From 2b0e1fd1705840f14eb1df5a4ed5a871045f996d Mon Sep 17 00:00:00 2001
From: ale <ale@incal.net>
Date: Sun, 18 Jan 2015 07:28:47 +0000
Subject: [PATCH] add debug page for lbv2
---
fe/http.go | 10 +++---
fe/http_debug.go | 2 +-
fe/http_test.go | 10 ++++++
fe/lbv2/debug.go | 80 ++++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 97 insertions(+), 5 deletions(-)
create mode 100644 fe/lbv2/debug.go
diff --git a/fe/http.go b/fe/http.go
index 73d8f392..89cd8fce 100644
--- a/fe/http.go
+++ b/fe/http.go
@@ -316,10 +316,12 @@ func (h *HttpRedirector) createHandler() http.Handler {
nil))
// Pass /debug/ to the default ServeMux, all the default debug
- // handlers are installed there.
- mux.Handle(
- "/debug/",
- handlers.GZIPHandler(http.DefaultServeMux, nil))
+ // handlers are installed there. Add a debug handler for the
+ // LoadBalancer data. Gzip the responses.
+ debugMux := http.NewServeMux()
+ debugMux.Handle("/debug/lbv2", h.lb)
+ debugMux.Handle("/", http.DefaultServeMux)
+ mux.Handle("/debug/", handlers.GZIPHandler(debugMux, nil))
// Optionally enable a reverse proxy to the local Icecast for
// the direct stream URLs (below IcecastMountPrefix).
diff --git a/fe/http_debug.go b/fe/http_debug.go
index 4861be2a..cb656ef3 100644
--- a/fe/http_debug.go
+++ b/fe/http_debug.go
@@ -2,10 +2,10 @@ package fe
import (
"fmt"
+ "html/template"
"net/http"
"sort"
"sync"
- "text/template"
"time"
)
diff --git a/fe/http_test.go b/fe/http_test.go
index 531e5919..2b849fc6 100644
--- a/fe/http_test.go
+++ b/fe/http_test.go
@@ -103,6 +103,16 @@ func TestHttpRedirector_Static(t *testing.T) {
}
}
+func TestHttpRedirector_LBDebugPage(t *testing.T) {
+ _, srv := createTestHttpServer(t)
+ defer srv.Close()
+
+ data := doHttpRequest(t, "GET", srv.URL+"/debug/lbv2", 200)
+ if !strings.Contains(data, "node1") {
+ t.Errorf("Bad response:\n%s", data)
+ }
+}
+
type httpTestContext struct {
srv *httptest.Server
targetSrv *httptest.Server
diff --git a/fe/lbv2/debug.go b/fe/lbv2/debug.go
new file mode 100644
index 00000000..6bf69cdd
--- /dev/null
+++ b/fe/lbv2/debug.go
@@ -0,0 +1,80 @@
+package lbv2
+
+import (
+ "fmt"
+ "html/template"
+ "net/http"
+)
+
+const debugText = `<html>
+ <body>
+ <title>Load Balancer</title>
+
+ <h3>Query costs</h3>
+ <table>
+ <tr><th>Node</th><th>Requests</th><th>Utilization/Cost</th></tr>
+ {{$dimensions := .Dimensions}}
+ {{range .Nodes}}
+ <tr>
+ <td>{{.Name}}</td>
+ <td>{{.Requests}}</td>
+ {{range $d := $dimensions}}
+ {{$data := index .Data $d}}
+ <td>
+ {{$data.PredictedUtilization}}/{{$data.ReportedUtilization}}/{{$data.Cost}}
+ </td>
+ {{end}}
+ </tr>
+ {{end}}
+ </table>
+ </body>
+ </html>`
+
+var debugTmpl = template.Must(template.New("lbv2 debug").Parse(debugText))
+
+type nodeDebugData struct {
+ Name string
+ Requests int
+ Data map[int]costAndUtil
+}
+
+type costAndUtil struct {
+ ReportedUtilization float64
+ PredictedUtilization float64
+ Cost float64
+}
+
+func (l *LoadBalancer) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+ // Build a view of the cost/utilization data.
+ l.lock.Lock()
+ var nodes []nodeDebugData
+ for _, n := range l.nodes {
+ ndata := nodeDebugData{Name: n.Name(), Data: make(map[int]costAndUtil)}
+ for dim, pred := range l.predictors {
+ util := n.Utilization(dim)
+ ndata.Requests = util.Requests
+ ndata.Data[dim] = costAndUtil{
+ ReportedUtilization: util.Utilization,
+ PredictedUtilization: pred.Utilization(n),
+ Cost: float64(pred.cost[n.Name()]),
+ }
+ }
+ nodes = append(nodes, ndata)
+ }
+ var dimensions []int
+ for dim := range l.predictors {
+ dimensions = append(dimensions, dim)
+ }
+ l.lock.Unlock()
+
+ ctx := struct {
+ Nodes []nodeDebugData
+ Dimensions []int
+ NumDimensions int
+ }{nodes, dimensions, len(dimensions)}
+
+ err := debugTmpl.Execute(w, ctx)
+ if err != nil {
+ fmt.Fprintln(w, "debug: error executing template: ", err.Error())
+ }
+}
--
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