Add a task queue task router to reduce amount of boilerplate.

scheduler/appengine/engine/cron/demo/main.go

Index: scheduler/appengine/engine/cron/demo/main.go
diff --git a/scheduler/appengine/engine/cron/demo/main.go b/scheduler/appengine/engine/cron/demo/main.go
index e24f1be0978f157051a71004853be5a507801aab..381f63877e45c67b091bbb6fc92b9ae19331fcf5 100644
--- a/scheduler/appengine/engine/cron/demo/main.go
+++ b/scheduler/appengine/engine/cron/demo/main.go
@@ -16,15 +16,13 @@
 package demo
 
 import (
-	"fmt"
 	"net/http"
-	"strconv"
 	"time"
 
 	"golang.org/x/net/context"
 
+	"github.com/golang/protobuf/proto"
 	"github.com/luci/gae/service/datastore"
-	"github.com/luci/gae/service/taskqueue"
 
 	"github.com/luci/luci-go/appengine/gaemiddleware"
 	"github.com/luci/luci-go/common/clock"
@@ -33,9 +31,13 @@ import (
 	"github.com/luci/luci-go/server/router"
 
 	"github.com/luci/luci-go/scheduler/appengine/engine/cron"
+	"github.com/luci/luci-go/scheduler/appengine/engine/internal"
+	"github.com/luci/luci-go/scheduler/appengine/engine/tq"
 	"github.com/luci/luci-go/scheduler/appengine/schedule"
 )
 
+var tasks = tq.Dispatcher{}
+
 type CronState struct {
 	_extra datastore.PropertyMap `gae:"-,extra"`
 
@@ -72,23 +74,23 @@ func evolve(c context.Context, id string, cb func(context.Context, *cron.Machine
 		}
 
 		for _, action := range machine.Actions {
-			var task *taskqueue.Task
+			var task tq.Task
 			switch a := action.(type) {
 			case cron.TickLaterAction:
 				logging.Infof(c, "Scheduling tick %d after %s", a.TickNonce, a.When.Sub(time.Now()))
-				task = &taskqueue.Task{
-					Path: fmt.Sprintf("/tick/%s/%d", id, a.TickNonce),
-					ETA:  a.When,
+				task = tq.Task{
+					Payload: &internal.TickLaterTask{JobId: id, TickNonce: a.TickNonce},
+					ETA:     a.When,
 				}
 			case cron.StartInvocationAction:
-				task = &taskqueue.Task{
-					Path:  fmt.Sprintf("/invocation/%s", id),
-					Delay: time.Second, // give the transaction time to land
+				task = tq.Task{
+					Payload: &internal.StartInvocationTask{JobId: id},
+					Delay:   time.Second, // give the transaction time to land
 				}
 			default:
 				panic("unknown action type")
 			}
-			if err := taskqueue.Add(c, "default", task); err != nil {
+			if err := tasks.AddTask(c, &task); err != nil {
 				return err
 			}
 		}
@@ -112,15 +114,17 @@ func startJob(c context.Context, id string) error {
 	})
 }
 
-func handleTick(c context.Context, id string, nonce int64) error {
-	return evolve(c, id, func(c context.Context, m *cron.Machine) error {
-		return m.OnTimerTick(nonce)
+func handleTick(c context.Context, task proto.Message, execCount int) error {
+	msg := task.(*internal.TickLaterTask)
+	return evolve(c, msg.JobId, func(c context.Context, m *cron.Machine) error {
+		return m.OnTimerTick(msg.TickNonce)
 	})
 }
 
-func handleInvocation(c context.Context, id string) error {
-	logging.Infof(c, "INVOCATION of job %q has finished!", id)
-	return evolve(c, id, func(c context.Context, m *cron.Machine) error {
+func handleInvocation(c context.Context, task proto.Message, execCount int) error {
+	msg := task.(*internal.StartInvocationTask)
+	logging.Infof(c, "INVOCATION of job %q has finished!", msg.JobId)
+	return evolve(c, msg.JobId, func(c context.Context, m *cron.Machine) error {
 		m.RewindIfNecessary()
 		return nil
 	})
@@ -130,6 +134,10 @@ func init() {
 	r := router.New()
 	gaemiddleware.InstallHandlers(r)
 
+	tasks.RegisterTask(&internal.TickLaterTask{}, handleTick, "default", nil)
+	tasks.RegisterTask(&internal.StartInvocationTask{}, handleInvocation, "default", nil)
+	tasks.InstallRoutes(r, gaemiddleware.BaseProd())
+
 	// Kick-start a bunch of jobs by visiting:
 	//
 	// http://localhost:8080/start/with 10s interval
@@ -145,23 +153,5 @@ func init() {
 		}
 	})
 
-	r.POST("/tick/:JobID/:TickNonce", gaemiddleware.BaseProd(), func(c *router.Context) {
-		jobID := c.Params.ByName("JobID")
-		nonce, err := strconv.ParseInt(c.Params.ByName("TickNonce"), 10, 64)
-		if err != nil {
-			panic(err)
-		}
-		if err := handleTick(c.Context, jobID, nonce); err != nil {
-			panic(err)
-		}
-	})
-
-	r.POST("/invocation/:JobID", gaemiddleware.BaseProd(), func(c *router.Context) {
-		jobID := c.Params.ByName("JobID")
-		if err := handleInvocation(c.Context, jobID); err != nil {
-			panic(err)
-		}
-	})
-
 	http.DefaultServeMux.Handle("/", r)
 }