update container, add collect methods and main entrypoint

container.go

@@ -1,22 +1,77 @@
 package main
 
 import (
+	"fmt"
+	"math"
+
+	"github.com/fsouza/go-dockerclient"
 	ui "github.com/gizak/termui"
 )
 
-type Container struct {
+type Widgets struct {
 	cid    *ui.Par
 	cpu    *ui.Gauge
 	memory *ui.Gauge
 }
 
-func (c *Container) UpdateCPU(n int) {
-	c.cpu.BarColor = colorScale(n)
-	c.cpu.Percent = n
+func NewWidgets(id string) *Widgets {
+	cid := ui.NewPar(id)
+	cid.Border = false
+	cid.Height = 2
+	cid.Width = 10
+	cid.TextFgColor = ui.ColorWhite
+	return &Widgets{cid, mkGauge(), mkGauge()}
 }
 
-func (c *Container) UpdateMem(n int) {
-	c.memory.Percent = n
+type Container struct {
+	id      string
+	widgets *Widgets
+	stats   chan *docker.Stats
+	done    chan bool
+}
+
+func NewContainer(cid string) *Container {
+	return &Container{
+		id:      cid,
+		widgets: NewWidgets(cid),
+		stats:   make(chan *docker.Stats),
+		done:    make(chan bool),
+	}
+}
+
+func (c *Container) Collect(client *docker.Client) {
+
+	go func() {
+		fmt.Sprintf("starting collector for container: %s\n", c.id)
+		opts := docker.StatsOptions{
+			ID:     c.id,
+			Stats:  c.stats,
+			Stream: true,
+			Done:   c.done,
+		}
+		client.Stats(opts)
+		fmt.Sprintf("stopping collector for container: %s\n", c.id)
+	}()
+
+	go func() {
+		for s := range c.stats {
+			c.UpdateMem(s.MemoryStats.Usage, s.MemoryStats.Limit)
+		}
+	}()
+
+}
+
+func (c *Container) UpdateCPU(n int) {
+	c.widgets.cpu.BarColor = colorScale(n)
+	c.widgets.cpu.Percent = n
+}
+
+func (c *Container) UpdateMem(cur uint64, limit uint64) {
+	c.widgets.memory.Percent = round((float64(cur) / float64(limit)) * 100)
+}
+
+func round(num float64) int {
+	return int(num + math.Copysign(0.5, num))
 }
 
 func colorScale(n int) ui.Attribute {