milo: Add a build info Swarming implementation.

milo/appengine/swarming/html.go

 // Copyright 2015 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 swarming
 
 import (
         "net/http"
         "os"
 
-        "google.golang.org/api/googleapi"
-
         "github.com/julienschmidt/httprouter"
         "golang.org/x/net/context"
+        "google.golang.org/api/googleapi"
+        "google.golang.org/grpc/codes"
 
+        "github.com/luci/luci-go/grpc/grpcutil"
         "github.com/luci/luci-go/milo/appengine/settings"
         "github.com/luci/luci-go/milo/common/miloerror"
         "github.com/luci/luci-go/server/templates"
 )
 
 const (
         defaultSwarmingServer    = "chromium-swarm.appspot.com"
         defaultSwarmingDevServer = "chromium-swarm-dev.appspot.com"
 )
 
 func getSwarmingService(c context.Context, r *http.Request) (swarmingService, error) {
         server := r.FormValue("server")
         // TODO(hinoka): configure this mapping in luci-config
         switch server {
         case "":
                 server = defaultSwarmingServer
         case "dev":
                 server = defaultSwarmingDevServer
+        default:
+                return nil, grpcutil.Errf(codes.InvalidArgument, "invalid swarming server")
         }
         return newProdService(c, server)
 }
 
 // Log is for fetching logs from swarming.
 type Log struct{}
 
 // Build is for deciphering recipe builds from swarming based off of logs.
 type Build struct{}
 
@@ skipping 80 matching lines @@
 }
 
 // isAPINotFound returns true if err is a HTTP 404 API response.
 func isAPINotFound(err error) bool {
         if apiErr, ok := err.(*googleapi.Error); ok && apiErr.Code == http.StatusNotFound {
                 return true
         }
 
         return false
 }