Initial distributor implementation

appengine/cmd/dm/distributor/notify_execution.go

Index: appengine/cmd/dm/distributor/notify_execution.go
diff --git a/appengine/cmd/dm/distributor/notify_execution.go b/appengine/cmd/dm/distributor/notify_execution.go
new file mode 100644
index 0000000000000000000000000000000000000000..0470b2413a3735654ba3d8fb772b9b4326aba11f
--- /dev/null
+++ b/appengine/cmd/dm/distributor/notify_execution.go
@@ -0,0 +1,56 @@
+// 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 distributor
+
+import (
+	"github.com/luci/gae/service/datastore"
+	"github.com/luci/luci-go/appengine/cmd/dm/model"
+	"github.com/luci/luci-go/appengine/tumble"
+	"github.com/luci/luci-go/common/logging"
+	"golang.org/x/net/context"
+)
+
+// NotifyExecution is used to finish an execution. Specifically it allows the
+// appropriate distributor to HandleNotification, and then when that concludes,
+// invokes DM's FinishExecution (see mutate.FinishExecution).
+type NotifyExecution struct {
+	CfgName      string
+	Notification *Notification
+}
+
+// Root implements tumble.Mutation.
+func (f *NotifyExecution) Root(c context.Context) *datastore.Key {
+	return model.ExecutionKeyFromID(c, f.Notification.ID)
+}
+
+// RollForward implements tumble.Mutation.
+func (f *NotifyExecution) RollForward(c context.Context) (muts []tumble.Mutation, err error) {
+	reg := GetRegistry(c)
+	dist, _, err := reg.MakeDistributor(c, f.CfgName)
+	if err != nil {
+		logging.Fields{
+			logging.ErrorKey: err,
+			"cfg":            f.CfgName,
+		}.Errorf(c, "Failed to make distributor")
+		return
+	}
+	rslt, err := dist.HandleNotification(f.Notification)
+	if err != nil {
+		// TODO(riannucci): check for transient/non-transient
+		logging.Fields{
+			logging.ErrorKey: err,
+			"cfg":            f.CfgName,
+		}.Errorf(c, "Failed to handle notification")
+		return
+	}
+	if rslt != nil {
+		return reg.FinishExecution(c, f.Notification.ID, rslt)
+	}
+	return
+}
+
+func init() {
+	tumble.Register((*NotifyExecution)(nil))
+}