Butler: export Coordinator host in environment.

logdog/client/butler/bootstrap/env.go

 // Copyright 2016 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 bootstrap handles Butler-side bootstrapping functionality.
 package bootstrap
 
 import (
         "github.com/luci/luci-go/common/config"
         "github.com/luci/luci-go/common/system/environ"
         "github.com/luci/luci-go/logdog/client/butlerlib/bootstrap"
         "github.com/luci/luci-go/logdog/common/types"
 )
 
 // Environment is the set of configuration parameters for the bootstrap.
 type Environment struct {
+        // CoordinatorHost is the coordinator host name, or empty string if we are
+        // not outputting to a Coordinator.
+        CoordinatorHost string
+
         // Project is the project name. If not empty, this will be exported to
         // subprocesses.
         Project config.ProjectName
         // Prefix is the prefix name. If not empty, this will be exported to
         // subprocesses.
         Prefix types.StreamName
         // StreamServerURI is the streamserver URI. If not empty, this will be
         // exported to subprocesses.
         StreamServerURI string
 }
 
 // Augment augments the supplied base environment with LogDog Butler bootstrap
 // parameters.
 func (e *Environment) Augment(base environ.Env) {
         exportIf := func(envKey, v string) {
                 if v != "" {
                         base.Set(envKey, v)
                 }
         }
 
+        exportIf(bootstrap.EnvCoordinatorHost, e.CoordinatorHost)
         exportIf(bootstrap.EnvStreamPrefix, string(e.Prefix))
         exportIf(bootstrap.EnvStreamProject, string(e.Project))
         exportIf(bootstrap.EnvStreamServerPath, e.StreamServerURI)
 }