Reverts commit f40b1b to a6a67e

os.go

@@ -7,12 +7,19 @@ import (
 	"os"
 	"os/signal"
 	"strings"
+	"sync"
+	"syscall"
+	"time"
 )
 
 var (
 	GoPath = os.Getenv("GOPATH")
 )
 
+func init() {
+	initAFSIGHUPWatcher()
+}
+
 func TrapSignal(cb func()) {
 	c := make(chan os.Signal, 1)
 	signal.Notify(c, os.Interrupt)
@@ -105,25 +112,159 @@ func WriteFileAtomic(filePath string, newBytes []byte, mode os.FileMode) error {
 
 //--------------------------------------------------------------------------------
 
-func Tempfile(prefix string) (*os.File, string) {
-	file, err := ioutil.TempFile("", prefix)
-	if err != nil {
-		PanicCrisis(err)
+/* AutoFile usage
+
+// Create/Append to ./autofile_test
+af, err := OpenAutoFile("autofile_test")
+if err != nil {
+	panic(err)
+}
+
+// Stream of writes.
+// During this time, the file may be moved e.g. by logRotate.
+for i := 0; i < 60; i++ {
+	af.Write([]byte(Fmt("LOOP(%v)", i)))
+	time.Sleep(time.Second)
+}
+
+// Close the AutoFile
+err = af.Close()
+if err != nil {
+	panic(err)
+}
+*/
+
+const autoFileOpenDuration = 1000 * time.Millisecond
+
+// Automatically closes and re-opens file for writing.
+// This is useful for using a log file with the logrotate tool.
+type AutoFile struct {
+	ID     string
+	Path   string
+	ticker *time.Ticker
+	mtx    sync.Mutex
+	file   *os.File
+}
+
+func OpenAutoFile(path string) (af *AutoFile, err error) {
+	af = &AutoFile{
+		ID:     RandStr(12) + ":" + path,
+		Path:   path,
+		ticker: time.NewTicker(autoFileOpenDuration),
 	}
-	return file, file.Name()
+	if err = af.openFile(); err != nil {
+		return
+	}
+	go af.processTicks()
+	autoFileWatchers.addAutoFile(af)
+	return
+}
+
+func (af *AutoFile) Close() error {
+	af.ticker.Stop()
+	err := af.closeFile()
+	autoFileWatchers.removeAutoFile(af)
+	return err
+}
+
+func (af *AutoFile) processTicks() {
+	for {
+		_, ok := <-af.ticker.C
+		if !ok {
+			return // Done.
+		}
+		af.closeFile()
+	}
+}
+
+func (af *AutoFile) closeFile() (err error) {
+	af.mtx.Lock()
+	defer af.mtx.Unlock()
+
+	file := af.file
+	if file == nil {
+		return nil
+	}
+	af.file = nil
+	return file.Close()
+}
+
+func (af *AutoFile) Write(b []byte) (n int, err error) {
+	af.mtx.Lock()
+	defer af.mtx.Unlock()
+	if af.file == nil {
+		if err = af.openFile(); err != nil {
+			return
+		}
+	}
+	return af.file.Write(b)
 }
 
-func Tempdir(prefix string) (*os.File, string) {
-	tempDir := os.TempDir() + "/" + prefix + RandStr(12)
-	err := EnsureDir(tempDir, 0700)
+func (af *AutoFile) openFile() error {
+	file, err := os.OpenFile(af.Path, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0600)
 	if err != nil {
-		panic(Fmt("Error creating temp dir: %v", err))
+		return err
 	}
-	dir, err := os.Open(tempDir)
+	af.file = file
+	return nil
+}
+
+//--------------------------------------------------------------------------------
+
+var autoFileWatchers *afSIGHUPWatcher
+
+func initAFSIGHUPWatcher() {
+	autoFileWatchers = newAFSIGHUPWatcher()
+
+	c := make(chan os.Signal, 1)
+	signal.Notify(c, syscall.SIGHUP)
+
+	go func() {
+		for _ = range c {
+			autoFileWatchers.closeAll()
+		}
+	}()
+}
+
+type afSIGHUPWatcher struct {
+	mtx       sync.Mutex
+	autoFiles map[string]*AutoFile
+}
+
+func newAFSIGHUPWatcher() *afSIGHUPWatcher {
+	return &afSIGHUPWatcher{
+		autoFiles: make(map[string]*AutoFile, 10),
+	}
+}
+
+func (afw *afSIGHUPWatcher) addAutoFile(af *AutoFile) {
+	afw.mtx.Lock()
+	afw.autoFiles[af.ID] = af
+	afw.mtx.Unlock()
+}
+
+func (afw *afSIGHUPWatcher) removeAutoFile(af *AutoFile) {
+	afw.mtx.Lock()
+	delete(afw.autoFiles, af.ID)
+	afw.mtx.Unlock()
+}
+
+func (afw *afSIGHUPWatcher) closeAll() {
+	afw.mtx.Lock()
+	for _, af := range afw.autoFiles {
+		af.closeFile()
+	}
+	afw.mtx.Unlock()
+}
+
+//--------------------------------------------------------------------------------
+
+func Tempfile(prefix string) (*os.File, string) {
+	file, err := ioutil.TempFile("", prefix)
 	if err != nil {
-		panic(Fmt("Error opening temp dir: %v", err))
+		PanicCrisis(err)
 	}
-	return dir, tempDir
+	return file, file.Name()
 }
 
