func handleWebsocket(
w http.ResponseWriter,
r *http.Request,
rep Reporter,
renderer render.Renderer,
loop time.Duration,
) {
conn, err := upgrader.Upgrade(w, r, nil)
if err != nil {
// log.Println("Upgrade:", err)
return
}
defer conn.Close()
quit := make(chan struct{})
go func(c *websocket.Conn) {
for { // just discard everything the browser sends
if _, _, err := c.NextReader(); err != nil {
close(quit)
break
}
}
}(conn)
var (
previousTopo render.RenderableNodes
tick = time.Tick(loop)
wait = make(chan struct{}, 1)
)
rep.WaitOn(wait)
defer rep.UnWait(wait)
for {
newTopo := renderer.Render(rep.Report()).Prune()
diff := render.TopoDiff(previousTopo, newTopo)
previousTopo = newTopo
if err := conn.SetWriteDeadline(time.Now().Add(websocketTimeout)); err != nil {
return
}
if err := conn.WriteJSON(diff); err != nil {
return
}
select {
case <-wait:
case <-tick:
case <-quit:
return
}
}
}
func TestTopoDiff(t *testing.T) {
nodea := render.RenderableNode{
ID: "nodea",
LabelMajor: "Node A",
LabelMinor: "'ts an a",
Pseudo: false,
Node: report.MakeNode().WithAdjacent("nodeb"),
}
nodeap := nodea
nodeap.Adjacency = []string{
"nodeb",
"nodeq", // not the same anymore
}
nodeb := render.RenderableNode{
ID: "nodeb",
LabelMajor: "Node B",
}
// Helper to make RenderableNode maps.
nodes := func(ns ...render.RenderableNode) render.RenderableNodes {
r := render.RenderableNodes{}
for _, n := range ns {
r[n.ID] = n
}
return r
}
for _, c := range []struct {
label string
have, want render.Diff
}{
{
label: "basecase: empty -> something",
have: render.TopoDiff(nodes(), nodes(nodea, nodeb)),
want: render.Diff{
Add: []render.RenderableNode{nodea, nodeb},
},
},
{
label: "basecase: something -> empty",
have: render.TopoDiff(nodes(nodea, nodeb), nodes()),
want: render.Diff{
Remove: []string{"nodea", "nodeb"},
},
},
{
label: "add and remove",
have: render.TopoDiff(nodes(nodea), nodes(nodeb)),
want: render.Diff{
Add: []render.RenderableNode{nodeb},
Remove: []string{"nodea"},
},
},
{
label: "no change",
have: render.TopoDiff(nodes(nodea), nodes(nodea)),
want: render.Diff{},
},
{
label: "change a single node",
have: render.TopoDiff(nodes(nodea), nodes(nodeap)),
want: render.Diff{
Update: []render.RenderableNode{nodeap},
},
},
} {
sort.Strings(c.have.Remove)
sort.Sort(ByID(c.have.Add))
sort.Sort(ByID(c.have.Update))
if !reflect.DeepEqual(c.want, c.have) {
t.Errorf("%s - %s", c.label, test.Diff(c.want, c.have))
}
}
}