From 86c271caba071ef087037d924e579f88873d357e Mon Sep 17 00:00:00 2001
From: Brad Fitzpatrick <bradfitz@tailscale.com>
Date: Mon, 19 Oct 2020 07:56:23 -0700
Subject: [PATCH] types/logger: move RusagePrefixLog to logger package, disable
 by default

The RusagePrefixLog is rarely useful, hasn't been useful in a long
time, is rarely the measurement we need, and is pretty spammy (and
syscall-heavy). Disable it by default. We can enable it when we're
debugging memory.
---
 cmd/tailscaled/tailscaled.go                   | 6 +++++-
 {wgengine => types/logger}/rusage.go           | 6 ++----
 {wgengine => types/logger}/rusage_nowindows.go | 2 +-
 {wgengine => types/logger}/rusage_windows.go   | 2 +-
 4 files changed, 9 insertions(+), 7 deletions(-)
 rename {wgengine => types/logger}/rusage.go (86%)
 rename {wgengine => types/logger}/rusage_nowindows.go (97%)
 rename {wgengine => types/logger}/rusage_windows.go (94%)

diff --git a/cmd/tailscaled/tailscaled.go b/cmd/tailscaled/tailscaled.go
index 995277cd4..e09f59c90 100644
--- a/cmd/tailscaled/tailscaled.go
+++ b/cmd/tailscaled/tailscaled.go
@@ -19,6 +19,7 @@ import (
 	"os/signal"
 	"runtime"
 	"runtime/debug"
+	"strconv"
 	"syscall"
 	"time"
 
@@ -115,7 +116,10 @@ func run() error {
 		pol.Shutdown(ctx)
 	}()
 
-	logf := wgengine.RusagePrefixLog(log.Printf)
+	var logf logger.Logf = log.Printf
+	if v, _ := strconv.ParseBool(os.Getenv("TS_DEBUG_MEMORY")); v {
+		logf = logger.RusagePrefixLog(logf)
+	}
 	logf = logger.RateLimitedFn(logf, 5*time.Second, 5, 100)
 
 	if args.cleanup {
diff --git a/wgengine/rusage.go b/types/logger/rusage.go
similarity index 86%
rename from wgengine/rusage.go
rename to types/logger/rusage.go
index b39667f6f..feb6fd19c 100644
--- a/wgengine/rusage.go
+++ b/types/logger/rusage.go
@@ -2,19 +2,17 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package wgengine
+package logger
 
 import (
 	"fmt"
 	"runtime"
-
-	"tailscale.com/types/logger"
 )
 
 // RusagePrefixLog returns a Logf func wrapping the provided logf func that adds
 // a prefixed log message to each line with the current binary memory usage
 // and max RSS.
-func RusagePrefixLog(logf logger.Logf) logger.Logf {
+func RusagePrefixLog(logf Logf) Logf {
 	return func(f string, argv ...interface{}) {
 		var m runtime.MemStats
 		runtime.ReadMemStats(&m)
diff --git a/wgengine/rusage_nowindows.go b/types/logger/rusage_nowindows.go
similarity index 97%
rename from wgengine/rusage_nowindows.go
rename to types/logger/rusage_nowindows.go
index 54f17e889..c5d0e706d 100644
--- a/wgengine/rusage_nowindows.go
+++ b/types/logger/rusage_nowindows.go
@@ -4,7 +4,7 @@
 
 // +build !windows
 
-package wgengine
+package logger
 
 import (
 	"runtime"
diff --git a/wgengine/rusage_windows.go b/types/logger/rusage_windows.go
similarity index 94%
rename from wgengine/rusage_windows.go
rename to types/logger/rusage_windows.go
index f4bf15119..ec5cf5513 100644
--- a/wgengine/rusage_windows.go
+++ b/types/logger/rusage_windows.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package wgengine
+package logger
 
 func rusageMaxRSS() float64 {
 	// TODO(apenwarr): Substitute Windows equivalent of Getrusage() here.