feat: read harder

Instead of retrying in get only, retry everywhere we read a file.

flatfs.go

@@ -652,24 +652,6 @@ func (fs *Datastore) putMany(data map[datastore.Key][]byte) error {
 }
 
 func (fs *Datastore) Get(key datastore.Key) (value []byte, err error) {
-	value, err = fs.get(key)
-
-	// Fallback retry for temporary error.
-	if err != nil && isTooManyFDError(err) {
-		for i := 0; i < 6; i++ {
-			time.Sleep(time.Duration(i+1) * RetryDelay)
-
-			value, err = fs.get(key)
-			if err == nil || !isTooManyFDError(err) {
-				break
-			}
-		}
-	}
-
-	return
-}
-
-func (fs *Datastore) get(key datastore.Key) (value []byte, err error) {
 	// Can't exist in datastore.
 	if !keyIsValid(key) {
 		return nil, datastore.ErrNotFound

go.mod

 module github.com/ipfs/go-ds-flatfs
 
 require (
-	github.com/alexbrainman/goissue34681 v0.0.0-20191006012335-3fc7a47baff5 // indirect
+	github.com/alexbrainman/goissue34681 v0.0.0-20191006012335-3fc7a47baff5
 	github.com/ipfs/go-datastore v0.4.4
 	github.com/ipfs/go-log v1.0.3
 	github.com/jbenet/goprocess v0.1.4

util.go

@@ -3,6 +3,7 @@ package flatfs
 import (
 	"io"
 	"os"
+	"time"
 )
 
 // From: http://stackoverflow.com/questions/30697324/how-to-check-if-directory-on-path-is-empty
@@ -19,3 +20,15 @@ func DirIsEmpty(name string) (bool, error) {
 	}
 	return false, err // Either not empty or error, suits both cases
 }
+
+func readFile(filename string) (data []byte, err error) {
+	// Fallback retry for temporary error.
+	for i := 0; i < 6; i++ {
+		data, err = readFileOnce(filename)
+		if err == nil || !isTooManyFDError(err) {
+			break
+		}
+		time.Sleep(time.Duration(i+1) * RetryDelay)
+	}
+	return data, err
+}

util_unix.go

@@ -11,6 +11,6 @@ func tempFile(dir, pattern string) (*os.File, error) {
 	return ioutil.TempFile(dir, pattern)
 }
 
-func readFile(filename string) ([]byte, error) {
+func readFileOnce(filename string) ([]byte, error) {
 	return ioutil.ReadFile(filename)
 }

util_windows.go

@@ -75,7 +75,7 @@ func tempFile(dir, pattern string) (f *os.File, err error) {
 	return
 }
 
-func readFile(filename string) ([]byte, error) {
+func readFileOnce(filename string) ([]byte, error) {
 	f, err := goissue34681.Open(filename)
 	if err != nil {
 		return nil, err