Initial distributor implementation

appengine/cmd/dm/distributor/notify_execution.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 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))
+}