 //--------------------------------------------------------------------------------

os_test.go

@@ -0,0 +1,64 @@
+package common
+
+import (
+	"os"
+	"syscall"
+	"testing"
+)
+
+func TestSIGHUP(t *testing.T) {
+
+	// First, create an AutoFile writing to a tempfile dir
+	file, name := Tempfile("sighup_test")
+	err := file.Close()
+	if err != nil {
+		t.Fatalf("Error creating tempfile: %v", err)
+	}
+	// Here is the actual AutoFile
+	af, err := OpenAutoFile(name)
+	if err != nil {
+		t.Fatalf("Error creating autofile: %v", err)
+	}
+
+	// Write to the file.
+	_, err = af.Write([]byte("Line 1\n"))
+	if err != nil {
+		t.Fatalf("Error writing to autofile: %v", err)
+	}
+	_, err = af.Write([]byte("Line 2\n"))
+	if err != nil {
+		t.Fatalf("Error writing to autofile: %v", err)
+	}
+
+	// Send SIGHUP to self.
+	syscall.Kill(syscall.Getpid(), syscall.SIGHUP)
+
+	// Move the file over
+	err = os.Rename(name, name+"_old")
+	if err != nil {
+		t.Fatalf("Error moving autofile: %v", err)
+	}
+
+	// Write more to the file.
+	_, err = af.Write([]byte("Line 3\n"))
+	if err != nil {
+		t.Fatalf("Error writing to autofile: %v", err)
+	}
+	_, err = af.Write([]byte("Line 4\n"))
+	if err != nil {
+		t.Fatalf("Error writing to autofile: %v", err)
+	}
+	err = af.Close()
+	if err != nil {
+		t.Fatalf("Error closing autofile")
+	}
+
+	// Both files should exist
+	if body := MustReadFile(name + "_old"); string(body) != "Line 1\nLine 2\n" {
+		t.Errorf("Unexpected body %s", body)
+	}
+	if body := MustReadFile(name); string(body) != "Line 3\nLine 4\n" {
+		t.Errorf("Unexpected body %s", body)
+	}
+
+}

service.go

@@ -65,7 +65,6 @@ type BaseService struct {
 	name    string
 	started uint32 // atomic
 	stopped uint32 // atomic
-	Quit    chan struct{}
 
 	// The "subclass" of BaseService
 	impl Service
@@ -75,7 +74,6 @@ func NewBaseService(log log15.Logger, name string, impl Service) *BaseService {
 	return &BaseService{
 		log:  log,
 		name: name,
-		Quit: make(chan struct{}),
 		impl: impl,
 	}
 }
@@ -104,8 +102,6 @@ func (bs *BaseService) Start() (bool, error) {
 }
 
 // Implements Service
-// NOTE: Do not put anything in here,
-// that way users don't need to call BaseService.OnStart()
 func (bs *BaseService) OnStart() error { return nil }
 
 // Implements Service
@@ -115,7 +111,6 @@ func (bs *BaseService) Stop() bool {
 			bs.log.Info(Fmt("Stopping %v", bs.name), "impl", bs.impl)
 		}
 		bs.impl.OnStop()
-		close(bs.Quit)
 		return true
 	} else {
 		if bs.log != nil {
@@ -126,8 +121,6 @@ func (bs *BaseService) Stop() bool {
 }
 
 // Implements Service
-// NOTE: Do not put anything in here,
-// that way users don't need to call BaseService.OnStop()
 func (bs *BaseService) OnStop() {}
 
 // Implements Service
@@ -158,10 +151,6 @@ func (bs *BaseService) IsRunning() bool {
 	return atomic.LoadUint32(&bs.started) == 1 && atomic.LoadUint32(&bs.stopped) == 0
 }
 
-func (bs *BaseService) Wait() {
-	<-bs.Quit
-}
-
 // Implements Servce
 func (bs *BaseService) String() string {
 	return bs.name
@@ -171,13 +160,25 @@ func (bs *BaseService) String() string {
 
 type QuitService struct {
 	BaseService
+	Quit chan struct{}
 }
 
 func NewQuitService(log log15.Logger, name string, impl Service) *QuitService {
-	if log != nil {
-		log.Warn("QuitService is deprecated, use BaseService instead")
-	}
 	return &QuitService{
 		BaseService: *NewBaseService(log, name, impl),
+		Quit:        nil,
+	}
+}
+
+// NOTE: when overriding OnStart, must call .QuitService.OnStart().
+func (qs *QuitService) OnStart() error {
+	qs.Quit = make(chan struct{})
+	return nil
+}
+
+// NOTE: when overriding OnStop, must call .QuitService.OnStop().
+func (qs *QuitService) OnStop() {
+	if qs.Quit != nil {
+		close(qs.Quit)
 	}
 }

service_test.go

@@ -1,24 +0,0 @@
-package common
-
-import (
-	"testing"
-)
-
-func TestBaseServiceWait(t *testing.T) {
-
-	type TestService struct {
-		BaseService
-	}
-	ts := &TestService{}
-	ts.BaseService = *NewBaseService(nil, "TestService", ts)
-	ts.Start()
-
-	go func() {
-		ts.Stop()
-	}()
-
-	for i := 0; i < 10; i++ {
-		ts.Wait()
-	}
-
-}