Butler stream servers can generate client address.

logdog/client/cmd/logdog_butler/subcommand_run.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 main
 
 import (
         "encoding/json"
         "io"
         "os"
@@ skipping 160 matching lines @@
         }
 
         // Update our environment for the child process to inherit
         bsEnv := bootstrap.Environment{
                 Project:         a.project,
                 Prefix:          a.prefix,
                 CoordinatorHost: a.coordinatorHost,
         }
 
         // Configure stream server
-        streamServer := streamserver.StreamServer(nil)
+        var streamServer streamserver.StreamServer
         streamServerOwned := true
         if cmd.streamServerURI != "" {
                 log.Fields{
                         "url": cmd.streamServerURI,
                 }.Infof(a, "Creating stream server.")
-                streamServer = createStreamServer(a, cmd.streamServerURI)
+                var err error
+                if streamServer, err = createStreamServer(a, cmd.streamServerURI); err != nil {
+                        log.WithError(err).Errorf(a, "Failed to create stream server.")
+                        return runtimeErrorReturnCode
+                }
 
                 if err := streamServer.Listen(); err != nil {
-                        log.Errorf(log.SetError(a, err), "Failed to connect to stream server.")
+                        log.WithError(err).Errorf(a, "Failed to connect to stream server.")
                         return runtimeErrorReturnCode
                 }
                 defer func() {
                         if streamServerOwned {
                                 streamServer.Close()
                         }
                 }()
 
-                bsEnv.StreamServerURI = string(cmd.streamServerURI)
+                bsEnv.StreamServerURI = streamServer.Address()
         }
 
         // Build our command enviornment.
         env := environ.System()
         bsEnv.Augment(env)
 
         // Construct and execute the command.
         procCtx, procCancelFunc := context.WithCancel(a)
         defer procCancelFunc()
 
@@ skipping 193 matching lines @@
 // callbackReadCloser invokes a callback method when closed.
 type callbackReadCloser struct {
         io.ReadCloser
         callback func()
 }
 
 func (c *callbackReadCloser) Close() error {
         defer c.callback()
         return c.ReadCloser.Close()
 }