grumble, pkg/freezer: more stable freezing on Windows.

freeze.go

@@ -20,69 +20,48 @@ import (
 	"time"
 )
 
-// Freeze a server to disk, and re-open the log, if needed.
+// Freeze a server to disk and closes the log file.
 // This must be called from within the Server's synchronous handler.
-func (server *Server) FreezeToFile() (err error) {
-	// Close the log file, if it's open
-	if server.freezelog != nil {
-		err = server.freezelog.Close()
-		if err != nil {
-			return err
-		}
-	}
-
-	// Make sure the whole server is synced to disk
-	fs, err := server.Freeze()
-	if err != nil {
-		return err
-	}
-	f, err := ioutil.TempFile(filepath.Join(Args.DataDir, "servers", strconv.FormatInt(server.Id, 10)), ".main.fz_")
-	if err != nil {
-		return err
-	}
-	buf, err := proto.Marshal(fs)
-	if err != nil {
-		return err
-	}
-	_, err = f.Write(buf)
-	if err != nil {
-		return err
-	}
-	err = f.Sync()
-	if err != nil {
-		return err
-	}
-	err = f.Close()
-	if err != nil {
-		return err
-	}
-	err = os.Rename(f.Name(), filepath.Join(Args.DataDir, "servers", strconv.FormatInt(server.Id, 10), "main.fz"))
+func (server *Server) FreezeToFile() error {
+	// See freeeze_{windows,unix}.go for real implementations.
+	err := server.freezeToFile()
 	if err != nil {
 		return err
 	}
 
-	// Re-open a new log file
+	if server.running {
+		// Re-open the freeze log.
 		err = server.openFreezeLog()
 		if err != nil {
 			return err
 		}
+	}
 
 	return nil
 }
 
-// Open a new freeze log
-func (server *Server) openFreezeLog() (err error) {
+// Open a new freeze log.
+func (server *Server) openFreezeLog() error {
+	if server.freezelog != nil {
+		err := server.freezelog.Close()
+		if err != nil {
+			return err
+		}
+	}
+
 	logfn := filepath.Join(Args.DataDir, "servers", strconv.FormatInt(server.Id, 10), "log.fz")
-	err = os.Remove(logfn)
+	err := os.Remove(logfn)
 	if os.IsNotExist(err) {
-		// OK. File does not exist...
+		// fallthrough
 	} else if err != nil {
 		return err
 	}
+
 	server.freezelog, err = freezer.NewLogFile(logfn)
 	if err != nil {
 		return err
 	}
+
 	return nil
 }
 
@@ -406,12 +385,22 @@ func NewServerFromFrozen(name string) (s *Server, err error) {
 
 	path := filepath.Join(Args.DataDir, "servers", name)
 	mainFile := filepath.Join(path, "main.fz")
-	logFile := filepath.Join(path, "log.fz")
+	backupFile := filepath.Join(path, "backup.fz")
+	logFn := filepath.Join(path, "log.fz")
 
 	r, err := os.Open(mainFile)
+	if os.IsNotExist(err) {
+		err = os.Rename(backupFile, mainFile)
 		if err != nil {
 			return nil, err
 		}
+		r, err = os.Open(mainFile)
+		if err != nil {
+			return nil, err
+		}
+	} else if err != nil {
+		return nil, err
+	}
 	defer r.Close()
 
 	buf, err := ioutil.ReadAll(r)
@@ -504,7 +493,8 @@ func NewServerFromFrozen(name string) (s *Server, err error) {
 	}
 
 	// Attempt to walk the stored log file
-	walker, err := freezer.NewFileWalker(logFile)
+	logFile, err := os.Open(logFn)
+	walker, err := freezer.NewReaderWalker(logFile)
 	if err != nil {
 		return nil, err
 	}
@@ -512,6 +502,10 @@ func NewServerFromFrozen(name string) (s *Server, err error) {
 	for {
 		values, err := walker.Next()
 		if err == io.EOF {
+			err = logFile.Close()
+			if err != nil {
+				return nil, err
+			}
 			break
 		} else if err != nil {
 			return nil, err

freeze_unix.go

@@ -0,0 +1,49 @@
+// Copyright (c) 2012 The Grumble Authors
+// The use of this source code is goverened by a BSD-style
+// license that can be found in the LICENSE-file.
+
+// +build !windows
+
+package main
+
+func (server *Server) freezeToFile() (err error) {
+	// Close the log file, if it's open
+	if server.freezelog != nil {
+		err = server.freezelog.Close()
+		if err != nil {
+			return err
+		}
+	}
+
+	// Make sure the whole server is synced to disk
+	fs, err := server.Freeze()
+	if err != nil {
+		return err
+	}
+	f, err := ioutil.TempFile(filepath.Join(Args.DataDir, "servers", strconv.FormatInt(server.Id, 10)), ".main.fz_")
+	if err != nil {
+		return err
+	}
+	buf, err := proto.Marshal(fs)
+	if err != nil {
+		return err
+	}
+	_, err = f.Write(buf)
+	if err != nil {
+		return err
+	}
+	err = f.Sync()
+	if err != nil {
+		return err
+	}
+	err = f.Close()
+	if err != nil {
+		return err
+	}
+	err = os.Rename(f.Name(), filepath.Join(Args.DataDir, "servers", strconv.FormatInt(server.Id, 10), "main.fz"))
+	if err != nil {
+		return err
+	}
+
+	return nil
+}

