dashboard: store front page in memcache

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/5503056

diff --git a/misc/dashboard/app/build/handler.go b/misc/dashboard/app/build/handler.go
index facfeea8141f047c1cd17806d3600dcb59da546f..576d7cb132156c3d5a3f3c1bc9663fe6679c2ccf 100644 (file)
--- a/misc/dashboard/app/build/handler.go
+++ b/misc/dashboard/app/build/handler.go
@@ -7,6 +7,7 @@ package build
 import (
        "appengine"
        "appengine/datastore"
+       "appengine/memcache"
        "crypto/hmac"
        "fmt"
        "http"
@@ -58,6 +59,7 @@ func commitHandler(r *http.Request) (interface{}, os.Error) {
        if err := com.Valid(); err != nil {
                return nil, fmt.Errorf("validating Commit: %v", err)
        }
+       defer invalidateCache(c)
        tx := func(c appengine.Context) os.Error {
                return addCommit(c, com)
        }
@@ -131,6 +133,7 @@ func tagHandler(r *http.Request) (interface{}, os.Error) {
                return nil, err
        }
        c := appengine.NewContext(r)
+       defer invalidateCache(c)
        _, err := datastore.Put(c, t.Key(c), t)
        return nil, err
 }
@@ -226,6 +229,7 @@ func resultHandler(r *http.Request) (interface{}, os.Error) {
        if err := res.Valid(); err != nil {
                return nil, fmt.Errorf("validating Result: %v", err)
        }
+       defer invalidateCache(c)
        // store the Log text if supplied
        if len(res.Log) > 0 {
                hash, err := PutLog(c, res.Log)
@@ -375,3 +379,11 @@ func logErr(w http.ResponseWriter, r *http.Request, err os.Error) {
        w.WriteHeader(http.StatusInternalServerError)
        fmt.Fprint(w, "Error: ", err)
 }
+
+// invalidateCache deletes the ui cache record from memcache.
+func invalidateCache(c appengine.Context) {
+       err := memcache.Delete(c, uiCacheKey)
+       if err != nil && err != memcache.ErrCacheMiss {
+               c.Errorf("memcache.Delete(%q): %v", uiCacheKey, err)
+       }
+}

diff --git a/misc/dashboard/app/build/ui.go b/misc/dashboard/app/build/ui.go
index 5070400d96ac880cecbbcc11a92c8364b611bd99..8a1cca320d5c304b07d8d896ef0574dad75a4d6a 100644 (file)
--- a/misc/dashboard/app/build/ui.go
+++ b/misc/dashboard/app/build/ui.go
@@ -10,6 +10,8 @@ package build
 import (
        "appengine"
        "appengine/datastore"
+       "appengine/memcache"
+       "bytes"
        "exp/template/html"
        "http"
        "os"
@@ -20,6 +22,11 @@ import (
        "template"
 )
 
+const (
+       uiCacheKey    = "build-ui"
+       uiCacheExpiry = 10 * 60 // 10 minutes in seconds
+)
+
 func init() {
        http.HandleFunc("/", uiHandler)
        html.Escape(uiTemplate)
@@ -27,7 +34,6 @@ func init() {
 
 // uiHandler draws the build status page.
 func uiHandler(w http.ResponseWriter, r *http.Request) {
-       // TODO(adg): put the HTML in memcache and invalidate on updates
        c := appengine.NewContext(r)
 
        page, _ := strconv.Atoi(r.FormValue("page"))
@@ -35,6 +41,18 @@ func uiHandler(w http.ResponseWriter, r *http.Request) {
                page = 0
        }
 
+       // Used cached version of front page, if available.
+       if page == 0 {
+               t, err := memcache.Get(c, uiCacheKey)
+               if err == nil {
+                       w.Write(t.Value)
+                       return
+               }
+               if err != memcache.ErrCacheMiss {
+                       c.Errorf("get ui cache: %v", err)
+               }
+       }
+
        commits, err := goCommits(c, page)
        if err != nil {
                logErr(w, r, err)
@@ -57,9 +75,26 @@ func uiHandler(w http.ResponseWriter, r *http.Request) {
                p.HasPrev = true
        }
        data := &uiTemplateData{commits, builders, tipState, p}
-       if err := uiTemplate.Execute(w, data); err != nil {
+
+       var buf bytes.Buffer
+       if err := uiTemplate.Execute(&buf, data); err != nil {
                logErr(w, r, err)
+               return
+       }
+
+       // Cache the front page.
+       if page == 0 {
+               t := &memcache.Item{
+                       Key:        uiCacheKey,
+                       Value:      buf.Bytes(),
+                       Expiration: uiCacheExpiry,
+               }
+               if err := memcache.Set(c, t); err != nil {
+                       c.Errorf("set ui cache: %v", err)
+               }
        }
+
+       buf.WriteTo(w)
 }
 
 type Pagination struct {