Add benchmark for list topologies API.

app/api_topologies.go

@@ -189,23 +189,25 @@ func (r *registry) walk(f func(APITopologyDesc)) {
 // makeTopologyList returns a handler that yields an APITopologyList.
 func (r *registry) makeTopologyList(rep Reporter) func(w http.ResponseWriter, r *http.Request) {
 	return func(w http.ResponseWriter, req *http.Request) {
-		var (
-			rpt        = rep.Report()
-			topologies = []APITopologyDesc{}
-		)
-		r.walk(func(desc APITopologyDesc) {
-			renderer := renderedForRequest(req, desc)
-			desc.Stats = decorateWithStats(rpt, renderer)
-			for i := range desc.SubTopologies {
-				renderer := renderedForRequest(req, desc.SubTopologies[i])
-				desc.SubTopologies[i].Stats = decorateWithStats(rpt, renderer)
-			}
-			topologies = append(topologies, desc)
-		})
+		topologies := r.renderTopologies(rep.Report(), req)
 		respondWith(w, http.StatusOK, topologies)
 	}
 }
 
+func (r *registry) renderTopologies(rpt report.Report, req *http.Request) []APITopologyDesc {
+	topologies := []APITopologyDesc{}
+	r.walk(func(desc APITopologyDesc) {
+		renderer := renderedForRequest(req, desc)
+		desc.Stats = decorateWithStats(rpt, renderer)
+		for i := range desc.SubTopologies {
+			renderer := renderedForRequest(req, desc.SubTopologies[i])
+			desc.SubTopologies[i].Stats = decorateWithStats(rpt, renderer)
+		}
+		topologies = append(topologies, desc)
+	})
+	return topologies
+}
+
 func decorateWithStats(rpt report.Report, renderer render.Renderer) topologyStats {
 	var (
 		nodes     int

render/render.go

@@ -3,42 +3,32 @@ package render
 import (
 	"fmt"
 	"reflect"
-	"strings"
 
 	"github.com/bluele/gcache"
 
 	"github.com/weaveworks/scope/report"
 )
 
 var renderCache = gcache.New(100).LRU().Build()
-var depth = 0
 
 func memoisedRender(r Renderer, rpt report.Report) RenderableNodes {
-	fmt.Printf("%sRendering: %#v\n", strings.Repeat("  ", depth), r)
-
 	key := ""
 	v := reflect.ValueOf(r)
 	switch v.Kind() {
 	case reflect.Ptr, reflect.Func:
 		key = fmt.Sprintf("%s-%x", rpt.ID, v.Pointer())
 	default:
-		fmt.Printf("%s- Cannot memoise: %v\n", strings.Repeat("  ", depth), r)
 		return r.Render(rpt)
 	}
 	if result, err := renderCache.Get(key); err == nil {
-		fmt.Printf("%s- Hit %s\n", strings.Repeat("  ", depth), key)
 		return result.(RenderableNodes)
 	}
-	fmt.Printf("%s- Miss %s\n", strings.Repeat("  ", depth), key)
-
-	depth += 1
 	output := r.Render(rpt)
-	depth -= 1
-
 	renderCache.Set(key, output)
 	return output
 }
 
+// ResetCache blows away the rendered node cache.
 func ResetCache() {
 	renderCache.Purge()
 }