Revert of Migrate tsmon protos to proto3

appengine/tsmon/middleware.go

Index: appengine/tsmon/middleware.go
diff --git a/appengine/tsmon/middleware.go b/appengine/tsmon/middleware.go
index f0c683db7132ac5a46d1bf8921dd36414a3a01ab..6cbff5015678978ef07176f983b5e7b68e46e886 100644
--- a/appengine/tsmon/middleware.go
+++ b/appengine/tsmon/middleware.go
@@ -11,6 +11,7 @@
 	"sync"
 	"time"
 
+	"github.com/golang/protobuf/proto"
 	"github.com/julienschmidt/httprouter"
 	"github.com/luci/gae/service/datastore"
 	"github.com/luci/gae/service/info"
@@ -72,11 +73,11 @@
 
 	// Create the target.
 	tar := &target.Task{
-		DataCenter:  targetDataCenter,
-		ServiceName: i.AppID(),
-		JobName:     i.ModuleName(),
-		HostName:    strings.SplitN(i.VersionID(), ".", 2)[0],
-		TaskNum:     -1,
+		DataCenter:  proto.String(targetDataCenter),
+		ServiceName: proto.String(i.AppID()),
+		JobName:     proto.String(i.ModuleName()),
+		HostName:    proto.String(strings.SplitN(i.VersionID(), ".", 2)[0]),
+		TaskNum:     proto.Int32(-1),
 	}
 
 	tsmon.Initialize(c, mon, store.NewInMemory(tar))
@@ -121,14 +122,14 @@
 	now := clock.Now(c)
 
 	if entity.TaskNum < 0 {
-		if task.TaskNum >= 0 {
+		if *task.TaskNum >= 0 {
 			// We used to have a task number but we don't any more (we were inactive
 			// for too long), so clear our state.
 			logging.Warningf(c, "Instance %s got purged from Datastore, but is still alive. "+
 				"Clearing cumulative metrics", info.Get(c).InstanceID())
 			tsmon.ResetCumulativeMetrics(c)
 		}
-		task.TaskNum = -1
+		task.TaskNum = proto.Int32(-1)
 		lastFlushed.Time = entity.LastUpdated
 
 		// Start complaining if we haven't been given a task number after some time.
@@ -140,7 +141,7 @@
 		return nil
 	}
 
-	task.TaskNum = int32(entity.TaskNum)
+	task.TaskNum = proto.Int32(int32(entity.TaskNum))
 	tsmon.Store(c).SetDefaultTarget(task)
 
 	// Update the instance entity and put it back in the datastore asynchronously.