tailscale/tstest/log.go

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// Copyright (c) 2020 Tailscale Inc & 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 tstest
import (
"bytes"
"fmt"
"log"
"os"
"sync"
"testing"
"tailscale.com/types/logger"
)
type testLogWriter struct {
t *testing.T
}
func (w *testLogWriter) Write(b []byte) (int, error) {
w.t.Helper()
w.t.Logf("%s", b)
return len(b), nil
}
func FixLogs(t *testing.T) {
log.SetFlags(log.Ltime | log.Lshortfile)
log.SetOutput(&testLogWriter{t})
}
func UnfixLogs(t *testing.T) {
defer log.SetOutput(os.Stderr)
}
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type panicLogWriter struct{}
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func (panicLogWriter) Write(b []byte) (int, error) {
// Allow certain phrases for now, in the interest of getting
// CI working on Windows and not having to refactor all the
// interfaces.GetState & tshttpproxy code to allow pushing
// down a Logger yet. TODO(bradfitz): do that refactoring once
// 1.2.0 is out.
if bytes.Contains(b, []byte("tshttpproxy: ")) {
os.Stderr.Write(b)
return len(b), nil
}
panic(fmt.Sprintf("please use tailscale.com/logger.Logf instead of the log package (tried to log: %q)", b))
}
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// PanicOnLog modifies the standard library log package's default output to
// an io.Writer that panics, to root out code that's not plumbing their logging
// through explicit tailscale.com/logger.Logf paths.
func PanicOnLog() {
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log.SetOutput(panicLogWriter{})
}
// NewLogLineTracker produces a LogLineTracker wrapping a given logf that tracks whether expectedFormatStrings were seen.
func NewLogLineTracker(logf logger.Logf, expectedFormatStrings []string) *LogLineTracker {
ret := &LogLineTracker{
logf: logf,
listenFor: expectedFormatStrings,
seen: make(map[string]bool),
}
for _, line := range expectedFormatStrings {
ret.seen[line] = false
}
return ret
}
// LogLineTracker is a logger that tracks which log format patterns it's
// seen and can report which expected ones were not seen later.
type LogLineTracker struct {
logf logger.Logf
listenFor []string
mu sync.Mutex
closed bool
seen map[string]bool // format string => false (if not yet seen but wanted) or true (once seen)
}
// Logf logs to its underlying logger and also tracks that the given format pattern has been seen.
func (lt *LogLineTracker) Logf(format string, args ...interface{}) {
lt.mu.Lock()
if lt.closed {
lt.mu.Unlock()
return
}
if v, ok := lt.seen[format]; ok && !v {
lt.seen[format] = true
}
lt.mu.Unlock()
lt.logf(format, args...)
}
// Check returns which format strings haven't been logged yet.
func (lt *LogLineTracker) Check() []string {
lt.mu.Lock()
defer lt.mu.Unlock()
var notSeen []string
for _, format := range lt.listenFor {
if !lt.seen[format] {
notSeen = append(notSeen, format)
}
}
return notSeen
}
// Close closes lt. After calling Close, calls to Logf become no-ops.
func (lt *LogLineTracker) Close() {
lt.mu.Lock()
defer lt.mu.Unlock()
lt.closed = true
}