blob: 3c5f780ac4d62b28b790e0c0d1a28e64deb5c681 [file] [log] [blame]
// Copyright 2017 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package testlog provides a back-channel communication path
// between tests and package os, so that cmd/go can see which
// environment variables and files a test consults.
package testlog
import "sync/atomic"
// Interface is the interface required of test loggers.
// The os package will invoke the interface's methods to indicate that
// it is inspecting the given environment variables or files.
// Multiple goroutines may call these methods simultaneously.
type Interface interface {
Getenv(key string)
Stat(file string)
Open(file string)
Chdir(dir string)
// logger is the current logger Interface.
// We use an atomic.Value in case test startup
// is racing with goroutines started during init.
// That must not cause a race detector failure,
// although it will still result in limited visibility
// into exactly what those goroutines do.
var logger atomic.Value
// SetLogger sets the test logger implementation for the current process.
// It must be called only once, at process startup.
func SetLogger(impl Interface) {
if logger.Load() != nil {
panic("testlog: SetLogger must be called only once")
// Logger returns the current test logger implementation.
// It returns nil if there is no logger.
func Logger() Interface {
impl := logger.Load()
if impl == nil {
return nil
return *impl.(*Interface)
// Getenv calls Logger().Getenv, if a logger has been set.
func Getenv(name string) {
if log := Logger(); log != nil {
// Open calls Logger().Open, if a logger has been set.
func Open(name string) {
if log := Logger(); log != nil {
// Stat calls Logger().Stat, if a logger has been set.
func Stat(name string) {
if log := Logger(); log != nil {