[logdog/common/types] make StreamAddr implement flag.Value.

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
 
         // Project is the LUCI project name that this log belongs to.
         Project cfgtypes.ProjectName
 
         // Path is the LogDog stream path.
         Path StreamPath
 }
 
+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
+        }
+        *s = *a
+        return nil
+}
+
 // String returns a string representation of this address.
 func (s *StreamAddr) String() string { return s.URL().String() }
 
 // URL returns a LogDog URL that represents this Stream.
 func (s *StreamAddr) URL() *url.URL {
         return &url.URL{
                 Scheme: logDogURLScheme,
                 Host:   s.Host,
                 Path:   strings.Join([]string{"", string(s.Project), string(s.Path)}, "/"),
         }
@@ skipping 35 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
 }