[grpc/logging] Update to LoggerV2.

logdog/client/cmd/logdog_butler/main.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 (
         "flag"
         "fmt"
         "net/http"
@@ skipping 249 matching lines @@
         if err := flags.Parse(argv); err != nil {
                 log.WithError(err).Errorf(a, "Failed to parse command-line.")
                 return configErrorReturnCode
         }
 
         a.Context = logConfig.Set(a.Context)
 
         // Install a global gRPC logger adapter. This routes gRPC log messages that
         // are emitted through our logger. We only log gRPC prints if our logger is
         // configured to log info-level or lower.
-        grpcLogging.Install(log.Get(a.Context), log.IsLogging(a.Context, log.Info))
+        logger := log.Get(a.Context)
+        if log.IsLogging(a.Context, log.Info) {
+                grpcLogging.Install(logger, log.GetLevel(a.Context))
+        } else {
+                // If we're not logging at INFO-level, suppress all gRPC logging output.
+                grpcLogging.Install(logger, grpcLogging.Suppress)
+        }
 
         if err := a.project.Validate(); err != nil {
                 log.WithError(err).Errorf(a, "Invalid project (-project).")
                 return configErrorReturnCode
         }
 
         // Validate our Prefix; generate a user prefix if one was not supplied.
         prefix := a.prefix
         if prefix == "" {
                 // Auto-generate a prefix.
@@ skipping 63 matching lines @@
 
         paniccatcher.Do(func() {
                 rc = mainImpl(ctx, chromeinfra.DefaultAuthOptions(), os.Args[1:])
         }, func(p *paniccatcher.Panic) {
                 log.Fields{
                         "panic.error": p.Reason,
                 }.Errorf(ctx, "Panic caught in main:\n%s", p.Stack)
                 rc = runtimeErrorReturnCode
         })
 }