freeze_windows.go

@@ -0,0 +1,59 @@
+// Copyright (c) 2012 The Grumble Authors
+// The use of this source code is goverened by a BSD-style
+// license that can be found in the LICENSE-file.
+
+package main
+
+import (
+	"code.google.com/p/goprotobuf/proto"
+	"mumbleapp.com/grumble/pkg/replacefile"
+	"io/ioutil"
+	"path/filepath"
+	"strconv"
+)
+
+func (server *Server) freezeToFile() (err error) {
+	// Close the log file, if it's open
+	if server.freezelog != nil {
+		err = server.freezelog.Close()
+		if err != nil {
+			return err
+		}
+	}
+
+	// Make sure the whole server is synced to disk
+	fs, err := server.Freeze()
+	if err != nil {
+		return err
+	}
+	f, err := ioutil.TempFile(filepath.Join(Args.DataDir, "servers", strconv.FormatInt(server.Id, 10)), ".main.fz_")
+	if err != nil {
+		return err
+	}
+	buf, err := proto.Marshal(fs)
+	if err != nil {
+		return err
+	}
+	_, err = f.Write(buf)
+	if err != nil {
+		return err
+	}
+	err = f.Sync()
+	if err != nil {
+		return err
+	}
+	err = f.Close()
+	if err != nil {
+		return err
+	}
+
+	src := f.Name()
+	dst := filepath.Join(Args.DataDir, "servers", strconv.FormatInt(server.Id, 10), "main.fz")
+	backup := filepath.Join(Args.DataDir, "servers", strconv.FormatInt(server.Id, 10), "backup.fz")
+	err = replacefile.ReplaceFile(dst, src, backup, replacefile.Flag(0))
+	if err != nil {
+		return err
+	}
+
+	return nil
+}

pkg/freezer/freezer_test.go

@@ -15,7 +15,7 @@ import (
 	"testing"
 )
 
-var testValues []interface{} = []interface{}{
+var testValues []proto.Message = []proto.Message{
 	&ConfigKeyValuePair{Key: proto.String("Foo")},
 	&BanList{Bans: []*Ban{&Ban{Mask: proto.Uint32(32)}}},
 	&User{Id: proto.Uint32(0), Name: proto.String("SuperUser")},
@@ -97,18 +97,26 @@ func TestLogging(t *testing.T) {
 		t.Error(err)
 		return
 	}
-	defer l.Close()
 	defer os.Remove("logging.log")
 
 	for _, val := range testValues {
 		err = l.Put(val)
 		if err != nil {
-			t.Error(err)
-			return
+			t.Fatal(err)
 		}
 	}
 
-	walker, err := NewFileWalker("logging.log")
+	err = l.Close()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	f, err := os.Open("logging.log")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	walker, err := NewReaderWalker(f)
 	if err != nil {
 		t.Error(err)
 		return
@@ -118,6 +126,10 @@ func TestLogging(t *testing.T) {
 	for {
 		entries, err := walker.Next()
 		if err == io.EOF {
+			err = f.Close()
+			if err != nil {
+				t.Fatal(err)
+			}
 			break
 		} else if err != nil {
 			t.Error(err)
@@ -127,7 +139,10 @@ func TestLogging(t *testing.T) {
 			t.Error("> 1 entry in log tx")
 			return
 		}
-		val := entries[0]
+		val, ok := entries[0].(proto.Message)
+		if !ok {
+			t.Fatal("val does not implement proto.Message")
+		}
 		if !proto.Equal(val, testValues[i]) {
 			t.Error("proto message mismatch")
 		}

pkg/freezer/walker.go

@@ -11,7 +11,6 @@ import (
 	"hash/crc32"
 	"io"
 	"math"
-	"os"
 )
 
 // Checks whether the error err is an EOF
@@ -79,19 +78,6 @@ func (txr *txReader) Consumed() int {
 	return txr.consumed
 }
 
-// Create a new Walker that iterates over the entries of the given log file.
-func NewFileWalker(fn string) (walker *Walker, err error) {
-	f, err := os.Open(fn)
-	if err != nil {
-		return nil, err
-	}
-
-	walker = new(Walker)
-	walker.r = f
-
-	return walker, nil
-}
-
 // Create a new Walker that iterates over the log entries of a given Reader.
 func NewReaderWalker(r io.Reader) (walker *Walker, err error) {
 	walker = new(Walker)