Milo: Buildbucket PubSub ingestion outline

milo/frontend/config.go

Index: milo/frontend/config.go
diff --git a/milo/frontend/config.go b/milo/frontend/config.go
index 5f09ac28ed2dda7bf8251655462af8e3fff6291a..2a17f2aa70f42bf49616180c2431e4f01ac4850b 100644
--- a/milo/frontend/config.go
+++ b/milo/frontend/config.go
@@ -8,6 +8,7 @@ import (
 	"net/http"
 
 	"cloud.google.com/go/datastore"
+	"google.golang.org/appengine"
 
 	"github.com/luci/luci-go/common/logging"
 	"github.com/luci/luci-go/milo/common"
@@ -41,6 +42,8 @@ func ConfigsHandler(c *router.Context) {
 // UpdateHandler is an HTTP handler that handles configuration update requests.
 func UpdateConfigHandler(ctx *router.Context) {
 	c, h := ctx.Context, ctx.Writer
+	// Needed to access the PubSub API
+	c = appengine.WithContext(c, ctx.Request)
 	projErr := common.UpdateProjectConfigs(c)
 	if projErr != nil {
 		logging.WithError(projErr).Errorf(c, "project update handler encountered error")