milo: Add BuildInfo implementation for BuildBot.

milo/appengine/buildinfo/service.go

 // Copyright 2017 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 buildinfo
 
 import (
         "github.com/luci/luci-go/grpc/grpcutil"
         "github.com/luci/luci-go/luci_config/common/cfgtypes"
         milo "github.com/luci/luci-go/milo/api/proto"
+        "github.com/luci/luci-go/milo/appengine/buildbot"
 
         "google.golang.org/grpc/codes"
 
         "golang.org/x/net/context"
 )
 
 // Service is a BuildInfoServer implementation.
-type Service struct{}
+type Service struct {
+        // BuildBot is the BuildInfoProvider for the BuildBot service.
+        BuildBot buildbot.BuildInfoProvider
+}
 
 var _ milo.BuildInfoServer = (*Service)(nil)
 
 // Get implements milo.BuildInfoServer.
 func (svc *Service) Get(c context.Context, req *milo.BuildInfoRequest) (*milo.BuildInfoResponse, error) {
         projectHint := cfgtypes.ProjectName(req.ProjectHint)
         if projectHint != "" {
                 if err := projectHint.Validate(); err != nil {
                         return nil, grpcutil.Errf(codes.InvalidArgument, "invalid project hint: %s", err.Error())
                 }
         }
 
         switch {
         case req.GetBuildbot() != nil:
-                return nil, grpcutil.Unimplemented
+                resp, err := svc.BuildBot.GetBuildInfo(c, req.GetBuildbot(), projectHint)
+                if err != nil {
+                        return nil, err
+                }
+                return resp, nil
 
         case req.GetSwarming() != nil:
                 return nil, grpcutil.Unimplemented
 
         default:
-                return nil, grpcutil.Unimplemented
+                return nil, grpcutil.Errf(codes.InvalidArgument, "must supply a build")
         }
 }