Make HTTP middleware easier to use

appengine/cmd/milo/buildbot/pubsub.go

 // Copyright 2016 The LUCI Authors. All rights reserved.
 // Use of this source code is governed under the Apache License, Version 2.0
 // that can be found in the LICENSE file.
 
 package buildbot
 
 import (
         "bytes"
         "compress/gzip"
         "compress/zlib"
         "encoding/base64"
         "encoding/json"
-        "net/http"
         "time"
 
         "github.com/luci/gae/service/datastore"
         "github.com/luci/luci-go/common/clock"
         "github.com/luci/luci-go/common/iotools"
         log "github.com/luci/luci-go/common/logging"
+        "github.com/luci/luci-go/server/router"
 
-        "github.com/julienschmidt/httprouter"
         "golang.org/x/net/context"
 )
 
 var (
         // subName is the name of the pubsub subscription that milo is expecting.
         // TODO(hinoka): This should be read from luci-config.
         subName = "projects/luci-milo/subscriptions/buildbot-public"
 )
 
 type pubSubMessage struct {
@@ skipping 79 matching lines @@
                         bm.Builds = append(bm.Builds, build)
                         slave.RunningbuildsMap[build.Buildername] = append(
                                 slave.RunningbuildsMap[build.Buildername], build.Number)
                 }
                 slave.Runningbuilds = nil
         }
         return bm.Builds, bm.Master, nil
 }
 
 // PubSubHandler is a webhook that stores the builds coming in from pubsub.
-func PubSubHandler(
-        c context.Context, h http.ResponseWriter, r *http.Request, p httprouter.Params) {
+func PubSubHandler(ctx *router.Context) {
+        c, h, r := ctx.Context, ctx.Writer, ctx.Request
+
         msg := pubSubSubscription{}
         defer r.Body.Close()
         dec := json.NewDecoder(r.Body)
         if err := dec.Decode(&msg); err != nil {
                 log.WithError(err).Errorf(
                         c, "Could not decode message.  %s", err)
                 h.WriteHeader(200) // This is a hard failure, we don't want PubSub to retry.
                 return
         }
         if msg.Subscription != subName {
@@ skipping 58 matching lines @@
                 if err != nil {
                         log.WithError(err).Errorf(
                                 c, "Could not save master in datastore %s", err)
                         // This is transient, we do want PubSub to retry.
                         h.WriteHeader(500)
                         return
                 }
         }
         h.WriteHeader(200)
 }