _, e := range tc.events {
+				h.HandleKeyEvent(e)
+			}
+			if diff := cmp.Diff(tc.wantState, *tc.state, cmp.AllowUnexported(State{}, redisInfo{})); diff != "" {
+				t.Errorf("after state was %+v, want %+v: (-want,+got)\n%s", *tc.state, tc.wantState, diff)
+			}
+		})
+	}
+
+}
+
+/*** fake implementation for tests ***/
+
+type fakeFetcher struct{}
+
+func (f *fakeFetcher) fetchQueues()                                                              {}
+func (f *fakeFetcher) fetchQueueInfo(qname string)                                               {}
+func (f *fakeFetcher) fetchRedisInfo()                                                           {}
+func (f *fakeFetcher) fetchTasks(qname string, taskState asynq.TaskState, pageSize, pageNum int) {}
+func (f *fakeFetcher) fetchAggregatingTasks(qname, group string, pageSize, pageNum int)          {}
+func (f *fakeFetcher) fetchGroups(qname string)                                                  {}
+
+type fakeDrawer struct{}
+
+func (d *fakeDrawer) draw(s *State) {}

tools/go.mod

@@ -7,6 +7,7 @@ require (
 	github.com/fatih/color v1.9.0
 	github.com/gdamore/tcell/v2 v2.5.1
 	github.com/go-redis/redis/v8 v8.11.4
+	github.com/google/go-cmp v0.5.6
 	github.com/hibiken/asynq v0.23.0
 	github.com/hibiken/asynq/x v0.0.0-20220131170841-349f4c50fb1d
 	github.com/mattn/go-runewidth v0.0.13