Surface errors while opening and closing value log.

badger/value.go

@@ -20,7 +20,6 @@ import (
 	"bufio"
 	"bytes"
 	"encoding/binary"
-	"errors"
 	"fmt"
 	"io"
 	"io/ioutil"
@@ -36,6 +35,7 @@ import (
 	"golang.org/x/net/trace"
 
 	"github.com/dgraph-io/badger/y"
+	"github.com/pkg/errors"
 
 	"github.com/bkaradzic/go-lz4"
 )
@@ -62,14 +62,19 @@ type logFile struct {
 }
 
 // openReadOnly assumes that we have a write lock on logFile.
-func (lf *logFile) openReadOnly() {
+func (lf *logFile) openReadOnly() error {
 	var err error
 	lf.fd, err = os.OpenFile(lf.path, os.O_RDONLY, 0666)
-	y.Check(err)
+	if err != nil {
+		return errors.Wrapf(err, "Unable to open %q as RDONLY.", lf.path)
+	}
 
 	fi, err := lf.fd.Stat()
-	y.Check(err)
+	if err != nil {
+		return errors.Wrapf(err, "Unable to check stat for %q", lf.path)
+	}
 	lf.size = uint32(fi.Size())
+	return nil
 }
 
 func (lf *logFile) read(buf []byte, offset int64) error {
@@ -442,9 +447,11 @@ func (l *valueLog) fpath(fid uint16) string {
 	return fmt.Sprintf("%s/%06d.vlog", l.dirPath, fid)
 }
 
-func (l *valueLog) openOrCreateFiles() {
+func (l *valueLog) openOrCreateFiles() error {
 	files, err := ioutil.ReadDir(l.dirPath)
-	y.Check(err)
+	if err != nil {
+		return errors.Wrapf(err, "Error while opening value log")
+	}
 
 	found := make(map[int]struct{})
 	for _, file := range files {
@@ -453,9 +460,11 @@ func (l *valueLog) openOrCreateFiles() {
 		}
 		fsz := len(file.Name())
 		fid, err := strconv.Atoi(file.Name()[:fsz-5])
-		y.Check(err)
+		if err != nil {
+			return errors.Wrapf(err, "Error while parsing value log id for file: %q", file.Name())
+		}
 		if _, ok := found[fid]; ok {
-			y.Fatalf("Found the same file twice: %d", fid)
+			return errors.Errorf("Found the same value log file twice: %d", fid)
 		}
 		found[fid] = struct{}{}
 
@@ -473,38 +482,52 @@ func (l *valueLog) openOrCreateFiles() {
 		lf := l.files[i]
 		if i == len(l.files)-1 {
 			lf.fd, err = y.OpenSyncedFile(l.fpath(lf.fid), l.opt.SyncWrites)
-			y.Check(err)
+			if err != nil {
+				return errors.Wrapf(err, "Unable to open value log file as RDWR")
+			}
 			l.maxFid = uint32(lf.fid)
 
 		} else {
-			lf.openReadOnly()
+			if err := lf.openReadOnly(); err != nil {
+				return err
+			}
 		}
 	}
 
 	// If no files are found, then create a new file.
 	if len(l.files) == 0 {
 		lf := &logFile{fid: 0, path: l.fpath(0)}
 		lf.fd, err = y.OpenSyncedFile(l.fpath(lf.fid), l.opt.SyncWrites)
-		y.Check(err)
+		if err != nil {
+			return errors.Wrapf(err, "Unable to open value log file as RDWR")
+		}
 		l.files = append(l.files, lf)
 	}
+	return nil
 }
 
-func (l *valueLog) Open(kv *KV, opt *Options) {
+func (l *valueLog) Open(kv *KV, opt *Options) error {
 	l.dirPath = opt.Dir
-	l.openOrCreateFiles()
+	if err := l.openOrCreateFiles(); err != nil {
+		return errors.Wrapf(err, "Unable to open value log")
+	}
 	l.opt = *opt
 	l.kv = kv
 
 	l.elog = trace.NewEventLog("Badger", "Valuelog")
+	return nil
 }
 
-func (l *valueLog) Close() {
+func (l *valueLog) Close() error {
 	l.elog.Printf("Stopping garbage collection of values.")
+	defer l.elog.Finish()
+
 	for _, f := range l.files {
-		y.Check(f.fd.Close())
+		if err := f.fd.Close(); err != nil {
+			return err
+		}
 	}
-	l.elog.Finish()
+	return nil
 }
 
 // Replay replays the value log. The kv provided is only valid for the lifetime of function call.