Log uses of isolate archive and exparchive when 'chromium' build tag is set.

client/cmd/isolate/common.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 (
         "errors"
         "flag"
         "fmt"
@@ skipping 117 matching lines @@
                 }
         }
         return nil
 }
 
 // loggingFlags configures eventlog logging.
 type loggingFlags struct {
         EventlogEndpoint string
 }
 
+const eventlogEndpointHelp = `The URL destination for eventlogs. The following special values are supported:
+\t"prod": use the prod eventlog endpoint
+\t"test": use the test eventlog endpoint
+\t"none": disable eventlogging
+\t"auto": use the prod endpoint if --isolate-server is set to the prod isolate server; otherwise disable eventlogging.`
+
 func (lf *loggingFlags) Init(f *flag.FlagSet) {
-        f.StringVar(&lf.EventlogEndpoint, "eventlog-endpoint", "", `The URL destination for eventlogs. The special values "prod" or "test" may be used to target the standard prod or test urls repspectively. An empty string disables eventlogging.`)
+        f.StringVar(&lf.EventlogEndpoint, "eventlog-endpoint", "auto", eventlogEndpointHelp)

[tandrii(chromium), 2017/06/06 07:14:48]

IMO, this should default to None, while recipe invocation on our bots should
explicitly state auto or maybe even just list prod.

This will be inline with other tooling that developers may directly or
indirectly invoke on their workstations.

 }