Merge pull request #296 from fkautz/pr_out_inmemory_donutbox_is_now_thread_safe

pkg/donutbox/donutbox.go

@@ -14,7 +14,7 @@ type DonutBox interface {
 	SetBucketMetadata(bucket, name string, metadata io.Reader) error
 
 	// object operations
-	GetObjectWriter(bucket, object string, column, blockSize uint) (io.WriteCloser, <-chan Result, error)
+	GetObjectWriter(bucket, object string, column, blockSize uint) *io.PipeWriter
 	GetObjectReader(bucket, object string, column int) (io.Reader, error)
 	StoreObjectMetadata(bucket, object, name string, reader io.Reader) error
 	GetObjectMetadata(bucket, object, name string) (io.Reader, error)

pkg/donutbox/donutmem/donutmem.go

@@ -7,28 +7,33 @@ import (
 	"io"
 	"strconv"
 	"strings"
+	"sync"
 )
 
 type bucket struct {
 	name     string
 	metadata map[string]string
-	objects  map[string]object
+	objects  map[string]*object
+	lock     *sync.RWMutex
 }
 
 type object struct {
 	name     string
 	data     []byte
 	metadata map[string]string
+	lock     *sync.RWMutex
 }
 
 type donutMem struct {
-	buckets map[string]bucket
+	buckets map[string]*bucket
+	lock    *sync.RWMutex
 }
 
 // NewDonutMem creates a new in memory donut
 func NewDonutMem() donutbox.DonutBox {
 	return donutMem{
-		buckets: make(map[string]bucket),
+		buckets: make(map[string]*bucket),
+		lock:    new(sync.RWMutex),
 	}
 }
 
@@ -48,9 +53,10 @@ func (donutMem donutMem) CreateBucket(b string) error {
 	newBucket := bucket{
 		name:     b,
 		metadata: metadata,
-		objects:  make(map[string]object),
+		objects:  make(map[string]*object),
+		lock:     new(sync.RWMutex),
 	}
-	donutMem.buckets[b] = newBucket
+	donutMem.buckets[b] = &newBucket
 	return nil
 }
 func (donutMem donutMem) ListObjects(bucket, prefix string) ([]string, error) {
@@ -64,37 +70,63 @@ func (donutMem donutMem) SetBucketMetadata(bucket, name string, metadata io.Read
 }
 
 // object operations
-func (donutMem donutMem) GetObjectWriter(bucket, key string, column uint, blockSize uint) (io.WriteCloser, <-chan donutbox.Result, error) {
-	if _, ok := donutMem.buckets[bucket]; ok {
-		if _, ok := donutMem.buckets[bucket].objects[key]; !ok {
+func (donutMem donutMem) GetObjectWriter(bucket, key string, column uint, blockSize uint) *io.PipeWriter {
 	reader, writer := io.Pipe()
-			ch := make(chan donutbox.Result)
-			go func() {
-				var objBuffer bytes.Buffer
-				_, err := io.Copy(&objBuffer, reader)
+	donutMem.lock.RLock()
+	defer donutMem.lock.RUnlock()
+	if curBucket, ok := donutMem.buckets[bucket]; ok {
+		curBucket.lock.Lock()
+		defer curBucket.lock.Unlock()
+		if _, ok := curBucket.objects[key]; !ok {
+			// create object
 			metadata := make(map[string]string)
 			metadata["key"] = key
 			metadata["blockSize"] = strconv.FormatInt(int64(blockSize), 10)
-				if err == nil {
+
 			newObject := object{
 				name:     key,
-						data:     objBuffer.Bytes(),
+				data:     make([]byte, 0),
 				metadata: metadata,
+				lock:     new(sync.RWMutex),
 			}
-					donutMem.buckets[bucket].objects[key] = newObject
+
+			newObject.lock.Lock()
+			curBucket.objects[key] = &newObject
+			go func() {
+				defer newObject.lock.Unlock()
+				var objBuffer bytes.Buffer
+				_, err := io.Copy(&objBuffer, reader)
+				if err == nil {
+					newObject.data = objBuffer.Bytes()
+					writer.Close()
+				} else {
+					donutMem.lock.RLock()
+					defer donutMem.lock.RUnlock()
+					bucket, _ := donutMem.buckets[bucket]
+					bucket.lock.Lock()
+					defer bucket.lock.Unlock()
+					delete(bucket.objects, key)
+					writer.CloseWithError(err)
 				}
-				ch <- donutbox.Result{Err: err}
 			}()
-			return writer, ch, nil
+			return writer
 		}
-		return nil, nil, errors.New("Object exists")
+		writer.CloseWithError(errors.New("Object exists"))
+		return writer
 	}
-	return nil, nil, errors.New("Bucket not found")
+	writer.CloseWithError(errors.New("Bucket does not exist"))
+	return writer
 }
 func (donutMem donutMem) GetObjectReader(bucket, key string, column int) (io.Reader, error) {
-	if b, ok := donutMem.buckets[bucket]; ok {
-		if obj, ok := b.objects[key]; ok {
-			return bytes.NewBuffer(obj.data), nil
+	donutMem.lock.RLock()
+	defer donutMem.lock.RUnlock()
+	if curBucket, ok := donutMem.buckets[bucket]; ok {
+		curBucket.lock.RLock()
+		defer curBucket.lock.RUnlock()
+		if curObject, ok := curBucket.objects[key]; ok {
+			curObject.lock.RLock()
+			defer curObject.lock.RUnlock()
+			return bytes.NewBuffer(curObject.data), nil
 		}
 		return nil, errors.New("Object not found")
 	}

pkg/donutbox/donutmem/donutmem_test.go

@@ -3,9 +3,8 @@ package donutmem
 import (
 	"testing"
 
-	"bytes"
 	. "gopkg.in/check.v1"
-	"io"
+	"io/ioutil"
 )
 
 func Test(t *testing.T) { TestingT(t) }
@@ -15,30 +14,27 @@ type MySuite struct{}
 var _ = Suite(&MySuite{})
 
 func (s *MySuite) TestAPISuite(c *C) {
-	c.Skip("Not implemented")
+	data := "Hello World"
 	donut := NewDonutMem()
 
-	writer, ch, err := donut.GetObjectWriter("foo", "bar", 0, 2)
-	c.Assert(writer, IsNil)
-	c.Assert(ch, IsNil)
+	writer := donut.GetObjectWriter("foo", "bar", 0, 2)
+	count, err := writer.Write([]byte("hello"))
 	c.Assert(err, Not(IsNil))
 
 	err = donut.CreateBucket("foo")
 	c.Assert(err, IsNil)
 
-	writer, ch, err = donut.GetObjectWriter("foo", "bar", 0, 2)
+	writer = donut.GetObjectWriter("foo", "bar", 0, 2)
+	count, err = writer.Write([]byte(data))
+	c.Assert(count, Equals, len(data))
 	c.Assert(err, IsNil)
-	c.Assert(ch, Not(IsNil))
-	writer.Write([]byte("Hello World"))
 	writer.Close()
-	res := <-ch
-	c.Assert(res.Err, IsNil)
+	c.Assert(err, IsNil)
+
+	//	time.Sleep(1 * time.Second)
 
 	reader, err := donut.GetObjectReader("foo", "bar", 0)
 	c.Assert(err, IsNil)
-	var target bytes.Buffer
-	_, err = io.Copy(&target, reader)
-	c.Assert(err, IsNil)
-	c.Assert(target.Bytes(), DeepEquals, []byte("Hello World"))
-
+	result, err := ioutil.ReadAll(reader)
+	c.Assert(result, DeepEquals, []byte(data))
 }