[logdog/common/types] custom JSON encoding to allow streamaddr to be zero.

logdog/common/types/streamaddr.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 types
 
 import (
         "flag"
         "net/url"
         "strings"
 
         "github.com/luci/luci-go/common/errors"
         "github.com/luci/luci-go/luci_config/common/cfgtypes"
 )
 
 const logDogURLScheme = "logdog"
 
 // StreamAddr is a fully-qualified LogDog stream address.
 type StreamAddr struct {
         // Host is the LogDog host.
-        Host string
+        Host string `json:"host,omitempty"`
 
         // Project is the LUCI project name that this log belongs to.
-        Project cfgtypes.ProjectName
+        Project cfgtypes.ProjectName `json:"project,omitempty"`
 
         // Path is the LogDog stream path.
-        Path StreamPath
+        Path StreamPath `json:"path,omitempty"`
 }
 
 var _ flag.Value = (*StreamAddr)(nil)
 
 // Set implements flag.Value
 func (s *StreamAddr) Set(v string) error {
         a, err := ParseURL(v)
         if err != nil {
                 return err
         }
@@ skipping 68 matching lines @@
         }
 
         if err := addr.Path.Validate(); err != nil {
                 return nil, errors.Annotate(err).Reason("invalid stream path: %(path)q").
                         D("path", addr.Path).
                         Err()
         }
 
         return &addr, nil
 }