Set the refresh rate of the monitor widget

By default refresh rate is set to 500 ms, but it can now be changed by
the user. refs #87.

app/help_texts.go

@@ -101,7 +101,7 @@ const (
 		"<b>[m]:<darkgrey>Monitor mode</> <b>[2]:<darkgrey>Images</> <b>[3]:<darkgrey>Networks</> <b>[4]:<darkgrey>Nodes</> <b>[5]:<darkgrey>Services</> <b>[6]:<darkgrey>Stacks</> <blue>|</> <b>[Enter]:<darkgrey>Commands</></>"
 
 	monitorMapping = commonMappings +
-		"<b>[m]:<darkgrey>Monitor mode</> <b>[1]:<darkgrey>Containers</> <b>[2]:<darkgrey>Images</> <b>[3]:<darkgrey>Networks</> <b>[4]:<darkgrey>Nodes</> <b>[5]:<darkgrey>Services</> <b>[6]:<darkgrey>Stacks</>"
+		"<b>[m]:<darkgrey>Monitor mode</> <b>[1]:<darkgrey>Containers</> <b>[2]:<darkgrey>Images</> <b>[3]:<darkgrey>Networks</> <b>[4]:<darkgrey>Nodes</> <b>[5]:<darkgrey>Services</> <b>[6]:<darkgrey>Stacks</> <blue>|</> <b>[s]:<darkgrey>Set refresh rate</></>"
 
 	swarmMapping = commonMappings +
 		"<b>[m]:<darkgrey>Monitor mode</> <b>[1]:<darkgrey>Containers</> <b>[2]:<darkgrey>Images</> <b>[3]:<darkgrey>Networks</> <b>[4]:<darkgrey>Nodes</> <b>[5]:<darkgrey>Services</> <b>[6]:<darkgrey>Stacks</>"

app/monitor_events.go

@@ -1,8 +1,12 @@
 package app
 
 import (
+	"errors"
+	"fmt"
 	"github.com/moncho/dry/appui"
+	"github.com/moncho/dry/ui"
 	termbox "github.com/nsf/termbox-go"
+	"strconv"
 )
 
 type monitorScreenEventHandler struct {
@@ -52,8 +56,39 @@ func (h *monitorScreenEventHandler) handle(event termbox.Event, f func(eventHand
 			handled = true
 			cursor.Bottom()
 			h.widget.OnEvent(nil)
-		default:
-			handled = false
+		case 's': // Set the delay between updates to <delay> seconds.
+			handled = true
+			h.widget.Unmount()
+			prompt := appui.NewPrompt("Set the delay between updates (in milliseconds)")
+			widgets.add(prompt)
+			forwarder := newEventForwarder()
+			f(forwarder)
+			h.dry.ViewMode(NoView)
+			refreshScreen()
+			go func() {
+				defer h.widget.Mount()
+				defer h.dry.ViewMode(Monitor)
+				defer f(h)
+				events := ui.EventSource{
+					Events: forwarder.events(),
+					EventHandledCallback: func(e termbox.Event) error {
+						return refreshScreen()
+					},
+				}
+				prompt.OnFocus(events)
+				input, cancel := prompt.Text()
+				widgets.remove(prompt)
+				if cancel {
+					return
+				}
+				refreshRate, err := toInt(input)
+				if err != nil {
+					h.dry.appmessage(
+						fmt.Sprintf("Error setting refresh rate: %s", err.Error()))
+					return
+				}
+				h.widget.RefreshRate(refreshRate)
+			}()
 		}
 	}
 	if !handled {
@@ -67,3 +102,15 @@ func (h *monitorScreenEventHandler) handle(event termbox.Event, f func(eventHand
 		h.baseEventHandler.handle(event, nh)
 	}
 }
+
+func toInt(s string) (int, error) {
+	i, err := strconv.Atoi(s)
+
+	if err != nil {
+		return -1, errors.New("Be nice, a number is expected")
+	}
+	if i < 0 {
+		return -1, errors.New("Negative values are not allowed")
+	}
+	return i, nil
+}

appui/monitor.go

@@ -2,6 +2,7 @@ package appui
 
 import (
 	"context"
+	"strconv"
 	"sync"
 	"time"
 
@@ -10,6 +11,8 @@ import (
 	"github.com/moncho/dry/ui"
 )
 
+var defaultRefreshRate time.Duration = 500 * time.Millisecond
+
 //Monitor is a self-refreshing ui component that shows monitoring information about docker
 //containers.
 type Monitor struct {
@@ -23,6 +26,7 @@ type Monitor struct {
 	x, y                 int
 	height, width        int
 	startIndex, endIndex int
+	refreshRate          time.Duration
 	sync.RWMutex
 }
 
@@ -40,21 +44,26 @@ func NewMonitor(daemon docker.ContainerDaemon, y int) *Monitor {
 		height:        height,
 		width:         ui.ActiveScreen.Dimensions.Width,
 		unmount:       make(chan struct{}),
+		refreshRate:   defaultRefreshRate,
 	}
 	return &m
 }
 
 //Buffer returns the content of this monitor as a termui.Buffer
 func (m *Monitor) Buffer() gizaktermui.Buffer {
-	m.Lock()
-	defer m.Unlock()
+	m.RLock()
+	defer m.RUnlock()
 	y := m.y
 	buf := gizaktermui.NewBuffer()
+	widgetHeader := NewWidgetHeader()
+	widgetHeader.HeaderEntry("Running Containers", strconv.Itoa(m.RowCount()))
+	widgetHeader.HeaderEntry("Refresh rate", m.refreshRate.String())
 
-	widgetHeader := WidgetHeader("Containers", m.RowCount(), "")
 	widgetHeader.Y = y
 	buf.Merge(widgetHeader.Buffer())
-	y += widgetHeader.Height
+	y += widgetHeader.GetHeight()
+	//Empty line between the header and the rest of the content
+	y++
 
 	m.header.SetY(y)
 	buf.Merge(m.header.Buffer())
@@ -78,6 +87,8 @@ func (m *Monitor) Filter(filter string) {
 
 //Mount prepares this widget for rendering
 func (m *Monitor) Mount() error {
+	m.Lock()
+	defer m.Unlock()
 	daemon := m.daemon
 	containers := daemon.Containers(
 		[]docker.ContainerFilter{docker.ContainerFilters.Running()}, docker.SortByName)
@@ -110,11 +121,20 @@ func (m *Monitor) OnEvent(event EventCommand) error {
 	return nil
 }
 
+//RefreshRate sets the refresh rate of this monitor to the given amount in
+//milliseconds.
+func (m *Monitor) RefreshRate(millis int) {
+	m.Lock()
+	defer m.Unlock()
+	m.refreshRate = time.Duration(millis) * time.Millisecond
+}
+
 //RenderLoop makes this monitor to render itself until stopped.
 func (m *Monitor) RenderLoop(ctx context.Context) {
 
 	go func() {
-		refreshTimer := time.NewTicker(500 * time.Millisecond)
+		m.refresh()
+		refreshTimer := time.NewTicker(m.refreshRate)
 		defer refreshTimer.Stop()
 		defer func() {
 			for _, c := range m.openChannels {